AMOS National Conference 2015

Research to Community Communicating our science

BCEC, Brisbane, 15-17 July 2015

AMOS

AustralianMeteorological& OceanographicSocietyAMOS

PLENARY SESSIONS.................................................................................................................................... 1Communicatng complex weather and climate informaton to the public......................................................1Emerging Methods for Weather Predicton and Observaton.........................................................................2Communicatng Science: Lessons for Scientsts, Forecasters, Educators, and Students.................................3Sea-level change: A scientfc and social challenge for the 21st century........................................................4Southern Ocean Clouds and the Earth's Climate: A Research Fronter...........................................................5Answers and Problems: Towards Robust Palaeo-Science...............................................................................6

S1.0 General - Communicatng our Science................................................................................................7Climate and Weather Research Services Phase 2: Overview and where to next?..........................................7AN ALERT SYSTEM FOR EL NINO-SOUTHERN OSCILLATION (ENSO)................................................................8A Minimum Standard for Publishing Computatonal Results in the Weather and Climate Sciences..............9Climate Analysis Services: providing Statstcal Downscaling to the broader community using the Virtual Laboratory......................................................................................................................................................10Weatherzone Total Lightning Network..........................................................................................................11

S1.1 Educaton and outreach (Lightning Lectures)....................................................................................12On-line and Switched On? Are High Tech Secondary Educaton Resources Efectve Learning Tools for Climate Science?............................................................................................................................................12Seasonal Climate Outlooks: an Upgraded Service for the Community.........................................................13Scientsts and Mathematcians in Schools: inspiring the next generaton...................................................14Tweetng the Heat and Blogging the Fog: A Science and Social Media Snapshot........................................15How to engage the public with research using video....................................................................................16Weather and Climate Schools Outreach Program: Proposal.........................................................................17Integratng research infrastructure into educaton— bringing ocean observatons to the classroom.........18A Simple Climate Model for School and University Students, Researchers and Policy makers....................19Distncton with a Diference: Exploring the ECOSPHERES of the Galapagos and Lord Howe Islands with Controlled Tourism........................................................................................................................................20

S1.2a Forecastng, Characterising and Communicatng Extreme Weather and Climate Events...................21Communicatng uncertainty during tropical cyclone events: forecastng challenges and opportunites.....21The Power of Twiter in Communicatng Cyclones Lam and Marcia.............................................................22ENSO, outlooks, science and headlines: the brave new world of delivering the Seasonal Outlook.............23Communicaton dynamic risk for decision making........................................................................................24

S1.2b Forecastng, Characterising and Communicatng Extreme Weather and Climate Events...................25Why was it so hot? Australia’s record heat in late spring 2014....................................................................25Intensifcaton of precipitaton in the wetest and driest regions of the globe.............................................26Projectons of the ETCCDI-based modifed Climate Extremes Index for Australia........................................27Exploring the signifcant disparites in gridded daily precipitaton products................................................28

S2.0a General - Climate - Variability and Change......................................................................................29Identfcaton of regional-scale day-of-the-week variatons in fres..............................................................29Southern Hemisphere Planetary Wave Actvity and its Infuence on Weather and Climate Extremes........30Systematc characterisaton and atributon of observed changes in the Southern Hemisphere midlattude atmospheric circulaton.................................................................................................................................31Rainfall drives uncertain future fre weather in southeast Australia............................................................32Charging El Niño with of-equatorial westerly wind bursts...........................................................................33The Impact of Weather Noise on the ENSO-Australian Rainfall Teleconnecton..........................................34

S2.0b General - Climate - Variability and Change......................................................................................35EXTREME MONTHLY RAINFALL in a CHANGING CLIMATE.............................................................................35Idealised AGCM experiments with prescribed land surface temperatures..................................................36Recalibratng palaeoclimate data for regionally-specifc applicatons: A hydroclimatc case study for South East Queensland.............................................................................................................................................37Reconstructon of runof using tree rings in a high elevaton catchment in central Chile............................38

S2.1a Regional climate projectons and applicaton..................................................................................39Evaluatng Regional Climate Simulaton Errors Over Australia as a Functon of Spatal Resoluton.............39Comparison of Various Climate Change Projectons of Eastern Australian Rainfall......................................40Marine Projectons for Natural Resource Management (NRM) regions of Australia....................................41CORDEX: Current Status, Future Plans...........................................................................................................42

S2.1b Regional climate projectons and applicaton..................................................................................43High-resoluton Projectons of Heat Wave Changes in South-East Australia................................................43

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High Resoluton Modelling for Projectons of Extreme Rainfall Using the Conformal Cubic Atmospheric Model.............................................................................................................................................................44The NARCliM Project: Signifcance and Model Agreement on Climate Projectons......................................45Changes in Synoptc Circulaton Paterns Associated with Projected Future Climate over NSW.................46

S2.2 Reconciling Climate Change and Variability on Decadal Scales..........................................................47Non-Uniform and Step-Like Migraton of Species Habitats in a Warming Ocean.........................................47Reconciling Anthropogenic Climate Change and Variability on Decadal Timescales: the Challenge............48Low-frequency variability in Australian daily temperature mean and variance...........................................49Changes in Natural Variability under Global Warming..................................................................................50A new index to track the Interdecadal Pacifc Oscillaton in observatons and models................................51Recent increases in occurrence of low temperatures in northwestern Australia.........................................52

S2.3 ENSO and ENSO Impacts - Past, Present and Future..........................................................................53More-frequent extreme La Niña events under greenhouse warming..........................................................53What Makes a Good Australian Snow Season?.............................................................................................54LESSONS FROM THE PAST FOR UNDERSTANDING PRESENT-DAY ENSO.......................................................55THE ROLE OF CLIMATE VARIABILITY MODES AS DRIVERS OF AUSTRALIAN HEAT WAVES............................56The Role of the Southward Wind Shif in both, the Seasonal Synchronizaton and Duraton Asymmetry of ENSO Events...................................................................................................................................................57

S2.3 ENSO and ENSO impacts - past, present and future (Lightning Lecture).............................................58Trends and Variability in Precipitaton-Bearing Synoptc Circulaton, Snowy Mountains, Australia............58ENSO in a warmer world: clearer than ever before.......................................................................................59Mechanisms of ENSO Phase Locking Bias in the ACCESS Coupled Models...................................................60Variatons of Near-Surface Salinity in the Tropical Pacifc Associated with ENSO........................................61Coral record of southeast Indian Ocean heat waves with intensifed Western Pacifc temperature gradient........................................................................................................................................................................62Simulatng current and future teleconnectons of ENSO to north-eastern Australia...................................63Increasing frequency of extreme El Nino events due to greenhouse warming............................................64

S2.4 Reconstructon and modelling of past climate..................................................................................65SYNOPTIC CLIMATOLOGY OF SE AUSTRALIA AND NEW ZEALAND AT THE LGM BASED ON PROXY DATA....65Developing Probabilistc Estmates of Protracted Low-fow Events from Palaeostreamfow Reconstructons in Western Tasmania.....................................................................................................................................66Moon Point, Fraser Island— A 40,000 year window into subtropical eastern Australian environments.....67Feasibility of climate feld reconstructon for Australia.................................................................................68Major coastal fooding in SE Australia 1860-2012, associated deaths and weather systems.......................69New Records and Approaches for Past Climate Reconstructon in the Kimberley Region of Northwest Australia.........................................................................................................................................................70

S3.0 - General - Climate - mitgaton, resilience.......................................................................................71Trade-ofs between transmission costs of geographical distributon of renewable energy power statons and storage and demand-side management.................................................................................................71Efects of temperature extremes on Indigenous health in Northern Australia.............................................72Using the latest palaeoclimate insights to beter quantfy drought risk and water security in major urban water supply systems in eastern Australia....................................................................................................73A Climatc Perspectve on Current and Future Water Availability in Victoria...............................................74Temporal and Spatal Paterns of the Adelaide Urban Heat Island...............................................................75Potental Constraints on CMIP5 Climate Projectons of Australian Temperature and Southern Australian Rainfall............................................................................................................................................................76

S3.1 Climate and human health............................................................................................................... 77Assessment of Sector-relevant Climate Indices for New South Wales..........................................................77Temperature and humidity efects on hospital morbidity in Darwin, Australia............................................78Spatal Analysis of Drought and Wellbeing in Rural Australia.......................................................................79In 30 years, how might climate change afect the Australian diet?..............................................................80

S3.2 Drought: from monitoring and land Surface mo................................................................................81Can Australian multyear droughts be internally forced?..............................................................................81Assessing the Potental of Land-Surface Models in Soil Moisture and Drought Monitoring........................82An update on PALS and CABLE benchmarking - the case for drought capability metrics.............................83Untangling the cause of the Millennium Drought using GCM simulatons...................................................84

S3.3 Energy.............................................................................................................................................. 85

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Categorising the meteorological origins of critcal ramp events in collectve photovoltaic array output....85Optmising the Deployment of Renewable Energy Resources for the Australian NEM and the Infuence of Seasonality and Decorrelaton Length Scales................................................................................................86Development of Hybrid Numerical and Statstcal Short Term Horizon Weather Predicton Models for Building Energy Management Optmisaton..................................................................................................87Synergy between Solar and Wind Energy in Australia...................................................................................88The Impact of Climate Change on the Brazilian Northeast’s Electricity Matrix............................................89Efects of Spatal Resoluton On the Forecastng Accuracy of Solar Energy Using NWP Models..................90

S3.4 Urban climate.................................................................................................................................. 91Climate change impact on air quality— Urban troposphere ozone in metropolitan Sydney.......................91Heat Distributon through Suburban Adelaide..............................................................................................92Sea Breeze Cooling Power in the Adelaide Metropolitan Area.....................................................................93Comparison of modelled thermal comfort during a heatwave in Melbourne..............................................94Infuence of urban expansion and densifcaton on local climate.................................................................95The Urban Heat Island Efect during Heatwaves in Melbourne....................................................................96

S4.1a Circulaton and Climate Variability in the Indian Ocean...................................................................97Progress in Observing and Predictng the Tropical Pacifc Ocean.................................................................97Would the real Indian Ocean Dipole please stand up?..................................................................................98Toward Sustained Ocean Observing across Tropical Northern Australian Shelf Seas...................................99Subtdal circulaton on the Australian North West shelf: Local versus remote forcing..............................100

S4.1b Circulaton and Climate Variability in the Indian Ocean.................................................................101The 2011-2014 Pacifc and Indian Ocean exchange: inital results from the IMOS Timor Passage and Ombai Strait Moorings.............................................................................................................................................101SEA SURFACE SALINITY MAXIMUM OF THE SOUTH INDIAN OCEAN FROM AQUARIUS AND SMOS SATELLITES, ARGO AND RAMA DATA...........................................................................................................102Decadal increase in Ningaloo Niño since the late 1990s.............................................................................103Investgaton of the Leeuwin Undercurrent Source Waters and Pathways................................................104

S5.0 General oceanography - general.....................................................................................................105Pathways of East Australian Current antcyclonic eddies............................................................................105Impact of Periodic Forcing on Western Boundary Current Time-Dependence: Phase-Locking, Chaos and the Origins of Low-Frequency Variability.....................................................................................................106Impact of intraseasonal salinity fuctuatons on sea surface temperature in the eastern equatorial Indian Ocean...........................................................................................................................................................107Cloud Condensaton Nuclei over the Southern and South Pacifc Oceans..................................................108

S5.1 A review of Australian Coastal upwelling........................................................................................108A Numerical Investgaton of the Southeast Fraser Island Upwelling System.............................................109Coastal Upwelling along south-west Australia............................................................................................110Upwelling along southeastern Australia......................................................................................................111Cool, Near-Botom Intrusions in the Central Great Barrier Reef.................................................................112

Sd Ocean mixing maters....................................................................................................................... 113Internal Tides of Eastern Tasmania and the T-Tide Project........................................................................113The Role of Internal Wave-driven Near-bed Turbulent Dynamics on Mixing and Sediment Mobilisaton in the Coastal Ocean........................................................................................................................................114Characterising the semidiurnal internal tde of Tasmania using glider data...............................................115Internal Tides of Eastern Australia..............................................................................................................116Estmatng mixing by submesoscale eddies using super-resolved satellite images....................................117Anisotropy of Ocean Eddies.........................................................................................................................118

S5.3 Variability of Physics and Bio-geo-chemistry in Semi-enclosed and Shelf Seas.................................119Closing the Nutrient Budget on the Australian Northwest Shelf.................................................................119Infuence of the East Australian Current on shelf dynamics, upwelling and bio-physical variability from repeat glider deployments...........................................................................................................................120A coupled hydrodynamic, optcal, sediment, biogeochemical model of coastal waters of the Great Barrier Reef: system behaviour and assessment.....................................................................................................121Biogeophysical remote sensing of the Great Barrier Reef...........................................................................122Towards Biogeochemical Modeling of the NW Iberian Margin..................................................................123Decadal variatons of ocean boundary currents around Australia, as simulated with an eddy-resolving numerical model..........................................................................................................................................124

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S5.4 The Global Infuence of the Southern Ocean and Antarctc Seas......................................................125Controls on the Silicon Isotope Distributon in the Ocean: New Diagnostcs from a Data-Constrained Model......................................................................................................................................................................125Meltng West Antarctc ice-shelves: role of coastal warming versus changes in cavity geometries..........126The Role of the SOUTHERN OCEAN OVERTURNING CIRCULATION for OCEAN CARBON UPTAKE..............127Contrastng CMIP5 and Observed Trends in Southern Ocean Sea Ice and Temperature...........................128Early onset of Southern Ocean hypercapnia and its implicatons for fsheries...........................................129Tidal Mixing and Deep Water Formaton in the Amundsen Sea.................................................................130

S5.5 Waves,StormsSurges and tsunamis................................................................................................131Meteotsunamis: generaton, predicton and impacts.................................................................................131Tsunamis Generated by Landslides: A Parametric Analysis.........................................................................132Improved Performance of Operatonal Wave Models at Australian Coast.................................................133The Global Structure of long term mean Sea Surface Drif Currents..........................................................134

S6.0a General - Tropical/subtropical oceanograpy..................................................................................135Seasonal Evoluton and Interannual Variability of Precipitaton in the Australian Monsoon.....................135Extreme rainfall in the Top End and its link to weather in Western Australia............................................136Impacts of convectve entrainment and heatng profle on simulatons of tropical climate and its variability......................................................................................................................................................................137STUDY OF NORTH QUEENSLAND RAINFALL USING MONSOON ONSET TECHNIQUES................................138Convectve Actvity Associated With the 5-day Wave in Re-analysis and CMIP5 Data...............................139Modelling extratropical-tropical interacton and the Australian monsoon................................................140

S6.0b General - Tropical/subtropical oceanograpy.................................................................................141The Internatonal Years of the Maritme Contnent (YMC) Project.............................................................141Simulatons of Radiatve-Convectve Equilibrium: is there a Memory Efect in the system?......................142Convectvely coupled mesoscale gravity waves in idealized simulatons of tropical convecton...............143Evaluaton of Satellite Rainfall Climatology over Various Locatons of the Maritme Contnent................144

S6.1 The Indo-Pacifc Warm Pool............................................................................................................ 145Future Precipitaton changes in the Tropical Pacifc are Sensitve to the Structure of the Warming Anomaly.......................................................................................................................................................145The relatonship between tropical warm pool Sea Surface Temperature and Hadley Circulaton.............146Nonlinear processes reinforce extreme Indian Ocean Dipole events.........................................................147Interannual to Mult-Decadal Variability of Indo-Pacifc SST.......................................................................148

S6.2 Tropical cyclones............................................................................................................................ 149Tropical Cyclone Storm Tide Risk Assessment based on an Updated Track Model....................................149A Signifcant Decrease in Observed Australian Tropical Cyclone Numbers.................................................150The Usefulness of Pre-Satellite era Tropical Cyclone Data: An Intercomparison of three Best-Track Products for the Southwest Pacifc..............................................................................................................151Developing Tropical Cyclones moving ofshore from Northwest Australia: Characteristcs and Forecastng Challenges....................................................................................................................................................152

S6.3a Maritme Contnent: ProceSes, Weather, and Climate...................................................................153Analysis of Convectve Momentum Transport during TWP-ICE using Radar Observatons........................153Untangling Microphysical Impacts on Deep Convecton over Maritme Contnent Applying a Novel Modeling Methodology...............................................................................................................................154An investgaton of the causes of rainfall bias over the Maritme Contnent: Experiments with the UK Met Ofce Unifed Model....................................................................................................................................155Sensitvity of the Maritme Contnent Precipitaton to Horizontal Resoluton in a Coupled Regional Model......................................................................................................................................................................156

S6.3b Maritme Contnent: ProceSes, Weather, and Climate...................................................................157Comparison of Mass fuxes from WRF simulatons and radar for SCOUT-O3 and TWP-ICE.......................157Modelling and observing the evoluton of the diurnal precipitaton cycle with the passage of the MJO through the Maritme Contnent.................................................................................................................158Convergence Lines in the Australian Tropics and Maritme Contnent.......................................................159Impact of convectve invigoraton due to aerosols on shallow clouds........................................................160

S7.0a General meteorology - general.....................................................................................................161Spatal and temporal hydroclimatc variability in eastern Australia— quantfying the magnitude and spatal extent of East Coast Low (ECL) impacts.......................................................................................................161

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A Stochastc Model for Rainfall Generaton with Long-term Variability – Calibraton to NARCliM Data at Catchments with Characteristc Infuence of East Coast Lows....................................................................162Meteorological conditons interactng with topography leading to the Brisbane and Lockyer Valley foods made QPF of catchment average rainfall between 8 and 11 January 2011 extremely difcult.................163Large Amplitude Rossby Waves and Extreme Weather..............................................................................164

S7.0b General meteorology - general.....................................................................................................165A new link between Indian Ocean sea surface temperatures and Australian tropical cyclone actvity.....165Marine cold air outbreaks in the Southern Ocean......................................................................................166The efects of the thermodynamic environment on the statstcal propertes of convectve storms in SouthEast Queensland.................................................................................................................................167Statstcal Validaton of Dynamically Downscaled Climate Data for the Hunter Region of New South Wales, Australia.......................................................................................................................................................168SOUTHERN OCEAN PRECIPITATION AS OBSERVED AT MACQUARIE ISLAND..............................................169EVALUATION of TMPA 3B42 TROPICAL CYCLONE PRECIPITATION ESTIMATES over NEW CALEDONIA.....170

S7.1 Past, Present and Future East Coast Low Actvity and Impacts.........................................................171Long-Term Natural Variability Of East Coast Lows Over The Past Millennium...........................................171Coastal Response To Extreme East Coast Storm Climate Between 1600-1900 CE, Determined From A Coupled Climate Reconstructon And Coastal Morphodynamic Approach.................................................172Use of a stochastc rainfall generaton model calibrated to NARCliM data to simulate runof in the Lower Hunter for water security assessment.........................................................................................................173East Coast Low Projectons from a Regional Climate Model Ensemble......................................................174

S7.2a High-Impact Weather in Research and Operatons........................................................................175The Subjectve Evaluaton of a Convecton-Allowing High Resoluton NWP...............................................175How Good is Ensemble-based Calibrated Thunderstorm Probability Predicton over Australia?..............176Link Between Warm Conveyor Belts and Fronts and the Impact on Extreme Rainfall...............................177The Impact of Variatons in Upper-Level Shear on simulated supercell storms..........................................178Inference of Surface Wind Speeds During Tropical Cyclone Marcia Based on Damage Observatons.......179

S7.2b High-Impact Weather in Research and Operatons........................................................................180Rossby Waves, Extreme Fronts, and Bushfres in Southeastern Australia..................................................180Heat wave - SST relatonship: an example of non-reversibility in statstcal methods................................181The Value of High Resoluton NWP..............................................................................................................182Long-Range Spotng by Bushfre Plumes: The Efects of In-Plume Turbulence on Firebrand Trajectory. .183Coupled fre-atmosphere simulatons.........................................................................................................184The Generaton of Upper-Level Near-Cloud Turbulence in a Warm-Season Mesoscale Convectve System......................................................................................................................................................................185

S8. Emerging methods for weather observaton.....................................................................................186Fire Weather and Air Quality Predicton in the Sydney Forecast Demonstraton Project..........................186Assimilaton of Doppler winds in high resoluton NWP...............................................................................187Near Real-Time Rainfall Informaton Retrieved from Wind Profling Radars..............................................188The dynamics of pyro-tornadogenesis using a coupled fre-atmosphere model........................................189Advances in Post-Processing to Improve Forecast Accuracy.......................................................................190Measurement of temperature and wind felds in the atmospheric boundary layer using unmanned aerial vehicles.........................................................................................................................................................191

LIGHTNING LECTURES - ROOM B1 - TOPICS 2,3.......................................................................................192Tropical fngerprints of low and high sensitvites in CMIP5 models...........................................................192Comparing Forced and Internal Sea Level Signals at Regional Scales in CMIP5 Models............................193A New Perspectve on Australian Snow.......................................................................................................194Exploring Decadal Regimes with the Maronna Bivariate Test.....................................................................195Potental for Seasonal Forecastng of Thunderstorm Risk...........................................................................196Generic Estmaton of Monthly and Daily Solar Radiaton from Rainfall and Temperature.......................197Zonal Winds and Southeast Australian Rainfall in Observatons and Models.............................................198Atmospheric changes through 2012 as shown by iteratvely homogenised radiosonde temperature and wind data......................................................................................................................................................199Projectons of heatwaves using a Regional Climate Model ensemble for NSW and the ACT.....................200Forecastng Air Polluton Impacts from Hazard Reducton Burns................................................................201The Impact of the El Nino Southern Oscillaton on Wind Resources in Australia and New Zealand..........202

LIGHTNING LECTURES - ROOM B2 – TOPICS 4, 5.....................................................................................203

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Bio-Argo Floats Reveal Subsurface Structure of Southeast Indian Ocean Eddies.......................................203Real-Time Marine Observing Systems in Australian Tropical Seas..............................................................204Coastal fronts and upwelling areas utlised by migratng humpback whales, Megaptera novaeanglia, on the Gold Coast, Australia.............................................................................................................................205Observed Internal Tides on the contnental shelf of Eastern Australia......................................................206A regime diagram for ocean geostrophic turbulence..................................................................................207Areas of Re-emergence of Sea Surface Temperature Anomalies in the Global Oceans from Observatons and Model Simulatons................................................................................................................................208Observaton impact in Australia’s Western Boundary Current...................................................................209The eReefs marine model suite: tools for beter quantfying and understanding the Great Barrier Reef circulaton and water quality.......................................................................................................................210The plumbing of the global biological pump...............................................................................................211

LIGHTNING LECTURES - ROOM B3 – TOPICS 1,6,7,8................................................................................212Investgatng The Efect Of Interpolaton On Daily Precipitaton And Extremes.........................................212Bushfre Danger in the Southern Hemisphere: Investgatng Seasonal Predictability and Circulaton Links......................................................................................................................................................................213Aircraf Observatons of Microphysical Propertes of Winter-tme Low Alttude Cloud over The Sothern Ocean...........................................................................................................................................................214The representaton of north Australian rainfall in CMIP5...........................................................................215Surface Energy and Radiaton Budgets for a Subtropical Groundwater Dependent Ecosystem under Extreme Changes in Surface Conditons......................................................................................................216Meso-scale forcing of Maritme Contnent rainfall......................................................................................217Large-Eddy Simulatons of Pyro-Convecton and its Sensitvity to Environmental Conditons...................218A comparison of rainfall characteristcs between radar-based rainfall estmates and downscaled Global Climate Model output..................................................................................................................................219Discriminatng Super-cooled Liquid and Ice Partcles in Fog.......................................................................220Increasing forecast accuracy in the context of a mult-model ensemble framework.................................221

POSTERS 1 – THURSDAY 14:30 – 16:00...................................................................................................222S1.0 General - Communicatng our science............................................................................................222

1. Build Your Own Earth: Exploring Climate Model Output for Teaching and Research............................2222. Growing “Real-World-Ready” Scientsts: Using Undergraduate Higher Educaton to Train our Scientsts......................................................................................................................................................................223

S1.1 Educaton and outreach.................................................................................................................. 2243. Seasonal Climate Outlooks: an Upgraded Service for the Community...................................................2244. On-line and Switched On? Are High Tech Secondary Educaton Resources Efectve Learning Tools for Climate Science?..........................................................................................................................................2255. Distncton with a Diference: Exploring the ECOSPHERES of the Galapagos and Lord Howe Islands with Controlled Tourism......................................................................................................................................2266. A Simple Climate Model for School and University Students, Researchers and Policy makers..............2277. How to engage the public with research using video..............................................................................2288. Weather and Climate Schools Outreach Program: Proposal...................................................................2299. Scientsts and Mathematcians in Schools: inspiring the next generaton.............................................23010. Tweetng the Heat and Blogging the Fog: A Science and Social Media Snapshot................................23111. Integratng research infrastructure into educaton— bringing ocean observatons to the classroom.232

S1.2 Forecastng, Characterising and Communicatng Extreme Weather and Climate Events...................23312. Investgatng The Efect Of Interpolaton On Daily Precipitaton And Extremes...................................23313. Communicatng the uncertainty in frequency estmates of climate extremes.....................................23414. Bushfre Danger in the Southern Hemisphere: Investgatng Seasonal Predictability and Circulaton Links..............................................................................................................................................................235

S2.0 General - Climate - Variability and Change......................................................................................23615. Tropical fngerprints of low and high sensitvites in CMIP5 models.....................................................23616. The Subtropical Ridge in CMIP5 Models, and Implicatons for Projectons of Rainfall in Southeast Australia.......................................................................................................................................................23717. Heatwaves and Their Impact on Wheat Yields in Australia...................................................................23818. 2014 – the world’s hotest year on record............................................................................................239

S2.1 Regional climate projectons and applicatons................................................................................24019. Comparing Forced and Internal Sea Level Signals at Regional Scales in CMIP5 Models......................240

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20. Rainfall Changes over Southwestern Australia in Observatons and Select CMIP-5 Simulatons.........24121. The impacts of Tasman Sea warming on regional precipitaton extremes...........................................24222. Infuence of domain locaton, spatal extent, and resoluton in resolving coastal precipitaton from cold-fronts in the southwest of Western Australia.....................................................................................24323. Dynamical Downscaling Of Climate Changes With A High-Resoluton OGCM.....................................24424. How Much Rainfall Projecton Uncertainty in CMIP5 Can Be Atributed to SST Warming Intensity/Paterns: ACCESS1.3 Experiments................................................................................................245

S2.2 Reconciling climate change and variability on decadal scales..........................................................24625. A New Perspectve on Australian Snow.................................................................................................24626. Inability of CMIP5 models to simulate recent strengthening of the Walker Circulaton: implicatons for projectons...................................................................................................................................................24727. Exploring Decadal Regimes with the Maronna Bivariate Test...............................................................248

S2.3 ENSO and ENSO impacts - past, present and future.........................................................................24928. Simulatng current and future teleconnectons of ENSO to north-eastern Australia...........................24929. How Increasing Ocean Resoluton Alters ENSO Dynamics....................................................................25030. Potental for Seasonal Forecastng of Thunderstorm Risk.....................................................................25131. ENSO in a warmer world: clearer than ever before...............................................................................25232. Mechanisms of ENSO Phase Locking Bias in the ACCESS Coupled Models...........................................25333. Trends and Variability in Precipitaton-Bearing Synoptc Circulaton, Snowy Mountains, Australia....25434. Increasing frequency of extreme El Nino events due to greenhouse warming....................................25535. Variatons of Near-Surface Salinity in the Tropical Pacifc Associated with ENSO................................25636. Coral record of southeast Indian Ocean heat waves with intensifed Western Pacifc temperature gradient........................................................................................................................................................25737. Evaluatng mid-Holocene precipitaton over Australasia and the Maritme Contnent in climate models.......................................................................................................................................................................25838. Towards cool season temperature reconstructons in southeastern Australia....................................259

S2.4 Reconstructon and modelling of past climates to improve understanding of climate processes and future change........................................................................................................................................ 260

39. Generic Estmaton of Monthly and Daily Solar Radiaton from Rainfall and Temperature.................26040. Drought variability in the Southern Hemisphere: insights from recent advances in palaeoclimatology......................................................................................................................................................................26141. Zonal Winds and Southeast Australian Rainfall in Observatons and Models.......................................26242. Atmospheric changes through 2012 as shown by iteratvely homogenised radiosonde temperature and wind data...............................................................................................................................................26343. There Be Dragons: Human Impact on the Unique Environments of the Galapagos and Lord Howe Islands...........................................................................................................................................................26444. Interannual Variability In The South Indian Ocean Countercurrent: Dominance Of The Quasi-Biennial Band.............................................................................................................................................................26545. Surface Circulaton and Upwelling paterns around Sri Lanka and Formaton of the Sri Lanka Dome 266

S4.1 Circulaton and Climate Variability in the Indian Ocean...................................................................26746. Bio-Argo Floats Reveal Subsurface Structure of Southeast Indian Ocean Eddies.................................26747. Real-Time Marine Observing Systems in Australian Tropical Seas........................................................26848. The Trade Wind Regime of eastern Australia and its Inversion............................................................26949. The representaton of north Australian rainfall in CMIP5.....................................................................27050. Surface Energy and Radiaton Budgets for a Subtropical Groundwater Dependent Ecosystem under Extreme Changes in Surface Conditons......................................................................................................271

S6.1 The Indo-Pacifc Warm Pool............................................................................................................ 27251. A new ‘energetc’ approach into the variability and trends of the Hadley circulaton and energy transports to the high southern lattudes....................................................................................................27252. Drivers Of Australian Climate Change Based On Paterns Of Trends Among CMIP5 Models..............273

S6.3 Maritme Contnent: processes, weather and climate....................................................................27453. Meso-scale forcing of Maritme Contnent rainfall................................................................................27454. Sensitvity of the ACCESS regional forecast model statstcal rainfall propertes to resoluton...........275

POSTERS 2 – FRIDAY 14:00 – 15:30............................................................................................................. 276S3.1 Climate and human health............................................................................................................. 276

55. Projectons of heatwaves using a Regional Climate Model ensemble for NSW and the ACT...............276

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56. Forecastng Air Polluton Impacts from Hazard Reducton Burns..........................................................277S3.2 Drought: from monitoring and land surface mo..............................................................................278

57. Understanding the contrast of Australian springtme rainfall of 1997 and 2002 in the frame of two favors of El Niño..........................................................................................................................................278

S3.3 Energy............................................................................................................................................ 27958. Simulatng City-Wide Distributed Photovoltaic Producton under Critcal Collectve Ramp Events....27959. The Impact of the El Nino Southern Oscillaton on Wind Resources in Australia and New Zealand....280

S3.4 Urban climate................................................................................................................................ 28160. Assessing Fine-Scale Urban Temperature Projectons based on Building Densites............................281

S5.1 A review of Australian coastal upwelling........................................................................................28261. Coastal fronts and upwelling areas utlised by migratng humpback whales, Megaptera novaeanglia, on the Gold Coast, Australia.............................................................................................................................282

S5.2 Ocean mixing maters..................................................................................................................... 28362. Observed Internal Tides on the contnental shelf of Eastern Australia................................................28363. A regime diagram for ocean geostrophic turbulence............................................................................28464. Areas of Re-emergence of Sea Surface Temperature Anomalies in the Global Oceans from Observatons and Model Simulatons..........................................................................................................285

S5.3 Variability of physics and biogeochemistry in semi-enclosed and shelf seas....................................28665. Biogeochemical modeling of SE Australia - a PhD proposal................................................................28666. Observaton impact in Australia’s Western Boundary Current.............................................................28767. Investgatons into seasonal variability on the contnental shelf adjacent to the East Australian Current......................................................................................................................................................................28868. The eReefs marine model suite: tools for beter quantfying and understanding the Great Barrier Reef circulaton and water quality.......................................................................................................................289

S5.4 The Global Infuence of the Southern Ocean and Antarctc Seas......................................................29069. The plumbing of the global biological pump........................................................................................290

S5.5 Waves, storms surges and tsunamis...............................................................................................29170. Wave Operatonal Consensus Forecasts...............................................................................................291

S7.0 General meteorology - general....................................................................................................... 29271. Aircraf Observatons of Microphysical Propertes of Winter-tme Low Alttude Cloud over The Sothern Ocean...........................................................................................................................................................29272. Common Characteristcs and Propagaton of Wind Directon Shifs in the Nocturnal Boundary Layer......................................................................................................................................................................29373. Seamless Precipitaton Predicton Skill Comparison between Two Global Models..............................29474. Performance Assessment of PME Probability Matched Precipitaton Forecast and New Calibrated Precipitaton Forecast..................................................................................................................................29575. Using QuikSCAT wind data to evaluate some propertes of ECLs as derived from reanalysis products......................................................................................................................................................................296

S7.2 High-Impact Weather in Research and Operatons..........................................................................29776. A Modifed Global Climate Simulaton Model.......................................................................................29777. Coastal Convectve Interactons Experiment - Preliminary Findings.....................................................29878. Large-Eddy Simulatons of Pyro-Convecton and its Sensitvity to Environmental Conditons.............29979. Modelling The Fire Weather Of The Blue Mountains Fires Of October 2013......................................30080. Identfcaton Of Flood Producing Atmospheric Circulaton Paterns In The Brisbane River Basin, Australia.......................................................................................................................................................301

S8. Emerging methods for weather observaton and Predicton..............................................................30281. A comparison of rainfall characteristcs between radar-based rainfall estmates and downscaled Global Climate Model output..................................................................................................................................30282. Discriminatng Super-cooled Liquid and Ice Partcles in Fog.................................................................303Increasing forecast accuracy in the context of a mult-model ensemble framework.................................30484. Establishing the Hierarchy of Infuence of Drivers of Seasonal Rainfall Variability in South Australia. 305

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PLENARY SESSIONSSession tme: WEDNESDAY 08:45-09:30

Communicatng complex weather and climate informaton to the public

Karl Braganza Bureau of Meteorology

Modern modes of communication have lead to an increased expectation that science and research be made more accessible to funding bodies, stakeholders and the general public. Indeed, it could be argued that the communication of science is now intrinsically entwined with the tangible benefits of research itself.

A positive outcome of these changes is a stronger drive amongst scientists to engage with stakeholders, and have science understood, appreciated, and adopted.

Up until recently, an appreciation and development of communication skills were not part of a research scientist’s training — particularly for physical scientists. However, the effective communication of science to a range of audiences is now a field of research in it’s own right, and physical scientists would do well to integrate this into their own practice.

This presentation will talk about the lessons learned from cognitive science and personal experience in formulating climate science communication, including around climate change. This includes an understanding of audience, and the use of language and scientifically sound narratives to facilitate important public conversations, particularly amongst communities that manage climate risk.

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PLENARY SESSIONSSession tme: WEDNESDAY 13:15-14:00

RH CLARKE LECTURE

Emerging Methods for Weather Predicton and Observaton

Beth Ebert Bureau of Meteorology, Melbourne

It's an exciting time to be in the weather business, with the tools and technologies available for weather prediction and observation advancing rapidly. The increasing capability of high performance computing is enabling numerical weather prediction (NWP) at higher spatial and vertical resolutions than ever before, providing better predictions of convection and detailed local atmospheric circulations. Ensemble predictions support probabilistic forecasting and risk-based decision making at a variety of space and time scales. In particular, multi-week predictions are starting to bridge the gap between weather and seasonal climate regimes.

This growth in NWP capability calls for new ways to deal with the increasingly large quantity of output. Post-processing techniques are being developed and applied to downscale and remove bias, generate alerts for forecasters, and derive new products such as thunderstorm probability. Operational forecast production systems now make direct use of NWP and NWP-based products, supporting a trend toward greater automation of routine forecasts.

Weather forecasts are starting to feed directly into hazard impact prediction. The explicit use of rainfall forecasts in flood prediction is now being done in the Bureau, and opportunities are emerging to partner with the emergency management, health, infrastructure, resource, and other sectors to provide new targeted products to help meet their needs.

New observations are becoming available to monitor the weather, assimilate into NWP models, and improve our understanding of meteorological processes. Perhaps the most exciting new development here in Australia is the 10-minute 16-channel imagery from the Japanese Himawari-8 geostationary satellite. This is revolutionising our ability to watch weather unfold, and we look forward to many beneficial applications for weather prediction enabled by these data. New types of observations from third party networks, crowd-sourcing, and social media such as Twitter, also offer promise for detecting and characterizing high impact weather and verifying hazard impact forecasts.

The international community is actively developing and promoting advances in weather prediction science and methodology. WMO's World Weather Research Programme has initiated a new 10-year High Impact Weather project that aims to improve community resilience through "improving forecasts for timescales of minutes to two weeks and enhancing their communication and utility in social, economic and environmental applications." Australian participation in this project is welcome.

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PLENARY SESSIONSSession tme: THURSDAY 08:30-09:15

Communicatng Science: Lessons for Scientsts, Forecasters, Educators, and Students

Prof. David M. Schultz Centre for Atmospheric Science, School of Earth, Atmospheric and Environmental Sciences,

University of Manchester

Social media has changed the landscape for the communication of science. Not only are scientists communicating to other scientists through such media, but they are providing a growing amount of engagement with the public. The popularity of geek culture is likely one outcome of such engagement, making it more cool to be out as a scientist. Yet, the flip side is the credibility gap between scientists and the general public on important science issues. The emphasis on research to operations through testbeds, interdisciplinary research, and impact for stakeholders means that scientists must communicate with an increasingly diverse constituency. The nature of communication between scientists is also changing with the rise of altimetrics and open access. For forecasters, at a time when they have more accurate guidance than ever before, methods of communicating highly detailed forecasts in space and time remain hindered. Education, yet another form of communication, is also changing because of the internet, and as an added benefit placing a greater emphasis on high-quality and innovative teaching at universities.

This presentation provides my perspective through opportunities that I have had throughout my career to develop effective communication skills, whether through the publication of Eloquent Science, my interests in peer review and scientific publication, or my passion for teaching. Thus, my talk provides guidance for those looking to improve their skills and food for further thought. Among the themes explored in this presentation are the following:

Good communication skills are essential for any career-minded individual.

Communication skills must change, even for scientists communicating amongst themselves.

Scientists must start a new dialog with the public about the scientific process.

Communication of forecasts to the public must evolve, consistent with our abilities and understanding.

The opportunities for involving students in enquiry-based learning have never been greater.

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PLENARY SESSIONSSession tme: THURSDAY 10:45-11:30

Sea-level change: A scientfc and social challenge for the 21st century

John A. Church Centre for Australian Weather and Climate Research,

Relatively stable sea levels over the two thousand years prior to the 19th century allowed the development of the World’s coastal zone such that now about 150 million people live and 1 trillion dollars of GDP are generated on land less than 1 m above the current day high tide level. These stable sea levels contrast with changes of over 100 m during the glacial/interglacial cycles of the last million years. An increase in sea level over the last 200 years and the projected sea-level rise during the 21st century and beyond are critically important for our modern coastal society.

Understanding of 20th century sea-level rise and our ability to simulate this rise have increased significantly since Munk (2002) outlined the sea-level enigma (the inability to reconcile observations and understanding of 20th century sea-level rise). Future regional sea-level change will result from ocean thermal expansion, loss of mass from glaciers and ice sheets, changes in the storage of water on land, vertical land motion and changes in the Earth’s gravitational field (Church et al., 2013) and will be distinguishable from natural variability over most of the global ocean within decades. For continuing business as usual greenhouse-gas emissions, the rate of rise by the end of the 21st century is projected to be similar to that experienced during the last deglaciation of the Earth, with major longer-term commitments. Despite scientific challenges and uncertainties in this multidisciplinary field, urgent mitigation will be essential if the World is to avoid the most severe projections of sea-level rise. Even with significant mitigation, adaptation to future sea-level change will be necessary and involve ongoing challenges for society.

References

Church, J. A., P. U. Clark, A. Cazenave, J. M. Gregory, S. Jevrejeva, A. Levermann, M. A. Merrifield, G. A. Milne, R. S. Nerem, P. D. Nunn, A. J. Payne, W. T. Pfeffer, D. Stammer and A. S. Unnikrishnan, 2013: Sea Level Change. Pages 1137-1216, in: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T. F., D. Qin, G.-K. Plattner, M. Tignor, S. K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P. M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Munk, W. (2002). "Twentieth century sea level: An enigma." Proceedings National Academy of Science 99(10): 6550-6555.

Page 4

PLENARY SESSIONSSession tme: THURSDAY 14:00 -14:30

UWE RADOK AWARD

Southern Ocean Clouds and the Earth's Climate: A Research Fronter

Yi Huang Monash University

Clouds over the remote Southern Ocean exert an enormous influence on the regional climate and the energy and water transport to the Antarctic. However, disproportionately large biases in the shortwave radiative budget over the Southern Ocean continue to be identified in both reanalysis and coupled global climate models, which is directly linked to the poor representation of clouds in this region. Given its critical role, the Southern Ocean has been called out by the US National Science Foundation Advisory Committee for Geosciences as a key research frontier for 2015-2020.

This talk provides a fresh overview of our latest understanding of clouds and precipitation characteristics over this climatically important region, using the new-generation remote-sensing observations, ground-based and in-situ measurements, and state-of-the-art model simulations. The unique nature of the Southern Ocean clouds and precipitation is described via a direct comparison against the Northern Hemisphere counterparts. Potential mechanisms and physical processes that are shaping the observed properties in the Southern Ocean are further explored. The discussion will cover recent critical science findings, the observational knowledge gaps, and the key scientific questions that yet to be answered in order to better understand the model deficiencies in this region. The talk will also consider the challenging issues presented in current observations, and the international efforts under-way to tackle the difficulties.

Page 5

PLENARY SESSIONSSession tme: FRIDAY 13:30 – 14:00

EARLY CAREER RESEARCH AWARD

Answers and Problems: Towards Robust Palaeo-Science

Sophie LewisAustralian Natonal University

There are only around 100 years of ground-based climate observations, which likely underestimate the full range of unforced variability in the climate system. This makes it difficult to put recently observed climate change and variability into context. Are recent trends or extremes unusual? Proxy records of long-term climate change, such as ice cores and cave deposits, can help provide valuable information about the characteristics of climate over time. However, proxy records often integrate complex climatic information that is difficult to interpret. Furthermore, interpretations of proxy records often rely on untested assumptions.

The hydrological cycle is an integral component of the earth’s climate system and water isotopes (oxygen and hydrogen) are key tracers in the hydrological cycle. Water isotopes archives can help provide evidence of past changes in the atmospheric water cycle. These archives have helped reveal a dynamic climate system, including abrupt past changes in both the tropics and the high-latitudes.

In a series of studies, I have explored several examples of water isotope records of climate (“answers”) and investigated what water isotopes really tell us about palaeoclimates (“problems”). This approach uses a combination of model and data techniques to explore proxy interpretations, with the ultimate aim of providing a robust context for understanding recently observed climate change and variability.

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S1.0 General - Communicatng our Science

Submission ID: 320Presentng Author: Aurel Moise

Session tme: FRIDAY 08:30 - 10:00

1

Climate and Weather Research Services Phase 2: Overview and where to next?

MOISE Aurel*1; PUGH Tim 2

1) Bureau of Meteorology, a.moise@bom.gov.au; 2) Bureau of Meteorology

The presentation will provide an overview of the 2nd Phase of the CWSLab project to build research infrastructure, services, tools, and repositories for the climate and weather community and the Centre for Australian Weather and Climate Research (CAWCR) at the National Computational Infrastructure (NCI) petascale facility at the Australian National University.

During the second Phase the project developed a Virtual Laboratory and web portal called “the Climate and Weather Science Laboratory”. The laboratory utilises and integrates the Australian Community Climate Earth-System Simulator (ACCESS) infrastructure to support coupled and uncoupled model simulations of climate and weather phenomena.

Through the proposed integration and enhancements of existing community software such as ACCESS, the laboratory produces an integrated facility for climate and weather process studies in areas such as weather prediction and extreme events, atmosphere-ocean-land-ice interactions, climate variability and change, greenhouse gases, water cycles, and carbon cycles. Additionally, the laboratory provides a facility for the analysis of climate simulations, which will assist in the assessments of Australian climate change and contribute to the future assessment reports of the United Nations Intergovernmental Panel on Climate Change (IPCC).

The virtual laboratory is a community project to establish an integrated national facility for research in climate and weather sciences that complements and leverages the Australian Super Science initiative investments in computational and storage infrastructure at the ANU/NCI facility, and the strong collaboration in place by the Australian National University (nci.org.au), Australian Bureau of Meteorology (www.bom.gov.au), the CSIRO (www.csiro.au/cmar), the Centre for Australian Weather and Climate Research (www.cawcr.gov.au), and the Australian R e s e a r c h C o u n c i l ’ s C e n t r e o f E x c e l l e n c e f o r C l i m a t e S y s t e m S c i e n c e (www.climatescience.org.au).

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S1.0 General - Communicatng our ScienceSubmission ID: 293Presentng Author: Felicity Gamble

Session tme: FRIDAY 08:30 - 10:00

2

AN ALERT SYSTEM FOR EL NINO-SOUTHERN OSCILLATION (ENSO)

GAMBLE Felicity*1; WATKINS Andrew 2

1) Bureau of Meteorology, f.gamble@bom.gov.au; 2) Bureau of Meteorology

Getting an early indication that an El Niño or La Niña event might be developing can give those most susceptible to our variable climate time to prepare— potentially preventing or mitigating financial losses and other adverse consequences.

After conception in 2001, the ENSO Tracker, a system aimed to provide public alerts of developing ENSO events, was launched by the Bureau of Meteorology in May 2014. The ENSO Tracker was developed in line with the WMO's Guidelines on Climate Watches produced in 2005 through its Commission for Climatology (CCl) Open Plan Area Group (OPAG) on Monitoring and Analysis of Climate Variability and Change.

The ENSO Tracker is based upon a comprehensive analysis by Bureau climatologists, using several oceanic and atmospheric criteria, including the output of eight international climate models. The status of the ENSO Tracker is presented via a simple dial graphic indicating the level of risk that an event will occur in the following three to six months. With the unusual near-El Niño pattern observed during 2014, the ENSO Tracker has proved to be a useful tool for communicating the risk of El Niño (or La Niña) to the public, but there is still room for improvement.

The ENSO Tracker is available via the Bureau's climate webpages and is updated fortnightly.

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S1.0 General - Communicatng our Science

Submission ID: 43Presentng Author: Damien Irving

Session tme: FRIDAY 08:30 - 10:00

3

A Minimum Standard for Publishing Computatonal Results in the Weather and Climate Sciences

IRVING Damien*1

1) University of Melbourne, d.irving@student.unimelb.edu.au

As in many other research disciplines, weather and climate science has undergone a computational revolution in recent decades. Modern practitioners— most of whom are not computational experts— now primarily analyse data using a wide variety of software tools and packages. While the rapid rise of computational research has facilitated new and exciting findings, commentators note that it is impossible to replicate and verify most of today's published computational results.

This presentation argues that the primary cause of the reproducibility crisis is not a lack of computational competence, adequate tooling or motivation on the part of scientists, but rather a lack of appropriate examples and protocols to follow. Most editorial/advice pieces tend to focus on production style code and/or large data processing pipelines, whereas a typical weather and climate scientist writes code for a very specific purpose (i.e. not for community uptake) and relatively modest pipelines. It is therefore not surprising that while authors are typically sympathetic to the cries of commentators, they have yet to change their ways.

A simple procedure for communicating computational results is demonstrated and its rationale discussed. The procedure involves three key additions to traditional scientific papers: (1) a short computation section within the paper, (2) the availability of a (preferably ‘version controlled’ and publicly accessible) code repository and (3) the provision of supplementary log files that capture the data processing steps taken in producing each key result. Importantly, the procedure does not substantially increase the workload of the author, reviewers or publisher. It should provide a starting point for weather and climate scientists (and perhaps computational scientists more broadly) looking to publish reproducible research, and could be adopted as a minimum standard by academic journals including the Australian Meteorological and Oceanographic Journal.

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S1.0 General - Communicatng our Science

Submission ID: 311Presentng Co-Author: Tim Bedin

Session tme: FRIDAY 08:30 - 10:00

4

Climate Analysis Services: providing Statstcal Downscaling to the broader community using the Virtual Laboratory

TIMBAL Bertrand1; HEADY Craig 2; BEDIN Tim*3 ; ERWIN Tim4; WANG Yang5

1) Bureau of Meteorology, B.Timbal@bom.gov.au; 2) CSIRO; 3) Bureau of Meteorology; 4) CSIRO; 5) Bureau of Meteorology

In this presentation, we detail the work performed to enhance VisTrails, a workflow management system to support the climate model statistical downscaling. The statistical downscaling method (BoM-SDM) is based on weather analogues developed by the Bureau of Meteorology used extensively in recent scientific climate projects (e.g. ACCSP, NRM, SEACI, VicCI). Currently the BoM-SDM is using CMIP5 climate experiment data products and other data sources published internationally or derived locally. The VisTrails package and workflow allows the scientific community to easily access existing statistical downscaling results from CMIP5 climate simulations. In the future the package will support additional downscaling approaches thus enabling and building support for comparative assessments of downscaling methods and data products. The workflow provides runtime support for the execution of the downscaling methods based on the user’s selection of variables, climate model and experiment, and the temporal range for a given geographical location. The end product is statistically downscaled information from CMIP5 climate models tailored to the user needs. The user interface allows to choose which predictands are required and the geographical area of interest. Several additional options are provided: emission scenarios, number of climate models to be downscaled from, what time slice in the future. This constitutes the first level of service and delivers data quickly by relying on pre-computed change of date (selected meteorological analogues) files, a second level will allow users to changes parameters within the SDM itself to generate new outputs. Future development of the VisTrails downscaling package will allow the generation of downscaled results using other downscaling approaches.

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S1.0 General - Communicatng our Science

Submission ID: 198Presentng Co-Author: Martn Palmer*

Session tme: FRIDAY 08:30 - 10:00

5

Weatherzone Total Lightning Network

GONZALEZ Max1; PALMER, Martn*2

1) Weatherzone, mgonzalez@weatherzone.com.au, 2) Weatherzone

The Weatherzone Total Lightning Network (WZTLN) is Australia’s first national Total Lightning network. Utilising the latest in lightning detection and storm tracking technology, the WZTLN will deliver new solutions, capabilities and visualisation of lightning and thunderstorms for users.

Weatherzone utilises Earth Network’s technology, which is a superior solution in the detection accuracy for both cloud-to-ground and cloud-to-cloud strikes. The new Total Lightning Network provides nationwide coverage with a strike location accuracy of below 200 metres and detection efficiency greater than 95%.

The Total Lightning aspect of the WZTLN provides the earliest possible alert of impending danger, as cloud-to-cloud strikes are normally the precursor to ground strikes which threaten life and assets. Further, Total Lightning gives users much better “situational awareness “of the development, track and position of thunderstorm cells.

Additionally, research has shown that Total Lightning serves as an indicator of severe weather, from heavy rain to hail, tornados and damaging winds.

The use of a Total Lightning solution can provide the earliest possible warning on threatening weather. Using patented technology, Total Lightning can provide Dangerous Thunderstorm Alerts, a highly accurate severe thunderstorm tracking system.

Since its launch in late 2014, the WZTLN has been utilised across Australia by various industry sectors, including;

Mining

Construction

Ports and Transport Networks

Aviation

Electricity Networks

Insurance

The Total Lightning network maximises safety, minimises risk to assets and provides an unprecedented level of situational awareness of both lightning detection and thunderstorm tracking.

Page 11

S1.1 Educaton and outreach (Lightning Lectures)

Submission ID: 227 Presentng Author: Keith HuangLightning Lecture and PosterLightning Lecture – Thursday 09:15-10:15Posters 1 - Thursday 14:30-16:00Poster #4

On-line and Switched On? Are High Tech Secondary Educaton Resources Efectve Learning Tools for Climate Science?

HUANG Keith*1; MAHARAJ Angela2

1) CCRC, keith.s.huang@gmail.com; 2)CCRC

Participation of Australian high school students in STEM subjects has seen a dramatic decrease in the recent decade, indicating declining interest in science. In the same time, previous studies have found a number of common climate science misconceptions amongst students internationally and in Australia. On the other hand, a good understanding of climate science is becoming increasingly imperative to enable current and future generations to make scientifically justifiable decisions. This calls for more effective education methods and resources.

Digital resources have been favoured in recent years in education to cater for the learning preferences of ‘Generation Z’ or ‘Digital Natives’. Few resources are thoroughly evaluated and even fewer actually target established misconceptions. It is important to evaluate and reflect on how to maximise effectiveness of resources for increasing both engagement and performance.

To address some of these issues, we surveyed more than 400 stage 5 students in four high schools in Sydney region before and after they attempted a newly developed interactive digital module on climate science. Together with the data collected within the online resource it appears that i) sampled students performed poorly in comparison to other populations in previous research using the same test items, regardless of school types and ii) misconceptions common in previous research were also present in this sample. The analysis also revealed that while the online resource failed to eliminate misconceptions it did generally improve student understandings significantly. These results suggest an insufficient level of climate science literacy amongst stage 5 secondary school students in NSW and while this digital tool demonstrated promising potential it needs to be further refined and specifically tailored in order to be effective to tackle misconceptions.

Page 12

S1.1 Educaton and outreach (Lightning Lectures)Submission ID: 201 Presentng Author: Catherine GanterLightning Lecture and PosterLightning Lecture – Thursday 09:15-10:15Posters 1 - Thursday 14:30-16:00Poster #3

Seasonal Climate Outlooks: an Upgraded Service for the Community

GANTER Catherine1; WATKINS Andrew*2; DUELL Robyn3 ; SHELLEY Luke4

1) Bureau of Meteorology, c.ganter@bom.gov.au; 2)Bureau of Meteorology; 3)Bureau of Meteorology; 4)Bureau of Meteorology

We present a case study for an upgraded operational service based upon user consultation and feedback. The Bureau's operational seasonal outlook service is a long established product, with the first rainfall outlook issued back in 1989. Originally this service was based on the statistical relationships between rainfall and the Southern Oscillation Index, with a later statistical model based on the two leading empirical orthogonal functions of sea surface temperature variability.

In 2010 to 2011, the Predictive Ocean Atmosphere Model for Australia (POAMA), the dynamical model run in the Bureau and developed in conjunction with CSIRO, was producing skill and reliability measures that exceeded those from the statistical model. The subsequent change in operations from a statistical to dynamical model involved a two-step process: firstly to change the model and educate this science; and secondly, an upgrade of the current service in terms of language, understanding, and layout to ensure the public could make the best use of the outlooks.

To rebuild the service, a 5-stage market research and user-centred design process took place, which included in-depth discussions with ‘VIP’ users, a survey of roughly 960 users, and focus groups consisting of stakeholders. These results helped guide upgrades to the service. Outlook text is notoriously difficult to understand, with survey results proving some insight into what did and didn’t work for communicating probabilistic outlooks. For instance, in a True/False question, 34% of respondents misunderstood 40% chance of exceeding median spring rainfall to mean the area “can expect less than 40% of its median rainfall for spring“. Further consultation was performed in the draft stages of the new website, including seeking feedback from the Managing Climate Variability Climate Champions. These consultation processes aided in providing an upgraded service better tailored to industry, government and emergency service decision making.

Page 13

S1.1 Educaton and outreach (Lightning Lectures)Submission ID: 292 Presentng Author: Jen ParsonsLightning Lecture and PosterLightning Lecture – Thursday 09:15-10:15Posters 1 - Thursday 14:30-16:00Poster #9

Scientsts and Mathematcians in Schools: inspiring the next generaton

PARSONS Jen*1

1) CSIRO, scientistsinschools@csiro.au

Scientists and Mathematicians in Schools (SMiS) is a successful national Australian program which has been in operation since 2007. Supported by a national coordinating team, state-based project officers match and support volunteer scientists, mathematicians and teachers in on-going, flexible and effective partnerships. The program encourages participation across the fields of science, technology, engineering and maths, and includes weather and climate professionals who work with primary and secondary school teachers and students. These weather and climate based partnerships show students a new way of looking at the world by learning weather observation skills and understanding forecasting, data collection, weather in Antarctica, and Australian weather and climate impacts on farming. Through interactions with ‘real scientists’, students receive insight into careers in meteorology and other physical sciences. This presentation brings together relevant examples from across Australia with program evaluation to explain the benefits of SMiS to teachers, scientists and students.

Page 14

S1.1 Educaton and outreach (Lightning Lectures)

Submission ID: 257 Presentng Author: Karen PearceLightning Lecture and PosterLightning Lecture – Thursday 09:15-10:15Posters 1 - Thursday 14:30-16:00Poster #10

Tweetng the Heat and Blogging the Fog: A Science and Social Media Snapshot

PEARCE Karen*1

1) Bloom Communication, karen@bloomcommunication.com.au

The rise and rise of social media offers scientists and science communicators unprecedented opportunities to engage with the public and peers, and to promote their science. However, with so many channels, so much content and so many players, social media also throws up its fair share of challenges.

To ensure we are making the most of social media opportunities (and minimising the challenges) it is useful to characterise our current activities and attitudes when using these tools for science communication. To this end, a survey will be conducted across the Australian science community to develop a snapshot of social media use for science engagement in this country. The survey will seek to find out who is using social media, what social media they are using and how they are using it, and also what attitudes are held by scientists and science communicators about the value and success of social media for public engagement and promoting science.

This presentation will focus on the results obtained from respondents who have identified as working in weather and climate-related fields. They will respond to questions such as: Are they tweeters or bloggers? Who do they follow? Who follows them? What is their preferred social network? Do they think social media is worth the effort? How do employer rules affect social media use? What implications do these practices and attitudes have for effective science communication via social media?

Page 15

S1.1 Educaton and outreach (Lightning Lectures)

Submission ID: 128 Presentng Author: Ben McNeilLightning Lecture and PosterLightning Lecture – Thursday 09:15-10:15Posters 1 - Thursday 14:30-16:00Poster #7

How to engage the public with research using video

MCNEIL Ben*1

1) UNSW, b.mcneil@unsw.edu.au

The more we as scientists publish hyper-specialist manuscripts with jargon and complexity, the more we alienate the public and stifle cross-fertilisation of ideas, so important for discovery. Thinkable.org is a new web platform that uses video to break down the barriers between scientists and the public that allows on-going engagement and collaboration with research. By connecting scientists with their peers and the public using video as the knowledge medium, it gives a new level of transparency, trust and education to anyone wanting to be part of research. Here, I will give an overview of how scientists can use video to build on-going trusted connections with a wide audience that benefits all involved.

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S1.1 Educaton and outreach (Lightning Lectures)

Submission ID: 251Presentng Author: Laura O'BrienLightning Lecture and PosterLightning Lecture – Thursday 09:15-10:15Posters 1 - Thursday 14:30-16:00Poster #8

Weather and Climate Schools Outreach Program: Proposal

O'BRIEN Laura1

1) Monash, laura.obrien@monash.edu

A group of early career researchers from the ARC Centre of Excellence for Climate System Science (ARCCSS) are proposing establishing a formal schools outreach program. The intent is to facilitate an efficient and easy way for teachers and scientists to arrange classroom sessions based on weather and climate. The group proposes a suite of experimental equipment and guidelines to be made available to the nodes of the ARCCSS and, an online system where teachers could easily request a particular scientist to visit their class. The expectation on scientists involved in the program would be to produce one presentation that could be distributed to multiple schools. The scientists would have access to equipment for fun experiments that could also be incorporated.

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S1.1 Educaton and outreach (Lightning Lectures)

Submission ID: 124 Presentng Co-Author: Katherine TatersallLightning Lecture and PosterLightning Lecture – Thursday 09:15-10:15Posters 1 - Thursday 14:30-16:00Poster #11

Integratng research infrastructure into educaton— bringing ocean observatons to the classroom

PROCTOR Roger1; HOENNER Xavier 2; MANCINI Sebasten3 ; TATTERSALL Katherine*4; EVERETT Jason5; SUTHERS Iain6; Steinberg Peter7; Doblin Martna8

1) UTAS-IMOS, roger.proctor@utas.edu.au; 2)UTAS-IMOS; 3)UTAS-IMOS; 4)UTAS-IMOS; 5)UNSW; 6)UNSW; 7)SIMS; 8)UTS

The Integrated Marine Observing System (IMOS, www.imos.org.au), established in 2007 as a component of the National Research Infrastructure Strategy, is collecting unprecedented volumes of multi-disciplinary oceanographic data in the ocean and on the continental shelf which is made freely available through the IMOS Ocean Portal (http://imos.aodn.org.au). IMOS frequently runs ‘data user workshops’ throughout Australia to introduce scientists and managers to the wealth of observations available at their fingertips.

For the past 3 years the Sydney Institute for Marine Science, in partnership with Macquarie University, the University of NSW, the University of Sydney and the University of Technology Sydney, has been running a Master’s degree course called Topics in Australian Marine Science (TAMS, http://sims.org.au/education/). This course is unique in that the core of the course is built around IMOS - understanding how different measurement platforms work and exploring the data that these platforms collect. Students combine attending seminars and lectures with hands on practicals and personal assignments, all built around access to IMOS data and the many tools available to visualise and analyse.

The course attracts a diverse class with many mature students (i.e. > 25 years old) from a range of backgrounds who find that the ease of discovering and accessing data, coupled with the available tools, enables them to easily study the marine environment without the need for high level computational skills. Since its inception the popularity of the course has increased with 38 students undertaking the subject in 2014.

The consensus from students and lecturers is that integrating ‘real’ observations into the classroom is beneficial to all, and IMOS is seeking to extend this approach to other university campuses.

The talk will describe the experiences from the TAMS course and highlight the IMOS approach to data discovery, availability and access through course examples.

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S1.1 Educaton and outreach (Lightning Lectures)

Submission ID: 331 Presentng Co-Author: Angela MaharajLightning Lecture and PosterLightning Lecture – Thursday 09:15-10:15Posters 1 - Thursday 14:30-16:00Poster #6

A Simple Climate Model for School and University Students, Researchers and Policy makers

SEN GUPTA Alex1; MAHARAJ Angela* 2; VANSEBILLE Erik3 ; SHERWOOD Steven4; ABRAMOWITZ Gab5

1) CCRC ARCCSS UNSW, a.sengupta@unsw.edu.au; 2)CCRC ARCCSS UNSW; 3)Imperial College London; 4)CCRC ARCCSS UNSW; 5)CCRC ARCCSS UNSW

Climate change has been flagged as the greatest challenge of our time and one that will require collaboration and ingenuity across numerous fields. However climate science and its workhorse, the climate model, is largely inaccessible to non-specialists. Furthermore, the various aspects of what is inherently an interdisciplinary issue are taught within silos of science, economics, engineering and social sciences. This poses a significant barrier to students trying to grapple with understanding climate system science and how it relates to impacts, climate policy or adaptation/mitigation solutions.

We have developed a simplified (energy-balance/ carbon cycle) climate model that is able to reproduce the globally averaged output from state-of-the-art climate models. The model is embedded in an easy to use graphical interface suitable for a wide range of users. At this stage, the user specifies time series of greenhouse gas emissions, solar intensity and other basic physical forcings, either from (i) pre-defined scenarios (including standard RCP scenarios), (ii) using a scenario builder or (iii) from externally imported data. The model then calculates a variety of output time series including, greenhouse gas concentrations, average temperature, sea-level and ocean pH. Future extensions will allow users to examine more output variables and tie emission to economics factors/population

Users can run multiple what-if scenarios to examine how different choices we make can affect important global characteristic. The simple interface makes it usable by school students and the general public (and even politicians!), while its ability to produce results comparable to those produced my complex climate models make it a suitable tool for research.

Page 19

S1.1 Educaton and outreach (Lightning Lectures)

Submission ID: 329 Presentng Author: Lea Kannar-LichtenbergerLightning Lecture and PosterLightning Lecture – Thursday 09:15-10:15Posters 1 - Thursday 14:30-16:00Poster #5

Distncton with a Diference: Exploring the ECOSPHERES of the Galapagos and Lord Howe Islands with Controlled Tourism

KANNAR-LICHTENBERGER Lea1

1) leakannar@bigpond.com

My poster presentation will include (but will not be exclusive to) my exploration (including first hand research) and comparison of the islands of the Galapagos (Ecuador— Research Oct 2014) and Lord Howe Island (NSW Australia— Research on going);

This poster will be looking at the impact controlled tourism is having on native flora, fauna and aquatic ecologies. How they are influenced by the Anthropocene along with site specific evidence that question the effect on both these islands.

With waters rich in marine life and fluctuating ocean temperatures how does the life in these places cope with the increased tourism that their uniqueness attracts?

My investigation, which involves a studio art practice, looks to create awareness surrounding the alterations we make in nature to transform not only the flora but also social, ethical and cultural values in society. Through this I create metaphors for our connection to these changes and the Anthropocene through images that use cellular, geographical and habitational images.

This poster submission could also also take the form of/or include a display of sound (by headphones supplied) and moving images within the designated displayed area.

I hope to convey to the viewer through the recognizable what impact the current and increase in tourism will have on the uniqueness of these islands.

Page 20

S1.2a Forecastng, Characterising and Communicatng Extreme Weather and Climate Events

Submission ID: 206Presentng Author: Joe Courtney

Session tme: WEDNESDAY - 9:30 - 10:30

1

Communicatng uncertainty during tropical cyclone events: forecastng challenges and opportunites

COURTNEY Joe*1; BURTON Andrew 2

1) Bureau of Meteorology, j.courtney@bom.gov.au; 2) Bureau of Meteorology

Forecasters face many challenges when a cyclone approaches the coast. There are the scientific challenges— where is it, how strong is it and how big is it; where will it go and how will it change; how much rainfall and where; where and when will gales occur and how bad will it get; what about the storm tide? A huge range of information has to be analysed to determine the expected outcomes. A significant challenge is then to convert this into an appropriate description for the suite of products to be issued by the scheduled time and to describe the associated uncertainties.

Awaiting these forecasts are the many decision makers of the community, including emergency managers, industry, businesses and the wider local community. Ideally forecasts convey the required information in a manner that is readily understood and enables the best possible decisions to be made in order to mitigate the potential impact of the cyclone. But how well does the forecast convey these key messages and uncertainties, and are they adequately understood?

The language of a forecast is largely deterministic by nature: “It is a category one cyclone with wind gusts to 130 kilometres per hour forecast to develop into a category two system by landfall tomorrow”. Do people understand the underlying skill of the forecast? If a threshold for action is a category three cyclone, what is the likelihood of this happening? What about a significant storm tide which may have a low probability of occurring but has a high consequence? These are ongoing communication challenges.

There are opportunities to improve how forecasters communicate uncertainty including using consistent language, explaining forecast accuracy, displaying more information graphically, through video and social media and to working with key decision-makers to shape these improvements. This engagement process needs to be ongoing, beginning well before the cyclone approaches and continuing after each cyclone passes.

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S1.2a Forecastng, Characterising and Communicatng Extreme Weather and Climate Events

Submission ID: 330Presentng Author: Adam Morgan

Session tme: WEDNESDAY - 9:30 - 10:30

2

The Power of Twiter in Communicatng Cyclones Lam and Marcia

MORGAN Adam*1

1) Bureau of Meteorology, adam.morgan@bom.gov.au

Cyclones Lam and Marcia were the first major cyclone events to occur following the introduction of the Bureau of Meteorology's Twitter service in December 2014. Meteorologists, hydrologists and communicators are now able to disseminate critical warning, observation and situational awareness information during extreme weather events faster and more directly than ever before. During rapidly unfolding extreme weather events such as tropical cyclones, communication through traditional media takes time, and information can quickly become outdated. The experience of Twitter during Cyclones Lam and Marcia demonstrated the power of the platform in reaching and influencing key decision makers, media and the broader community, as critical situational awareness information is pushed directly to a follower's news feed on their mobile device.

The Bureau's first foray into Twitter during the cyclone events was a great success. Bureau tweets across all states and territories attracted more than 1.5 million views during the week 16-22 February 2015, covering both the Cyclone Lam and Cyclone Marcia events. Almost 4000 'retweets' saw information disseminated far and wide beyond the Bureau's 30000+ followers. A notable observation was the ability of the mainstream media to broadcast updated information far more rapidly than during previous events.

Future development of the Bureau's Twitter service will involve fostering creative communication capabilities within the operational environment, as well as improvements to internal forecast and warning systems to help streamline the physical process of 'tweeting' for forecasters during high-demand extreme weather events.

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S1.2a Forecastng, Characterising and Communicatng Extreme Weather and Climate Events

Submission ID: 212Presentng Co-Author: Clare Mullen

Session tme: WEDNESDAY - 9:30 - 10:30

3

ENSO, outlooks, science and headlines: the brave new world of delivering the Seasonal Outlook

WATKINS Andrew1; MULLEN Clare* 2; YOUNG Leigh3 ; STAFIELD Josh4; SHIRVILL James5 ; FEIKEMA Paul6

1) Bureau of Meteorology, a.watkins@bom.gov.au; 2) Bureau of Meteorology; 3) Bureau of Meteorology; 4) Bureau of Meteorology; 5) Bureau of Meteorology; 6) Bureau of Meteorology

Even with the best model in the world, if the data it provides cannot be turned into intelligence and delivered clearly to those that need it , then its value is largely lost. Climate Services aim to ensure that climate information reaches users as clearly as possible, in forms that are digestible and ultimately enhance decision making.

In recent years the Bureau has moved into the social media sphere, embracing Facebook, twitter, YouTube, blogs and even Google+, on top of the standard Bureau web pages. This has presented new challenges to the delivery of quite complex information - in this case seasonal forecasts, which present information in terms of probabilistic outlooks best used over longer periods, rather than deterministic forecasts that can be assessed over just days or weeks.

While some mediums can present difficulties, such as twitter - how do you make the seasonal outlook message clear in just 95 characters, a picture and a URL - others, such as YouTube, actually provide opportunities for the Bureau of Meteorology to bring its diverse areas of expertise, monitoring and prediction all into one location. Video also allows the Bureau to clearly deliver its climate outlook messages without fear of attention grabbing, but incorrect, headlines, and with statistics and intelligence that is Bureau endorsed. Producing the video briefings involves a small team of people, who start with a blank sheet of paper and in less than 5 working days release a polished four minute video delivered to the web, Facebook, YouTube and to ABC-TV Landline.

This talk will cover the great change observed in the past few years in delivering climate outlook information via several different channels, and will highlight the video delivery process, highlights, low-lights, and its value to the Bureau and its stakeholders. The importance of education complementing information will also be covered.

As with any of our products, we are always seeking feedback on how they can be improved.

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S1.2a Forecastng, Characterising and Communicatng Extreme Weather and Climate Events

Submission ID: 273Presentng Author: Celeste Young

Session tme: WEDNESDAY - 9:30 - 10:30

4

Communicaton dynamic risk for decision making

YOUNG Celeste*1

1) Victoria University, celeste.young@vu.edu.au

Communicating climate science for decision making based situations is a complex task due to the diversity of end users and dynamic nature of the risk . The decisions made can range from individuals deciding whether to leave due to fire risk, to high level decision makers who plan strategically for the risk of potential future impacts of extreme weather events. This type of decision making requires transitioning beyond the provision of information to a single point, to engagement across a communication chain with multiple access and translation points. Understanding factors such as fear responses, risk perception and values which shape how this information is received and heard, and the contexts different decisions are made in, is also crucial for effective uptake. It requires the building of relationships where climate information is understood, valued and trusted.

So what are the key factors that support this type of engagement? What sort of working relationships do scientists, communicators and decision makers need to develop to support it?

Using case studies from climate change and the emergency sectors, this presentation will examine the dynamic nature of this type of communication and the different factors that enable or disable it. It will also show how different methods of engagement are being applied to support science into decision making through bridging the theory to practice gap.

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S1.2b Forecastng, Characterising and Communicatng Extreme Weather and Climate Events

Submission ID: 232Presentng Co-Author: Eunpa Lim

Session tme: WEDNESDAY - 11:00 - 12:00

1

Why was it so hot? Australia’s record heat in late spring 2014

HOPE Pandora1; LIM Eunpa*2; WANG Guomin3 ; ARBLASTER Julie4; MARTIN David5 ; LEWIS Sophie6 ; Barnes-Keoghan Ian7 ; Hendon Harry8 ; Colman Robert9

1) Bureau of Meteorology, p.hope@bom.gov.au; 2) Bureau of Meteorology; 3) Bureau of Meteorology; 4) Bureau of Meteorology; 5) Bureau of Meteorology; 6) Australian National University; 7) Bureau of

Meteorology; 8) Bureau of Meteorology; 9) Bureau of Meteorology

Characterising the causes of a major heat event such as the record warm spring 2014 across Australia provides an opportunity to clearly communicate the relative roles of internal variability and climate change for promoting climate extremes. Our previous work (Arblaster et al. 2014) has shown that the global warming trend, the state of the Pacific and Indian oceans, the state of the Southern Annular Mode (SAM) and local factors such as the synoptic situation and antecedent soil conditions all work to either enhance or reduce the chance of extreme high temperatures. We can characterise the cause of an event using a number of methods. For example, the role of enhanced levels of carbon dioxide can be assessed by the likelihood of occurrence of an equivalent event from climate model simulations with or without enhanced levels of carbon dioxide (Lewis and Karoly, 2013) .Further, the influence of major climatic drivers such as ENSO and the SAM can be inferred using a regression analysis (e.g. Arblaster et al., 2014). Climate model forecast sensitivity experiments can provide details on the synoptic features that played a role in a particular event, and the response to the pattern of ocean temperatures (Lim and Hendon, 2014). Drawing on these different methods, in this presentation we characterise the causes of the record warm spring of 2014.

Arblaster, J. M. et al. 2014: Understanding Australia's hottest September on record. Explaining extremes of 2013 from a climate perspective, S. C. Herring, M. P. Hoerling, T. C. Peterson, and P. A. Stott, Eds., Bulletin of the American Meteorological Society, S37-S41.

Lewis, S. C. and D. J. Karoly, 2013: Anthropogenic contributions to Australia's record summer temperatures of 2013. Geophysical Research Letters, 40, 3705-3709.

Lim, E.-P. and H. H. Hendon 2014: Understanding and predicting the strong Southern Annular Mode and its impact on the record wet east Australian spring 2010 Climate Dynamics DOI:10.1007/s00382-014-2400-5

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S1.2b Forecastng, Characterising and Communicatng Extreme Weather and Climate Events

Submission ID: 210Presentng Author: Markus Donat or Lisa Alexander

Session tme: WEDNESDAY - 11:00 - 12:00

2

Intensifcaton of precipitaton in the wetest and driest regions of the globe

DONAT Markus*1; LOWRY Andrew 2; ALEXANDER Lisa3 ; MAHER Nicola4

1) UNSW, m.donat@unsw.edu.au; 3) UNSW; 4) UNSW

Intensification of the hydrological cycle is expected as a direct consequence of warming climate, and shifts in the spatial distribution of precipitation have been posed but also disputed based on observational data. Understanding changes in the distribution of rainfall is vital if we are to understand general changes in water availability. However it is in understanding precipitation intensity and in particular extreme precipitation that is crucial for preparedness to changing flood risk and related hazards. Here we investigate changes in precipitation amounts and intensities in the driest and wettest regions of the globe using observational data and climate models. While we find uncertainties about the changes in total precipitation in particular in the wettest regions, extreme precipitation and precipitation intensity shows robust significant increases in both observations and climate models over the past six decades— in both the driest and the wettest regions. Climate projections show continued intensification of precipitation, which scale with the strength of the emissions scenario chosen. In particular the precipitation intensity measures averaged over the driest regions show a significant scaling with global mean temperature changes: model simulations with stronger global temperature increase also have stronger intensification of precipitation.

Thus, while it remains hard to generalise changes to the spatial distribution of total precipitation, our results give clear indication of more intense rainfall as a common feature of change in the wettest and driest regions of the globe. Scaling with temperature increase is significant in particular in the driest regions of the globe. This has implications for increasing risk of flooding in arid regions.

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S1.2b Forecastng, Characterising and Communicatng Extreme Weather and Climate Events

Submission ID: 137Presentng Author: Andrea Ditus

Session tme: WEDNESDAY - 11:00 - 12:00

3

Projectons of the ETCCDI-based modifed Climate Extremes Index for Australia

DITTUS Andrea*1; KAROLY David 2; LEWIS Sophie3 ; ALEXANDER Lisa4

1) The University of Melbourne, adittus@student.unimelb.edu.au; 2) The University of Melbourne; 3) The Australian National University; 4) University of New South Wales

The ETCCDI-based modified Climate Extremes Index (EmCEI) is an index of combined temperature and precipitation extremes, measuring the percentage area experiencing extreme conditions in these variables. It is based on the use of standard extreme indices derived from daily data, known as ETCCDI indices. It consists of five components: a maximum and minimum temperature component, a total and heavy precipitation component and a wet and dry day component. Extreme conditions are defined as above (below) the 90th (10th) percentile. These five components are combined to form the EmCEI, which can be interpreted as the average area experiencing temperature and precipitation extremes. Here, we present climate model results for the EmCEI and its components for Australia, using ETCCDI indices computed for the Coupled Model Intercomparison Project Phase 5 global climate models (Sillmann et al., 2013). A particular focus is on projected changes in these extremes across Australia until 2100 under the RCP8.5 scenario, including uncertainties due to internal variability and different model responses.

Sillmann, J., V. V. Kharin, X. Zhang, F. W. Zwiers, and D. Bronaugh (2013), Climate extremes indices in the CMIP5 multimodel ensemble: Part 1. Model evaluation in the present climate, J. Geophys. Res. Atmos., 118, 1716–1733, doi:10.1002/jgrd.50203

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S1.2b Forecastng, Characterising and Communicatng Extreme Weather and Climate Events

Submission ID: 205Presentng Author: Nicholas Herold

Session tme: WEDNESDAY - 11:00 - 12:00

4

Exploring the signifcant disparites in gridded daily precipitaton products

HEROLD Nicholas*1

1) UNSW, nicholas.herold@unsw.edu.au

Reliable datasets of observed daily precipitation are fundamental to accurately characterise and communicate potential trends in extreme precipitation events. Despite the availability of several at least nominally global datasets of daily precipitation, based on gauge measurements, remote-sensing and satellites, or reanalyses, we demonstrate a large disparity in the measure of a simple precipitation intensity index developed by the Expert Team on Climate Change Detection and Indices (ETCCDI). The variation in global mean precipitation intensity between datasets is over 50% in some cases, the majority of which originates in the tropical latitudes. The variation among these products is related primarily to differences in total accumulated precipitation, and less so the frequency of precipitation. For gauge and remote sense/satellite datasets these can be linked to differences in the methodology of their creation as well as the instruments used. Fortunately, the trends among most datasets are robust. We explore the causes of these significant differences and provide some words of caution for the use of gridded datasets of precipitation.

Page 28

S2.0a General - Climate - Variability and Change

Submission ID: 192Presentng Author: Nick Earl

Session tme: FRIDAY 10:30 - 12:30

1

Identfcaton of regional-scale day-of-the-week variatons in fres

EARL Nick*1

1) University of Melbourne, nearl@unimelb.edu.au

One approach to investigating Man’s impact on the atmosphere is based on day of the week variations (DOWV). As there is no evidence of natural processes occurring on a weekly cycle (WC), any signal in meteorological parameters varying on such a time-scale can be considered as anthropogenic. DOWV provides an interesting insight into the role that human activities (e.g. industrial activity), commonly reduced at weekends, have on the atmosphere over large domains. There are a number of studies addressing WCs at the synoptic and even global scale. A potential causal mechanism for WCs is the anthropogenic release of aerosols and the associated knock on direct and indirect effects on the atmosphere. A major source of aerosols on the large scale is fire; however, no study has investigated the WC of active fires. Bushfires can be caused naturally by lightning strikes; however a significant proportion of fires are caused by humans, in, e.g., burning and clearing land for agricultural and domestic uses. Here we investigate the WCs of active fires at a number of spatial scales, ranging from the global domain, to regions of interest within continents and individual countries. We quantify the amplitude of the WCs in each area, using the active fire product (2001-2013) from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on the Terra and Aqua satellites. We explore the extent to which any signal can be explained by the culture, fire management and social and religious practises of the interest area, with particular attention paid to Australia.

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S2.0a General - Climate - Variability and Change

Submission ID: 44Presentng Author: Damien Irving

Session tme: FRIDAY 10:30 - 12:30

2

Southern Hemisphere Planetary Wave Actvity and its Infuence on Weather and Climate Extremes

IRVING Damien*1; SIMMONDS Ian 2

1) University of Melbourne, d.irving@student.unimelb.edu.au; 2) University of Melbourne

Southern Hemisphere mid-to-upper tropospheric planetary wave activity is characterised by the superposition of two zonally-oriented, quasi-stationary waveforms: zonal wavenumber one (ZW1) and zonal wavenumber three (ZW3). Previous studies have tended to consider these waveforms in isolation and with the exception of sea ice, little is known about their impact on surface extremes.

Borrowing from recent advances in the automated identification of Rossby wave packets, this study makes use of a signal processing technique known as the Hilbert Transform to define a new metric of total zonal wave activity. By capturing the envelope of the combined ZW1 and ZW3 waveform, it improves on existing metrics by allowing for variations in both wave phase and amplitude.

Composites of the mean surface conditions for months of strong planetary wave activity reveal highly anomalous sea ice concentrations over the Amundsen/Bellingshausen Seas during autumn and along much of the East Antarctic coastline throughout most of the year. Strong planetary wave activity is also associated with highly anomalous precipitation in regions where orographic precipitation dominates (e.g. New Zealand, Chile, coastal Antarctica), wet and cool conditions over eastern and southern Australia during spring and anomalously warm temperatures over much of the Antarctic continent. The latter has potentially important implications for the interpretation of recent warming over West Antarctica and the Antarctic Peninsula.

Page 30

S2.0a General - Climate - Variability and Change

Submission ID: 18Presentng Author: Terence O'Kane

Session tme: FRIDAY 10:30 - 12:30

3

Systematc characterisaton and atributon of observed changes in the Southern Hemisphere midlattude atmospheric circulaton

O'KANE Terence*1; RISBEY James 2; FRANZKE Christan3 ; MONSELESAN Didier4; HORENKO Illia5

1) CSIRO, terence.okane@csiro.au; 2) CSIRO; 3) University of Hamburg; 4) CSIRO; 5) Universita della Svizzera Italiana

A critical question in the global warming debate concerns the causes of the secular trends of the Southern Hemisphere (SH) atmospheric circulation over recent decades. Secular trends have been identified in the frequency of occurrence of circulation regimes, namely the positive phase of the Southern Annular Mode (SAM) and the hemispheric wave 3 pattern and associated blocking. Previous investigations of the causes of these secular trends have either been purely model based, have not included observational forcing data or have mixed external forcing with indices of internal climate variability impeding a systematic and unbiased attribution of the causes of the secular trends. Most model studies also focused mainly on the austral summer season however the largest changes to the subtropical jet have occurred in the winter when mid-latitude blocking is most active and ozone plays no role. Here we systematically attribute the secular trends over the recent decades using advanced non-stationary vector autoregressive methods applied to both reanalysis and observational forcing data from all seasons. While most previous studies emphasized the importance of stratospheric Ozone depletion in causing summer SH circulation trends, we show here observational evidence that anthropogenic greenhouse gas emissions have been the major driver of these secular trends in the SAM and blocking when all seasons are considered. This suggests that the recovery of the Ozone hole might delay the signal of global warming less strongly than previously thought and that seasonal effects are likely crucial in understanding the causes of the secular trends.

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S2.0a General - Climate - Variability and Change

Submission ID: 101Presentng Author: Hamish Clarke

Session tme: FRIDAY 10:30 - 12:30

4

Rainfall drives uncertain future fre weather in southeast Australia

CLARKE Hamish*1; EVANS Jason 2

1) OEH, hamish.clarke@environment.nsw.gov.au; 2) University of NSW

We present fine scale (10 km) projections of fire weather under climate change in southeast Australia. Projections are from an objectively designed 12 member regional climate model ensemble, built from four global climate models and three configurations of the Weather Research and Forecasting regional climate modelling system. Global and regional climate models are selected for their skill in simulating observed climate, their independence as models and their ability to span a range of possible climate futures. Projections are for present day (1990-2009), near future (2020-2039) and far future (2060-2079) periods. Fire weather conditions are represented by the McArthur Forest Fire Danger Index (FFDI).

The response of fire weather to climate change is highly dependent on the global climate model used, with two of four global models (driving 6 of 12 ensemble members) projecting strong increases in mean and extreme FFDI, and the other two (6) projecting little change including small decreases. Ensemble differences in projected rainfall are strongly linked to these divergent fire weather projections. In the group projecting strong increases in FFDI, changes to 2070 are generally bigger than those projected out to 2070. Out to 2070, the largest increases are projected to occur in spring, suggesting a lengthening of the fire season.

In addition to the fire weather projections based on direct model output, FFDI was also calculated from bias-corrected temperature and precipitation model output. Partially corrected FFDI values are generally higher than uncorrected values, but both corrected and uncorrected datasets perform comparably with respect to observations. Projected changes in partially corrected FFDI are similar to those for uncorrected FFDI.

These results suggest that resolving uncertainties in regional rainfall responses to climate change will be critical to reducing uncertainty in the future trajectory of fire weather conditions in southeast Australia.

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S2.0a General - Climate - Variability and Change

Submission ID: 41Presentng Author: Shayne McGregor

Session tme: FRIDAY 10:30 - 12:30

5

Charging El Niño with of-equatorial westerly wind bursts

MCGREGOR Shayne*1; TIMMERMANN Axel 2; JIN Fei-Fei3

1) CCRC UNSW, shayne.mcgregor@unsw.edu.au; 2) IPRC University of Hawaii; 3) University of Hawaii

The buildup of the warm water in the equatorial Pacific prior to an El Niño event is considered a necessary precondition for the events development, while the event initiation is thought to be triggered by bursts of westerly wind. However, in contrast to the view that warm water slowly builds up prior to an El Niño event, the volume of warm water in equatorial Pacific doubled in the first few months of 2014, reaching values in march that were consistent with the warm water buildup prior to the extreme 1997/1998 El Niño. It is notable that this dramatic WWV buildup co-occurred with a series of westerly wind bursts in the western tropical Pacific. Here, we detail how idealized bursts of westerly wind can produce a buildup of equatorial Pacific warm water, detailing differences in the zonal and meridional extent of the wind burst, the meridional location of the wind burst and the timing of the WWV change. We then attempt to reconcile these results with our current view of ENSO dynamics and predictability.

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S2.0a General - Climate - Variability and Change

Submission ID: 129Presentng Author: Peter van Rensch

Session tme: FRIDAY 10:30 - 12:30

6

The Impact of Weather Noise on the ENSO-Australian Rainfall Teleconnecton

VAN RENSCH Peter*1; GALLANT Ailie 2; CAI Wenju3 ; NICHOLLS Neville4

1) CSIRO/Monash University, peter.vanrensch@csiro.au; 2) Monash University; 3) CSIRO; 4) Monash University

Many studies have found a connection between the El Niño/Southern Oscillation (ENSO) and Australian climate. It is now accepted that El Niño typically brings a dry year, and La Niña typically brings a wet year. These two phases of ENSO must enact their influence on the underlying weather events passing through regions of Australia. However, little is known about how this seasonal scale sea surface temperature (SST) influence can be modified due to stochastic noise inherent in weather. It could be possible that an SST pattern is favourable for a certain rainfall anomaly, but if individual weather events behave differently than expected, the SST-rainfall connection could be either amplified or dampened.

Using a suite of atmospheric general circulation models (AGCMs) forced with historical SSTs, we highlight the variation of weather noise compared to the influence of SST forcing across the Australian region. Ensemble means of September-November (SON) Australian rainfall versus Niño-3.4 regression coefficients generally agree with observations during the 1979-2008 period. Although they are of lesser magnitude, the higher regression coefficients in the north and east of the country are well represented in the ensemble mean. However, this region also corresponds with the region of largest disagreement between individual AGCM regression coefficients in the country. As the intensity of weather events has a greater variability in this region of Australia, it acts as a mechanism to provide a greater modification of the ENSO-rainfall teleconnection.

The AGCMs also reveal individual events in the observational record where the teleconnection appears to have been amplified by weather noise. For example, the 1991 and 2002 El Niño events were associated with a strong decrease in east Australian rainfall during SON. Examining the ensemble spread of AGCM rainfall in these years demonstrates that this deficiency was likely not a result of SST forcing.

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S2.0b General - Climate - Variability and Change

Submission ID: 158Presentng Author: Ian Waterson

Session tme: FRIDAY 15:30 - 16:30

1

EXTREME MONTHLY RAINFALL in a CHANGING CLIMATE

WATTERSON Ian*1; CHUA Zhi-Weng 2; HOPE Pandora3

1) CSIRO, ian.watterson@csiro.au; 2) University of Melbourne; 3) Bureau of Meteorology

The new CSIRO and BOM climate projections for Australia are largely based on simulations of the coming century from an ensemble of some 40 CMIP5 global climate models. By 2080-2099, with strong global warming under the RCP8.5 forcing scenario, the median projection for mean annual rainfall is a decrease of around 10%, aside from little change in northern Australia, however the 10 to 90 percentile range is typically 30% about the median. Projections for extreme daily rainfall within a year, based on the models, are mostly positive changes, indicating a broadening of the distribution of daily rainfall amounts. We focus on the distribution of monthly mean amounts, a time scale with important implications for agricultural and pastoral activity and for large-scale flood events. Averages of the top 10 percent of observational (ERA-Interim) monthly amounts, partitioned by season, at most locations over Australia are typically two to three times the mean monthly rainfall for the season. The extremes are relatively smaller in the south in winter months. Initial CMIP5 results, from the ACCESS1.3 and CESM1-CAM5 models, show good agreement with this. Composite maps, for the extreme rainfall months for selected locations, show that rainfall anomalies extend over much of Australia, and are associated with cooler daily maximum temperatures. There are circulation anomalies consistent with regional moisture flux convergence, often associated with a large-scale La Niña pattern. Regional rainfall and temperature anomalies show some persistence, over following months. Under strong global warming, there is a similar character to the anomalies of both rainfall and associated circulations. However, there is some indication of a broadening of the rainfall distributions. Using multiple models, projections of the high monthly rainfall amounts can be made, with changes attributed to a combination of changes in atmospheric saturation humidity and in large-scale circulation patterns.

Page 35

S2.0b General - Climate - Variability and Change

Submission ID: 316Presentng Author: DUNCAN ACKERLEY

Session tme: FRIDAY 15:30 - 16:30

2

Idealised AGCM experiments with prescribed land surface temperatures.

ACKERLEY DUNCAN*1

1) Monash University, duncan.ackerley@monash.edu

General Circulation Models (GCMs) are routinely used to represent the global climate of the last thirty years with prescribed sea surface temperatures (SSTs). These types of simulations are commonly referred to as AMIP runs. While the SSTs are prescribed, the land surface temperatures are not and they are allowed to vary; however, there is no reason why the land surface temperatures cannot also be prescribed in order to run idealised experiments of the global climate. This presentation shows how a low-resolution (N48) version of the Australian Community Climate and Earth System Simulator (ACCESS) has been developed with prescribed land surface temperatures (for example, how the diurnal cycle was taken into consideration). Moreover, the results of some initial ‘proof-of-concept’ simulations are presented to highlight the use of this new version of ACCESS in idealised experiments (for example the impact of a prescribed local warming on the larger-scale circulation). It is hoped that this model will provide a useful tool to the research community in addition to the suite of ACCESS models already available.

Page 36

S2.0b General - Climate - Variability and Change

Submission ID: 307Presentng Co-Author: Carly Tozer

Session tme: FRIDAY 15:30 - 16:30

3

Recalibratng palaeoclimate data for regionally-specifc applicatons: A hydroclimatc case study for South East Queensland

VANCE Tessa1; ROBERTS Jason 2; KIEM Anthony3 ; CURRAN Mark4; TOZER Carly*5 ; FLACK Anna6 ; Barr Cameron7

; Day Ken8 ; Dalla_Pozza Ramona9

1) Antarctic Climate & Ecosystems CRC Hobart Tasmania, tessa.vance@utas.edu.au; 2) Department of the Environment Australian Antarctic Division Hobart Tasmania; 3) Faculty of Science & Information

Technology University of Newcastle Callaghan New South Wales; 4) Department of the Environment Australian Antarctic Division Hobart Tasmania; 5) Faculty of Science & Information Technology University of

Newcastle Callaghan New South Wales; 6) Faculty of Science & Information Technology University of Newcastle Callaghan New South Wales; 7) Department of Geography Environment and Population University

of Adelaide Adelaide South Australia; 8) Department of Science Information Technology & Innovation Queensland State Government Brisbane Queensland; 9) Department of Science Information Technology &

Innovation Queensland State Government Brisbane Queensland

South East Queensland (SEQ) has a highly variable, summer dominated (November-March) hydroclimate combined with a rapidly increasing population. Water security is and will continue to be a critical issue for SEQ water resource managers.

Two recent publications (Vance et al., 2013, 2015) have identified a 1000-year proxy record for rainfall in eastern Australia from the Law Dome ice core drilled in East Antarctica. A number of trace chemistry records from Law Dome that vary with multidecadal components of the Southern Hemisphere circulation were exploited to produce a 1000 year Interdecadal Pacific Oscillation reconstruction. This allowed the differentiation of periods where the rainfall proxy shows high skill in reproducing the eastern Australian rainfall record over the calendar year (January to December).

Here we show how this annual rainfall proxy, combined with emerging local hydroclimate proxies (Stradbroke Island lake, as well as other cave and sediment records) can be recalibrated to be seasonally-specific for SEQ (November-March). This regionally specific proxy record will significantly improve understanding of long-term hydroclimatic variability in SEQ and enhance outcomes for agriculture, planning and water security for Queensland. Furthermore, this study will demonstrate how high resolution palaeoclimate data coupled with stochastic modeling that replicates statistics that are important for hydrology at the catchment scale can be utilized to better understand, quantify and plan for low probability, high impact events.

Vance, T. et al., 2015: Interdecadal Pacific variability and eastern Australian mega-droughts over the last millennium. Geophys. Res. Lett., 41, DOI:10.1002/2014GL062447.

Vance, T., et al. 2013: A millennial proxy record of ENSO and eastern Australian rainfall from the Law Dome ice core, East Antarctica. J. Clim., 26, DOI: 10.1175/JCLI-D-12-00003.1

Page 37

S2.0b General - Climate - Variability and Change

Submission ID: 112Presentng Author: Pilar Barria

Session tme: FRIDAY 15:30 - 16:30

4

Reconstructon of runof using tree rings in a high elevaton catchment in central Chile

BARRIA Pilar*1; WALSH Kevin 2; PEEL Murray3

1) University of Melbourne, pbarria@student.unimelb.edu.au; 2) University of Melbourne; 3) University of Melbourne

In this study we use tree ring chronologies of A. araucana and A. Chilensis to reconstruct 500 years of Biobío river hydrologic annual runoff (April-March), winter (April-September) and summer (October-March) runoff and analyze current natural variability in a historical context.

The high elevation part of Biobío river is very important because it presents a hydrologic regime characterized by two main pulses: one dominated by winter precipitation and another driven by spring-summer snowmelt that is fundamental for hydroelectricity and agriculture in the region. However, according to the information provided by the instrumental data, reductions in streamflow has been observed during the last 50 years. The reconstruction also indicated significant negative trends in annual and summer runoff since 1850.

Significant correlations (p<0.05) between JJA ENSO 3.4 (El Niño Southern Oscillation) and between DJFM SAM (Southern Annular Mode) and observed annual runoff were found. Using a 350 year ENSO reconstruction and 500 years of SAM reconstructions, we observed that the correlations have been significant during the last 300 years.

Runoff from two high elevation stations from Biobío river are analyzed and the results of both of them will be presented. A comparison of the evolution in time of seasonal and annual runoff will also be presented.

Page 38

S2.1a Regional climate projectons and applicaton

Submission ID: 61Presentng Author: Marcus Thatcher

Session tme: WEDNESDAY - 9:30 - 10:30

1

Evaluatng Regional Climate Simulaton Errors Over Australia as a Functon of Spatal Resoluton

THATCHER Marcus*1; NGUYEN Kim 2; RAFTER Tony3 ; KATZFEY Jack4; MCGREGOR John5 ; DOBROHOTOFF Peter6

1) CSIRO, Marcus.Thatcher@csiro.au; 2) CSIRO; 3) CSIRO; 4) CSIRO; 5) CSIRO; 6) CSIRO

Regional Climate Models (RCMs) are often used to dynamically downscale Global Climate Models (GCMs) to better understand atmospheric behaviour at finer spatial scales (e.g., monsoons, cyclones and topographic forcing). In this talk we evaluate the skill of dynamical downscaling over Australia as a function of spatial resolution, using the global Australian Community Climate and Earth System Simulator (ACCESS) and the stretched grid Conformal Cubic Atmospheric Model (CCAM). We survey model resolutions ranging from 13 km to 400 km for 30-year simulations, nudged towards ERA-Interim reanalyses. Errors in the mean and variance of 2m air temperatures show a linear dependence on resolution. However, errors in mean rainfall show a logarithmic dependence on resolution and a rapid improvement in the variance of daily rainfall was found between 100 km and 30 km resolution. Although improvements in the mean rainfall are often associated with better resolving topographic features, the improvements in the rainfall variance were found to be widespread over the Australian continent. The regional model’s ability to reduce simulated rainfall errors when downscaling an imperfect GCM was also considered by replacing the ERA-Interim reanalyses with the ACCESS GCM. Although we only downscale the GCM to 50 km resolution, the higher-resolution regional model was found to be still capable of reducing errors in the mean and variance of the simulated rainfall. Nevertheless, GCM errors do affect the accuracy of the downscaled results and techniques like sea surface temperature bias correction may lead to further improvements in the simulated rainfall. The results of this work has implications for determining the appropriate grid resolution for RCM experiments such as CORDEX.

Page 39

S2.1a Regional climate projectons and applicaton

Submission ID: 324Presentng Author: Michael Grose

Session tme: WEDNESDAY - 9:30 - 10:30

2

Comparison of Various Climate Change Projectons of Eastern Australian Rainfall

GROSE Michael*1; BHEND Jonas 2; ARGUESSO Daniel3 ; EKSTROM Marie4; DOWDY Andrew5 ; HOFFMANN Peter6

; Evans Jason7 ; Timbal Bertrand8

1) CSIRO, Michael.Grose@csiro.au

The Australian eastern seaboard is a distinct climate entity from the interior of the continent, with different climatic influences on each side of the Great Dividing Range. Therefore, it is plausible that downscaling of global climate models could reveal meaningful regional detail, or ‘added value’, in the climate change signal of mean rainfall change in eastern Australia under future scenarios. However, because downscaling is typically done using a limited set of global climate models and downscaling methods, it is important to quantify any differences in the change signal between global climate models and downscaling. Further, it is useful to understand the cause of these differences in terms of plausible added regional detail in the climate change signal, the impact of sub-sampling global climate models and the effect of the downscaling models themselves. Here we examine rainfall projections in eastern Australia under a high emissions scenario by late in the century from ensembles of global climate models, two dynamical downscaling models and one statistical downscaling model. We find no cases where all three downscaling methods show the same clear regional spatial detail in the change signal that is distinct from the host models. However, some downscaled projections suggest that the eastern seaboard could see little change in spring rainfall, in contrast to the substantial rainfall decrease inland. Also, there are some instances where a downscaling method produces changes outside the range of host models over eastern Australia as a whole, thus expanding the projected range of uncertainty. Results are particularly uncertain for summer, where no two downscaling studies clearly agree. There are also some confounding factors from the model configuration used in downscaling, where the particular zones used for statistical models and the model components used in dynamical models have an influence on results and produce additional uncertainty.

Page 40

S2.1a Regional climate projectons and applicaton

Submission ID: 246Presentng Author: Kathleen McInnes

Session tme: WEDNESDAY - 9:30 - 10:30

3

Marine Projectons for Natural Resource Management (NRM) regions of Australia

MCINNES Kathleen*1; CHURCH John 2; LENTON Andrew3 ; MONSELESAN Didier4; O'GRADY Julian5 ; ZHANG Xuebin6

1) CSIRO, kathleen.mcinnes@csiro.au; 2) CSIRO; 3) CSIRO; 4) CSIRO; 5) CSIRO; 6) CSIRO

Coastal systems are particularly sensitive to changes in sea level, ocean temperature and ocean acidification (Wong et al., 2014). In Australia where the majority of the population resides in coastal cities and settlements, rising sea levels and associated coastal impacts are of considerable concern. In the marine environment, there is increasing evidence that ecosystems are already responding to changed climate conditions. Marine species have been observed further southwards in response to rising sea temperatures and some calcifying species are showing reduced rates of calcification. The recent release of updated climate projections for Australia’s Natural (CSIRO and Bureau of Meteorology, 2015) is therefore timely in offering the most up-to-date and comprehensive projections for the coastal and marine environment to assist coastal managers and researchers to better understand and manage the anticipated future changes. The projections include spatially variable projections of sea level rise (SLR), sea surface temperature, ocean acidification and aragonite concentration. Sea level allowances are also provided, which give the height that present assets or their protective measures would need to be raised to ensure that the risk of exceedance of those levels in the future does not change from the present climate. The projections highlight that future changes are likely to be spatially heterogenous and the implications of this will be discussed. The talk will conclude with related emerging issues and future research priorities for the coastal zone.

Page 41

S2.1a Regional climate projectons and applicaton

Submission ID: 302Presentng Author: Jason Evans

Session tme: WEDNESDAY - 9:30 - 10:30

4

CORDEX: Current Status, Future Plans

EVANS Jason*1; TIMBAL Bertrand 2; KATZFEY Jack3

1) University of New South Wales, jason.evans@unsw.edu.au; 2) Bureau of Meteorology; 3) CSIRO

The World Climate Research Programme (WCRP) is backing an international initiative called the COordinated Regional climate Downscaling EXperiment (CORDEX). The goal of the initiative is to provide regionally downscaled climate projections for most land regions of the globe, as a compliment to the global climate model projections performed within the fifth Coupled Model Intercomparison Project (CMIP5). It is anticipated that the CORDEX dataset will provide a link to the impacts and adaptation community through its better resolution and regional focus. Participation in CORDEX is open and any researchers performing climate downscaling are encouraged to engage with the initiative.

The model evaluation framework consists of RCM simulations performed using the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim re-analysis (Uppala et al., 2008) as “perfect boundary conditions”. The climate projection framework within CORDEX is based on CMIP5. CORDEX will focuses on the GCM experiments using emission scenarios known as RCP4.5 and RCP8.5 which represent a mid and a high-level emission scenarios.

A number of groups have performed simulations for the CORDEX-AustralAsia domain. While these groups continue to perform and evaluate their simulations the next step is to make the data available through the Earth System Grid Federation Node at the National Computational Facility in Canberra which will be progressively done through 2015.

The next phase of CORDEX is currently being planned around five key challenges: Coordination of Regional Coupled Modelling, Added value, Human elements, Precipitation and Local Wind systems. In addition to the key challenges, four cross cutting themes were identified: Water resources and Hydrological cycle, Development of process based metrics, The water-energy nexus and Extremes. Flagship Pilot Studies are one proposed mechanism through which CORDEX will attempt to address these issues.

Page 42

S2.1b Regional climate projectons and applicaton

Submission ID: 99Presentng Co-Author: Alejandro DiLuca

Session tme: WEDNESDAY - 11:00 - 12:00

1

High-resoluton Projectons of Heat Wave Changes in South-East Australia

ARGÜESO Daniel 1; EVANS Jason 2; PERKINS Sarah3 ; DILUCA Alejandro*4

1) University of New South Wales, d.argueso@unsw.edu.au; 2) University of New South Wales; 3) University of New South Wales; 4) University of New South Wales

The NSW/ACT Regional Climate Modelling (NARCliM) project is an initiative to provide high-resolution climate projections over South-East Australia. The project downscaled four Global Climate Models using three Regional Climate Models and thus created a twelve-member ensemble to generate robust projections of future climate at 10-km spatial resolution. The models were selected upon their performance and their independency in order to optimally sample the future space of changes in the region. Three periods were simulated (1990-2009, 2020-2039 and 2060-2079) to assess changes in the near and far future.

This study focuses on climate projections for the far future period and analyses changes in summer heat wave characteristics as defined by the Excess Heat Factor, which includes both maximum and minimum temperature and incorporates a term to account for short-term acclimatisation. A number of indices were calculated using the Excess Heat Factor to measure heat wave intensity, frequency and duration. Changes in these heat wave features were determined at unprecedented spatial resolution by comparison of the far future and present simulations. Both the ensemble mean and each individual member will be examined to estimate the magnitude of the changes as well as the agreement among models, and thus the robustness of the changes.

Finally, these changes will be put in the context of large-scale drivers such as ENSO and Southern Annular Mode (SAM), and the rainfall conditions in the preceding months to elucidate factors that favour more severe heatwaves in the future other than the expected increase in temperature

Page 43

S2.1b Regional climate projectons and applicaton

Submission ID: 270Presentng Author: Tony Rafer

Session tme: WEDNESDAY - 11:00 - 12:00

2

High Resoluton Modelling for Projectons of Extreme Rainfall Using the Conformal Cubic Atmospheric Model

RAFTER Tony*1; THATCHER Marcus 2; NGUYEN Kim3 ; LAU Rex4; PHATAK Aloke5 ; LAVENDER Sally6 ; Abbs Deborah7

1) CSIRO, Tony.Rafter@csiro.au; 2) CSIRO; 3) CSIRO; 4) CSIRO; 5) CSIRO; 6) CSIRO; 7) CSIRO

Extreme rainfall events of the type experienced, on average, once in multiple years— or even decades— are of great interest to many sectors, due to the severity and consequence of the impacts these events can cause. For example, the design of many varied types of infrastructure must take into consideration the frequency, intensity and duration of heavy rainfall events across the lifespan of the structure, and so the potential changes brought upon these events in a warmer future climate will likely impact upon many long-lived items of infrastructure.

There is clear potential for increased greenhouse gas levels in the atmosphere to lead to increases in heavy rainfall through the thermodynamic relationship between the atmosphere’s temperature and its ability to hold moisture, however how this will play out on varied temporal and spatial scales is unclear. Additionally, the resolution of global climate models is generally insufficient to satisfactorily resolve the types of rainfall events that lead to extremely heavy rainfall events, especially those at sub-daily time scales.

In order to provide an indication of potential changes to extreme rainfall at time scales from minutes to days, we have performed a set of dynamical downscaling experiments at a spatial resolution of 2km over two Australian regions— centred over Sydney and Brisbane— using the Conformal Cubic Atmospheric Model (CCAM). We have downscaled from the ERA-Interim reanalysis data set from 1980 to 2012, and from an RCP8.5-forced simulation of the ACCESS1.0 global model to provide a baseline and future (mid-21st century) extreme rainfall climatology. We will show results from the analysis and evaluation of these simulations, focusing on what we may be able to infer regarding future changes in extreme rainfall.

Page 44

S2.1b Regional climate projectons and applicaton

Submission ID: 36Presentng Author: Roman Olson

Session tme: WEDNESDAY - 11:00 - 12:00

3

The NARCliM Project: Signifcance and Model Agreement on Climate Projectons

OLSON Roman*1; EVANS Jason 2; ARGÜESO Daniel3 ; DILUCA Alejandro4

1) UNSW Australia, roman.olson@unsw.edu.au

NARCliM (NSW / ACT Regional Climate Modelling) is a regional climate downscaling project providing climate projections for Australia and the surrounding area. The project has two domains. The first domain has a 50 km resolution and covers the CORDEX-AustralAsia region. The second, at 10 km resolution, encompasses South-East Australia. The project improves on previous work in the rigor of model selection: model independence and performance are taken into account in a systematic way to select the driving General Circulation Models (GCMs) and the Regional Climate Models (RCMs) to downscale the GCMs. The project provides climate projections for a large range of climate variables for two periods: near future (years 2020-2039) and far future (2060-2079). Evaluation of present-day (1990-2009) model biases, and simulations over the reanalysis period (1950-2009) are also conducted. While the experiment generates projections for a large set of variables, we limit our analysis to mean near-surface air temperature and precipitation over South-East Australia.

First, we evaluate the significance and inter-model agreement of present-day RCM biases for temperature and precipitation, and compare the results to the driving GCMs. Then, we focus on the significance and inter-model agreement on future climate changes from years 1990-2009.

We find that present-day RCM-observations biases are more consistently cold than the GCM biases. The RCMs are wetter than the GCMs, especially during warm seasons. The downscaled far-future projections show less warming over land than the driving GCMs. In all cases, the RCM output exhibits a finer spatial structure. Far-future and near-future warming is generally statistically significant. No significant precipitation changes are expected by 2020-2039. In the far future, significant drying is expected in Victoria in spring, and significant responses in contradicting directions are projected for parts of NSW during winter.

Page 45

S2.1b Regional climate projectons and applicaton

Submission ID: 88Presentng Author: Ningbo Jiang

Session tme: WEDNESDAY - 11:00 - 12:00

4

Changes in Synoptc Circulaton Paterns Associated with Projected Future Climate over NSW

JIANG Ningbo*1; JI Fei 2; DILUCA Alejandro3 ; SCORGIE Yvonne4; RILEY Mat5 ; EVANS Jason6

1) OEH, ningbo.jiang@environment.nsw.gov.au; 2) OEH; 3) UNSW; 4) OEH; 5) OEH; 6) UNSW

The NSW/ACT Regional Climate Modelling (NARCliM) project is a multi-agency research partnership between the NSW and ACT governments and the Climate Change Research Centre at the University of NSW. It provides dynamically downscaled climate datasets for southeast Australia at a scale (10 km) that supports local decision makers to formulate climate change adaption plans (Evans et al., 2014). The Weather Research and Forecasting regional climate model (RCM) was run in three different configurations to downscale projections from four global climate models (MIROC3.2, ECHAM5, CCCMA3.1 and CSIRO Mk3.0) selected from the Coupled Model Inter-comparison Project Phase 3 collection. There is a total of 12 RCM simulations, each providing high-resolution climate data for the present (1990-2009), and projected near future (2020-2039) and far future (2060-2079) climate.

Based on the NARCliM datasets, the present study investigates possible changes in synoptic-scale circulations over southeast Australia and how such changes relate to the projected changes in local climate conditions at the 10 km resolution. In this talk, we will present preliminary results based on the ECHAM5-driven simulations. These simulations generally project decreases in winter and spring rainfall and increases in summer and autumn rainfall over much of southeast Australia for the far future compared to the present period. Synoptic circulation patterns are first identified using a non-linear classification method called “self-organising map” (Jiang et al., 2014). Then, the occurrence of these patterns is examined and linked to changes in local precipitation. The questions to be answered include:

1) Do different RCMs provide similar pattern recognition in the synoptic classification?

2) Will the occurrence of typical synoptic patterns identified for the present period change across the two future periods?

3) How do changes in circulation patterns relate to projected changes in precipitation at a local scale?

Page 46

S2.2 Reconciling Climate Change and Variability on Decadal Scales

Submission ID: 150Presentng Co-Author: Jaclyn Brown*

Session tme: FRIDAY 08:30 - 10:00

1

Non-Uniform and Step-Like Migraton of Species Habitats in a Warming Ocean

SEN GUPTA Alex1; BROWN Jaclyn* 2; JOURDAIN Nicolas3 ; VANSEBILLE Erik4; GANACHAUD Alex5 ; VERGÉS Adriana6

1) CCRC ARCCSS UNSW, a.sengupta@unsw.edu.au; 2) CSIRO; 3) CCRC UNSW; 4) Imperial College London; 5) IRD; 6) BEES UNSW

Temperature is a major factor determining a species’ distribution. Stray too far form a species optimal temperature and a population must migrate or ultimately perish. Ocean temperatures have warmed in most regions over the last century and are expected to warm faster in the future. Consistent with this, many marine species have already undergone poleward range shifts in line with warming trends. Using a combination of historical observations and CMIP5 model projections, we examine the implied migration of isotherms marking the boundaries for populations’s thermal habitats.

The speed of migration of these thermal boundaries can vary considerably in different ocean regions and at different time scales. This makes it difficult to attribute species migrations using the often short and regionally confined observational population data.

Climate models suggest that median isotherm migration speeds will be about seven times faster in the 21st century compared to the 20th century under a business as usual emissions scenario. As migration speeds are sensitive to background temperature gradients, habitat boundaries will exhibit erratic migration rates over time, even if future warming were monotonic. We show that in the face of progressive warming, isotherms tend to remain co-located with a thermal front for extended periods of time and then rapidly shift to a new position, marked by a more poleward thermal front. This implies that species habitats will also undergo sudden rapid shifts rather than exhibiting a gradual poleward march.

Page 47

S2.2 Reconciling Climate Change and Variability on Decadal Scales

Submission ID: 268Presentng Author: Roger Jones

Session tme: FRIDAY 08:30 - 10:00

2

Reconciling Anthropogenic Climate Change and Variability on Decadal Timescales: the Challenge

JONES Roger*1

1) Victoria University, roger.jones@vu.edu.au

Published and emerging evidence prosecutes the case that gradual increases in radiative forcing produce a non-linear climate response on decadal timescales when climate change and variability interact. The conclusion from this is that the dominant gradualist narrative of how climate changes is incorrect and the alternative explanation of climate change and variability interacting is a more viable alternative. This paper summarises the major findings of this work and proposes a mechanism for how climate may change. The dominant narrative of how climate changes suggests that atmospheric variables change in a trend-like manner. Most of the statistical techniques in use support and re-affirm this assumption. The proposed mechanism is to follow the heat. If the atmosphere can be shown to warm gradually, independent of the ocean, or warms gradually under the influence of the ocean, then the hypothesis that climate change occurs independently of variability is confirmed. If the ocean and atmosphere under gradual radiative forcing show regime-like step changes, then they can be considered as being part of a coupled, complex system. Currently, climate science in its ‘normal’ role treats climate change and variability as being independent of each other. If they are coupled, methods of climate attribution, prediction, adaptation, mitigation and communication will need to be substantially re-thought.

Page 48

S2.2 Reconciling Climate Change and Variability on Decadal Scales

Submission ID: 159Presentng Author: Mat Fischer

Session tme: FRIDAY 08:30 - 10:00

3

Low-frequency variability in Australian daily temperature mean and variance

FISCHER Mat*1

1) ANSTO, mjf@ansto.gov.au

This study investigates six methods for extracting decadal and multidecadal modes of variability from climate fields: Optimal Persistence Analysis (OPA), Slow Feature Analysis (SFA), Principal Trend Analysis (PTA), Average Predictability Time Decomposition (APTD), Forecastable Components Analysis (ForeCA) and Stationary Subspace Analysis (SSubA). All these methods are nonparametric and find optimal projection vectors that separate signals from noise in a climate field. The first three methods find signals that are the most persistent, APTD and ForeCA find signals that are the most predictable, and SSubA finds signals which are the most non-stationary. The six methods are applied to 51 stations from the Australian daily near-surface temperature network, spanning the years 1910-2013. For all the methods, the two leading components are a long-term trend, and a low-frequency pattern that decreased in the first half of the twentieth century, and increased after that. The spatial pattern for the second component has large weights in the south east region. The third component for OPA is a multidecadal oscillation, which shows large weights in the coastal stations. The first five methods are also applied to the Australian daily temperature variance field (i.e. absolute temperature anomalies). There is a long-term decreasing trend in temperature variance, with large weights in coastal Queensland. In contrast to the other methods, Stationary Subspace Analysis can simultaneously find signals which are the most non-stationary in both mean and variance. The third SSubA component has spectral power at 3-4 years, but shows decadal step-like changes in temperature variance. SSubA is an effective method for investigating regime-like changes in the mean and variance of climate fields.

Fischer, M. J. 2015. Predictable components in Australian daily temperature data. Journal of Climate, in review

Page 49

S2.2 Reconciling Climate Change and Variability on Decadal Scales

Submission ID: 60Presentng Co-Author: John Bye

Session tme: FRIDAY 08:30 - 10:00

4

Changes in Natural Variability under Global Warming

ZHU Xiuhua1; BYE John* 2; FRAEDRICH Klaus3

1) University of Hamburg, xiuhua.zhu@zmaw.de; 2) School of Earth Sciences University of Melbourne; 3) Max Planck Institute for Meteorology

To which extent the ongoing global warming and observed changes in climate statistics are attributed to natural variability of the climate system or to the anthropogenic greenhouse-gas emission is being heavily discussed. In this study, we aim to identify changes in natural variability of the global mean surface temperature (ST) by comparing three simulations of ECHAM5-MPIOM: 1) the 3100-year unforced control run, 2) the equilibrium contemporary run (800-1799), and 3) the future projection forced by AR4 A1B scenario, which is divided into the transient (2006-2099) and equilibrium (2100-2199) periods. The analysis considers the climate statistics on a time scale of averaging of 100 years, which is significantly greater than the random walk length.

The following results will be presented:

1) Natural variability in terms of SST standard deviation (STD) is predicted to retain the same pattern in 2006-2099 and 2100-2199 as in the contemporary climate but to be of progressively milder amplitude.

2) The model shows little evidence of geographical shifts in the patterns of natural variability.

3) Throughout the continents and in the North Pacific and equatorial Pacific Oceans, the STD of the linear trend (‘linear mode’) in the transient period (2006-2099) is greater than that due to the concurrent natural variability, however the linear mode and the natural variability are almost independent, due to the slow rate of global warming.

4) Quite distinct from the natural variability, this linear mode is also equatorially trapped, calling on caution when calculating indices (like Nino3) based on equatorial surface temperatures for the transient period of global warming.

Page 50

S2.2 Reconciling Climate Change and Variability on Decadal Scales

Submission ID: 81Presentng Author: Benjamin Henley

Session tme: FRIDAY 08:30 - 10:00

5

A new index to track the Interdecadal Pacifc Oscillaton in observatons and models

HENLEY Benjamin*1; GERGIS Joelle 2; KAROLY David3 ; POWER Scot4; DELAGE Francois5 ; KENNEDY John6 ; Folland Chris7

1) University of Melbourne, bhenley@unimelb.edu.au; 2) University of Melbourne; 3) University of Melbourne; 4) Bureau of Meteorology; 5) Bureau of Meteorology; 6) UK Met Office; 7) UK Met Office

A new index is presented for the Interdecadal Pacific Oscillation (IPO), termed the IPO Tripole Index (TPI). The IPO is associated with a distinct ‘tripole’ pattern of sea surface temperature anomalies (SSTA), with three large centres of action and variations on decadal timescales, evident in the second principal component (PC) of low-pass filtered global SST. The new index is based on the difference between the SSTA averaged over the central equatorial Pacific and the average of the SSTA in the Northwest and Southwest Pacific. The TPI is an easily calculated, non-PC based index for tracking decadal SST variability associated with the IPO. The TPI time series bears a close resemblance to previously published PC-based indices and has the advantages of being simpler to compute and more consistent with methods used to track the El Niño–Southern Oscillation (ENSO), such as the Niño 3.4 and Trans Niño Indices. The TPI also provides a simple metric, with physical units of °C, for evaluating decadal and interdecadal variability of SST fields in a straightforward manner, and can be used to evaluate the skill of dynamical decadal prediction systems. Composites of SST and mean sea level pressure anomalies will be presented, which reveal that the IPO has maintained a broadly stable structure across the seven most recent positive and negative epochs during 1870-2013. The TPI is a robust and stable representation of the IPO phenomenon in instrumental records, with relatively more variance in decadal than shorter timescales compared to Niño 3.4, due to the explicit inclusion of off-equatorial SST variability associated with the IPO. This presentation will also report on progress on evaluating the representation of the IPO in CMIP5 models using the new index.

Page 51

S2.2 Reconciling Climate Change and Variability on Decadal Scales

Submission ID: 64Presentng Author: Blair Trewin

Session tme: FRIDAY 08:30 - 10:00

6

Recent increases in occurrence of low temperatures in northwestern Australia

TREWIN Blair*1; LISONBEE Joel 2; HOPE Pandora3

1) Bureau of Meteorology, b.trewin@bom.gov.au; 2) Bureau of Meteorology; 3) Bureau of Meteorology

Northwestern Australia, encompassing much of the Kimberley and the northern half of the Northern Territory, is one of few land areas in the world which show cooling of mean temperatures over the period from 1970 to the present. This cooling has coincided with an increase in wet season rainfall over the region but is also present during the core of the dry season.

A notable feature of the recent dry-season cooling has been seasons with many nights with low minimum temperatures. For example, in 2012, Darwin Airport had its largest number of nights on record below 18°C (54), while 2011 ranked third. Overall, the mean annual frequency of nights below 18°C at Darwin increased from 17 in the period 1970-1999 to 28 from 2000-2014. Similar changes exist at locations such as Victoria River Downs, Rabbit Flat and Halls Creek.

Synoptically, southerly surges that advect dry continental airmasses over northwestern Australia, leading to cool nights, occur when strong anticyclones move over southwest Australia. Dewpoint data shows a marked increase in the occurrence of dry air, with the frequency of days with 0900 dewpoint below 2.5°C at Darwin being 6.4 days per year for 2000-2014, compared with 4.3 days per year for 1970-1999.

Seasonal composites of June-August mean sea level pressure (MSLP), and 700 hPa geopotential heights, indicate that winters with large numbers of cool nights and/or low dewpoints in northwestern Australia typically coincide with strong positive MSLP and height anomalies along an east-west axis over southern Australia centred on approximately 35°S. MSLP and 700 hPa heights in this area show upward trends over the 1979-2014 period, indicating that synoptic changes over southern Australia may be a major driver of observed temperature changes in northwestern Australia. This suggests that synoptic changes may produce regional seasonal cooling despite background warming trends at the continental and global scale.

Page 52

S2.3 ENSO and ENSO Impacts - Past, Present and Future

Submission ID: 27Presentng Author: Guojian Wang

Session tme: WEDNESDAY - 15:30 - 17:00

1

More-frequent extreme La Niña events under greenhouse warming

CAI Wenju*1; WANG Guojian 2; SANTOSO Agus3

1) CSIRO, Wenju.Cai@csiro.au; 2) CSIRO; 3) UNSW

The El Niño Southern Oscillation (ENSO) is Earth's most prominent source of interannual climate variability, alternating irregularly between El Niño and La Niña, and resulting in global disruption of weather patterns, ecosystems, fisheries, and agriculture. The 1998/99 extreme La Niña event that followed the 1997/98 extreme El Niño event, switched extreme El Niño-induced severe droughts to devastating floods in western Pacific countries, and vice versa in the southwestern US. During extreme La Niña events, cold sea surface conditions develop in the central Pacific, creating an enhanced temperature gradient from the Maritime continent to the central Pacific. Recent studies have revealed robust changes in El Niño characteristics in response to simulated future greenhouse warming, but how La Niña will change remain unclear. Here we present climate modelling evidence, from simulations conducted for the Coupled Model Intercomparison Project phase 5 (CMIP5), for a near doubling in the frequency of future extreme La Niña events, from one in every 23 years to one in every 13 years. This occurs because projected faster mean warming of the Maritime continent, compared to the central Pacific, facilitates stronger easterly Trade Winds conducive for development of the extreme La Niña events. Furthermore, approximately 75% of the increase occurs in years following extreme El Niño events, thus projecting more frequent swings between opposite extremes from one year to the next.

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S2.3 ENSO and ENSO Impacts - Past, Present and Future

Submission ID: 197Presentng Co-Author: Catherine Ganter

Session tme: WEDNESDAY - 15:30 - 17:00

2

What Makes a Good Australian Snow Season?

PEPLER Acacia1; GANTER Catherine* 2; TREWIN Blair3

1) Bureau of Meteorology, a.pepler@bom.gov.au; 2) Bureau of Meteorology; 3) Bureau of Meteorology

The well-known association between the El Niño-Southern Oscillation (ENSO) and winter and spring rainfall in southeastern Australia has led to an expectation of lower Australian snow depths in El Niño years, and higher snow depths in La Niña years. However, such relationships might be confounded by difference in temperature and the nature of weather events.

In this study, we use the long-term weekly snow depth record at Spencer’s Creek (1830 m elevation) in the New South Wales' Snowy Mountains region to assess the influence of ENSO as well as other drivers on snow depths throughout the season. The influence of ENSO is found to be nonlinear and changing, with La Niña events in recent years not associated with above average snowfall owing to rising temperatures. In terms of climate drivers, the state of the Southern Annular Mode has the largest impact on seasonal snow depths. We also present an early assessment of how climate drivers contribute to the ability of artificial snowmaking to counteract poor seasonal snowfall depths, which will be of growing importance in future decades.

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S2.3 ENSO and ENSO Impacts - Past, Present and Future

Submission ID: 249Presentng Author: Helen McGregor

Session tme: WEDNESDAY - 15:30 - 17:00

3

LESSONS FROM THE PAST FOR UNDERSTANDING PRESENT-DAY ENSO

MCGREGOR Helen*1

1) University of Wollongong, mcgregor@uow.edu.au

Views of past ENSO as seen through paleoclimate data and model simulations offer a means to test the sensitivity of ENSO to external climate forcing, be that from greenhouse gas, orbital, and/or volcanic forcing. Numerous models with idealised, full coupled or snapshot simulations of past climate provide substantive evidence that changes in the Earth’s orbit (orbital forcing), does indeed have an impact on ENSO variability. However, the model simulations of ENSO variability from the mid-Holocene to present do not fully reproduce the magnitude of the changes seen in paleoclimate data. In further contrast to the model simulations coral evidence from the central Pacific has challenged the notion that natural factors have driven changes in ENSO variability. The conflicting evidence for past ENSO remains a significant barrier to improved understanding of ENSO dynamics. This presentation will outline the contribution of past ENSO to the understanding of present-day ENSO and will explore new directions in paleo-ENSO research. Multi-century ENSO reconstructions, novel and forward modelling of proxies, and ENSO field reconstructions offer opportunities to refine ENSO knowledge and resolve past ENSO data-model differences.

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S2.3 ENSO and ENSO Impacts - Past, Present and Future

Submission ID: 263Presentng Author: Tammas Loughran

Session tme: WEDNESDAY - 15:30 - 17:00

4

THE ROLE OF CLIMATE VARIABILITY MODES AS DRIVERS OF AUSTRALIAN HEAT WAVES

LOUGHRAN Tammas*1; PERKINS Sarah 2

1) Climate Change Research Centre University of New South Wales, t.loughran@student.unsw.edu.au; 2) Climate Change Research Centre University of New South Wales

El Niño–Southern Oscillation (ENSO), the Southern Annular Mode (SAM) and the Indian Ocean Dipole (IOD) are a few of the dominant modes of climate variability that are well known to influence the Australian climate on seasonal to interannual time scales. Recent studies have shown that these modes can also influence temperature extremes. However, there has been little focus in the literature on how these modes may influence heat waves. This requires specific focus since heat waves have huge impacts across many sectors of society and environments. Understanding the relationships between these modes and heat waves may therefore aid in prediction and planning.

In this study we aim to determine the extent each of these modes contribute to the development of heat waves in Australia. We identify heat waves using the Excess Heat Factor index using maximum and minimum temperatures from the Australian Water Availability Project gridded dataset. We use principle component analysis to identify the dominant modes of variability in several heat waves characteristics and to identify any signals of the corresponding climate variability modes mentioned above. So far, we have found that the dominant mode of summer heat wave variability is influenced by ENSO and that there are longer and more frequent heat waves during El Niño. This relationship is active across the north-eastern regions of Australia in both spring and summer.

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S2.3 ENSO and ENSO Impacts - Past, Present and Future

Submission ID: 97Presentng Author: Esteban Abellan

Session tme: WEDNESDAY - 15:30 - 17:00

5

The Role of the Southward Wind Shif in both, the Seasonal Synchronizaton and Duraton Asymmetry of ENSO Events

ABELLAN Esteban*1

1) Climate Change Research Centre, esteban.abellan@gmail.com

Near the end of the calendar year, when El Niño events typically reach their peak amplitude, there is a southward shift of the zonal wind anomalies, which were centred around the equator prior to the event peak. Previous studies have shown that ENSO’s anomalous wind stresses, including this southward shift, can be reconstructed with the two leading EOFs of wind stresses over the tropical Pacific. Here a hybrid coupled model is developed, featuring a statistical atmosphere that utilises these first two EOFs along with a linear shallow water model ocean, and a stochastic westerly wind burst model. This hybrid coupled model is then used to assess the role of this meridional wind movement on both the seasonal synchronization as well as the duration of the events. It is found that the addition of the southward wind shift in the model leads to a Christmas peak in variance similar to that seen in the observations. Regarding the duration of modelled ENSO events, on average El Niño events tend to be 5 months shorter in simulations with the southward wind shift compared to those without, whereas the southward wind shift is shown to make no discernable difference to the duration of La Niña events. Thus, our results strongly suggest that the meridional movement of ENSO zonal wind anomalies is at least partly responsible for seasonal synchronization of ENSO events and the duration asymmetry between the warm (El Niño) and cool (La Niña) phases.

Page 57

S2.3 ENSO and ENSO impacts - past, present and future (Lightning Lecture)

Submission ID: 123Presentng Author: Alison TheobaldSession: Lightning Lecture (Session 2.3) Plenary TheatreSession tme: Wednesday 15:30Posters 1Poster #33

Trends and Variability in Precipitaton-Bearing Synoptc Circulaton, Snowy Mountains, Australia

THEOBALD Alison*1; MCGOWAN Hamish 2

1)University of Queensland, a.theobald@uq.edu.au; 2)University of Queensland

The hydroclimate of the Snowy Mountains, south-east Australia (SEA) is highly variable. Inflows generated from precipitation falling in the region provide critical water resources for hydro-power generation and are a major source of environmental flows, supporting agriculture in the Murray-Darling Basin (MDB).

Positioned at a junction between the influence of tropical and extra-tropical synoptic scale weather systems, the hydroclimate is sensitive to change in the mid-latitude westerly wind belt, the dominant driver of precipitation in winter, and tropical moisture advection, particularly during the warmer months.

A multi-decade (1958-2012) objective climatology of precipitation-bearing synoptic weather systems is developed from re-analysis data and regional precipitation data.

Trend analyses show declining frequency of inflow-generating precipitation days (days on which __‚10 mm is observed), whilst the precipitation they generate has increased. In line with climate change projections, we conclude that precipitation intensity has increased.

Historically a cool-season (April_–ÐOctober) dominated precipitation regime is observed. However evidence is presented of a decline in precipitation during autumn and spring months - important for crop sowing in the MDB and replenishment of water storages. Change in annual precipitation distribution is evident with a shift towards greater precipitation during warmer months.

Results indicate synoptic type frequency varies according to ENSO phase, in line with dominant moisture pathways. Preliminary trend analyses of atmospheric variables during precipitation days associated with ENSO phases are presented.

Seasonal changes have implications for filling of water storages and agriculture. Also, effects of increasingly intense precipitation, e.g. erosion and flooding, may have major impacts in SEA. Ongoing research will quantify combined effects of drivers of variability in synoptic circulation responsible for precipitation.

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S2.3 ENSO and ENSO impacts - past, present and future (Lightning Lecture)Submission ID: 229 Presentng Author: Scot PowerSession: Lightning Lecture (Session 2.3) Plenary TheatreSession tme: Wednesday 15:30Posters 1Poster #31

ENSO in a warmer world: clearer than ever before

POWER scot*1; DELAGE Francois 2; CHUNG Christne3 ; KOCIUBA Greg4; KEAY Kevin5

1) Bureau of Meteorology, s.power@bom.gov.au; 2)Bureau of Meteorology; 3)Bureau of Meteorology; 4)Bureau of Meteorology; 5)bureau of meteorology

The El Niño-Southern Oscillation (ENSO) drives substantial variability in rainfall, severe weather, agricultural production, ecosystems and disease in many parts of the world. As further human-forced changes in the earth’s climate system appear inevitable, the possibility exists that the character of ENSO and its impacts might change over the coming century. While this issue has been investigated many times during the last 20 years, there was, until very recently, very little consensus on future changes in ENSO, apart from an expectation that ENSO will continue to be a dominant source of year-to-year variability. This has now changed. Why? The main reason is the unexpected presence of robust, non-linear changes in precipitation anomalies during El Niño years. This nonlinear response is, surprisingly and amazingly, large enough and robust enough to overwhelm uncertain projected changes in the amplitude of ENSO-driven surface temperature variability. Some of the implications of this discovery will be described. If time, projected changes in Modoki El Ninos evident in the latest generation of climate models will also be outlined.

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S2.3 ENSO and ENSO impacts - past, present and future (Lightning Lecture)Submission ID: 254 Presentng Author: Harun RashidSession: Lightning Lecture (Session 2.3) Plenary TheatreSession tme: Wednesday 15:30Posters 1Poster #32

Mechanisms of ENSO Phase Locking Bias in the ACCESS Coupled Models

RASHID Harun*1; HIRST Anthony 2

1) CSIRO Oceans and Atmosphere, harun.rashid@csiro.au; 2) CSIRO Oceans and Atmosphere

The mechanisms of coupled model bias in seasonal ENSO phase locking are investigated using versions 1.0 and 1.3 of the ACCESS coupled models. The two ACCESS models are mostly similar in construction except for some differences, the most notable of which are in the cloud and land surface schemes used in the models. ACCESS1.0 simulates a realistic seasonal phase locking, with the ENSO variability peaking in December as in observations. On the other hand, the simulated ENSO variability in ACCESS1.3 peaks in March, a bias shown to be shared by many other CMIP5 models. To explore the mechanisms of this model bias, we contrast the atmosphere-ocean feedbacks associated with ENSO in both ACCESS model simulations and also compare the key feedbacks with those in other CMIP5 models.

We find evidence that the ENSO phase locking bias in ACCESS1.3 is primarily caused by incorrect simulations of the shortwave feedback and the thermocline feedback in this model. The bias in the shortwave feedback is brought about by unrealistic SST-cloud interactions leading to a positive cloud feedback bias that is largest around March, in contrast to the strongest negative cloud feedback found in ACCESS1.0 simulations and observations at that time. The positive cloud feedback bias in ACCESS1.3 is the result of a dominant role played by the low-level clouds in its modeled SST-cloud interactions in the tropical eastern Pacific. Two factors appear to contribute to the dominance of low-level clouds in ACCESS1.3: the occurrence of a stronger mean descending motion bias and a larger mean SST cold bias during March-April in ACCESS1.3 than in ACCESS1.0. A similar association is found between the positive cloud feedback bias and the biases in spring-time mean descending motion and SST for a group of CMIP5 models that show a seasonal phase locking bias similar to ACCESS1.3. The thermocline feedback also significantly differs in the two models, reinforcing the phase locking bias in ACCESS1.3.

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S2.3 ENSO and ENSO impacts - past, present and future (Lightning Lecture)Submission ID: 102Presentng Author: Mei ZhaoSession: Lightning Lecture (Session 2.3) Plenary TheatreSession tme: Wednesday 15:30Posters 1Poster #35

Variatons of Near-Surface Salinity in the Tropical Pacifc Associated with ENSO

ZHAO mei*1; HENDON Harry 2; YIN Yonghong3 ; ALVES Oscar4

1) R&D branch Bureau of Meteorology, m.zhao@bom.gov.au; 2)R&D branch Bureau of Meteorology; 3)Bureau of Meteorology; 4)Bureau of Meteorology

Interannual variation of upper-ocean salinity in the tropical Pacific and its relation to ENSO is investigated using the Bureau of Meteorology PEODAS ocean reanalyses 1980-2012. Along the equator, interannual variations of temperature tend to be largest along the thermocline and maximize in the eastern Pacific whereas for salinity the largest variations are near the surface (above ~50 m) and largely confined to the western Pacific fresh pool. Empirical orthogonal function (EOF) analysis of temperature and salinity in the equatorial-depth plane (0-250m) reveals the systematic co-evolution of salinity with temperature during ENSO. Mature El Niño (La Niña) conditions are associated with eastward (westward) displacements of the western Pacific fresh pool and warm pool. The strong asymmetry of El Niño/La Niña temperature anomalies is equally expressed in the fresh pool salinity anomalies (less relative eastward shift during La Niña). The occurrence of extreme El Niño conditions during 1982/83 and 1997/98, when the strong positive temperature anomaly extended to the South American coast, is also well depicted in near-surface salinity by an additional eastward extension of the fresh pool to just east of the dateline. Systematic freshening of the western Pacific fresh pool in advance of El Niño during the recharge phase, which might contribute to subsequent evolution of El Niño, is also revealed and is shown to result largely from anomalous E-P. Additional implications of the variation of salinity for the ENSO cycle, including its role in the variation of the barrier layer, and the possible impacts of recent trends of near-surface salinity on ENSO behaviour will be discussed.

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S2.3 ENSO and ENSO impacts - past, present and future (Lightning Lecture)Submission ID: 278Presentng Author: Jens ZinkeSession: Lightning Lecture (Session 2.3) Plenary TheatreSession tme: Wednesday 15:30Posters 1Poster #36

Coral record of southeast Indian Ocean heat waves with intensifed Western Pacifc temperature gradient

ZINKE Jens*1; HOELL Andrew 2; LOUGH JaniceM.3 ; FENG Ming4; KURET AntonJ.5 ; CLARKE Harry6 ; Ricca Vincenzo7 ; McCulloch MalcolmT.8

1)Curtin University of Technology, jen.zinke@gmail.com; 2)University of California Santa Barbara; 3)Australian Institute of Marine Science; 4)CSIRO; 5)UWA School Earth and Environment ARC CoE for Coral

Reef Studies; 6)UWA School Earth and Environment ARC CoE for Coral Reef Studies; 7)UWA School Earth and Environment; ARC CoE for Coral Reef Studies; 8)UWA School of Earth and Environment; ARC Centre of

Excellence for Coral Reef Studies

Marine heat waves (1-3) of increasing intensity which cause widespread mass coral bleaching events are threatening the integrity and functional diversity of corals reefs. Here, we demonstrate the role of inter-ocean coupling in escalating thermal stress on reefs in the poorly studied southeast Indian Ocean (SEIO), through a robust 215 year (1795-2010) geochemical proxy sea surface temperature (SST) record. The emergent long-term SST trends and inter-annual to multi-decadal variability in our proxy record highlight the key role of an increased WPG(4-5), often in concert with strong La Niña’s, in triggering extreme warm events in the SEIO. We trace the cause of historical heat waves to large heat flux changes associated with an increased WP (4,5) as a result of the western Pacific warming faster than the central Pacific. We show that the magnitude of the WPG varies independently between individual El Niño and La Niña events (4-5) resulting in modification of the large-scale tropical circulation and precipitation fields (4,5) affecting the energy and heat flux terms, warm water ocean advection through the coastal waveguide and sea-level pressure in the SEIO and ultimately the magnitude of SEIO marine heat waves. Thus, the independent variability of the WPG from ENSO is of pivotal importance for Indo-Pacific climate connectivity and their impacts on the environment and human society. Better understanding of the zonal SST gradient in the western Pacific is expected to improve projections of the future activity of SEIO heatwaves and their ecological impacts on the important coral reef ecosystems of Western Australia.

1. Feng, M. et al.Sci. Rep. 3, 1277 (2013).

2. Moore et al., PLoS ONE 7, (2012).

3. Zinke, J. et al. Nature Communications 5, doi:10.1038/ncomms4607 (2014).

4. Hoell, A., Funk, C. J. of Clim. 26, 9545-9562 (2013).

5. Hoell, A. et al. Climate Dynamics, doi: 10.1007/s00382-014-2083-y (2014).

Page 62

S2.3 ENSO and ENSO impacts - past, present and future (Lightning Lecture)

Submission ID: 149 Presentng Author: Jaclyn BrownSession: Posters 1Session tme: Thursday 14:30-16:00Poster #28

Simulatng current and future teleconnectons of ENSO to north-eastern Australia.

DONOVAN Elizabeth*1; BROWN Jaclyn 2; MCINTOSH Peter3 ; RISBEY James4; POOK Michael5

1) Bureau of Meteorology, elizabeth.donovan@utas.edu.au; 2) CSIRO; 3) CSIRO; 4) CSIRO; 5) CSIRO

North-eastern Australian rainfall variability is dominated by El Niño Southern Oscillation. Wet years are associated with La Niña and dry years with El Niño, as evidenced by the strong correlation between precipitation and the Nino3.4 index. Climate change may alter the strength of this teleconnection through changes in features such as the south pacific convergence zone, local positions of troughs, surrounding sea surface temperatures, or even ENSO flavour.

To understand potential changes to the Queensland-ENSO relationship in the future we rely on projections from climate models. Such an assessment requires that the climate model is firstly able to simulate the historical ENSO rainfall teleconnection patterns. Here we test this relationship in the ACCESS1-0 climate model and find that the teleconnection is not evident. AMIP-style runs are able to capture the teleconnection, so we infer that the coupling biases are introducing this error. We find that the teleconnection breakdown is due to the poor simulation of the western Pacific including the SPCZ, ocean temperature variability and surface winds. We explore more robust methods for estimating changes in QLD rainfall in climate models.

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S2.3 ENSO and ENSO impacts - past, present and future (Lightning Lecture)Submission ID: 26Presentng Author: Guojian WangSession: Lightning Lecture (Session 2.3) Plenary TheatreSession tme: Wednesday 15:30Posters 1Poster #34

Increasing frequency of extreme El Nino events due to greenhouse warming

CAI Wenju1; WANG Guojian* 2

1)CSIRO, Wenju.Cai@csiro.au; 2)CSIRO

El Niño events are a prominent feature of climate variability with global climatic impacts. The 1997/98 episode, often referred to as ‘the climate event of the twentieth century, and the 1982/83 extreme El Niño, featured a pronounced eastward extension of the west Pacific warm pool and development of atmospheric convection, and hence a huge rainfall increase, in the usually cold and dry equatorial eastern Pacific. Such a massive reorganization of atmospheric convection, which we define as an extreme El Niño, severely disrupted global weather patterns, affecting ecosystems, agriculture, tropical cyclones, drought, bushfires, floods and other extreme weather events worldwide. Potential future changes in such extreme El Niño occurrences could have profound socio-economic consequences. Here we present

climate modelling evidence for a doubling in the occurrences in the future in response to greenhouse warming.We estimate the change by aggregating results from climate models in the Coupled Model Intercomparison Project phases 3 (CMIP3) and 5 (CMIP5) multi-model databases, and a perturbed physics ensemble. The increased frequency arises from a projected surface warming over the eastern

equatorial Pacific that occurs faster than in the surrounding ocean waters, facilitating more occurrences of atmospheric convection in the eastern equatorial region.

Page 64

S2.4 Reconstructon and modelling of past climate

Submission ID: 95Presentng Author: James Shulmeister

Session tme: THURSDAY 15:30 - 17:30

1

SYNOPTIC CLIMATOLOGY OF SE AUSTRALIA AND NEW ZEALAND AT THE LGM BASED ON PROXY DATA

SHULMEISTER James*1

1) University of Queensland, james.shulmeister@uq.edu.au

This talk summarises new information on LGM conditions in eastern Australia and New Zealand. The LGM emerges as a long duration (15-20 kyr) and complex event in New Zealand. Peak glacial advances occurred at least 5 kyr before the Northern Hemisphere. The global LGM is a double event with glacial re-advances or at least still stands at c. 22-21 ka and c. 18 ka. Overall cooling in New Zealand cannot exceed 6.5°C and most likely falls in the range of 5°C and while absolute precipitation maybe lower, effective precipitation cannot be much reduced. Tasmania appears to follow New Zealand patterns. Overall cooling in mainland SE Australia is higher, at least in winter, at 8-11°C. Freeze-thaw dominated landscapes are widespread on the high country as far north as 29°S. LGM aridity is less significant than previously envisioned. In particular, there is clear evidence for a humid belt along the east coast of Australia. Further west, the evidence for greater moisture availability is more ambiguous but speleothem records confirm the general pattern of more positive water balances.

The emerging synoptic climatology of SE Australia at the LGM is remarkably similar to modern. A key observation is that there is an at least seasonal increase in temperature difference across the Tasman Sea, driven by stronger winter cooling in mainland Australia. This is likely a response to a stronger winter blocking high in SE Australia. One effect of the blocking high is to direct onshore easterlies onto the east coast of Australia. The intensified high should drive stronger baroclinic circulation in the Tasman Sea in winter. An effect of this might be to project stronger SW flows onto NZ at the LGM. This would simulate the modern effects of the El Nino-Southern Oscillation and may explain the dichotomy of little LGM activity in the mountains of SE Australia at a time of glacial stillstand/re-advance in New Zealand.

Page 65

S2.4 Reconstructon and modelling of past climate

Submission ID: 189Presentng Co-Author: Stuart Allie

Session tme: THURSDAY 15:30 - 17:30

2

Developing Probabilistc Estmates of Protracted Low-fow Events from Palaeostreamfow Reconstructons in Western Tasmania

BAKER Patrick1; ALLEN Kathryn 2; ALLIE Stuart*3 ; EVANS Robert4; NICHOLS Scot5 ; COOK Edward6 ; Carson Greg7 ; Ling Fiona8

1) Univerity of Melbourne, Patrick.Baker@unimelb.edu.au; 2) University of Melbourne; 3) Hydro Tasmania; 4) Silviscan Pty Ltd; 5) University of Melbourne; 6) Lamont Dhoerty Earth Observatory; 7) Hydro Tasmania;

8) Entura

Changes to the amount and seasonal distribution of precipitation will have profound impacts on the ability to generate hydroelectricity in Tasmania. The occurrence of protracted low-flow events presents a particular threat because of competing demands on water supplies that require minimum base levels to be maintained for environmental purposes. However, the frequency of such events is poorly understood, primarily due to the short observational record of streamflow. Here we describe a 478-year (1530-2007) reconstruction of summer streamflow and inflow for western Tasmania developed from tree rings to provide a longer historical context for recent observed low-flow events. The reconstructions indicate that 20th-Century conditions, including the severe 2007-2009 event, were well within the range of historical variability, and in the broader historical context have been relatively wet. The tree-ring reconstructions highlight a period of enhanced variability from ~1600-1750 and suggest that a high proportion of extreme high and low flow events occurred in the 1600s. In addition, the tree-ring reconstructions allowed us to apply a Markov chain Monte Carlo method to generate synthetic century-long time series of streamflow from the palaeostreamflow reconstruction to identify the probability of protracted low-flow events.

Page 66

S2.4 Reconstructon and modelling of past climate

Submission ID: 294Presentng Author: Patrick Moss

Session tme: THURSDAY 15:30 - 17:30

3

Moon Point, Fraser Island— A 40,000 year window into subtropical eastern Australian environments

MOSS Patrick*1; PETHERICK Lynda 2; STEWART Philip3 ; GONTZ Allen4; SLOSS Craig5 ; BALTAIS Simon6 ; Prideaux Alex7

1) The University of Queensland, patrick.moss@uq.edu.au; 2) Xi'an Jiatong-Liverpool University; 3) The University of Queensland; 4) University of Massachusetts-Boston; 5) Queensland University of Technology; 6)

The University of Queensland; 7) The University of Queensland

Moon Point contains numerous wetlands that provide an environmental record of at least 40,000 years for the iconic Fraser Island, subtropical eastern Australia. This study, based on sedimentological and palynological analysis of six cores, has primarily focussed on Empodisma minus dominated mire communities within the Moon Point region, but there are a variety of other wetlands (mangroves and Melaleuca swamps) that can provide additional complimentary records located across Moon Point. There is evidence of significant environmental change, possibly associated with human arrival, between 40,000 to 35,000 years ago, with a transition from a rainforest dominated community to a sclerophyll one and associated increase in burning. In addition, a significant alteration from lacustrine to E.minus dominated swamps is observed at the beginning of the Holocene, which may be a hydroseral succession process and associated with the formation of the globally unique patterned fen ecosystems of the Great Sandy Region. Finally there is evidence of vegetation thickening occurring at the edge of the wetland, as well as other hydrological changes (increase in mangroves and grass), which is possibly associated with alterations in fire regimes and road construction linked to European settlement of the island.

Page 67

S2.4 Reconstructon and modelling of past climate

Submission ID: 203Presentng Author: Mandy Freund

Session tme: THURSDAY 15:30 - 17:30

4

Feasibility of climate feld reconstructon for Australia

FREUND Mandy*1; GERGIS Joelle 2; KAROLY David3

1) University of Melbourne, mfreund@student.unimelb.edu.au; 2) University of Melbourne; 3) University of Melbourne

A network of annually resolved climate archives (tree-rings, corals, ice cores and cave deposits) is investigated for its sensitivity to large-scale climate circulation influencing the Australasian region.

Previous research has highlighted that the El Nino- Southern Oscillation (ENSO), Interdecadal Pacific Oscillation (IPO), Southern Annual Mode (SAM) and Indian Ocean Dipole (IOD) govern large-scale climate variability over the Australian landmass.

Here we explore the relationship between palaeoclimate and observational data using the gridded temperature and precipitation data developed by the Australian Water Availability Project (AWAP) over the instrumental period. We provide an assessment of the potential of local and remote proxies to resolve spatial climate variability associated with circulation modes.

Analysis of instrumental climate data revealed generally strong spatial coherence of temperature and precipitation fields. We then investigate how covariations in proxy data may be physically related to large-scale climate circulation modes and discuss the issue of non-stationary teleconnections and its implications for a climate field reconstruction.

We performed climate sensitivity experiments with instrumental and palaeoclimate data to assess the suitability of each record for developing climate field reconstructions. Those experiments revealed ENSO as a significant driver of interannual and decadal proxy and climate variations in eastern Australia? IOD and IPO also influence covariations in temperature and rainfall variability especially in north-west and southern Australia. Our results suggest that there is good potential to develop spatial climate field reconstructions for Australia using a sparse palaeoclimate network.

Page 68

S2.4 Reconstructon and modelling of past climate

Submission ID: 228Presentng Co-Author: Scot Power

Session tme: THURSDAY 15:30 - 17:30

5

Major coastal fooding in SE Australia 1860-2012, associated deaths and weather systems

CALLAGHAN Jef1; POWER Scot* 2

1) Bureau of Meteorology (retired), jeffjcallaghan@gmail.com; 2) Bureau of Meteorology

We will describe a new historical database on major floods (and associated weather systems) that occurred in a 1500km strip in coastal southeastern Australia during 1860-2012. That's right - 1860! The method used to identify the major floods will be outlined and some of the dramatic events that occurred during some of the major floods will be described. Two types of weather systems are found to trigger all of the 253 major floods identified: East Coast Lows (ECLs) and three different types of “Tropical Interactions” (TIs). ECLs triggered somewhat more major floods than TIs, but death tolls from freshwater flooding linked to TIs tend to be much higher. Some of the most extreme events identified occurred in the 19th and early 20th centuries. If such events were to occur nowadays they would have catastrophic impacts. It is therefore crucial that weather and flood information beyond recent experience is factored in to planning.

Reference:

Callaghan, J., and S.B. Power, 2015: Major coastal flooding in south-eastern Australia 1860–2012, associated deaths and weather systems. Australian Meteorol. Oceanogr. Journal, (in press).

Page 69

S2.4 Reconstructon and modelling of past climate

Submission ID: 295Presentng Author: Emily Field

Session tme: THURSDAY 15:30 - 17:30

6

New Records and Approaches for Past Climate Reconstructon in the Kimberley Region of Northwest Australia

FIELD Emily*1

1) School of Geography Planning and Environmental Management University of Queensland, e.field@uq.edu.au

There are few terrestrial palaeoenvironmental records from the monsoonal Kimberley region of northwest Australia. Such records are critical in reconstructing climate’s potential role in influencing human activity, and will increase current knowledge of the Australian summer monsoon. The Kimberley’s predominantly arid interior contains mound springs which can promote peat growth. These peatlands therefore offer a new opportunity to examine late Quaternary climatic change in the tropics.

A peat core from Black Springs in North Kimberley has been analysed for pollen, micro-charcoal, dust and sedimentological changes spanning the last 6.3ka (McGowan et al., 2012). The vegetation and dust records contain evidence of a wetter environment prior to the late-mid Holocene which becomes progressively drier into the late Holocene. They then indicate a return to wetter conditions in the last millennia, coeval with peak charcoal concentrations inferred as reflecting an increase in anthropogenic burning and Aboriginal populations. A new age model now extends this record past 9ka. Subsequent pollen and micro-charcoal analysis has both extended the vegetation record and increased the temporal resolution of the published data. New analysis of diatoms and peat humification has also enabled the palaeohydrology of the site to be investigated. This is the first down-core diatom dataset in tropical Western Australia, and the study’s approach is novel in using established proxies which are previously untested in mound spring sediment archives.

Additional sites will be sampled in mid-2015 to allow a synthesis of records and disentangle local and regional signals observed in the proxy data. This will facilitate a comprehensive assessment of past climate variability across the Kimberley.

McGowan, H., Marx, S., Moss, P., Hammond, A. (2012) Evidence of ENSO mega-drought triggered collapse of prehistory Aboriginal society in northwest Australia. Geophys. Res. Lett. 39, L22702.

Page 70

S3.0 - General - Climate - mitgaton, resilience

Submission ID: 174Presentng Author: Roger Dargaville

Session tme: FRIDAY 10:30 - 12:30

1

Trade-ofs between transmission costs of geographical distributon of renewable energy power statons and storage and demand-side management

DARGAVILLE Roger*1; WANG Changlong 2; HUVA Robert3

1) University of Melbourne, rogerd@unimelb.edu.au; 2) University of Melbourne; 3) University of Melbourne

Renewable energy generation from wind and solar resources carries inherent variability as the wind ebbs and flows and the sun varies in intensity. This variability can be reduced by aggregating wind and solar generation over large geographic regions. Studies have show that the distances required to harness decorrelated wind and solar resources are in the order of hundreds to thousands of kilometres. The transmission lines required to cover these distances are costly, and understanding whether the expense is justified is an important question.

We use the Melbourne University Renewable Energy Integration Laboratory (MUREIL) to compare costs of electrical energy systems over Australia with large-scale high capacity transmission linking major centres against systems with dispatchable renewables (i.e. geothermal, biomass), storage (pumped hydro, CAES, lithium ion batteries) and demand-side management. The model finds least cost combinations of technologies using a genetic algorithm. The model is driven with hourly wind and solar fields from the Australian Bureau of Meteorology regional forecast model (ACCESS-A) and technology costs from the Australian Energy Technology Assessment report. We consider a range of scenarios of renewable energy penetration from low to medium and high. A 21 node DC approximation transmission model ensures transmission capacities are adhered to.

Results will show at what transmission cost a widely distributed renewable energy system is cost effective. If the costs are equal or lower than current costs of transmission then the geographic distributed model could be the optimal solution. The results are sensitive to the assumed current and future costs of the alternate technologies such as pumped hydro, batteries or dispatchable technologies, and so significant uncertainty must be attached to the results.

Page 71

S3.0 - General - Climate - mitgaton, resilience

Submission ID: 69Presentng Author: Donna Green

Session tme: FRIDAY 10:30 - 12:30

2

Efects of temperature extremes on Indigenous health in Northern Australia

GREEN Donna*1; GOLDIE James2; ALEXANDER Lisa3 ; TAIT Peter 3; BAMBRICK Hilary4

1) UNSW, donna.green@unsw.edu.au 2) PHAA 3) UWS

Research on the indirect impacts of climate change reinforces the need to understand the relationship between climate and human health. A wide gap already exists between the health of Indigenous and non-Indigenous Australians, and consequently it is important to identify any impacts that might exacerbate that gap. To explore the issue, this presentation analyses how increases in temperature extremes might disproportionately affect Indigenous people living in different climates in the Northern Territory. We examined admissions to the major hospitals in the region of patients with acute and chronic respiratory diagnoses during the period 1993-2011. Our analysis showed that: extreme ambient temperatures were more likely to be associated with Indigenous than non-Indigenous hospital admissions for acute and chronic respiratory disease; and that these associations varied between the tropical ‘Top End’ north and drier ‘Central Desert’ zones. The findings support our two hypotheses: (1) that the health risks associated with a warming climate are non-uniform between Indigenous and non-Indigenous people, and (2) that the health risks vary between different climate zones. These findings have implications for health policy in northern Australia since climate change is likely to further exacerbate heat extremes in the region in the near future.

Page 72

S3.0 - General - Climate - mitgaton, resilience

Submission ID: 282Presentng Author: Anthony Kiem

Session tme: FRIDAY 10:30 - 12:30

3

Using the latest palaeoclimate insights to beter quantfy drought risk and water security in major urban water supply systems in eastern Australia

KIEM Anthony*1; VANCE Tessa 2; ROBERTS Jason3 ; TOZER Carly4; FLACK Anna5

1) University of Newcastle, anthony.kiem@newcastle.edu.au; 2) Antarctic Climate and Ecosystems Cooperative Research Centre University of Tasmania; 3) Department of the Environment Australian

Antarctic Division; 4) University of Newcastle; 5) University of Newcastle

Droughts always have and always will occur in Australia. Both natural climate variability and anthropogenic change influence drought risk but their exact roles, and proportional importance, are not yet properly understood or quantified. To address these challenges, and to move towards more resilient, well adapted urban climates, a paradigm shift is required that accepts and accounts for the non-linear and non-stationary nature of the processes that drive hydroclimatic risk. This study utilizes several independently derived palaeoclimate reconstructions to better understand interannual to multidecadal climate variability and to provide improved quantification of the risk of low probability, high impact hydrological droughts in the heavily populated eastern Australian region. It is demonstrated that the instrumental hydroclimatic records (covering only the last ~100 years at best) do not capture the full range of drought duration, frequency, magnitude or spatial extent. Also discussed are the water resources management implications of the realisation that hydroclimatic risk changes over time— fundamental questions of whether drought risk and urban water security in eastern Australia will increase or decrease in the future (and where and when and by how much) are as yet unanswered, as are issues relating to how decision makers can best deal with such uncertainty.

Page 73

S3.0 - General - Climate - mitgaton, resilience

Submission ID: 274Presentng Author: Sonya Fiddes

Session tme: FRIDAY 10:30 - 12:30

4

A Climatc Perspectve on Current and Future Water Availability in Victoria

FIDDES Sonya*1; TIMBAL Bertrand2

1) University of Melbourne, sonya.fiddes@unimelb.edu.au; 2) Bureau of Meteorology

In the recent past, Victoria experienced its worst drought on record, the Millennium Drought, from 1997-2009. Catchment streamflow in some parts of the state were reduced to as little as 13% of the 30 year average while in other part the reduction was only to about 80-90% of the long-term mean. This study has used the high resolution gridded Bureau of Meteorology operational rainfall and temperature data generated as part of the Australian Water Availability Project, over several temporal scales, to statistically reconstruct streamflow for 27 of Victoria’s key water catchments using a simple linear regression. This simple reconstruction is a novel approach, first attempted for Melbourne Catchment and proven successful in reproducing key statistics, such as the depth of the decline during the Millennium Drought. Across the more diverse types of catchment selected across the state of Victoria, the reconstruction is shown to be successful, capturing not only the mean and variability of the streamflows, but also the magnitude of the drought and longer term streamflow trends. Using this simple reconstruction method, it is now possible to use statistically downscaled CMIP5 global climate model projections to gain an insight as to what the future of Victoria’s streamflow may be under several emission scenarios. Broadly, it is found that by 2080, the streamflow experienced during the Millennium Drought will become the norm under the higher emission scenario (RCP 8.5, on which we are currently tracking). The reduction in mean streamflow is halved if mid-range emission scenario (RCP 4.5, which assumes important mitigation will be implemented). This study was conducted as part of the Victorian Climate Initiative (VicCI) in partnership between the Bureau of Meteorology and the Victoria Government (Department of Environment, Land, Water and Planning— DELWP).

Page 74

S3.0 - General - Climate - mitgaton, resilience

Submission ID: 322Presentng Author: Huade Guan

Session tme: FRIDAY 10:30 - 12:30

5

Temporal and Spatal Paterns of the Adelaide Urban Heat Island

GUAN Huade*1; GHARIB Saeedeh2; WAITE Jared3 ; BENNETT John4; KENT Chris5 ; EWENZ Caecilia6 ; Kumar Vinod7 ; Simmons Craig8

1) Flinders University, huade.guan@flinders.edu.au; 2) Flinders University; 3) Flinders University; 4) Flinders University; 5) Bureau of Meteorology; 6) Flinders University; 7) Bureau of Meteorology; 8) Flinders

University

A temperature monitoring network has been set up and in operation since mid 2010 over the Adelaide metropolitan area. This presentation will report the urban heat island (UHI) patterns over the metropolitan area and the Central Business District (CBD) based on these multi-year data. The focus will be on the UHI seasonal variations, specific UHI patterns for selected extreme weather conditions, and their associated influences of urban cover and environmental winds typical to Adelaide (e.g., sea breezes and gully winds). Possibility of using the unique Adelaide Parklands surrounding CBD as the reference to calculate urban heat island intensity is also explored. Finally, the UHI maps will be compared to those produced in 1970s to examine the effects of urban development on Adelaide UHI.

Page 75

S3.0 - General - Climate - mitgaton, resilience

Submission ID: 327Presentng Author: Michael Grose

Session tme: FRIDAY 10:30 - 12:30

6

Potental Constraints on CMIP5 Climate Projectons of Australian Temperature and Southern Australian Rainfall

GROSE Michael*1; BHEND Jonas 2; RISBEY James3 ; WILSON Louise4; OSBROUGH Stacey5 ; MOISE Aurel6

1) CSIRO, Michael.Grose@csiro.au

The set of global climate model (GCM) simulations from CMIP5 run for the Representative Concentration Pathways (RCPs) give a range of plausible responses to each given pathway, and are now used in climate change impact research and to plan for future climate changes. Due to our imperfect and incomplete knowledge of the climate system and how it responds to forcings, the real response of the climate to an RCP may be in fact be within a restricted part of this projected range, or outside this projected range altogether. Constraints, which are compelling reasons to define the range of projected change to a given set of forcings, can be very useful in more confidently using projections. Here we examine and review potential sources of constraints on the climate projections of Australian temperature and southern Australian rainfall. These constraints are from physical principles and ‘emergent constraints’ based on relationships across the model ensemble. We examine emergent constraints using the climatology and recent trends of surface variables, and also using indices of southern hemisphere atmospheric circulation.

Page 76

S3.1 Climate and human health

Submission ID: 289Presentng Author: Lisa Alexander

Session tme: FRIDAY 15:30 - 16:30

1

Assessment of Sector-relevant Climate Indices for New South Wales

ALEXANDER Lisa*1; HEROLD Nicholas 2; GROSS Mia3

1) UNSW, l.alexander@unsw.edu.au; 2) UNSW; 3) UNSW

The World Meteorological Organisation (WMO) has developed the Global Framework for Climate Services (GFCS) with the intent to provide climate information and services to meet user requirements. Under this framework, the Expert Team on Climate Risk and Sector-Specific Climate Indices (ET-CRSCI) has worked to identify and evaluate sector-specific indices mostly focussed on more extreme climatic events, for the agriculture and food security, water resources and health sectors. The development of the indices was aimed at providing a systematic and globally-consistent approach to help characterize the susceptibility of various sectors to climate variability and change. This presentation will highlight the objectives of the ET-CRSCI including the sector-focused indices, with examples of the importance of such uniformly-developed indices (e.g. droughts and heatwaves) to the relevant sectors. We show an application for these indices using observations and high resolution modelling for New South Wales. The results show that there are strong relationships between temperature and precipitation-based indices and sector data such as annual wheat yields. Projections of increases in the frequency, intensity and duration of heatwaves using the high resolution model simulations indicate a likely increase in the health burden from these extreme heat events in NSW in the future. Results are aimed to help the preparedness of our agriculture, health and water resources sectors to future climate change.

Page 77

S3.1 Climate and human health

Submission ID: 49Presentng Author: James Goldie

Session tme: FRIDAY 15:30 - 16:30

2

Temperature and humidity efects on hospital morbidity in Darwin, Australia

GOLDIE James*1; SHERWOOD Steven 2; GREEN Donna3 ; ALEXANDER Lisa4

1) Climate Change Research Centre, j.goldie@unsw.edu.au; 2) Climate Change Research Centre; 3) Climate Change Research Centre; 4) Climate Change Research Centre

Many studies have explored the relationship between temperature and health in the context of a changing climate, but few have considered the impact of humidity, particularly in tropical locations, on human health and well-being. To investigate this potential relationship, we assessed the main and interacting effects of daily temperature and humidity on hospital admission rates in Darwin, Australia. Univariate and bivariate Poisson Generalized Linear Models were used to find statistically significant predictors and the admission rates within bins of predictors were compared to explore non-linear effects. The analysis indicated that nighttime humidity is the most statistically significant predictor (p < 0.001), followed by daytime temperature and average daily humidity (p < 0.05). There is no evidence of a significant interaction between them or other predictors. The nighttime humidity effect appears to be strongly non-linear: hot days appear to have higher admission rates when they are preceded by high nighttime humidity. From this analysis we suggest that heat-health policies in tropical regions similar to Darwin need to accommodate the effects of temperature and humidity at different times of day. This may challenge the use of heat stress indices, such as Wet Bulb Globe Temperature, in the design of heat alert systems.

Page 78

S3.1 Climate and human health

Submission ID: 243Presentng Author: Emma Austn

Session tme: FRIDAY 15:30 - 16:30

3

Spatal Analysis of Drought and Wellbeing in Rural Australia

AUSTIN Emma*1; KIEM Anthony 2; PERKINS David3 ; RICH Jane4; KELLY Brian5

1) University of Newcastle, emma.austin@newcastle.edu.au; 2) University of Newcastle; 3) Centre for Rural and Remote Mental Health; 4) Centre for Rural and Remote Mental Health; 5) School of Medicine and Public

Health University of Newcastle

Rural and remote farming communities most often constitute the majority of drought declared areas. These communities are characterised by a complex interaction of a range of social and economic factors which compound the impacts of drought. In addition, the duration, insidiousness and pervasiveness of droughts result in unique social and health impacts when compared with other climatic extremes (e.g. floods, bushfires, cyclones, etc.). In Australia, these key experiences of drought can be identified from existing social analyses of rural and remote areas so as to improve understanding into the characteristics of drought that cause the most impacts to humans. This is a necessary step towards increasing resilience and adaptive capacity in efforts to implement successful drought adaptation actions. The research focuses specifically on how drought impacts the wellbeing of people in rural communities in non-metropolitan New South Wales. Importantly, in line with recent hydroclimatic studies that demonstrate that all droughts are different, this work quantifies how wellbeing varies in space and time in relation to different drought metrics (e.g. frequency, duration, intensity etc.) and also includes analysis on the various drought indices and their suitability as indicators of wellbeing.

Page 79

S3.1 Climate and human health

Submission ID: 90Presentng Author: Jaclyn Brown

Session tme: FRIDAY 15:30 - 16:30

4

In 30 years, how might climate change afect the Australian diet?

1) BROWN, Jaclyn*

CSIRO, jaci.brown@csiro.au

Under climate change, many studies suggest that, in key food producing regions of Australia, water may become scarcer and temperatures higher. These climatic changes have the potential to change the quality and quantity of food that we are able to supply to the nation and the rest of the globe (Reisinger et al. 2014). Australia produces 93% of its domestic food requirements and exports 76% of its agricultural production (Reisinger et al., 2014). It is necessary to think about, and prepare for, the potential impacts of climate change on the Australian diet. Food security is already an issue Australia's vulnerable groups, such as indigenous, unemployed, aged and disabled groups. At any one time, around 5% of Australians are food insecure and around 40% of these are severely food insecure (Temple 2008). Experience shows that when food prices rise, people will adjust their diet based on both availability and affordability, to lower quality food. In this discussion we explore the typical Australian diet as suggested by the recent Australian Health Survey. We assess the ingredients that make up this diet and discuss how the pressures of climate change may affect availability of these foods and our dietary choices. While the interplay between climate, agriculture, economics and human health is complex, discussion can begin on the many feedbacks that are likely to occur. This cross-disciplinary review was inspired by the Theo Murphy High Flyers Think Tank run by the Australian Academy of Science and involves authors from wide ranging disciplines including climate, agriculture, pests, technology and health.

Reisinger, A., et al. (2014) Australasia. Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part B: Regional Aspects. Contribution of Working Group II to the Fifth Assessment Report of the IPCC Temple, J. B., 2008, 'Severe and Moderate Forms of Food Insecurity in Australia: Are They Distinguishable?' Aust. J. of Social Issues, Vol. 43, No. 4, pp 649-668

Page 80

S3.2 Drought: from monitoring and land Surface mo

Submission ID: 138Presentng Author: Andrea Tascheto

Session tme: WEDNESDAY - 14:00 - 15:00

1

Can Australian multyear droughts be internally forced?

TASCHETTO Andrea*1; SENGUPTA Alex 2; UMMENHOFER Caroline3 ; ENGLAND Mathew4

1) Climate Change Research Centre / ARC Centre of Excellence for Climate System Science, a.taschetto@unsw.edu.au; 2) Climate Change Research Centre / ARC Centre of Excellence for Climate System Science; 3) Woods Hole Oceanographic Institution MA USA; 4) Climate Change Research Centre / ARC Centre

of Excellence for Climate System Science

Australia has experienced many dry spells since the end of 19th century, e.g. the Federation Drought (1895-1902) ; the World War II Drought (1937-1945) ; and, the more recent Millennium Drought (1995-2009). Some of the Australian historical droughts were driven by warm conditions in the Pacific, such as the short 1982-83 and long 1991-95 El Niño droughts. The association with oceanic conditions makes droughts predictable to some extent. However, prediction can be difficult when there is no clear external forcing such as El Niños. One may question whether the ocean is the only source contributing to long-term droughts in Australia. Can dry spells be triggered and maintained with no ocean memory? This study addresses these questions.

We use the NCAR CESM model to assess two millennium-length simulations: i. a fully coupled climate run from the pre-industrial control scenario using the CMIP5 protocol; and, ii. an atmospheric general circulation model (AGCM) run forced with seasonally varying SST. The first simulation contains long-term variability in the ocean, the most important source of thermal memory of the climate system. The second simulation eliminates the ocean memory; thus, any long-term droughts found here are driven by atmospheric internal variability and interactions with the land surface.

Results reveal that multi-year droughts can indeed be generated by internal variability of the atmosphere. The intensity of the internally driven droughts is lower than those in the fully coupled model, however the duration of dry spells is comparable between simulations. While the Pacific Decadal Oscillation plays an important role in generating droughts in the fully coupled model, perturbations of monsoonal winds seem to be the main trigger of dry spells in the AGCM case. Droughts in the mid-latitude regions like in Tasmania can be driven by perturbations in the Southern Annular Mode, not necessarily linked to oceanic conditions even in the fully-coupled model.

Page 81

S3.2 Drought: from monitoring and land Surface mo

Submission ID: 219Presentng Author: Huqiang Zhang

Session tme: WEDNESDAY - 14:00 - 15:00

2

Assessing the Potental of Land-Surface Models in Soil Moisture and Drought Monitoring

ZHANG Huqiang*1; ZHANG Liang2

1) Bureau of Meteorology, h.zhang@bom.gov.au; 2) Institute of Arid Meteorology CMA China

In this study, we present some assessment of using ACCESS land-surface model (CABLE/JULES) in drought and soil moisture monitoring. Using the same meteorological forcing, we compared the drought products derived from different approaches: CPI - cumulative precipitation index (rainfall only); PDSI - Palmer Drought Severity Index (rainfall & estimated evap loss); SPEI - Standardized Precipitation Evapotranspiration Index (rainfall with improved estimation of evap loss); CABLE - rainfall and physically based calculation of Evap lose and consistency in energy and water budgets. We have used extensive soil moisture observations in China in this collaborative study. Preliminary results will be presented.

Page 82

S3.2 Drought: from monitoring and land Surface mo

Submission ID: 107Presentng Author: Gab Abramowitz

Session tme: WEDNESDAY - 14:00 - 15:00

3

An update on PALS and CABLE benchmarking - the case for drought capability metrics

ABRAMOWITZ Gab*1

1) ARCCSS / UNSW, gabsun@gmail.com

Understanding the strengths and weaknesses of a modelling system is key to understanding the circumstances in which trust can be placed in its predictions. In the case of drought, the effective time-scale of a model’s state - temporally appropriate limitation of soil moisture availability - is clearly critical, and is affected not just by the nominal size of the modelled store, but a model’s controls on the flux in and out of this store.

The Protocol for the Analysis of the Land Surface models (PALS) is an online, automated model evaluation and benchmarking tool, now hosted at NCI. It aims to host a variety of model evaluation experiments that can examine both process level representation and the impact that changes to this representation have at catchment, regional and global scales. High temporal resolution datasets from heavily instrumented sites are critically important for improving process representation, yet it is only by examining larger regional scales that we can understand which processes lead to longer term effects.

This talk will detail recent developments in PALS toward meeting these aims, as well as its use for benchmarking CABLE.

Page 83

S3.2 Drought: from monitoring and land Surface mo

Submission ID: 56Presentng Author: Ailie Gallant

Session tme: WEDNESDAY - 14:00 - 15:00

4

Untangling the cause of the Millennium Drought using GCM simulatons

GALLANT Ailie*1; LEWIS Sophie 2

1) Monash University, ailie.gallant@monash.edu; 2) Australian National University

Prolonged droughts on the order of a multiple years to a decade have recently afflicted many parts of highly populated regions around the globe, for example, the southwest United States and southeast Australia. However, the causes of these droughts remain unclear. A significant contribution from natural decadal-scale climate variability is likely, but there is also conflicting evidence of any contribution from anthropogenic climate change.

This work aims to untangle the causes of the 13-year 'Millennium Drought' in southeast Australia spanning 1997–2009. A suite of historical and control simulations from fully coupled GCMs contained in the CMIP5 archive are employed, and the potential contributions of random climate variability, SST forcing and anthropogenic forcing to the drought are examined in detail.

It is likely that random, decadal-scale variability played a significant role in producing the prolonged rainfall deficits across southeast Australia. These were reinforced by several years with El Niño-like conditions, which commonly induce drought in the region, and a lack of La Niña conditions, which are more likely to bring rain. Evidence of contribution of anthropogenic forcing to the drought is limited.

Page 84

S3.3 Energy

Submission ID: 48Presentng Author: Nicholas Engerer

Session tme: WEDNESDAY - 15:30 - 17:00

1

Categorising the meteorological origins of critcal ramp events in collectve photovoltaic array output

ENGERER Nicholas*1

1) The ANU Fenner School of Environment and Society, nicholas.engerer@anu.edu.au

Photovoltaic (PV) solar power use is increasing globally. The Australian Capital Territory (A.C.T.), Australia, has legislated a renewable energy target of 90% by 2020; to reach this target, use of distributed PV solar arrays is expected to increase. Cloud cover can cause PV installations to rapidly increase or decrease their power output, resulting in A.C.T.-wide collective ramp events. Accurate forecasts of when the ramp events will occur are needed for electricity providers to plan for these abrupt output changes and ensure electricity supplies remain stable. This paper classifies the weather events causing changes in the output of rooftop PV arrays in the A.C.T., providing a foundation for future PV output forecasting to be based on weather event identification. This paper identifies city-wide collective ramp events, which occur when a 60% change in collective PV power output (with respect to the clear sky potential) is experienced within 60 minutes. Throughout the period between January 2012 to July 2014, 28 critical ramp events occurred. Sixteen of these events were positive collective ramp events, caused most frequently by Australian north-west cloud bands and radiation fog dissipation. Twelve events were negative collective ramp events, and were caused most frequently by the passage of cold fronts and thunderstorms. We conclude that the categories developed herein will make it possible to improve short term solar forecasting methods and enable meteorologists to contribute to the forecasting of critical events.

Page 85

S3.3 Energy

Submission ID: 96Presentng Author: Robert Huva

Session tme: WEDNESDAY - 15:30 - 17:00

2

Optmising the Deployment of Renewable Energy Resources for the Australian NEM and the Infuence of Seasonality and Decorrelaton Length

Scales

HUVA Robert*1; DARGAVILLE Roger 2; RAYNER Peter3

1) University of Melbourne, r.huva@pgrad.unimelb.edu.au; 2) University of Melbourne; 3) University of Melbourne

In Australia there is a growing amount of studies that suggest large penetrations of renewable electricity into the National Electricity Market (NEM) (up to 100%) can maintain reliability standards, as well as be cost competitive with fossil fuels into the future (Elliston et al. 2013; AEMO 2013). However, specifically how the large-scale variability in the wind and solar fields influences the design of a highly renewable NEM remains largely unpublished. Using high resolution gridded numerical weather model output from the Bureau of Meteorology’s regional model–(ACCESS-A) –for the period 2010-2011, in tandem with electrical demand data from the Australian Electricity Market Operator and a Genetic Algorithm we investigate the influence of the seasonality in resource availability on the optimal system design. We do so by optimising the winter and summer seasons separately. We also optimise the whole data set and incorporate a transmission cost for connecting remote locations to the nearest capital city, followed by a transmission cost sensitivity study. We find that the winter scenario uses predominantly Queensland wind power with no solar utilised while the summer scenario uses southern wind locations and also incorporates a significant amount of solar. We also find that the design of the electricity network utilising all available data can be summarised by the wintertime and summertime electricity networks. When conducting the transmission cost sensitivity study we find that increasing the cost from $1M/km to $8M/km results in all renewable resources contracting to four main, and very large, wind installations. These locations are on average 884km apart and are uncorrelated.

AEMO, 2013: 100 Per Cent Renewables Study–Modelling Outcomes. Tech. Rep. July, 111 pp., Melbourne.

Elliston, B., I. MacGill, and M. Diesendorf, 2013: Least cost 100% renewable electricity scenarios in the Australian National Electricity Market. Energy Policy, 59, 270-282.

Page 86

S3.3 Energy

Submission ID: 28Presentng Author: Dimitris Lazos

Session tme: WEDNESDAY - 15:30 - 17:00

3

Development of Hybrid Numerical and Statstcal Short Term Horizon Weather Predicton Models for Building Energy Management Optmisaton

LAZOS Dimitris*1; KAY Merlinde 2

1) UNSW, d.lazos@zoho.com; 2) UNSW

Modern building system optimisation frameworks are able to utilise forecasts of generation and load to achieve financial and energy savings. To that end, weather variable predictions of various horizons are particularly useful, as major components of the energy system depend directly or indirectly on prevalent weather conditions. Instead of obtaining weather predictions from an external entity, this work proposes the use of a hybrid model that is able to generate localised predictions for ambient temperature, relative humidity and wind speed. A weighted regression and an autoregressive process were implemented in order to develop two hybrid models. The models produce forecasts in a horizon of six hours ahead, with an hourly temporal resolution and are based on two components. The persistence component assumes stationarity of the conditions in the atmosphere, while the numerical component downscales synoptic scale weather observations to a localised region. In this study the persistence will be used as both the reference model to determine the skill of the numerical and the hybrid models, as well as an input component with decreasing weighting for the hybrid models. The hybrid models show notable improvements in skill over both individual components up to 38% for temperature, 28% for relative humidity and 9% for wind speed respectively. More frequent update of reference component inputs, improved the accuracy of the hybrid models even further. Furthermore, the hybrid models were adjusted to develop forecasts useful for building energy system management, such as the occurrence of a sudden change or the chance of a peak temperature. This novel approach is relatively simple to implement and focuses on high spatial resolution regions and metrics tailored to the optimisation framework of energy management of buildings.

Page 87

S3.3 Energy

Submission ID: 196Presentng Author: Abhnil Prasad

Session tme: WEDNESDAY - 15:30 - 17:00

4

Synergy between Solar and Wind Energy in Australia

PRASAD Abhnil*1; KAY Merlinde 2

1) University of New South Wales, abhnil.prasad@unsw.edu.au; 2) University of New South Wales

Australia’s growing renewable energy industry aims to meet local electricity demands while reducing the dependence on fossil fuels. Solar and wind energy are the two most viable sources of renewable energy resources available. Optimizing both of these resources for the generation of power is crucial. Hybrid solar-wind power generation systems can boost energy production if greater complementary characteristics exist at potential sites. This study uses reduced hourly time averaged diagnostic fields from Modern Era Retrospective Analysis for Research and Applications (MERRA) reanalysis data over Australia from 1979-2014. The boundary layer flux data has been used to construct wind profile at 80 m turbine hub heights. The Wind Power Density (WPD) and surface incident shortwave flux (also available from MERRA surface flux data) were used to assess the feasibility of wind and solar energy, respectively. The complementary characteristics of solar and wind energy were investigated temporally at hourly and daily scales. Hourly anti-correlations in solar and wind energy were significant in northern Australia during morning, central Australia at noon and western Australia in the afternoon. Regions near the eastern, western and south-western coast dominate the frequency of daily anti-correlations. Further assessment of the complementary characteristics of usable wind (WPD >240 Wm-2) and solar (GHI >0 Wm-2) energy showed potential locations of hybrid wind-solar power generating systems. Wind complemented solar along the western and southern coast, whereas solar complemented wind along the eastern and northern coast. Overall, the synergy between solar and wind energy in Australia is within 30-60% of all days within the period of 1979-2014. A hybrid solar-wind power generating system is most feasible in the south-east region where solar and winds complement each other on > 50% of the days within the last 36 years.

Page 88

S3.3 Energy

Submission ID: 66Presentng Author: Pieter de Jong

Session tme: WEDNESDAY - 15:30 - 17:00

5

The Impact of Climate Change on the Brazilian Northeast’s Electricity Matrix

DE_JONG Pieter*1; KIPERSTOK Asher 2; ANDRADE_TORRES Ednildo3

1) Federal University of Bahia, pieterj@ufba.br; 2) Federal University of Bahia; 3) Federal University of Bahia

While Brazil overall has abundant water resources, Brazil’s Northeast region (NE) receives only a fraction of the total annual national rainfall. The interior of the NE region is mostly semi-arid and suffers from frequent droughts, which can also affect the region’s power supply. The majority of the NE’s electricity (typically 70%) is supplied from hydroelectric dams, which are located in the NE’s São Francisco basin (one of the driest regions in the country). However as a result of a drought in the region which began in 2012, in 2013 and 2014 the NE hydroelectric plants only contributed 42% and 39% respectively of the NE’s total electricity demand. This shortfall was mostly substituted by fossil fuel power. Moreover, in November 2014 the water level in the SÕ£o Francisco basin fell to only 13% of the total capacity in terms of stored energy (ONS, 2014).

Deteriorating rainfall patterns in the NE region due to Global Warming may threaten hydroelectricity production to an even greater degree. By 2070 rainfall will decline approximately 25–50% in semi-arid areas and up to 80% in coastal areas. This will cause a reduction in flow rates of 60–90% by 2070 for various rivers in the NE (TANAJURA et al 2009). The impacts of climate change could also threaten the hydroelectricity production in Brazil’s North because the North region, which today is very humid, is predicted to become drier with less rainfall toward the end of the century. Conversely, it is estimate that by 2100, wind power potential in the Brazilian North and NE will more than triple the 2001 baseline reference (PEREIRA DE LUCENA et al, 2010). Additionally, the decline in rainfall predicted for the NE and North regions due to climate change will also cause a significant increase in the regions’ average solar radiation levels. Therefore both wind and solar power could be significantly exploited which would enable the NE region to maintain its relatively low emissions factor from electricity generation.

Page 89

S3.3 Energy

Submission ID: 71Presentng Author: Jing Huang

Session tme: WEDNESDAY - 15:30 - 17:00

6

Efects of Spatal Resoluton On the Forecastng Accuracy of Solar Energy Using NWP Models

HUANG Jing*1; THATCHER Marcus 2

1) CSIRO, jing.r.huang@csiro.au; 2) CSIRO

Numerical weather prediction (NWP) is currently the best tool to forecast solar radiation beyond several hours ahead. However, due to the stochastic nature of clouds, spatial resolution used by NWP affects the forecasting accuracy of solar radiation and solar energy significantly. In this study, the effects of spatial resolution on the forecasting accuracy of solar energy are investigated systematically using the Cubic Conformal Atmospheric Model (CCAM) and Global Forecast System (GFS). Nudging from the NCEP global analysis, CCAM has been run to forecast solar radiation at a resolution of 4km in horizontal space covering the whole Australia. Bias correction is implemented on the original output of the NWP models by modelling the mean bias as a polynomial function of clear sky index and solar zenith angle. For the mean Global Horizontal Irradiance (GHI), it is found that the optimal horizontal resolution occurs typically at several hundreds km evidenced by the values of MAE and RMSE, which varies with the climatic characteristics of the location. However, for the ramp rate of the mean GHI, higher spatial resolution generally leads to higher forecasting accuracy. Other issues, such as the effects of clear sky index and vertical resolution of NWP, are explored as well.

Page 90

S3.4 Urban climate

Submission ID: 139Presentng Author: Hiep Duc

Session tme: THURSDAY 15:30 - 17:30

1

Climate change impact on air quality— Urban troposphere ozone in metropolitan Sydney

DUC Hiep*1

1) Office of Environment & Heritage NSW, hiep.duc@environment.nsw.gov.au

Climate change projections for NSW suggest increases in the frequency of hot days and extreme fire weather. This has important ramifications for air pollution and related health risks in the urban environment, as an increase in ozone concentrations and high pollution episodes is linked to the increase in temperature and frequency of hot, sunny days. Based on climate projections undertaken as part of the NSW and ACT Regional Climate Modelling project (NARCliM), a study is underway to assess the impact of climate change on air quality in the NSW Greater Metropolitan Region (GMR) comprising the Lower Hunter, Sydney and Illawarra regions. This study focuses on photochemical ozone projections for future climate epochs.

NARCliM projections used three configurations of the Weather Research and Forecasting (WRF) regional climate model to dynamically downscale four global climate model projections, resulting in an ensemble of twelve member runs to span the range of likely future changes in climate. Projections are available for a 10km resolution and for three time periods, 1990-2009 (base case), 2020-2039 (near future) and 2060-2079 (far future).

In this study, meteorological data selected from the NARCLiM ensemble outputs of the base case, near future and far future epochs is used to drive a regional air quality model, TAPM-CTM (The Air Pollution Model— Chemical Transport Model). Current (2008) emission inventory data for the GMR is input into the modelling to simulate ozone formation under projected recent and future climate scenarios. The method used to select ensemble members for the study will be presented. Tropospheric ozone levels modelled to occur for future epochs will be compared to ozone levels simulated for the base case epoch, with results analysed to determine the impact of future climate on urban ozone formation in the GMR.

Page 91

S3.4 Urban climate

Submission ID: 240Presentng Author: Cacilia Ewenz

Session tme: THURSDAY 15:30 - 17:30

2

Heat Distributon through Suburban Adelaide

EWENZ Cacilia*1; FAHEY Thomas 2; BENNETT John3

1) Airborne Research Australia Flinders University, cacilia.ewenz@internode.on.net; 2) Flinders University; 3) Flinders University

The city of Adelaide and surrounding suburbs stretch along the coast of St Vincent Gulf for more than 50km, approximately north-southward. With the ocean to the west and the Mount Lofty Ranges to the east, the cities climate is determined by local climate. During summer strong northerly winds lead to extreme temperature conditions. The afternoon seabreeze can mitigate these conditions.

Surfaces like builtup or parks, vegetation to street as well as housing ratios determine the character of each of Adelaide's suburbs. The classification of the various suburbs ranges from old to new residential to industrial character. The main difference here is the ratio between the property size and the size of the house built on this property. Additionally vegetation cover on the properties lead to variations in energy balance.

In the more industrial suburbs large areas are generally covered with corrugated roofing and large parking spaces. The mainly sealed surface and large concrete structures can store more energy over the day than the small old residential houses with their large front and backyard areas covered by trees, shrubs and flower beds.

Temperature data at up to 40 sites in Adelaide are collected since 2010. About half of all sites are located in the Adelaide CBD and North Adelaide area. The remaining sensors were placed around these in suburban Adelaide from Modbury in the north-east via Wingfield in the north-west to Seaview Heights in the south.

While the north-western suburbs are more of industrial character but affected early by the incoming sea breeze, the north-eastern suburban character can be described as residential. Most of these suburbs display a new residential character with a house size to property ratio of almost 90%, so very little space for front or backyard vegetation. The temperature here is generally higher compared to old residential areas where trees and large unsealed areas covered in vegetation lead to much cooler conditions.

Page 92

S3.4 Urban climate

Submission ID: 321Presentng Co-Author: Huade Guan

Session tme: THURSDAY 15:30 - 17:30

3

Sea Breeze Cooling Power in the Adelaide Metropolitan Area

GHARIB CHOOBARY Saeedeh1; GUAN Huade** 2

1) Flinders University, saeedeh.gharib@flinders.edu.au; 2) The Flinders University

Coastal cities, such as Adelaide in South Australia located approximately 10 km to the east of St Vincent Gulf, benefit from sea breeze cooling in summer months. Although the kinematics and dynamics of sea breeze and its interaction urban climate have been widely studied in the literature, analysing the cooling role of sea breeze has been unattended. The sea breeze occurrence and cooling effect during its inland progress to the Adelaide Central Business District (CBD) are investigated using high spatial and temporal resolution meteorological data during the summer months between 2010 and 2013. .A new approach to quantify the cooling effect of sea breeze is presented by introducing the quantitative parameter, Sea Breeze Cooling Power (SBCP), with the unit of °C•min. The results indicate that the Adelaide CBD experiences an average maximum temperature reduction of 1.2°C, 1°C, 0.9°C and 0.5°C due to the sea breeze in February, January, December and March, respectively. In the Adelaide CBD, the elevated sensible heat flux in the area resulted from the Urban Heat Island (UHI) phenomenon in addition to the blockage of the wind flow by the urban morphology may restricts some city areas from receiving the cool, moist sea breeze. This could also be related to the declining trend found in the SBCP during the cool air inland advance in all the summer months with a significant difference detected between the SBCP of the Adelaide Airport and the Adelaide CBD. In general, a declining trend is found in the SBCP during the sea breeze inland intrusion. The decline rate is estimated to be 45.5 ë_C.min/km in average for the all summer months.

Page 93

S3.4 Urban climate

Submission ID: 105Presentng Author: Stephanie Jacobs

Session tme: THURSDAY 15:30 - 17:30

4

Comparison of modelled thermal comfort during a heatwave in Melbourne

JACOBS Stephanie*1; GALLANT Ailie 2; TAPPER Nigel3

1) Monash University, stephanie.jacobs@monash.edu; 2) Monash University; 3) Monash University

Heatwaves have the highest mortality rates out of any natural disasters and they are becoming hotter, longer and more frequent with global warming. We use a case study of the devastating heatwave that affected Melbourne in 2009 during which there was an unprecedented three days above 43C, 374 excess deaths and 714 cases of people being admitted to hospital due to heat related illness. We assess the ability of the Weather Research Forecasting model (WRF) to simulate the near-surface temperatures and human thermal comfort during this heatwave. We compare a regular non-urban parameterised WRF run, WRF coupled with an urban land surface model and WRF coupled to a high-resolution urban surface data set. These simulations are then analysed with respect to high-resolution observational meteorological data available for Melbourne. This comparison is a crucial first step to modelling the effectiveness of urban heat mitigation techniques with the aim of improving human thermal comfort, and hence, saving lives during future extreme heatwaves. Melbourne serves as an example of the viability for the partial mitigation of heatwaves through intelligent urban design. The techniques generated during this study can then be applied to other cities, globally.

Page 94

S3.4 Urban climate

Submission ID: 261Presentng Author: Carlo Jamandre

Session tme: THURSDAY 15:30 - 17:30

5

Infuence of urban expansion and densifcaton on local climate

JAMANDRE Carlo*1; HART Melissa 2; PITMAN Andy3 ; ARGÜESO Daniel4

1) CCRC, c.jamandre@student.unsw.edu.au; 2) ARC Centre of Excellence for Climate System; 3) ARC Centre of Excellence for Climate System; 4) Climate Change Research Centre

Sydney is the most populous city in Oceania with a 4.7 million population and an estimated 1.6 million increase by 2031. To accommodate this population increase, urban area and density is projected to increase; however, little has been done to examine the effects of urban expansion in this region. In this study, Sydney’s expansion was classified under two forms, internally and externally expanding. Externally expanding areas are non-urban locations which will be converted into urban land-use over the next 20 years. Varying height and urban densities are examined for possible future scenarios in these areas. Internally expanding locations are urban areas whose expansions are projected to be through denser, taller, or higher intensity urban areas. Ensemble simulations for both are produced to determine expansion scenarios which minimize the effect of the urban heat island. This study addresses two main problems— the lack of a diversified urban land-use simulation of Sydney and an exploration on city designs for climate change adaptation through the alteration of city parameters ( such as building heights, aspect ratios, urban cover) within the weather research and forecasting model. A 2km spatial resolution was chosen and simulations were performed for January 2009 over Sydney with a 2 month spin-up. A 4-day heat wave event was also present during this period.

Page 95

S3.4 Urban climate

Submission ID: 104Presentng Author: Cassandra Rogers

Session tme: THURSDAY 15:30 - 17:30

6

The Urban Heat Island Efect during Heatwaves in Melbourne

ROGERS Cassandra*1; GALLANT Ailie 2; TAPPER Nigel3

1) Monash University, cassandra.rogers@monash.edu; 2) Monash University; 3) Monash University

In urban areas, extreme heat conditions can adversely affect population health, leading to increases in hospital admissions and even deaths. Urban temperatures are regulated by both synoptic weather conditions and the land surface. While urban areas are subject to higher than normal temperatures due to both heatwaves and the Urban Heat Island (UHI), the extent to which these co-occur is not yet known. The city of Melbourne has a typical UHI of between -3.2°C and 6.0°C, yet its typical strength during heatwave conditions has until now been unknown. Therefore, this research examines the association between the UHI and heatwaves and whether they are exacerbated, or dampened, by an UHI effect. Temperature data from urban and rural sites in and around Melbourne are used to determine the magnitude of the UHI during heatwave and non-heatwave conditions. If there is some contribution from an UHI during extreme heating, there exists the potential to partially mitigate any associated health impacts through urban design.

Given the adverse impacts of heatwaves on health in urban areas it is imperative that any potential additive effect of the UHI on heatwaves is quantified. This is particularly pertinent given the future increases in heatwaves that are likely with human-induced climate change. The proportion of Australians living in capital cities is expected to increase in the future, with the percentage expected to rise from 66% in 2013 to 72% in 2053. The percentage of elderly and heat-vulnerable will also increase. When combined with this expectation of future increases in Australia’s urban population, increasing heatwaves will have the potential to increase the number of heat related deaths in urban areas in Australia. This research improves the current understanding of the interactions between heatwaves and urban areas to better inform decisions around heat sensitive urban planning and design and health adaptation and management during heatwave conditions in urban areas.

Page 96

S4.1a Circulaton and Climate Variability in the Indian Ocean

Submission ID: 352Presentng Author: Neville Smith

Session tme: WEDNESDAY 14:00 - 15:00

1

Progress in Observing and Predictng the Tropical Pacifc Ocean

SMITH, Neville

Co-Chair TPOS 2020 Steering Commitee, nsmi3118@bigpond.net.au

Understanding of the onset and duration of the phases of the El Niño-Southern Oscillation (ENSO) provides a basis for routine delivery of seasonal climate outlooks and associated information and services for regions impacted by ENSO, including Australia. The journey to solving this problem started over 30 years ago and there are few if any natural semi-regular climate signals whose prediction can have such widespread impact … but we are not there yet. We continue to be surprised by the diversity of ENSO events. The recent period has been accompanied by changes in the mean state and reduced variability, sometimes confounding our attempts at prediction.During 1985 through 1994 a major international project, the Tropical Oceans-Global Atmosphere (TOGA) Experiment, established a tropical Pacific Ocean observing system. The primary rationale was to enable the prediction of large-scale interannual climate fluctuations, in particular El Niño and its global effects. The Pacific component of the TOGA observing system was completed in 1994, and has since supported routine forecasting systems and research.New in situ and satellite observational technologies have since emerged in the Tropical Pacific Observing System (TPOS). There has also been a profound evolution in the sophistication of analysis, modelling and predictions. The deterioration of the TOGA-based elements of the network in recent years challenged us to, first, consider the underpinning scientific understanding and rationale for the TPOS, and its implications for a more modern consideration of requirements, observing techniques, and data products. Second, we must forge a fresh international partnership to ensure an efficient, effective and sustainable observing network for the next decade and beyond.In January 2014 a Review of the TPOS was conducted, through a Workshop and associated set of White Papers, and led to the establishment of the TPOS 2020 Project. The TPOS 2020 Steering Committee met in October 2014 to launch the Project. The initial meeting agreed an initial set of activities needed to evolve TPOS. These included: Evaluation of the backbone of the observing network, including broad-scale aspects of the TPOS.

Elaboration of the scientific need and feasibility of observing the planetary boundary layers, including air-sea fluxes, near surface processes and diurnal variability,

Evaluation of approaches to observation of the eastern and western boundary regions,

Development of rationales, requirements and strategy for biogeochemical observations, and

Consideration of approaches to advancing modelling, data assimilation and synthesis so that observations can achieve their fullest impact.

The presentation will introduce the TPOS 2020 Project and discuss what it hopes to achieve over the coming 6 years. Particular points of relevance to the Australian oceanographic, atmospheric and climate community will be highlighted. We are at a critical stage in observing and predicting ENSO but the basis of such services is at risk and the evolution of the prediction systems is not keeping pace in terms of accuracy and reliability.

Page 97

S4.1a Circulaton and Climate Variability in the Indian Ocean

Submission ID: 218Presentng Author: Danielle Verdon-Kidd

Session tme: WEDNESDAY 14:00 - 15:00

2

Would the real Indian Ocean Dipole please stand up?

VERDON-KIDD Danielle*1

1) University of Newcastle, danielle.verdon@newcastle.edu.au

Numerous studies have confirmed the existence of a dipole mode in the Indian Ocean, characterised by a pattern of internal variability with anomalously low sea surface temperatures (SSTs) off Sumatra and high SSTs in the western Indian Ocean. The Dipole Mode Index (DMI) is most often used to represent the Indian Ocean Dipole (IOD), which has subsequently been linked to rainfall variability over eastern Africa, Indonesia, northeast Asia and southern and eastern Australia. While the physical description of the IOD is relatively consistent among studies, the definition of IOD events varies substantially, resulting in conflicting classifications. One source of this inconsistency is the range of SST datasets on which the IOD events have been defined. DMI timeseries have been calculated using a variety SST datasets that are derived from different base data and interpolation methods. This study shows that the choice of SST dataset significantly impacts on the resulting DMI and hence classification of IOD events. This is particularly evident during the most recent 15 years where there is a significant deviation between SST datasets, resulting in a bias towards positive dipole events for one particular SST dataset. An additional complication arises from the inconsistent use of a climatological baseline on which the SST anomalies are calculated, particularly given the significant warming trend evident in the Indian Ocean, requiring careful consideration. Finally, it is shown that not all dipoles are ‘equal’ and that some events that have previously been classified as positive (or negative) IOD events are in fact ‘pseudo dipoles’, where the SST anomalies in the two poles are not of opposite sign as one would expect of a true dipole, resulting in a very different impact pattern on rainfall around the Indian Basin region, including Australia.

Page 98

S4.1a Circulaton and Climate Variability in the Indian Ocean

Submission ID: 259Presentng Author: Craig Steinberg

Session tme: WEDNESDAY 14:00 - 15:00

3

Toward Sustained Ocean Observing across Tropical Northern Australian Shelf Seas

STEINBERG Craig*1; WILLIAMS David 2; MCALLISTER Felicity3 ; RIGBY Paul4; SPAGNOL Simon5 ; BRINKMAN Richard6 ; Benthuysen Jessica7 ; Pataratchi Chari8 ; Wijfels Susan9 ; Sloyan Bernadete10 ; Feng Ming11

1) AIMS, c.steinberg@aims.gov.au; 2) AIMS; 3) AIMS; 4) AIMS; 5) AIMS; 6) AIMS; 7) AIMS; 8) UWA; 9) CSIRO; 10) CSIRO; 11) CSIRO

Australia’s Tropical Northern Seas encompass a region of rich oceanographic complexity and ecological diversity. The region extends from Ningaloo Reef in the west, the resource rich North West Shelf to Darwin and along Queensland’s Great Barrier Reef (GBR).

Two of the primary objectives of the Australian Government NCRIS funded IMOS mooring array is to monitor boundary currents and cross shelf exchanges. From late 2007 a total of 24 moorings have been progressively rolled out across the shelf seas. These complement other arrays in more temperate regions and the Indonesian Throughflow moorings deployed by the Australian Bluewater Observing System facility of IMOS.

Observations reveal a rich amount of detail of the boundary currents which have a strong seasonal variation. Shelf waters exhibit a transition from well-mixed in winter to a strongly thermally stratified water column from spring-time warming through summer. Internal tides then are able propagate into the shallower shelf water. Along the GBR there are periods of sustained intrusions across the shelf through the reef matrix from a variety of mechanisms.

The Northern Australian array has also been embedded in a number of shorter term process based studies across the north and data is being utilized by a growing number of regional modelling efforts demonstrating significant researcher, management uptake of these observations.

The moorings are operated for IMOS by AIMS through the Queensland and Northern Australian sub-facility of the Australian National Mooring Network. The regional nodes Western Australia (WAIMOS) and Queensland (Q-IMOS) determine the guiding principles in order to achieve science outcomes. Support funding has been provided by the Western Australian and Queensland State Governments and the Darwin Port Corporation. All data is made publicly available through the IMOS data portal www.imos.org.au.

Page 99

S4.1a Circulaton and Climate Variability in the Indian Ocean

Submission ID: 239Presentng Author: Anne-Christne Pequignet

Session tme: WEDNESDAY 14:00 - 15:00

4

Subtdal circulaton on the Australian North West shelf: Local versus remote forcing

PEQUIGNET Anne-Christne*1; JONES Nicole 2; LOWE Ryan3 ; IVEY Greg4; BOOK JefreyW.5 ; BRINKMAN Richard6

; Steinberg Craig7 ; Macdonald Helen8

1) UWA, Christine.pequignet@uwa.edu.au; 2) UWA; 3) UWA; 4) UWA; 5) Naval Research Laboratory; 6) AIMS; 7) AIMS; 8) UWA

The Australian North West Shelf (NWS) is located between the Timor passage and North West Cape, but despite the ecological and economic importance of this region, the dynamics of the circulation along this wide and shallow shelf remain poorly understood. Six months (November 2011- April 2012) of shelf mooring observations extending from Ningaloo to the Kimberley are used, along with available remote sensing data, to assess the subtidal variability of the flow along the shelf during the summer and autumn seasons. The alongshore currents on the shelf are vertically uniform in the upper 100 m. Depth averaged alongshore currents at different mooring locations are highly coherent along the shelf from Ningaloo to the Kimberley, with a weak south-westward net flow that shows significant variability at periods of ~18 days. Alongshore current velocities are highly (negatively) correlated with local sea level, and comparison with altimetry indicates that geostrophy contributes to significantly (about 40%) to the variability of the alongshore flow. The base geostrophic flow is modulated by the local wind forcing which, even outside of the cyclone periods (Nov-April), experiences periodic weakening or reversal from the predominantly south-westerly direction. The spatial uniformity of both the meteorological forcing and the shelf geostrophic flow results in a very coherent flow along the shelf. Numerical simulations of currents on the NWS are used to put the season 2011-2012 into the context of inter-annual variability.

Page 100

S4.1b Circulaton and Climate Variability in the Indian Ocean

Submission ID: 351Presentng Author: Bernadete Sloyan

Session tme: THURSDAY 9:15 - 10:15

1

The 2011-2014 Pacifc and Indian Ocean exchange: inital results from the IMOS Timor Passage and Ombai Strait Moorings

SLOYAN Bernadete*1, WIJFFELS Susan2, COWLEY Rebecca3

1) CSIRO Ocean and Atmosphere Flagship Bernadette.Sloyan@csiro.au; 2) CSIRO Ocean and Atmosphere Flagship; 3) CSIRO Ocean and Atmosphere Flagship)

A fundamental aspect of observing, describing, understanding and modeling the global climate is a better knowledge of the fluxes of momentum, heat and freshwater in the ocean. The Indonesian seas are the only major low-latitude connection in the global oceans. This connection permits the transfer of Pacific waters into the Indian Ocean, known as the Indonesian Throughflow. The interaction of the Pacific and Indian basins and their modes of variability (El Niño–Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD)), both through atmospheric teleconnections and the ocean link via the Indonesian Throughflow, is now being hotly pursued in the research community.

We will present some initial finding from the 36-month time series (2011-2014) of the Timor Passage and Ombai Strait moorings. This mooring array is a component of the Australian Integrated Marine Observing System (IMOS), and builds on the earlier results of the INSTANT (2003-2006) observational program. The moorings comprise of velocity, temperature and salinity instruments. Observations from these moorings provide the required spatial and temporal coverage to understand ocean dynamics, the ocean’s role in climate variability and change, investigate forcing of the atmosphere and ocean and assess the realism of data-assimilative ocean models and coupled ocean-atmosphere models.

Page 101

S4.1b Circulaton and Climate Variability in the Indian Ocean

Submission ID: 238Presentng Author: Viviane Menezes

Session tme: THURSDAY 9:15 - 10:15

2

SEA SURFACE SALINITY MAXIMUM OF THE SOUTH INDIAN OCEAN FROM AQUARIUS AND SMOS SATELLITES, ARGO AND RAMA DATA

MENEZES Viviane*1; PHILLIPS Helen 2

1) Institute for Marine and Antarctic Studies (IMAS) University of Tasmania, vivianev@utas.edu.au; 2) Institute for Marine and Antarctic Studies (IMAS) University of Tasmania

Excess of evaporation over precipitation in the subtropical regions creates high salinity pools near the sea surface in all ocean basins. These subtropical salinity maxima, however, are not simply collocated with the regions of maximum evaporation minus precipitation (E-P). Instead, they are generally displaced 5 to 10 degrees poleward of the E-P maxima, indicating an important role of the ocean dynamics setting the large-scale SSS pattern. These regions are particularly important because the subtropical underwater (STW) is formed by subduction of surface waters in these areas. In all oceans, the STW is transported equatorward from the formation region. In the Atlantic and Pacific oceans, this transport is tightly related to the Subtropical-Tropical Cell (STC). In the South Indian Ocean (SIO), the picture is more complicated and not yet fully understood. The SIO salinity maximum is further poleward and eastward compared with its Atlantic and Pacific counterparts. It significantly impacts the dynamics of the eastern SIO, because the STW forms a strong haline front with the fresh Indonesian Throughflow waters. This haline front overwhelms the temperature contribution establishing the eastward Eastern Gyral Current, an important upstream source for the Leeuwin Current. In the present work, we analyze the seasonal and interannual variability of the SSS maximum using the newest Aquarius and SMOS satellites, an Argo gridded product and the RAMA mooring located at 25S-100E. This study is complemented by data from OAFLUX (E-P), 3B42 TRMM (precipitation), Ascat/Quikscat winds and OSCAR product. The SSS maximum varies in size but not in location. In the seasonal cycle, the minimum area defined by the isohaline of 35.5 is maximum in March-May and minimum in Oct-Nov, with the pool being saltiest in March. On interannual time-scales, the area of the pool has decreased from 2007 to 2014. We are investigating the processes controlling this variability.

Page 102

S4.1b Circulaton and Climate Variability in the Indian Ocean

Submission ID: 272Presentng Author: Ming Feng

Session tme: THURSDAY 9:15 - 10:15

3

Decadal increase in Ningaloo Niño since the late 1990s

FENG Ming*1

1) CSIRO, Ming.feng@csiro.au

Ningaloo Niño refers to the episodic occurrence of anomalously warm ocean conditions along the subtropical coast of Western Australia (WA). Ningaloo Niño typically develops in austral spring, peaks in summer, and decays in autumn, and it often occurs in conjunction with La Niña conditions in the Pacific which promote poleward transport of warm tropical waters by the Leeuwin Current. Since the late 1990s, there has been a marked increase in the occurrence of Ningaloo Niño, which is likely related to the recent swing to the negative phase of the Interdecadal Pacific Oscillation (IPO) and enhanced El Niño–Southern Oscillation variance since 1970s. The swing to the negative IPO sustains positive heat content anomalies and initiates more frequent cyclonic wind anomalies off the WA coast so favoring enhanced poleward heat transport by the Leeuwin Current. The anthropogenically forced global warming has made it easier for natural variability to drive extreme ocean temperatures in the region.

Page 103

S4.1b Circulaton and Climate Variability in the Indian Ocean

Submission ID: 106Presentng Author: Earl Duran

Session tme: THURSDAY 9:15 - 10:15

4

Investgaton of the Leeuwin Undercurrent Source Waters and Pathways

DURAN Earl*1; PHILLIPS Helen 2

1) IMAS, earl.r.duran@gmail.com; 2) IMAS

The Indian Ocean’s eastern boundary is characterized by a warm, swift and narrow current at the surface flowing poleward— the Leeuwin Current. Slightly offshore, adjacent to the continental slope and beneath the Leeuwin Current, the Leeuwin Undercurrent flows equatorward near 600 m depth, carrying cold, relatively fresh and oxygen-rich water, and is believed to include Subantarctic Mode Water.

Ridgway and Condie (2004) proposed a description of the circulation off southwestern Australia as a continuous system of currents between the North West Cape (NWC), along the Western Australian coast, eastward across the Great Australia Bight, and then poleward again to the southern tip of Tasmania at South East Cape (SEC). The surface currents flowing anti-clockwise around Australia from NWC to SEC are: the Leeuwin Current, the South Australian Current and the Zeehan Current. At deeper levels, the flow is in the opposite direction, from SEC to NWC: the Flinders Current and the Leeuwin Undercurrent. Recent studies strongly suggest the Flinders Current is fed by the Tasman Leakage. While the origin and characteristics of the Leeuwin Current is well documented, the Leeuwin Undercurrent and the relative contributions it receives from the Flinders Current and indirectly the Tasman Leakage is poorly resolved.

We use the CSIRO Atlas of Regional Seas (CARS) to map the Leeuwin Undercurrent along the western and southern coastlines of Australia. We examine temperature, salinity and associated density and geostrophic velocity fields, identifying the current based on horizontal density gradients. We present the variation of water mass properties and transport along the path of the Leeuwin Undercurrent in the climatological mean and seasonal cycle. In the next phase of work we will also examine the current in the BLUELink model to compare with the CARS observations.

RIDGWAY, K. R. & CONDIE, S. A. 2004. J. Geophys. Res., 109, doi:10.1029/2003JC001921

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S5.0 General oceanography - general

Submission ID: 70Presentng Author: Gabriela Pilo

Session tme: FRIDAY 15:30 - 16:30

1

Pathways of East Australian Current antcyclonic eddies

PILO Gabriela*1; OKE Peter 2; COLEMAN Richard3 ; RYKOVA Tatana4

1) CSIRO/UTAS, gabrielaspilo@gmail.com; 2) CSIRO; 3) University of Tasmania; 4) CSIRO

East Australian Current (EAC) anticyclonic eddies are shed by the current's retroflection and propagate southward along the continental slope down to Tasmania. Tasman Sea eddies can cross south of Tasmania and reach the Great Australian Bight (GAB). However, no link between these eddies has ever been documented. Our objective is to look for a link between EAC eddies and eddies found in the GAB region. To accomplish our goal, we use an eddy-resolving model output and a gridded altimetry product. We manually track anticyclonic eddies that last for up to 6 years. We show, for the first time, a typical pathway for anticyclonic EAC eddies that starts in the retroflection region and finished in the GAB. While this pathway is clearly seen in the model output, it is less clear in the gridded altimetry product. We show that this disparity is due to the lower spatial resolution of gridded altimetry. As the eddies propagate from the EAC retroflection to Tasmania they lose amplitude. This results in eddies reaching Tasmania with reduced surface signal, leading to a pathway interruption in gridded altimetry maps but not in the model output. The pathway shown here has regional and local implications for heat and biogeochemical components distribution.

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S5.0 General oceanography - general

Submission ID: 185Presentng Author: Andrew Kiss

Session tme: FRIDAY 15:30 - 16:30

2

Impact of Periodic Forcing on Western Boundary Current Time-Dependence: Phase-Locking, Chaos and the Origins of Low-Frequency Variability.

KISS Andrew*1; FRANKCOMBE Leela 2

1) University of New South Wales Canberra (ADFA) and ARCCSS, a.kiss@adfa.edu.au; 2) Climate Change Research Centre University of New South Wales and ARCCSS

Western boundary currents (WBCs, such as the East Australian Current) are regions of energetic, highly variable flow and large atmosphere-ocean heat fluxes. The origins of their variability have mostly been studied using either nonlinear models forced by steady winds (revealing their intrinsic variability) or linear models forced by time-varying winds (which generally give a filtered version of the forcing signal). We combine these approaches and present a detailed survey of the response of an idealised nonlinear, intrinsically periodic WBC to a time-periodic wind stress curl. An intricate regime diagram is revealed as a function of forcing amplitude and frequency, showing regions of phase-locking at multiple rational frequency ratios, quasiperiodic states, chaos and hysteresis. In particular, we show that the nonlinear WBC response can include long timescales which are absent from both the forcing and the steadily-driven current, and that these can arise even with weak forcing variations of under 1%. These results suggest that such nonlinear forced response phenomena should be considered when attempting to determine the cause of observed WBC timescales, and that studies omitting either forcing variation or nonlinearity provide an unrealistically narrow view of the origins of time-dependence in WBCs.

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S5.0 General oceanography - generalSubmission ID: 350 Presentng Author: Takanori Horii

Session tme: FRIDAY 15:30 - 16:30

3

Impact of intraseasonal salinity fuctuatons on sea surface temperature in the eastern equatorial Indian Ocean

HORII, Takanori*1 2, UEKI I1, ANDO K1, HASEGAWA T1, MIZUNO K1, SEIKI A3

Takanori.Horii@csiro.au, 1) Research and Development Center for Global Change (RCGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC) 2) CSIRO Oceans and Atmosphere Flagship 3) Department

of Coupled Ocean-Atmosphere-Land Processes Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC)

A systematic salinity change in the upper ocean may have an impact on air-sea interactions through a change in ocean stratification, and hence, the oceanic response to atmospheric forcing. In the present study, we investigated the mixed layer temperature (MLT) and salinity variation in the eastern Indian Ocean to determine the possible role of salinity variation in the oceanic response to intraseasonal atmospheric forcing. We primarily used data from three moored buoys located in an area of the eastern equatorial Indian Ocean with a large salinity gradient. Observed salinity variation in the upper layer has significant spectral peaks at intraseasonal time scales. The intraseasonal salinity variation correlated with surface zonal current and eastward propagating convection, suggesting an association with Madden-Julian Oscillation (MJO).Composite analyses, based on 35 significant MJO events during 2002–2012, confirmed that atmospheric intraseasonal forcing resulted in a reduced net surface heat flux, a decreased MLT, freshening, subsequent salting of upper layer salinity, and deepening of the ocean mixed layer. In this study, we also found that a large salinity change could cause a large amplitude of MLT variation, which was not dependent on the strength of MJOs. Our analysis suggests that salinity signals are produced by the eastward (westward) advection of high-salinity (low-salinity) water, driven by the westerly (easterly) phase of the MJO. A possible process by which intraseasonal salinity variation could have an impact on sea surface temperature (SST) is discussed.

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Submission ID: 193Presentng Author: Luke Cravigan

Session tme: FRIDAY 15:30 - 16:30

4

Cloud Condensaton Nuclei over the Southern and South Pacifc Oceans

CRAVIGAN Luke*1; RISTOVSKI Zoran 2; MALLET Marc3 ; ALROE Joel4; KEYWOOD Melita5 ; WARD Jason6 ; Lawson Sarah7 ; Molloy Suzie8 ; Harvey Mike9 ; Law Clif10 ; Olivares Gustavo11 ;Talbot Nick12 Co-Author

1) Queensland University of Technology, l.cravigan@hdr.qut.edu.au; 2) Queensland University of Technology; 3) Queensland University of Technology; 4) Queensland University of Technology; 5) CSIRO Marine and Atmospheric Research; 6) CSIRO Marine and Atmospheric Research; 7) CSIRO Marine and Atmospheric Research; 8) CSIRO Marine and Atmospheric Research; 9) National Institute of Water and Atmospheric

Research; 10) National Institute of Water and Atmospheric Research; 11) National Institute of Water and Atmospheric Research; 12) National Institute of Water and Atmospheric Research

Sensitivity analysis of a global aerosol model has suggested that natural aerosol emissions and processes are the largest contributor to modelled cloud radiative forcing variance (1). Measurements of remote marine aerosol composition and cloud condensation nuclei (CCN) concentrations are relatively scarce, particularly in the Southern Hemisphere. These observations are key to refining model representation of marine aerosol emissions and atmospheric processing of marine species.

In this presentation the results from aerosol volatility, hygroscopicity and CCN concentration measurements over the Southern and South Pacific Oceans will be discussed. Southern Ocean measurements were taken in January and February 2015 during the Cold Water Trials of the RV-Investigator (CSIRO, Hobart). Measurements in the South Pacific were undertaken at the Chatham Rise (East of New Zealand) during the IGBP-SOLAS Surface Ocean Aerosol Production (SOAP) voyages in February 2011 and February/March 2012 on board the research vessel Tangaroa (NIWA, Wellington, New Zealand).

Non-sea salt (nss) sulfates are formed from the atmospheric processing of dimethyl sulfide (DMS) and consistently dominate remote marine aerosol concentrations at peak CCN sizes (<200 nm). This work highlights the importance of nss sulfates to remote marine CCN concentrations.

Sub-200 nm sea- spray aerosols (SSA) are more transient than nss sulfates, yet provide significant enhancement in CCN concentrations (2). Observed size dependent organic enrichment of SSA is distinct from that observed in other ocean basins and has implications for SSA emission schemes.

1. Carslaw KS et al. (2013) Large contribution of natural aerosols to uncertainty in indirect forcing. Nature 503:67–71.

2. Cravigan LT, Ristovski Z, Modini RL, Keywood MD, Gras JL (2015) Observation of sea salt fraction in sub-100 nm diameter particles at Cape Grim. J Geophys Res Atmos:2014JD022601.

S5.1 A review of Australian Coastal upwelling

Submission ID: 135

Page 108

Presentng Author: Daniel Brieva

Session tme: WEDNESDAY - 9:30 - 10:30

1

A Numerical Investgaton of the Southeast Fraser Island Upwelling System

BRIEVA Daniel*1; RIBBE Joachim 2; LEMCKERT Charles3

1) USQ, w0104152@umail.usq.edu.au; 2) USQ; 3) Griffith University

The Southeast Fraser Island Upwelling System was recently identified from an analysis of remotely sensed reoccurring chlorophyll-a blooms (Brieva et al. 2015). The location of these blooms overlaps with a region previously identified as a key eastern Australian marine ecological site and important fisheries. The analysis found that these sporadic blooms are due to upwelling events that are primarily driven by the interaction of the East Australian Current (EAC) with the shelf-break. A particular Chl-a distribution pattern of these events is more frequent during the spring and summer months when the EAC is most intense and is in close proximity to the continental shelf. The regional ocean modelling system (ROMS) with a variable horizontal resolution of about 2.5 km by 2.5 km over the shelf and 64 sigma vertical levels is being implemented to investigate the on-shelf circulation, exchange processes with the EAC and the physical forcing that drives the observed upwelling events. Firstly, the model is forced with climatology data. Its boundary conditions are a daily year of averaged data from BRAN3.5. Secondly, the boundary conditions were updated to interpolated data from the BRAN3.5, year 2010 results. Initial results trace the intrusion of water over the shelf when the EAC is present and in proximity to the continental shelf and indicate the potential role of upwelling contributing eddies.

Brieva, D, Ribbe, J, and Lemckert, C, 2015. Is the East Australian Current causing a marine ecological hot-spot and an important fisheries near Fraser Island, Australia? Estuarine, Coastal and Shelf Science. 153,121— 134.

Page 109

S5.1 A review of Australian Coastal upwelling

Submission ID: 221Presentng Author: Charitha Pataratchi

Session tme: WEDNESDAY - 9:30 - 10:30

2

Coastal Upwelling along south-west Australia

PATTIARATCHI Charitha*1

1) The University of Western Australia, chari.pattiaratchi@uwa.edu.au

In each of the main ocean basins, the surface circulation forms a gyre with poleward flow along the westward boundary of the basin and equatorward flow along the eastern margin. In addition, the eastern margins (off south America and south Africa, for example) are areas of high productivity due to upwelling. The exception to this rule is off the West Australian coast, where the Leeuwin Current transports water poleward from Exmouth to Cape Leeuwin and onto the Great Australian Bight. Recent field data have shown that, particularly during the summer months there are several regions along the coast which are upwelling ‘hot spots’ and are due a variety of different processes. These include: (1) wind driven upwelling; (2) shelf break processes; and, (3) topographic effects due to islands and canyons (e.g. Rottnest Island). Wind driven upwelling occurs when the southerly winds overcome alongshore pressure gradient particularly during the summer months. This results in surface layers moving offshore, colder water upwelling onto the continental shelf, and the Leeuwin Current to migrate offshore. The main region for coastal upwelling is off the Capes region although wind driven upwelling exist along the whole coastline. At the shelf break, reversal of the shelf current system induces the formation of the shelf break ‘front’ resulting high production at the shelf break. The interaction between currents (shelf and/or deep currents) and topography results in upwelling within submarine canyons (e.g. Perth, Leeuwin) and in the lee of islands (e.g. Rottnest Island). These upwelling regions are documented through the use of field measurements obtained though moorings and ocean gliders as well as numerical modelling.

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S5.1 A review of Australian Coastal upwelling

Submission ID: 233Presentng Author: Moninya Roughan

Session tme: WEDNESDAY - 9:30 - 10:30

3

Upwelling along southeastern Australia

ROUGHAN Moninya*1

1) UNSW Australia, mroughan@unsw.edu.au

In recent years a significant effort has been placed on understanding cross shelf processes along the coast of southeastern Australia, adjacent to the East Australian Current, our major Western Boundary Current. Specifically the roles of wind and current in driving upwelling along the continental shelf. We have used a multi-pronged approach by combining state of the art observations obtained primarily through IMOS, with numerical models and satellite remote sensed data to understand spatio-temporal variability of upwelling on seasonal to inter-annual timescales. We have quantified the cross shelf transport variability, the driving mechanisms, and to some extent variability in the biological (phytoplankton) response. I will present a review of some of the key results from a number of recent studies.

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S5.1 A review of Australian Coastal upwelling

Submission ID: 75Presentng Author: Jessica Benthuysen

Session tme: WEDNESDAY - 9:30 - 10:30

4

Cool, Near-Botom Intrusions in the Central Great Barrier Reef

BENTHUYSEN Jessica*1; BRINKMAN Richard 2; TONIN Hemerson3 ; STEINBERG Craig4

1) Australian Institute of Marine Science, J.Benthuysen@aims.gov.au; 2) Australian Institute of Marine Science; 3) Australian Institute of Marine Science; 4) Australian Institute of Marine Science

The Central Great Barrier Reef is characterised by an open reef matrix on the outer continental shelf. Channels between emergent reefs facilitate the exchange of cool, nutrient-rich slope waters into the lagoon. Over the slope, the equatorward East Australian Current flows in the opposite direction of southeasterly winds. From moorings deployed as part of the Queensland node of the Integrated Marine Observing System (Q-IMOS), observations of ocean thermal structure reveal cool, near-bottom intrusions on the shelf in summer months. These intrusions are associated with cooling of near-bottom temperatures by 1 - 4 deg. C. These observations are compared with output from a regional baroclinic hydrodynamic model developed as part of the eReefs project. A metric is developed and used to identify significant bottom intrusion events in both observations and the model output. Summer intrusion events tend to occur during weakened southeasterly winds or wind reversals. Model analyses quantify the processes involved in driving these intrusions onto the shelf, including the roles of geostrophic flows and Ekman currents.

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Sd Ocean mixing maters

Submission ID: 20Presentng Author: Robin Robertson

Session tme: WEDNESDAY - 15:30 - 17:00

1

Internal Tides of Eastern Tasmania and the T-Tide Project

ROBERTSON Robin*1; HARTLIPP Paul 2

1) UNSW Canberra, r.robertson@adfa.edu.au; 2) UNSW Canberra

Global estimates of baroclinic tidal energy fluxes indicated a beam of tidal energy originating from Macquarie Ridge south of New Zealand, propagating northwest, and impacting waters off the east coast of Tasmania. An international, observational project, T-Tide, was organized to investigate this beam of tidal energy. In support of this effort, internal tides were simulated for the region using the Regional Ocean Modeling System (ROMS). The simulation indicated a beam of energy generated at Macquarie Ridge propagating to the waters off eastern Tasmania. Diffusivities from the model are compared to the observations. Mixing was increased at the continental shelf edge off eastern Tasmania due to tides.

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S5.2 Ocean mixing maters

Submission ID: 312Presentng Author: Cynthia Bluteau

Session tme: WEDNESDAY - 15:30 - 17:00

2

The Role of Internal Wave-driven Near-bed Turbulent Dynamics on Mixing and Sediment Mobilisaton in the Coastal Ocean

BLUTEAU Cynthia*1; JONES Nicole 2; IVEY Gregory3

1) University of Western Australia, cynthia.bluteau@uwa.edu.au; 2) University of Western Australia; 3) University of Western Australia

In the stratified-ocean, internal waves emanate from topographical features from the interaction of surface tides with local topography. When internal waves shoal and break, they modify the physical structure of the bottom boundary layer, generating localized intense shear and gust speeds and altering turbulence properties with implications for turbulent exchanges (e.g., nutrients, and heat) and sediment suspension. We present field observations from diverse field programmes on the Australian North-West Shelf (NWS) and off the east coast of Tasmania, where internal wave forcing is important. On the NWS, our measurements include through water column mean velocities and temperature profiles at multiple locations to document background forcing and internal wave characteristics. We also collected high frequency (1-8 Hz) temperature and velocity timeseries measurements to quantify turbulent properties in the near-bottom boundary region, in addition to repeated microstructure shear probe profiles over entire water column. We developed analysis techniques to correct motion contamination from a moored turbulence package designed by Rockland Scientific to extend our capability to acquire long-term measurements from moored platforms. We observed various baroclinic features that coincided with large turbulent overturning, increased turbulent kinetic energy dissipation, and intensified currents within meters of the seabed. Turbulent dissipation increased as the seabed was approached with values exceeding 1×10-6 W kg-1.The complex flow dynamics hindered the use of idealised laws for describing the size of the turbulent overturns: the basis of the two-point turbulence closure schemes that are embedded in circulation models to estimate mixing rates. We will discuss preliminary data from a field programme in Tasman waters focused on sediment mobilisation resulting from bottom boundary layer dynamics under a nonlinear internal waves.

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S5.2 Ocean mixing maters

Submission ID: 111Presentng Author: Daniel Boetger

Session tme: WEDNESDAY - 15:30 - 17:00

3

Characterising the semidiurnal internal tde of Tasmania using glider data

BOETTGER Daniel*1; ROBERTSON Robin 2; RAINVILLE Luc3

1) University of New South Wales Canberra; Royal Australian Navy, daniel.boettger@student.adfa.edu.au; 2) University of New South Wales Canberra; 3) Applied Physics Lab University of Washington

The spatial structure of the semidiurnal internal tide to the east and south of Tasmania is characterized using temperature and salinity data from Seaglider and Slocum glider deployments. Wavelet analysis of isopycnal displacements measured by the gliders was used to isolate the semidiurnal internal tide, with contrasting internal tide fields identified for each region. Whereas the signal south of Tasmania was attributed to local forcing, the signal to the east of Tasmania was found to be remotely generated. It's direction of propagation from the south east to the north west supports previous studies indicating the existence of an internal tidal beam originating over the Macquarie Ridge, south of New Zealand. Displacement amplitudes were observed to be amplified in the vicinity of the continental slope, with the incoming tidal beam shown to be both reflected as well as scattered, resulting in energy being transferred to higher modes.

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S5.2 Ocean mixing maters

Submission ID: 111Presentng Author: Paul Hartlipp

Session tme: WEDNESDAY - 15:30 - 17:00

4

Internal Tides of Eastern Australia

HARTLIPP Paul*1; ROBERTSON Robin 2

1)UNSW Canberra, p.hartlipp@adfa.edu.au; 2)UNSW Canberra

Internal tides affect ocean circulation in several ways. They induce mixing. They generate mean currents. They interact with mean currents retarding them. They interact with eddies modifying they behavior. To investigate the internal tidal fields off eastern Australia and their influence on the ocean circulation, the waters off eastern Australia were simulated using the Regional Ocean Modeling System (ROMS) both with and without tides. The model was verified through comparison to observations at 17 moorings from the Integrated Marine Observing System (IMOS). The model agreed well with the observations, with consideration of resolution and other operating considerations. Although the internal tides in the region were small, (typically < 2 cm s-1), they significantly increased mixing and modified transport of colder water onto the continental shelf. They showed many of the aforementioned effects on the ocean circulation, including modification of eddy behavior. Additionally, both diurnal and semidiurnal internal tides are affected by the location of the diurnal critical latitude in the domain. Diurnal internal tides peak near their critical latitudes and immediately south of the critical latitude, energy is shifted from the diurnal frequencies to the semidiurnal and higher frequencies. These energy shifts are accompanied by increases in mixing.

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S5.2 Ocean mixing maters

Submission ID: 34Presentng Author: Shane Keatng

Session tme: WEDNESDAY - 15:30 - 17:00

5

Estmatng mixing by submesoscale eddies using super-resolved satellite images

KEATING Shane*1

1) University of New South Wales, s.keating@unsw.edu.au

Submesoscale ocean turbulence on scales of 10-50 km plays a key role in biogeochemical processes, frontal dynamics, and tracer transport in the upper ocean. However, our understanding of these scales is limited because of the resolution of available observations. In this talk, I will describe a method for obtaining “super-resolved” satellite images using low-resolution observations in combination with an empirical parameterization for the unresolved scales. A novel feature of the methods is the use of computationally inexpensive stochastic models to forecast the unresolved scales. The stochastic model parameters are estimated from climatological data obtained from the observations themselves. The method enhances the effective resolution of satellite observations by exploiting the effect of spatial aliasing and generates an optimal estimate of small scales using standard Bayesian inference. The technique is tested using synthetic satellite observations of quasigeostrophic turbulence driven by realistic climatological shear and stratification profiles. The super-resolved satellite observations result in a considerable improvement in estimates of turbulent fluxes compared with the raw observations.

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S5.2 Ocean mixing maters

Submission ID: 127Presentng Author: Kial Stewart

Session tme: WEDNESDAY - 15:30 - 17:00

6

Anisotropy of Ocean Eddies

STEWART Kial*1; WATERMAN Stephanie 2; SPENCE Paul3 ; LESOMMER Julien4; MOLINES Jean-marc5 ; ENGLAND Mathew6

1) UNSW, kial.stewart@unsw.edu.au; 2) UBC; 3) UNSW; 4) LEGI; 5) LEGI; 6) UNSW

This presentation examines the anisotropy of ocean eddies in an eddy-resolving (1/12-degree) global ocean model. The variability of the horizontal velocity fields are analysed using the variance ellipse framework, which characterises the geometry of the variability in terms of the eddy kinetic energy, anisotropy and orientation. It is found that the eddy anisotropy has significant vertical structure and is strongest close to the ocean bottom, where the anisotropy tends to align with the underlying isobath. The strong anisotropic bottom signal is almost entirely contained in the barotropic variability. Upper-ocean variability is predominantly baroclinic and less sensitive to the underlying bathymetry. This finding provides guidance for introducing a parameterization based on the underlying bathymetry to operate on the barotropic flow, to better account for barotropic variability unresolved in coarse-resolution ocean models.

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S5.3 Variability of Physics and Bio-geo-chemistry in Semi-enclosed and Shelf Seas

Submission ID: 266Presentng Author: Nicole Jones

Session tme: FRIDAY 10:30 - 12:30

1

Closing the Nutrient Budget on the Australian Northwest Shelf

JONES Nicole*1; STRUTTON Peter 2; LOWE Ryan3 ; FALTER Jim4; JONES Katherine5

1) Univeristy of Western Australia, nicole.jones@uwa.edu.au; 2) University of Tasmania; 3) Univeristy of Western Australia; 4) Univeristy of Western Australia; 5) University of Tasmania

Waters on the Australian North West Shelf (NWS) are oligotrophic, with rapid (hours- days) turnover of dissolved nutrient species. Physical processes such as transient upwelling and non-linear internal waves have been identified as possible mechanisms for

the delivery of nutrients from depth to the euphotic zone. Here we quantify the cross-shelf transport of nitrate at three contrasting sites (Ningaloo, Pilbara and Kimberley) across the NWS using 2.5 y Integrated Marine Observing System data sets. The three sites have contrasting bathymetric cross-sections, experience different internal tide energy and have varying strengths of subtidal flow.

First, we successfully tested the efficacy of our depth-integrated nitrate flux methodology using short-term high temporal and spatial resolution data sets. We then applied wavelet analysis of the total depth-integrated cross-shelf nitrate flux for the 2.5 y data sets to determine the relevant timescales to separate tidal and subtidal fluxes at each of the sites. The relative importance of internal waves to subtidal cross-shelf processes, such as transient upwelling, varied with site and with season. At the Pilbara site subtidal transport dominated the onshore flux of nitrate, whereas internal wave fluxes were of equal important for nutrient delivery in the Kimberley. Chlorophyll a fluorometer and satellite data showed that increased biomass resulted from periods of large onshore nitrate fluxes. The three NWS data sets also revealed large inter-annual differences in fluxes, highlighting the importance of long-term data sets for gaining a comprehensive understanding of continental shelf nutrient budgets.

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S5.3 Variability of Physics and Bio-geo-chemistry in Semi-enclosed and Shelf Seas

Submission ID: 285Presentng Author: Amandine Schaefer

Session tme: FRIDAY 10:30 - 12:30

2

Infuence of the East Australian Current on shelf dynamics, upwelling and bio-physical variability from repeat glider deployments

SCHAEFFER Amandine*1; ROUGHAN Moninya 2; WHITE Dana3 ; SUTHERS Iain4

1) UNSW, a.schaeffer@unsw.edu.au; 2) UNSW; 3) UNSW; 4) UNSW

Along southeastern Australia, the East Australian Current (EAC) strongly influences the circulation and watermass characteristics of the adjacent continental shelf. In situ moored observations have shown dense water uplift resulting from EAC intrusions onto the shelf at 30 and 34oS, but sustained observations are lacking in the separation zone (~31-32oS).

The comprehensive dataset from 24 glider deployments along the inshore edge of the jet provides a new high resolution hydrographic and bio-geo-chemistry climatology. We exploit the climatology to understand the spatial variability of the watermass characteristics and the depth-averaged momentum balances across the EAC separation zone.

The predominantly geostrophic shelf circulation and temperature fields are least (most) variable upstream (downstream), where encroachment (separation) dominates. Advection is accentuated north of the separation, where the shelf is narrow and the jet is intensified. This is where dense bottom water with low dissolved oxygen (DO) is uplifted as much as 80 m towards the surface, in response to the high bottom stress. Downstream of the separation, the dynamic height minimum shows separation induced upwelling, resulting in a denser watermass with higher coloured dissolved organic matter and DO concentrations than the EAC water.

Spatial length scales of variability are investigated both horizontally (along and across the shelf) and vertically. In this way we estimate the resolved and unresolved variance of each bio-geochemical parameter, as well as the decorrelation length scales over the shelf. Results show a range of parameter dependent length scales which will be useful for constraining data assimilating models in the highly variable EAC separation zone.

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S5.3 Variability of Physics and Bio-geo-chemistry in Semi-enclosed and Shelf Seas

Submission ID: 186Presentng Author: Mark Baird

Session tme: FRIDAY 10:30 - 12:30

3

A coupled hydrodynamic, optcal, sediment, biogeochemical model of coastal waters of the Great Barrier Reef: system behaviour and assessment.

BAIRD Mark*1; HERZFELD Mike 2; WILD-ALLEN Karen3 ; MARGVELASHVILI Nugzar4; SKERRATT Jennifer5 ; MONGIN Mathieu6 ; Jones Emlyn7 ; Rizwi Farhan8 ; Robson Barbara9

1) CSIRO, mark.baird@csiro.au; 2) CSIRO; 3) CSIRO; 4) CSIRO; 5) CSIRO; 6) CSIRO; 7) CSIRO; 8) CSIRO; 9) CSIRO

The Great Barrier Reef is under threat from catchment-derived human impacts and climate change. Through the eReefs Project , a suite of hydrodynamic, sediment, spectrally-resolved optical and biogeochemical models have been developed to better understand biogeochemical processes in coastal and shelf waters. Here we provide an overview of the performance of the regional 4 km resolution model, and, in particular, consider the biogeochemical behaviour of the GBR lagoon. Model assessment includes comparison with remote sensing, in situ moorings, water sampling and glider transects. The optical model calculates simulated surface reflectance at 11 MODIS bands, which are used to assess the model's ability to predict water quality properties such as chlorophyll and total suspended sediment concentration, and light penetration. The comparison to in situ observations include nutrients, carbon chemistry, and plankton state. The model representation of the optical properties of river plumes and model generated carbon chemistry will be highlighted as new findings. Finally, we will introduce a new biogeochemical data assimilation system that is presently being developed that uses surface reflectance directly, not biogeochemical proxies, to constrain model behaviour.

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S5.3 Variability of Physics and Bio-geo-chemistry in Semi-enclosed and Shelf Seas

Submission ID: 291Presentng Author: Robert Johnson

Session tme: FRIDAY 10:30 - 12:30

4

Biogeophysical remote sensing of the Great Barrier Reef.

JOHNSON Robert*1

1) Bureau of Meteorology, rjohnson@bom.gov.au

The eReefs Marine Water Quality and ReefTemp systems were implemented and declared operational over the Great Barrier Reef (GBR) region by the Bureau of Meteorology National Meteorological and Oceanographic Centre (BNOC) on 22 October 2013. These systems are based on more than 10 years of research by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the core purpose is to produce accurate estimates of water quality indices and temperature within the optically complex and shallow waters typical of the GBR. Through these systems BNOC delivers daily, weekly, monthly, and annual estimates of Chlorophyll-a concentration (CHL), suspended sediment concentration (Non-Algal Particulates - NAP), coloured dissolved organic matter concentration (CDOM), diffuse attenuation coefficient (Kd), sea surface temperature, and degree-heating days for the whole GBR and some offshore regions. Data from July 2002 onward are available via the eReefs Marine Water Quality Dashboard (http://www.bom.gov.au/marinewaterquality/) and the eReefs THREDDS Catalog (http://ereeftds.bom.gov.au/ereefs/tds/catalog.html). Here we will present a series of tools and case studies that show how these data can be/are being used by scientists and managers to better investigate and manage the complex factors that affect the ecosystems and water quality of the GBR, along with putting out a call for collaboration to advance the development and use of these datasets into the future

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S5.3 Variability of Physics and Bio-geo-chemistry in Semi-enclosed and Shelf Seas

Submission ID: 308Presentng Author: Carlos Rocha

Session tme: FRIDAY 10:30 - 12:30

5

Towards Biogeochemical Modeling of the NW Iberian Margin

ROCHA Carlos*1

1) UNSW, c.vieirarocha@student.unsw.edu.au

Providing oceanographic data on biological and chemical variables has become an issue of scientific concern over recent years. The demand for this kind of information arises from a range of applications such as scientific research on marine ecosystems, monitoring of seawater quality and decision-making support for marine and coastal management. We present an overview on the incorporation of a nitrogen-based (NPZD) biogeochemical module into a regional oceanic circulation model (ROMS) for the NW Iberian Margin for the 2007- 2010 period. The study focuses on both empirical and objective model performance assessments. The model ability to reproduce theoretically expected processes is verified and chlorophyll-a outputs are compared to remote-sensed observations. Results show a satisfactory response of the model despite a general underestimation of chlorophyll-a surface values and an anticipation in the starting time of the spring bloom.

We present a case study of a significant bloom event in September 2007, characterised by a strong upwelling core detaching from the Galician NW coast (Spain) and extending towards the west-northwest. Several filaments were formed and featured high chlorophyll concentrations. The wind field main direction in conjunction with the coastline orientation was identified as an important driver for the development of the event. The analysis of the behaviour and evolution of this particular phytoplankton bloom may act as an initial basis for future work, giving further insight into the relationship between atmospheric forcing, coastal ocean processes and their conditioning on phytoplankton abundance and distribution.

Page 123

S5.3 Variability of Physics and Bio-geo-chemistry in Semi-enclosed and Shelf Seas

Submission ID: 303Presentng Author: Ming Feng

Session tme: FRIDAY 10:30 - 12:30

6

Decadal variatons of ocean boundary currents around Australia, as simulated with an eddy-resolving numerical model

FENG Ming*1; SCHILLER Andreas 2; OKE Peter3 ; ZHANG Xuebin4

1) CSIRO, Ming.feng@csiro.au; 2) CSIRO; 3) CSIRO; 4) CSIRO

Ocean boundary currents transport water masses and marine biota along the coastline which are important for regional climate and marine ecosystem function. Decadal variations of ocean boundary currents around Australia have been observed to modulate water properties on the continental shelf and drive extreme oceanography conditions along the coast. In this study, we use an eddy-resolving global ocean circulation model, the Ocean Forecast for Australia Model (OFAM), to understand the variability of ocean boundary currents around Australia over the past 3.5 decades. We have estimated the volume transports of the major boundary currents around Australia, the East Australian Current, the Indonesian Throughflow, the Leeuwin Current, and the South Australian Current/Flinders Current. The decadal variation of the ocean boundary currents around Australia are predominantly driven by large scale wind patterns associated with the dominant climate modes in the Pacific and Southern Ocean. The strengthening of the Indonesian Throughflow and the Leeuwin Current over the past two decades have been identified to cause the increase of upper ocean heat content and sea surface temperature off Western Australia coast. The variability of the East Australian Current is to some extent consistent with the water property variability of coastal observations at an Integrated Marine Observing System (IMOS) National Reference Station. Understanding the decadal derivations of the ocean boundary currents is important for us to project the future changes of the coastal marine systems under the influence of the human-induced greenhouse gas forcing.

Page 124

S5.4 The Global Infuence of the Southern Ocean and Antarctc Seas

Submission ID: 178Presentng Author: Mark Holzer

Session tme: THURSDAY 15:30 - 17:30

1

Controls on the Silicon Isotope Distributon in the Ocean: New Diagnostcs from a Data-Constrained Model

HOLZER Mark*1; BRZEZINSKI Mark 2

1) University of New South Wales, mholzer@unsw.edu.au; 2) UCSB

The global distributions of the silicon isotopes within silicic acid are estimated by adding isotope fractionation to an optimized, data-constrained model of the oceanic silicon cycle that is embedded in a data-assimilated steady circulation. Including fractionation during opal dissolution improves the model's ability to capture the approximately linear relation between isotope ratio, δ30Si, and inverse silicic-acid concentration observed in the deep Atlantic. To quantify the importance of hydrographic control on the isotope distribution, δ30Si is partitioned into contributions from preformed and regenerated silicic acid, further partitioned according to euphotic-zone origin. We find that the large-scale features of the isotope distribution in the Atlantic basin are dominated by preformed silicic acid, with regenerated silicic acid being important for setting vertical gradients. In the Pacific and Indian Oceans, preformed and regenerated silicic acid make roughly equally important contributions to the pattern of the isotope ratio, with gradients of the preformed and regenerated contributions tending to cancel each other in the deep Pacific. The Southern Ocean euphotic zone is the primary origin of both the preformed and regenerated contributions to δ30Si. Nearly the entire preformed part of δ30Si is of Southern Ocean and North Atlantic origin. The regenerated part of δ30Si in the Atlantic basin also has a contribution of central-Atlantic (40S to 40N) origin that is comparable in magnitude to the North Atlantic contribution. In other basins, the central Pacific and Indian Ocean are the second largest contributors to the regenerated part of δ30Si.

Page 125

S5.4 The Global Infuence of the Southern Ocean and Antarctc Seas

Submission ID: 42Presentng Author: Nicolas Jourdain

Session tme: THURSDAY 15:30 - 17:30

2

Meltng West Antarctc ice-shelves: role of coastal warming versus changes in cavity geometries

JOURDAIN Nicolas*1; MATHIOT Pierre 2; DURAND Gael3 ; LESOMMER Julien4; SPENCE Paul5

1) CNRS-LGGE/ARCCSS-UNSW, njourdain@lgge.obs.ujf-grenoble.fr; 2) BAS; 3) CNRS-LGGE; 4) CNRS-LGGE; 5) UNSW-CCRC-ARCCSS

The mass loss of West Antarctic glaciers has accelerated over the last 15 years, most likely in response to ocean warming in Antarctic coastal waters. This warming of Antarctic coastal waters seems to be caused by the positive trend of the Southern Annular Mode. But the mechanisms controlling he changes in melting rates underneath outlet glaciers are still poorly known. For instance, despite recent developments in glacier modelling, melting rates are usually prescribed in glacier models. This strongly limits the ability of glacier models to predict the future evolution of West Antarctic glaciers.

Several ocean models are now able to simulate ocean circulation beneath ice-shelves, therefore allowing a direct study of the mechanisms controlling the changes in melting rates underneath outlet glaciers. Building upon these developments, we here investigate the relative influence of ocean warming in coastal waters and changes in ice-shelves cavity geometries on melting rates underneath West Antarctic glaciers.

To this purpose, we use a regional ocean/sea-ice model configuration based on NEMO, centred on the Amundsen sea, that explicitly represents flows in ice-shelves cavities. A series of sensitivity experiments is conducted with different cavern geometries and under different atmospheric forcing scenarios in order to identify the leading mechanism controlling the changes in melting rates underneath West Antarctic glacier over the 21st century. Our results provide a first assessment on the importance of coupling glacier models to ocean models for predicting the future evolution of outlet glaciers.

Page 126

S5.4 The Global Infuence of the Southern Ocean and Antarctc Seas

Submission ID: 202Presentng Author: Andrew Gunn

Session tme: THURSDAY 15:30 - 17:30

3

The Role of the SOUTHERN OCEAN OVERTURNING CIRCULATION for OCEAN CARBON UPTAKE

GUNN Andrew*1; NIKURASHIN Maxim 2

1) ARCCSS/IMAS, algunn@utas.edu.au; 2) ARCCSS/IMAS

Anthropogenic carbon emissions in the last century have led to an increase in atmospheric carbon dioxide which strongly affects global climate. Fluxes of carbon dioxide between the atmosphere and the ocean and the storage of carbon in the deep ocean are important in understanding and quantifying changes to climate. However, the role of ocean physical and biological processes in the uptake and storage of carbon in the ocean remains poorly understood. In this study we develop a theoretical understanding of the Meridional Overturning Circulation's role in anthropogenic carbon uptake using an idealised model. The model includes a dynamic ocean overturning circulation driven by wind, eddies, and mixing, as well as a simple representation of the carbon cycle with biology. Results for the uptake of anthropogenic carbon agree well with similar studies based on comprehensive climate models. The study shows that the carbon storage of the ocean is set, to the leading order, by its volume and the intrinsic molecular properties of seawater, but can vary significantly due to ocean dynamical processes. An extensive parameter sensitivity study is used to quantify the dominant processes effecting ocean carbon uptake. The role of Southern Ocean wind, eddies and mixing are evaluated independently and their relative importance for the storage of carbon and associated uptake time scales are examined. Changes in the ocean circulation due to climate sensitivities and feedbacks are prescribed to the model and their impact is quantified.

Page 127

S5.4 The Global Infuence of the Southern Ocean and Antarctc Seas

Submission ID: 118Presentng Author: Ariaan Purich

Session tme: THURSDAY 15:30 - 17:30

4

Contrastng CMIP5 and Observed Trends in Southern Ocean Sea Ice and Temperature

PURICH Ariaan*1; CAI Wenju 2; ENGLAND Mathew3

1) CSIRO / UNSW, ariaan.purich@csiro.au; 2) CSIRO; 3) UNSW

Antarctic sea ice has increased over the past 35 years; however the majority of CMIP5 models simulate a decrease over this period. This discrepancy has been investigated in previous studies, but explanations remain limited. Here, we present a summary of CMIP5 trends in Antarctic sea ice, as well as trends in atmospheric and oceanic variables over 1979-2013. Over this period, observed high-latitude Southern Ocean sea surface temperature (SST) cools, suggesting that changes in ocean circulation may be related to the observed sea ice increase. Some CMIP5 models simulate a high-latitude cooling, but most show a weaker cooling or substantial warming compared to observed trends. We find a strong inter-model correlation between trends in Southern Ocean SST and Antarctic sea ice extent, with models with the most excessive warming showing the largest ice loss. We also investigate the relationship between the extratropical westerly jet and sea ice extent, and find that models with a stronger poleward shift in the jet tend to lose more sea ice. The implications that the jet shift has on Ekman pumping are investigated: at mid latitudes, the models overestimate strengthening in the Ekman pumping, offering an explanation for the larger than observed subsurface warming simulated at 45°S. At high latitudes, the role of strengthening Ekman suction is less clear, but seems to be associated with changes in sea surface salinity (SSS). The roles of changing SST, SSS and wind, and how these influence sea ice and feedback mechanisms in the models compared to the real world are discussed.

Page 128

S5.4 The Global Infuence of the Southern Ocean and Antarctc Seas

Submission ID: 131Presentng Author: Ben McNeil

Session tme: THURSDAY 15:30 - 17:30

5

Early onset of Southern Ocean hypercapnia and its implicatons for fsheries

MCNEIL Ben*1

1) UNSW, b.mcneil@unsw.edu.au

Seawater hypercapnia occurs when CO2 levels induce marine organisms to show neurological, physiological or behavioral effects. Evidence shows a range of fish species to have detrimental effects when exposed to pCO2 levels up to 1000µatm for short periods. Here, we combine a new data-based monthly ocean carbon climatology with output from an ensemble of Earth System Models to examine the future onset of surface ocean hypercapnia (pCO2 >1000 µatm). We find that rising anthropogenic CO2 amplifies seasonal CO2 variability in the Southern ocean up to 10-fold over the coming century, exposing marine organisms to hypercapnia much earlier than anticipated. Month-long hypercapnia events are projected to cover large areas of all major ocean basins once atmospheric CO2 exceeds 650ppm, spreading to 59% of the surface ocean by the year 2100 under a high-emissions scenario. Without slowing the increase of atmospheric CO2, the onset of hypercapnia events could have significant implications on fisheries over the coming century.

Page 129

S5.4 The Global Infuence of the Southern Ocean and AntarctcSeas

Submission ID: 23Presentng Author: Robin Robertson

Session tme: THURSDAY 15:30 - 17:30

6

Tidal Mixing and Deep Water Formaton in the Amundsen Sea

ROBERTSON Robin*1

1) UNSW Canberra, r.robertson@adfa.edu.au

In the Antarctic seas, tidal mixing plays a key role in water mass transformation. Different water masses meet at several locations in these seas. Two key ones are the continental shelf/slope break, where Warm Deep Water (WDW) meets Shelf Waters (SW), and the front of the ice shelf, where Modified Warm Deep Water (MWDW) and meets Ice Shelf Water (ISW) formed under the ice shelves. These locations coincide with abrupt topographic changes, where barotropic tides induce internal tides, leading to mixing. Mixing at these locations has the potential to produce deep water. Tidal mixing in the Amundsen Sea was investigated using numerical simulations with and without tides. Mixing increased significantly both along the continental shelf/slope break and the front of the ice shelves , when tides were included. The increased mixing leads to enhancement of deep water mass formation, with the potential for influence on the global meridional overturning circulation. As a result, mixing from internal tides should be represented in global ocean circulation models in order to reproduce the deep water cycle.

Page 130

S5.5 Waves,StormsSurges and tsunamis

Submission ID: 220Presentng Author: Charitha Pataratchi

Session tme: WEDNESDAY - 11:00 - 12:00

1

Meteotsunamis: generaton, predicton and impacts

PATTIARATCHI Charitha*1; WIJERATNE Sarath 2; SAHELI Alireza3

1) The University of Western Australia, chari.pattiaratchi@uwa.edu.au; 2) The University of Western Australia; 3) The University of Western Australia

Meteotsunamis are water level oscillations with similar characteristics to tsunami waves generated by seismic activity but are generated by meteorological events, and in particular, moving pressure disturbances due to squalls, thunderstorms, frontal passages, and atmospheric gravity waves. In this presentation we examine meteotsunamis generated along south-west Australia generated by thunderstorms and passage of frontal systems. The region is impacted anticyclones which move from west to east and cross the coast every 3-10 days throughout the year with ~30 mid-latitude depressions and associated frontal systems impacting the coast during the winter months. Thunderstorms occur mainly during the summer months but can effect around ~500km of the coastaline. A meteotsunami event due to the passage of a cold front contributed to the highest ever water level recorded at Fremantle in 2012. Similarly an incident where a ship broke moorings and impacted on a railway bridge was attributed to a meteotsunami generated by a cold front in 2014. Analysis of local water level records for 2014 revealed that there were > 30 events which could be classified as meteotsunamis with the majority occurring during the winter months associated with the passage of cold fronts. Time-frequency diagrams indicated that during the passage of a cold front the whole spectrum is energised similar to those observed during seismic tsunamis. The meteotsunami events are compared with simultaneous meteorological data, including the magnitude of the pressure jumps, speed and direction and are examined to identify the dominant parameters responsible for the generation of meteotsunamis.

Page 131

S5.5 Waves,StormsSurges and tsunamis

Submission ID: 248Presentng Author: Laura O'Brien

Session tme: WEDNESDAY - 11:00 - 12:00

2

Tsunamis Generated by Landslides: A Parametric Analysis

O'BRIEN Laura*1; DIAS Frederic 2; SALMANIDOU Dimitra3

1) Monash University, laura.obrien@monash.edu; 2) University College Dublin Ireland; 3) University College Dublin Ireland

Modelling tsunamis due to landslides is not as well understood as those caused by earthquakes. The maximum bottom deformation time is very short for an earthquake, so traditionally tsunamis are modelled by simply transferring the seabed deformation directly to the free surface. However, this does not accurately model the system for a landslide since the time scales are generally longer. Scarcity of events and a lack of data makes it difficult to predict potential submarine landslide hazards so it is essential to develop accurate modelling tools. This study implements a non-linear shallow water solver, VOLNA (Dutykh et al, 2011) to simulate gaussian shaped landslides. The differences between waves generated by landslides on a sloping beach and a flat sea floor are demonstrated. Additionally, a parametric analysis is carried out for submarine landslides on a sloping beach. The effects of varying the velocity, maximum depth, initial position, shape, beach slope and volume are investigated and a review of the basic characteristics presented.

Reference:

Dutykh, D., Poncet, R. and Dias, F. (2011). The VOLNA code for the numerical mod- eling of tsunami waves: Generation, propagation and inundation, European Journal of Mechanics - B/Fluids 30(6) : 598–615.

Page 132

S5.5 Waves,StormsSurges and tsunamis

Submission ID: 31Presentng Author: Aihong Zhong

Session tme: WEDNESDAY - 11:00 - 12:00

3

Improved Performance of Operatonal Wave Models at Australian Coast

ZHONG Aihong1

1) Bureau of Meteorology, a.zhong@bom.gov.au

The Australian wave model (AUSWAVE), based on the WAVEWATCH III® model has been the operational sea-state model run by the Bureau National Operations Centre (BNOC) since August 2010 (http://www.bom.gov.au/australia/charts/bulletins/nmoc_bulletin.shtml - Bulletin No 84). The AUSWAVE system is forced by the Australian Community Climate and Earth-System S i m u l a t o r ( A C C E S S ) N u m e r i c a l W e a t h e r P r e d i c t i o n ( N W P ) s y s t e m (http://www.bom.gov.au/australia/charts/bulletins/nmoc_bulletin.shtml -Bulletin Nos 93 & 98).

The operational wave models run at two different domains: global model at 40km resolution and regional model at 10km resolution. This presentation covers the evaluation of the performance of global and regional wave models at the Australian Coast. Around 30 wave rider buoys data is used to verify model forecasts accuracy.

To improve the wave model performance along the coast, sited wave OCF (Operational Consensus Forecasting) system was developed, which optimally combines the direct model outputs from a number of wave models and produces wave forecasts for the selected wave buoy sites around the Australian coasts. It produces forecasts of significant wave height, peak wave period, wind direction and wind speed up to 5 days ahead. Wave OCF is simpler methods that tend to outperform more expensive computational methods. The combined forecast is proved to be often the best forecasts for the Australian coast.

Page 133

S5.5 Waves,StormsSurges and tsunamis

Submission ID: 55Presentng Author: John Bye

Session tme: WEDNESDAY - 11:00 - 12:00

4

The Global Structure of long term mean Sea Surface Drif Currents

BYE John*1 ; WOLFF J.O2; LETTMANN K.A.3

1) University of Melbourne, jbye@unimelb.edu.au; 2) ICBM, Carl-von-Ossietzky University; 3) ICBM, Carl-von-Ossietzky University

Sea surface drift, which integrates the effects of the surface wind and wave fields, is a distinct component of ocean circulation, which is important for the motion of surface trapped biota and flotsam of various kinds. We present a numerical model of the dynamics of the global mean near surface drift circulation in which the pure drift is determined by the friction velocity and also importantly by the peak wave period, and the surface current is the sum of the pure drift and the surface geostrophic current. The results show that the pure drift contributes about 70 percent of the sea surface current in the Southern Ocean, where the theoretical predictions have been validated by historic drift bottle and drift card data, and that pure drift is the dominant component of surface flow along the eastern boundaries of the ocean basins, in contrast to the western boundaries. The divergence of the pure drift transport indicates that entrainment into the surface drift layer occurs in a narrow zone along the eastern boundaries with a ventilation time of about 20 days, and detrainment occurs in more diffuse regions in the west of the ocean basins.

Page 134

S6.0a General - Tropical/subtropical oceanograpy

Submission ID: 204Presentng Author: Michael Murphy

Session tme: FRIDAY 10:30 - 12:30

1

Seasonal Evoluton and Interannual Variability of Precipitaton in the Australian Monsoon

MURPHY Michael*1; SIEMS Steven 2; MANTON Michael3

1) Monash University, michael.j.murphy@monash.edu; 2) Monash University; 3) Monash University

Precipitation in the north Australian wet season (November-March) is examined, with a focus on its seasonal evolution and interannual variability, using AWAP gridded surface rainfall (TRMM satellite) observations over the period 1950-2010 (1998-2013). Regional differences are explored by dividing the study area into 3 areas: the northern parts of Queensland, the Northern Territory and Western Australia. Across the study area monthly mean precipitation is greatest during the middle of the wet season (January & February) while the highest variability in precipitation is found in the beginning and end of the wet season. The TRMM satellite reveals more precipitation features during the middle of the wet season and these features tend to be colder, larger and more stratiform in nature compared to those in the beginning and end of the wet season. The relationship between El Niño Southern Oscillation (ENSO) and precipitation is strongest in the early part of the wet season and in February across the study region, with the weakest magnitude of correlations in Western Australia. The late wet season month of March has a strong (weak) relationship with ENSO in northern Queensland (Western Australia), while the month of January has very weak correlations with ENSO compared to the other months throughout the study region, despite sharing a similar distribution of precipitation to February. The TRMM satellite shows colder and more stratiform precipitation features during years with positive Southern Oscillation Index (SOI), with opposite conditions during years with negative SOI, with the weakest differences in Western Australia and in January. The effect of the intraseasonal Madden-Julian oscillation (MJO) on monthly precipitation and characteristics of precipitation features with be explored along with the complex relationship between ENSO and the MJO.

Page 135

S6.0a General - Tropical/subtropical oceanograpy

Submission ID: 72Presentng Author: Lam Hoang

Session tme: FRIDAY 10:30 - 12:30

2

Extreme rainfall in the Top End and its link to weather in Western Australia

HOANG Lam*1; REEDER Michael 2; BERRY Gareth3

1) Monash University, lam.hoang@monash.edu; 2) Monash University ARC CoE CSS; 3) Monash University

Extreme rainfall in the Top End is often related to coherent potential vorticity (PV) maxima formed over the Gulf of Carpentaria. Some of them come from the midlatitude PV reservoir, move towards the Darwin area, before proceeding further southwestward to Western Australia. The coherent PV maxima, with the isentropes in low levels bowing upward, trigger convection and hence the rainfall on their leading edges. The time-lagged composites for the extreme rainfall events in the Top End show a possible link between the extreme rainfall in Northern Territory and positive rainfall anomaly in West Australia. TC Lam, 02/2015, is an example of this linkage.

Page 136

S6.0a General - Tropical/subtropical oceanograpy

Submission ID: 172Presentng Author: Hongyan Zhu

Session tme: FRIDAY 10:30 - 12:30

3

Impacts of convectve entrainment and heatng profle on simulatons of tropical climate and its variability

ZHU Hongyan*1; STRATTON Rachel 2; HENDON Harry3

1) Bureau of Meteorology, hzhu@bom.gov.au

The intraseasonal moisture budget is analyzed in simulations with the UK Met Office climate model , which produces a reasonable representation of the Madden-Julian Oscillation when the entrainment rate in the convective parameterization is increased by 50%. Analysis of the moisture budget shows that the total moisture tendency is asymmetric relative to the maximum precipitation, corresponding to the recharge and discharge process of organized convection in the Tropics. This moistening before and drying after the maximum precipitation is largely due to large-scale horizontal advection of moisture. By comparing with the control run that does not simulate a realistic MJO, we find that increasing the entrainment acts to reduce deep convection in the relatively dry environment by increasing the mixing of dry air. As a result, large scale convection and large-scale advective processes play a stronger role during the development stage, which implies that convection is necessarily better organized.

By increasing the entrainment rate only, the simulated precipitation field still lacks eastward propagation for MJO because convection is supressed at the Maritime continent region. Convective heating profiles show that the UM has a large cooling spike at the freezing level due to all the snow being melted in the layer where the environmental temperature reaches the freezing level. By allowing a mix of snow and rain between the freezing level and 3K above this, the convection becomes stronger for the higher surface temperature regions, which are mainly around Maritime continent and northern parts of Australia. As a result, the model bias for the DJF season in the Indian Ocean and West Pacific region has been improved. The increased convection in these regions helps the eastward propagation of organized convection.

Page 137

S6.0a General - Tropical/subtropical oceanograpy

Submission ID: 25Presentng Author: SHAIK HAKEEM

Session tme: FRIDAY 10:30 - 12:30

4

STUDY OF NORTH QUEENSLAND RAINFALL USING MONSOON ONSET TECHNIQUES.

HAKEEM SHAIK*1

1) JAMES COOK UNIVERSITY, SHAIK.HAKEEM@JCU.EDU.AU

Tropical north Queensland, which is about 54% of the state’s area, has signs of seasonal rainfall similar to monsoonal patterns. However, it is not certain if the weather systems, which bring monsoon conditions over north-western Australia, will be the same for north Queensland.

To understand the tropical weather patterns over northern Queensland an attempt has been made to apply the monsoon onset techniques, previously used for the Australian monsoon over north-western Australia, to tropical north Queensland.

Out of the four Australian monsoon monitoring techniques that were developed in the Darwin Regional Specialised Meteorological Centre, Bureau of Meteorology, three were used in this study. Out of these three techniques, two use rainfall data and one uses rainfall as well as wind data. Data from seven north Queensland stations spanning the data periods between 14 and 21 years were chosen for this study. Monsoon onset and active spell periods were calculated and compared with the northwest Australian monsoon data. The results indicate that though the rainfall pattern is seasonal in Tropical Queensland, it has shown less monsoonal characters, and different features to north-west Australian monsoon.

Page 138

S6.0a General - Tropical/subtropical oceanograpy

Submission ID: 144Presentng Author: Malcolm King

Session tme: FRIDAY 10:30 - 12:30

5

Convectve Actvity Associated With the 5-day Wave in Re-analysis and CMIP5 Data

KING Malcolm*1; WHEELER Mathew 2; LANE Todd3

1) ARCCSS School of Earth Sciences University of Melbourne, malcolmk@student.unimelb.edu.au; 2) CAWCR Bureau of Meteorology; 3) ARCCSS School of Earth Sciences University of Melbourne

The 5-day wave is the gravest symmetric zonal wavenumber 1 Rossby-Haurwitz (or external Rossby) wave, and as a Rossby-Haurwitz wave is characterised by a barotropic and minimally divergent structure. Despite these characteristics suggesting a weak and disorganised relationship between the wave and tropical convection, observational studies of space-time spectral coherences between zonal winds and convection as well as studies examining forcing mechanisms for the wave suggest there is a connection between tropical convection and the 5-day wave. Few studies have investigated how this connection manifests itself, and how this connection is represent in CMIP5 models is similarly not well investigated.

A lag-regression analysis of ERA Interim reanalysis horizontal winds, NOAA satellite-derived outgoing longwave radiation and TRMM 3B42 precipitation estimates are investigated to determine the geographical and temporal nature of coupling, and daily model data from CMIP5 historical runs are examined to gauge the model representation of the coupling. Strong convective signals associated with the wave activity are seen in the observational and reanalysis data over the Gulf of Guinea, in South America over the Andes and the eastern Pacific, and near the Marshall Islands. Convective activity in South America is in phase with peak zonal wind anomalies from the 5-day wave, but elsewhere the convective activity is in quadrature with the zonal wind anomalies. Around 40% of the CMIP5 models examined show 5-day wave associated convection in both the South American and African regions with similar phase relationships to that found in OLR and TRMM data.

Page 139

S6.0a General - Tropical/subtropical oceanograpy

Submission ID: 89Presentng Author: Sugata Narsey

Session tme: FRIDAY 10:30 - 12:30

6

Modelling extratropical-tropical interacton and the Australian monsoon

NARSEY Sugata*1

1) Monash University, sugsnarsey@gmail.com

Australian monsoon rainfall occurs as a series of episodic rainfall bursts and break periods. One of the key influences on Australian monsoon rainfall bursts is the intrusion of mid-latitude troughs into the tropical north of Australia. These intrusions are associated with mid-latitude Rossby waves refracting towards the north of Australia, or breaking near the east coast of Australia.

Model simulation of Australian monsoon rainfall is highly variable, and model projections of Australian monsoon rainfall are uncertain. This is in part due to model errors in simulating convection and important modes of variability, in particular the Madden Julian Oscillation. Nevertheless, synoptic scale features of the atmosphere such as the mid-latitude jets are often well represented in models.

In this study we evaluate the ability of a model (ACCESS1-0) to simulate the extratropical influence on Australian monsoon rainfall bursts. It is found that the model is able to capture some of the important aspects of the extratropical influence on Australian monsoon rainfall bursts. This result has implications for projections of Australian monsoon rainfall.

Authors:

Sugata Narsey, Michael Reeder, Duncan Ackerley, Christian Jakob, Gareth Berry

Page 140

S6.0b General - Tropical/subtropical oceanograpy

Submission ID: 80Presentng Author: Mathew Wheeler

Session tme: FRIDAY 15:30 - 16:30

1

The Internatonal Years of the Maritme Contnent (YMC) Project

WHEELER Mathew*1; JAKOB Christan 2; PROTAT Alain3 ; LANE Todd4; WIJFFELS Susan5

1) Bureau of Meteorology, m.wheeler@bom.gov.au; 2) Monash University; 3) Bureau of Meteorology; 4) Melbourne University; 5) CSIRO Oceans and Atmosphere Flagship

Planning is underway for a two-year (during 2017-2019) international project called Years of the Maritime Continent (YMC). Its overarching goal is to improve understanding and prediction of multi-scale variability of the MC weather-climate system and its global impact. Processes in this region have a large impact on Australian weather and climate. There are five proposed YMC themes: 1. Atmospheric convection; 2. Ocean and air-sea interaction; 3. Stratosphere-troposphere interaction; 4. Aerosol; 5. Prediction improvement.

To achieve the goals of these themes, five YMC activities are proposed:

1. Data Sharing: Collection, archival, and sharing of data from existing observing networks (including satellites) in the MC region, to build a database for new research.

2. Field Campaign: Collect intensive special observations through the two years to enhance the existing network.

3. Modelling: Coordinated numerical experiments focussing on the key MC issues.

4. Prediction and Applications: Data assimilation experiments, forecast demonstration, and improving the pathway to users.

5. Outreach and Capacity Building: Public education on the MC weather-climate system; Training of the next generation of scientists and forecasters.

Australian participation is planned through a proposal for the RV Investigator during 2018/19, with its advanced radar and ocean monitoring capabilities, as well as contributions to the modelling, prediction, and outreach activities.

Page 141

S6.0b General - Tropical/subtropical oceanograpy

Submission ID: 267Presentng Author: Maxime Colin

Session tme: FRIDAY 15:30 - 16:30

2

Simulatons of Radiatve-Convectve Equilibrium: is there a Memory Efect in the system?

COLIN Maxime*1; SHERWOOD Steven 2

1) CCRC / ARC CoECSS, colinmaxime@hotmail.fr; 2) CCRC / ARC CoECSS

Simulations of Radiative-Convective Equilibrium (RCE) are performed to investigate the memory-related processes involved in deep moist convection in the tropics. Memory has previously been noticed in preconditioning of convection, cold pools, entrainment processes, organisation effects, etc... But can we summarise all these effects in a simple way?

We use the Weather Research and Forecasting (WRF) model as a cloud-resolving model, at resolutions up to 250m as we aim at resolving convection as properly as possible. The simulations have periodic boundary conditions on both horizontal dimensions, and we apply a fixed SST at the bottom of the model throughout the whole simulations. We first study 2D simulations, and we plan to explore 3D cases as well.

We noted that it is critical for RCE simulations to represent ozone processes in order to avoid instability in the stratosphere, and to simulate a realistic stratospheric layer at the top of the model. Even without any initial wind, and without any Coriolis force (f=0 as the simulations are run at the equator), we have strong horizontal jets developing in the troposphere, both positive and negative, leading to high wind shear.

We plan to use these simulations run to equilibrium so as to identify which variables may have memory effects on convection. To do so, we will manually remove any variablity of the variables, one after one, and see how much that affects convection and how long it takes for convection to be back to the equilibrium state. If we can extract a few key variables that impact convection strongly when averaged over the whole domain, then we can deduce which ones are key memory variables.

Page 142

S6.0b General - Tropical/subtropical oceanograpy

Submission ID: 122Presentng Author: Todd Lane

Session tme: FRIDAY 15:30 - 16:30

3

Convectvely coupled mesoscale gravity waves in idealized simulatons of tropical convecton

LANE Todd*1; MONCRIEFF Mitchell 2; ZHANG Fuqing3

1) University of Melbourne / ARCCSS, tplane@unimelb.edu.au; 2) NCAR; 3) Penn State University

Dynamical models of organized mesoscale convective systems have identified the important features that help maintain their overarching structure and longevity. The standard model is the trailing stratiform archetype, which features a front-to-rear ascending circulation, a mesoscale downdraft circulation, and a cold pool / density current that controls the propagation speed and the maintenance of the system. However, this model does not represent all types of mesoscale convective systems, especially in moist environments like the tropical oceans and maritime continent, where the evaporation driven cold pools can be weak and the convective inhibition small. In particular, in such environments, ascent by mesoscale gravity waves has the potential to control the maintenance and propagation of organized convection, providing an alternate paradigm for convective organization in the tropics.

We present idealized simulations, representative of tropical oceanic convection that becomes self organized, with specific examples that expose the coupling between convection and the mesoscale gravity waves it generates. In one example we show how in unsheared environments the convection becomes organized along lines in spectral space that represent specific gravity wave modes, akin to results for larger scale convectively coupled Kelvin waves. In another example we show how in a sheared environment a preferred convective regime is coupled to a ducted gravity wave that propagates in the opposite direction to that predicted by the standard model of long-lived convection. These results provide convincing evidence of the critical role of mesoscale gravity waves for self-organizing convection.

Page 143

S6.0b General - Tropical/subtropical oceanograpy

Submission ID: 74Presentng Author: Surendra Rauniyar

Session tme: FRIDAY 15:30 - 16:30

4

Evaluaton of Satellite Rainfall Climatology over Various Locatons of the Maritme Contnent

RAUNIYAR Surendra*1; PROTAT Alain 2

1) Bureau of Meteorology, s.rauniyar@bom.gov.au; 2) Bureau of Meteorology

The accuracy of the satellite based rainfall (SBR) products has been assessed over various regions, but no such detailed evaluation exists over the Maritime Continent (MC), a region known as the 'boiler box' of the globe. The MC region is also known for the multi-scale interactions of weather and climate systems which many of the current numerical prediction models are unable to reproduce, resulting in large biases in rainfall, both spatially and temporally. In this study, the performance of six high spatial and temporal resolution SBR products (i.e., GSMaP, TRMM3B42, CMORPH, PERSIANN, PERSIANN-CDR and GPCP) and one state-of-the-art gridded rainfall product (APHRODITE) derived from rain gauge observations are evaluated against high quality ground based observations over various regions of the MC to quantify the uncertainties in these products. The results show that, over different locations of the MC, all the SBR products underestimate the observed variance at both daily and monthly resolutions. However, the correlation increases significantly at monthly scale compared with daily scale. The lower variance is mainly due to the fact that the SBR products significantly overestimate (underestimate) the frequency of lower (higher) rainrates. Over Sarawak (Malaysia), there exists a clear geographical difference in the accuracy of SBR products. Inland, all the SBR products significantly underestimate all the observed percentiles of rainrates, whereas closer to the coast, the difference depends on percentiles above and below the median value and individual SBR products. In summary, 3B42, CMORPH, and GSMaP perform better at daily resolution whereas 3B42, PERSIANN-CDR and GPCP outperform the other products at monthly scale. However, the APHRODITE product should not be used over this region. These products are currently being evaluated according to the different phases of the intra-seasonal oscillation.

Page 144

S6.1 The Indo-Pacifc Warm Pool

Submission ID: 157Presentng Author: Jaclyn Brown

Session tme: WEDNESDAY - 9:30 - 10:30

1

Future Precipitaton changes in the Tropical Pacifc are Sensitve to the Structure of the Warming Anomaly.

BROWN Jaclyn*1; MATEAR Richard 2; BROWN Josephine3

1) CSIRO, jaci.brown@csiro.au; 2) CSIRO; 3) Bureau of Meteorology

Future changes to tropical Pacific precipitation are largely a response to changes in the underlying sea surface temperature (SST) and its gradients. Unfortunately in most coupled climate models this region still suffers from an eastern Pacific cold tongue bias which pushes the Western Pacific Warm Pool edge to the west and causes the South Pacific Convergence Zone (SPCZ) to be too zonal. These biases impair our ability to interpret future changes to precipitation at the regional scale.

One method to reduce the impact of these biases is to force an atmosphere-only model with bias-adjusted SSTs. That is, the SST from the coupled climate model is used, but the model mean state is replaced with the observed mean state. This adjustment significantly improves the simulation of key features in the western Pacific.

It is less obvious how to bias-adjust the SST from the future climate runs. Often the SST warming anomaly is added to the observed mean state. The warming anomaly however is a strong function of the underlying mean state— that is the warm pool tends to warm uniformly, with a strip of stronger warming along the equator in the cold tongue region. The warming anomaly from the climate models tends to reflect the model mean state and hence the cold tongue bias. As a result, the warming signature that is supposed to act more strongly over the cold tongue, encroaches westward into the region where the observed warm pool lies. This introduces uneven warming to the warm pool region and induces meridional gradients.

In this study, we test the impact of bias-adjusting the warming anomaly in various ways to determine the extent to which the model bias matters. We also present alternative warming patterns that align dynamically with key features to give what we believe are more reliable estimates of future changes to precipitation.

Page 145

S6.1 The Indo-Pacifc Warm Pool

Submission ID: 92Presentng Author: Hanh Nguyen

Session tme: WEDNESDAY - 9:30 - 10:30

2

The relatonship between tropical warm pool Sea Surface Temperature and Hadley Circulaton

NGUYEN Hanh*1; HENDON Harry 2; LIM Eun-Pa3 ; LUCAS Chris4; MALONEY Eric5 ; TIMBAL Bertrand6

1) Bureau of Meteorology, h.nguyen@bom.gov.au; 2) Bureau of Meteorology; 3) Bureau of Meteorology; 4) Bureau of Meteorology; 5) CSU Department of Atmospheric Science; 6) Bureau of Meteorology

The Hadley Circulation has been expanding at an average rate of 50km per decade in each hemisphere during the recent few decades. The symmetry of this expansion—meridionally and zonally–remains unclear and observational data shortcomings prevent a more precise determination. Climate models largely underestimate the magnitude of expansion partly because they are unable to reproduce the main large scale natural variability (such as the El Niño-Southern Oscillation, the annular modes, or the Pacific Decadal Oscillation) in addition to the persistent cold tongue bias present in all models. Various anthropogenic factors, such as increasing greenhouse gases, stratospheric ozone depletion and aerosols, were identified to partially drive the expansion. Physical mechanisms for the expansion include increasing mean temperature and increasing meridional temperature gradients, interaction with extratropical baroclinic eddies and gross static stability. However, these are often seasonally and regionally dependent. Here we explore the regional aspects of the Hadley cells in both hemispheres and based on the three main centers of convergence located over Equatorial Africa, Equatorial America and the Maritime Continent. Preliminary results suggest that most of the expansion occurs in the Maritime Continent sector in association with the local tropical SST warming. Our preliminary assessment indicates that the decadal variability of the SST in the tropical warm pool may be driving the observed changes in the Hadley Circulation in both hemispheres.

Page 146

S6.1 The Indo-Pacifc Warm Pool

Submission ID: 300Presentng Author: Benjamin Ng

Session tme: WEDNESDAY - 9:30 - 10:30

3

Nonlinear processes reinforce extreme Indian Ocean Dipole events

NG Benjamin*1; CAI Wenju 2; WALSH Kevin3 ; SANTOSO Agus4

1) CSIRO, benjamin.ng@csiro.au; 2) CSIRO; 3) The University of Melbourne; 4) University of New South Wales

Under global warming, climate models show an almost three-fold increase in extreme positive Indian Ocean Dipole (pIOD) events by 2100. These extreme pIODs are characterised by a westward extension of cold sea surface temperature anomalies (SSTAs) which push the downstream atmospheric convergence further west. This induces severe drought and flooding in the surrounding countries, but the processes involved in this projected increase have not been fully examined. Here we conduct a detailed heat budget analysis of 19 models from phase 5 of the Coupled Model Intercomparison Project and show that nonlinear zonal and vertical heat advection are important for reinforcing extreme pIODs. Under greenhouse warming, these nonlinear processes do not change significantly in amplitude, but the frequency of occurrences surpassing a threshold increases. This is due to the projected weakening of the Walker circulation, which leads to the western tropical Indian Ocean warming faster than the east. As such, the magnitude of SSTAs required to shift convection westward is relatively smaller, allowing these convection shifts to occur more frequently in the future. The associated changes in wind and ocean current anomalies support the zonal and vertical advection terms in a positive feedback process and consequently, moderate pIODs become more extreme-like.

Page 147

S6.1 The Indo-Pacifc Warm Pool

Submission ID: 231Presentng Author: Joanna Slawinska

Session tme: WEDNESDAY - 9:30 - 10:30

4

Interannual to Mult-Decadal Variability of Indo-Pacifc SST

SLAWINSKA Joanna*1; GIANNAKIS Dimitrios 2

1) NYUAD, js6206@nyu.edu; 2) NYU

Low-frequency modes of ocean are important components of climate variability. With the rise of supercomputers, these modes are inferred often from long-term climate simulations after being preprocessed by low-pass filtering. Notably, the few modes that are consistently found in many climate models differ significantly, even in frequency, as every model has biases and model errors. At the same time, validation of the extracted signals against observations is limited by the time span of the observational record (e.g., SST observed during the satellite era), which is oftentimes shorter than the timescales of interest and also significantly altered by anthropogenic factors. More importantly, due to preprocessing as well as the subsequent data analysis techniques (such as EOFs), the results have frequently ambiguous physical interpretation.

Here, we investigate Indo-Pacific Ocean variability from 1300 control run of CCSM4. For that, we apply recently introduced technique called Nonlinear Laplacian Spectral Analysis (NLSA, Giannakis and Majda 2012). Through this technique, drawbacks associated with ad-hoc filtering are avoided as the extracted signals span many temporal scales without preprocessing the input data, enabling detection of low-frequency and intermittent modes not previously accessible with classical EOF-based approaches. Here, we identify spatiotemporal modes covering multiple scales of interest, including several interannual modes such as ENSO, the Indian Ocean Dipole, revealing refined linkages between these patterns. Additionally, the amplitudes of these patterns are modulated by low-frequency envelopes whose character can in certain cases be related to patterns of decadal or longer variability which are also identified. As such, our study unambiguously clarifies interdependencies between interannual modes which are sometimes treated in the climate science community as independent, but also lead to the verification of known decadal to multidecadal modes.

Page 148

S6.2 Tropical cyclones

Submission ID: 85Presentng Author: Joanna Burston

Session tme: WEDNESDAY - 11:00 - 12:00

1

Tropical Cyclone Storm Tide Risk Assessment based on an Updated Track Model

BURSTON Joanna*1; TAYLOR David 2; CHURCHILL Jim3

1) Baird Australia / Griffith University, jburston@baird.com; 2) Baird Australia; 3) Baird Australia

Calculation of risk for cyclonic winds and storm tide, it is necessary to extend the historical record of tropical cyclone tracks with synthetic events. Here we present a novel Monte Carlo synthetic tropical cyclone track generation system for the Australian region suitable for applications in risk assessment and several applications across the local government, insurance and research sectors.

Source terms for both the cyclogenesis within and for cyclones crossing into the basin are developed as Poisson point processes. Once genesis is simulated, the cyclone track is generated for each event using a random walk model drawing from the spatial distribution of differences in forward speed and direction in each grid cell over which the cyclone passes. This approach differs from similar models applied in this field by its spatial approach and the use of conditional probabilities on temporal differences in cyclone parameters.

A robust validation of the cyclone track model is demonstrated by comparison of the landfall strike rates and landfall intensity for coastal segments along the Australian coastline for the historical record and 500 realisations of the model. Since landfall location is not a parameter built into the method, it is an independent parameter by which its model skill can be assessed. The results shows good agreement with the historical record. Further, the spatial distribution of synthetic track landfall intensity also has good agreement with the historical data set.

Application of the resultant synthetic track database is presented for several case studies, including the web-based dynamic community risk assessment tool developed by Griffith University. This tool is designed for use by planners and other stakeholders considering long term infrastructure, land-use and emergency planning as well as climate change adaptation strategies, enabling dynamic interrogation of storm surge risk in North Queensland at a high spatial resolution.

Page 149

S6.2 Tropical cyclones

Submission ID: 148Presentng Author: Andrew Dowdy

Session tme: WEDNESDAY - 11:00 - 12:00

2

A Signifcant Decrease in Observed Australian Tropical Cyclone Numbers

DOWDY Andrew*1; NGUYEN Hanh 2

1) Bureau of Meteorology, a.dowdy@bom.gov.au; 2) Bureau of Meteorology

Many previous studies have examined whether or not long-term changes can be detected in tropical cyclone (TC) activity based on the observed records, with Knutson et al. (2010) concluding from such studies that it is uncertain whether or not past changes in TC activity have exceeded variability due to natural causes. The ability to investigate long-term changes in observed Australian TC numbers is shown here to improve when the El Niño-Southern Oscillation (ENSO) is considered: removing variability in TC numbers associated with ENSO shows a significant decreasing trend in TC numbers at the 93–98% confidence level (for the period 1982 to 2013) [Dowdy 2014]. In an effort to minimise satellite-induced inhomogeneities, these results do not use data prior to the 1982/83 Southern Hemisphere TC season. Additionally, there is some indication of a temporal change in the relationship between ENSO and TC numbers, with ENSO accounting for about 35–50% of the variance in TC numbers during the first half of the study period, but only 10% during the second half. These results have implications for TC seasonal prediction. Physical causes of a long-term change in TC activity are discussed, including hypotheses of previous studies such as Ashok et al. (2012), that increasing greenhouse gas concentrations could potentially influence the occurrence of different types of ENSO variability (such as Modoki events). The potential influence of tropical expansion on TC numbers is examined, following a recent study by Kossin et al. (2014).

Refs:

Ashok et al., 2012: Is a global warming signature emerging in the tropical Pacific? Geophys. Res. Lett., 39, L02701.

Dowdy, 2014: Long-term changes in Australian tropical cyclone numbers. Atmos. Sci. Lett., 15, DOI:10.1002/asl2.502.

Knutson et al., 2010: Tropical cyclones and climate change. Nature Geosci., 3, DOI:10.1038/ngeo779.

Kossin et al., 2014: The poleward migration of the location of tropical cyclone maximum intensity. Nature, 509, 349-352.

Page 150

S6.2 Tropical cyclones

Submission ID: 226Presentng Author: Andrew Magee

Session tme: WEDNESDAY - 11:00 - 12:00

3

The Usefulness of Pre-Satellite era Tropical Cyclone Data: An Intercomparison of three Best-Track Products for the Southwest Pacifc

MAGEE Andrew*1; VERDON-KIDD Danielle 2; KIEM Anthony3

1) Centre for Water Climate and Land-Use (CWCL) The University of Newcastle Callaghan NSW 2308 Australia, andrew.magee@uon.edu.au; 2) Centre for Water Climate and Land-Use (CWCL) The University of

Newcastle Callaghan NSW 2308 Australia; 3) Centre for Water Climate and Land-Use (CWCL) The University of Newcastle Callaghan NSW 2308 Australia

Recent efforts to better understand tropical cyclone (TC) activity in the South Pacific have led to the development of numerous TC databases. Constructed by consolidating TC tracks from various sources, many TC databases exist for the South Pacific basin (0°-35°S, 135°E-120°W), e.g. the Joint Typhoon Warning Center (JTWC), the International Best-track Archive for Climate Stewardship (IBTrACS) and the Southwest Pacific Enhanced Archive of Tropical Cyclones (SPEArTC). Given the findings of Holland (1981), the ‘status-quo’ for TC studies is to use data from the post-satellite only, from 1969 to the present, thus limiting the study of TC trends and their driving mechanisms to the most recent 45 years. This limitation inhibits the ability to assess any longer term trends in TCs for the region and negates the study of potential impacts of multi-decadal processes such as the Pacific Decadal Oscillation (PDO) on TC activity. To quantify the impact of changing observational technologies on TC databases, we apply a number of spatio-temporal analysis techniques to establish if pre-satellite era (1945-1969) data can be used in climate attribution and TC trend studies. Our spatio-temporal analysis suggests that pre-satellite TC observations may not be as erroneous as originally suggested by Holland (1981). Indeed, time series and trend analyses conducted indicate that the introduction of observational technologies have had no statistically significant influence on TC frequency and trends using a range of non-parametric tests and spatial analysis. This investigation also highlights significant variability between the various TC datasets available to researchers. We demonstrate why the choice of dataset should be carefully considered as it may influence the outcome of any analysis.

Reference:

Holland, G., 1981: On the quality of the Australian tropical cyclone data base. Aust. Met. Mag, 29, 169–181.

Page 151

S6.2 Tropical cyclones

Submission ID: 208Presentng Author: Joe Courtney

Session tme: WEDNESDAY - 11:00 - 12:00

4

Developing Tropical Cyclones moving ofshore from Northwest Australia: Characteristcs and Forecastng Challenges

COURTNEY Joe*1; HILLE Ron 2; WILKS Jessica3

1) Bureau of Meteorology, j.courtney@bom.gov.au; 2) Bureau of Meteorology; 3) Bureau of Meteorology

The area off northwest Australia between Exmouth and Darwin has the highest frequency of tropical cyclones in the Australian region. It is also the region of the offshore oil and gas industry as well as the ports servicing iron ore and other mining exports, which are vulnerable to disruptions and direct damage caused by cyclones. About twenty per cent of cyclones that occur in the region, equating to about one per season, form from a low that moves off the coast between Port Hedland and Darwin.

These tropical cyclones present particular forecasting challenges because:

they develop close to the coastline and the majority then cross the coast as a cyclone;

they can develop very rapidly once offshore;

they tend to be small systems traditionally not well resolved by computer models; and

standard intensity methods such as the Dvorak Technique, Scatterometry and microwave imagery do not work overland.

As a result the forecast intensity accuracy is much lower than for purely oceanic systems. The more rapidly developing systems are characterised by having a pre-existing low to mid-level circulation experiencing low vertical wind shear. By contrast non-developing lows tend to suffer high wind shear or have too weak a circulation as they move off the coast.

In most cases offshore moving systems have stable steering wind patterns allowing for accurate track predictions to be made, although there are some notable exceptions that have less predictable tracks.

Given the inherent forecast challenges they create, the modelling community is encouraged to investigate these cases further to improve available operational guidance.

Page 152

S6.3a Maritme Contnent: ProceSes, Weather, and Climate

Submission ID: 145Presentng Author: Rachel Badlan

Session tme: WEDNESDAY - 14:00 - 15:00

1

Analysis of Convectve Momentum Transport during TWP-ICE using Radar Observatons.

BADLAN Rachel*1; LANE Todd 2; PROTAT Alain3

1) The University of Melbourne, Rachel.Badlan@unimelb.edu.au; 2) The University of Melbourne; 3) CAWCR

Tropical convection is crucial for the redistribution of heat, moisture and momentum in the atmosphere. Convective systems can form various regimes, from disorganised cumuli to mesoscale convective systems (MCSs). The simulation of these systems and their effects on the momentum budget has proven to be difficult, especially at model resolutions where they are poorly resolved and require parameterisations. Vertical fluxes of horizontal momentum induced by organised convection are affected by factors such as environmental wind shear, storm-induced pressure gradients, and the strength of the density current. They in turn influence the development and regime of clouds, and the larger-scale flow due to changes in the environmental shear they induce. Parameterisation of these processes and effects are ultimately hampered by an incomplete understanding of the multiscale structure of convective momentum transport (CMT), its effects on the mean flow, and its role in convective organisation.

Presently, when analysing the behaviour and characteristics of CMT model simulations are mostly used, as observations are not as readily available. This work aims to use data from the Bureau of Meteorology radar in Darwin, encompassing the maritime continent to the north, to quantify momentum transport associated with observed MCSs. The calculations will employ winds derived from dual Doppler retrievals, and examine the momentum fluxes as well as their convective and mesoscale contributions. The analysis will focus on observations taken during the Tropical Warm Pool International Cloud Experiment, which will complement previous model-based examinations of the CMT. This work will result in a better understanding of how both the mesoscale and the convective scale transports behave with a variety of convective regimes. These findings into the behaviour of different scale momentum transports will aid in their study and help to better represent them in global and climate simulations.

Page 153

S6.3a Maritme Contnent: ProceSes, Weather, and Climate

Submission ID: 38Presentng Author: Wojciech Grabowski

Session tme: WEDNESDAY - 14:00 - 15:00

2

Untangling Microphysical Impacts on Deep Convecton over Maritme Contnent Applying a Novel Modeling Methodology

GRABOWSKI Wojciech*1

1) NCAR, grabow@ucar.edu

Formation and growth of cloud and precipitation particles (“cloud microphysics”) affect cloud dynamics and such macroscopic cloud field properties as the mean surface rainfall, cloud cover, and liquid/ice water paths. Traditional approaches to investigate the impacts rely on parallel simulations with different microphysical schemes or with the same scheme with different parameters. Such methodologies are not reliable because of the natural variability of a cloud field that is affected by the feedback between cloud microphysics and dynamics. We developed a novel modeling methodology to assess the impact of cloud microphysics on cloud dynamics and on simulated macroscopic cloud field characteristics. The main idea is to use two sets of thermodynamic variables driven by two microphysical schemes (or by the same scheme with different parameters), with one set coupled to the dynamics and driving the simulation, and the other set piggybacking the simulation, that is, responding to the simulated flow but not affecting it. We will discuss application of this methodology to cloud field simulations of deep convection. We will show that the methodology allows assessing the impact of cloud microphysics on cloud field properties with unprecedented accuracy. By switching the sets (i.e., the set driving the simulation becomes the piggybacking one, and vice versa), the impact on cloud dynamics can be isolated from purely microphysical effects. We will show that the new methodology documents a rather insignificant impact of the assumed cloud droplet concentration on convective dynamics for the case of scattered unorganized deep convection. These results cast doubt on the dynamic basis of the deep-convection invigoration in polluted environments. They also explain simulated impacts of pollution on deep convection over the Maritime Continent reported at the 2014 AMOS meeting.

Page 154

S6.3a Maritme Contnent: ProceSes, Weather, and Climate

Submission ID: 314Presentng Author: Harun Rashid

Session tme: WEDNESDAY - 14:00 - 15:00

3

An investgaton of the causes of rainfall bias over the Maritme Contnent: Experiments with the UK Met Ofce Unifed Model

RASHID Harun*1

1) CSIRO Oceans and Atmosphere, harun.rashid@csiro.au

The General Circulation Models (GCMs) experience a significant challenge in realistically simulating the tropical rainfall. Much of this rainfall is associated with deep convections that occur in abundance over the Maritime Continent and the adjacent warm pool region (hereafter, the MC region). Most GCMs show significant rainfall biases over the MC region, which may be related to errors in the representation of tropical deep convections in the GCMs.

In this work, we investigate the possible causes of the rainfall bias over the MC region seen in the UK Met Office Unified Model (UM) simulations. Specifically, we examine the impact of horizontal resolution changes on aspects of the simulated deep convections to help understand the causes of the rainfall bias. To this end, we conducted a pair of AMIP-style experiments with the UM with different horizontal resolutions. Comparative analyses of these two simulations reveal that the dry rainfall bias in the UM is somewhat reduced due to increased resolution. This is partly due to a slightly better simulation of the low-level horizontal moisture flux convergence in the higher-resolution simulation than in the lower-resolution one. The mid-tropospheric upward motion, indicative of the deep convective activity, is found to be markedly weaker than observed in both the simulations. However, the upward motion is significantly stronger (by up to 50%) in the higher-resolution simulation than in the lower-resolution simulation, consistent with the reduced dry bias found in the former. The joint dependence of the simulated rainfall on the atmospheric vertical motion and sea surface temperature is also studied, which will be discussed in the presentation.

Page 155

S6.3a Maritme Contnent: ProceSes, Weather, and Climate

Submission ID: 225Presentng Author: Yue Li

Session tme: WEDNESDAY - 14:00 - 15:00

4

Sensitvity of the Maritme Contnent Precipitaton to Horizontal Resoluton in a Coupled Regional Model

LI Yue*1; JOURDAIN NicolasC. 2; TASCHETTO AndreaS.3 ; SEN_GUPTA Alex4; CAI Wenju5

1) Climate Change Research Centre ARC Centre of Excellence for Climate System Science UNSW, yue.li@unsw.edu.au; 2) CNRS LGGE F-38401 Grenoble France; Univ. Grenoble Alpes LGGE F-38401 Grenoble

France; ARC Centre of Excellence for Climate System Science University of New South Wales Sydney Australia; 3) Climate Change Research Centre and ARC Centre of Excellence for Climate System Science

UNSW; 4) Climate Change Research Centre and ARC Centre of Excellence for Climate System Science UNSW; 5) CSIRO Marine and Atmospheric Research Aspendale

The Maritime Continent (MC) is located between the tropical Indian-Pacific ocean sector, consisting of Indonesia, Philippines, Papua New Guinea and other Southeast Asian countries. Characterized by massive tropical heating and precipitation, it is strongly influencing both the Hadley and Walker circulations. There are significant challenges to correctly represent climate of this region due to the complex topography and arrangement of land and sea. It is suggested that improved representation of diurnal cycle over islands and orographic-induced mesoscale processes can be important to the energy and hydrological cycles of this region.

To investigate the sensitivity of precipitation over the MC to model horizontal resolution, in this study, we perform three numerical experiments using the coupled regional NEMO-OASIS-WRF (NOW) model at different horizontal resolutions of 3/4°, 1/4° and 1/12° in both atmosphere and ocean components. The experiments with 3/4° and 1/4° horizontal resolutions operated on a large MC domain are run for 21 years from 1989 to 2009, while the experiment with horizontal resolution of 1/12° is nested within the domain with 1/4° horizontal resolution using two-way interactive nesting over 5 years. All experiments are parameterised by Grell-3D cumulus convective scheme.

A significant dependency of physical schemes of WRF on the resolution is found when increasing the horizontal resolution from 3/4° to 1/4°, with an effect on the mean sea surface temperature (SST). The increase of resolution from 3/4° to 1/4° reduces the annual mean precipitation dry biases and improves precipitation distribution, particularly, in coastal area. Furthermore, we developed a new method to comprehensively describe how land-sea breeze along the coast is affected by model horizontal resolution in order to investigate mesoscale local processes generated by land-sea thermal contrast.

Page 156

S6.3b Maritme Contnent: ProceSes, Weather, and Climate

Submission ID: 177Presentng Author: Robyn Schofeld

Session tme: THURSDAY 9:15 - 10:15

1

Comparison of Mass fuxes from WRF simulatons and radar for SCOUT-O3 and TWP-ICE

SCHOFIELD Robyn*1; FREY Wiebke 2; KUMAR Vickal3 ; PROTAT Alain4; HASSIM Muhammad5 ; LANE Todd6

1) University of Melbourne, robyn.schofield@unimelb.edu.au; 2) University of Melbourne; 3) Monash University; 4) Bureau of Meteorology; 5) Centre for Climate Research Singapore; 6) University of Melbourne

Understanding convection in the tropical western pacific is of crucial importance in determining very short lived substance delivery from the surface to the stratosphere. In particular, the stratospheric halogen and sulfur budgets, and the oxidative capacity of the tropical atmosphere are defined by these meso-scale processes. A critical examination of the mass fluxes is made using the Weather Research and Forecasting (WRF) convection resolving case studies during SCOUT-O3 and TWP-ICE campaigns (November 2005 and January - February 2006). These simulated mass-fluxes are compared with observational estimates from radar and the implications for trace-gas delivery is discussed. How quickly air-masses are replaced, an important quantity in chemistry climate modelling, is explored through the determination of detrainment rates from WRF simulations and radar observations.

Page 157

S6.3b Maritme Contnent: ProceSes, Weather, and Climate

Submission ID: 151Presentng Author: Claire Vincent

Session tme: THURSDAY 9:15 - 10:15

2

Modelling and observing the evoluton of the diurnal precipitaton cycle with the passage of the MJO through the Maritme Contnent

VINCENT Claire*1; LANE Todd 2

1) School of Earth Sciences and ARC Centre of Excellence for Climate System Science The University of Melbourne, claire.vincent@unimelb.edu.au; 2) School of Earth Sciences and ARC Centre of Excellence for

Climate System Science The University of Melbourne

Atmospheric convection in the Maritime Continent (MC) has a globally significant role as a heat source for global circulation and in modulating large-scale intraseasonal variability such as the Madden Julian Oscillation (MJO) [1]. Despite its importance, regional climate models tend to exhibit large precipitation biases in the region (eg. [2]).

Precipitation over the MC has been shown to peak over the land during the late afternoon or evening, and over the water during the early hours of the morning. Modelling and observational studies have suggested that precipitation propagates from the land to the sea, leading to the differential diurnal cycles between the land and the sea (eg. [3]). The diurnal precipitation cycle in the MC is also modulated by the MJO.

In this study, the propagation of the MJO through the MC from the eastern Indian Ocean to the western Pacific is investigated for a 31 day test period in January 2010. Satellite rainfall estimates from TRMM 3B42 and CMORPH are combined with simulations from the WRF model with a horizontal resolution of 4 km to explore the processes behind the seaward propagating precipitation northeast of New Guinea. Two distinct processes are identified: close to the coast, offshore propagation of precipitation is shown to be mainly associated with the land/valley breeze, while the propagation speed of precipitation further offshore and associated potential temperature anomalies are indicative of gravity wave propagation.

[1] Neale, R., & Slingo, J. (2003). The Maritime Continent and its role in the global climate: A GCM study. J. Clim., 16, 834–848.

[2] Gianotti R.L., & Zhang, D., & Eltahir, E.A.B. (2012). Assessment of the regional climate model version 3 over the Maritime Continent using different cumulus parameterization and land surface schemes. J Clim. 25, 638-656.

[3] Yang, G. Y., & Slingo, J. (2001). The diurnal cycle in the tropics. MWR, 129, 784–801.

Page 158

S6.3b Maritme Contnent: ProceSes, Weather, and Climate

Submission ID: 120Presentng Co-Author: Michael Reeder

Session tme: THURSDAY 9:15 - 10:15

3

Convergence Lines in the Australian Tropics and Maritme Contnent

SHELTON Kay1; REEDER Michael*2; BERRY Gareth3 ; JAKOB Christan4

1) Monash University, kay.shelton@monash.edu; 2) Monash University; 3) Monash University; 4) Monash University

Although it is well known that precipitation is often organized along coherent lines of low-level convergence, the role of these convergence lines (and the role of convergence more generally) in the initiation of convection remains a long-standing problem in atmospheric science. On the mesoscale, such convergence lines and their associated precipitation are often produced by the diurnal cycle of continental heating and cooling. Examples of this include, sea breezes, gravity waves, dry lines, and surface inhomogeneity. Such lines are thought to play an important role in the initiation and organization of clouds and convection in the tropics. At longer time and spaces scales, individual convergence lines are organized into larger structures such as the Intertropical Convergence Zone and South Pacific Convergence Zone. However, the link between convergence and convection is weak in both global and numerical weather prediction models, and this weakness is thought to be the source of some of the model biases in the tropics. As a first step in diagnosing the root cause of these problems, as well as a means of better understanding the organization of convection, an objective method has been developed to identify convergence lines in re-analysis and model data. The method is a variation on the algorithm described in Berry and Reeder [2014], and it is applied here to the ERA-Interim reanalysis. The rainfall associated with these convergence lines is quantified and the diurnal variation of both convergence lines and the rainfall discussed.

Berry, G. J., and M. J. Reeder. 2014. Objective identification of the intertropical convergence zone: Climatology and trends from the ERA-Interim reanalysis. J. Clim., 27, 1894— 1909

Page 159

S6.3b Maritme Contnent: ProceSes, Weather, and Climate

Submission ID: 100Presentng Author: Nidhi Nishant

Session tme: THURSDAY 9:15 - 10:15

4

Impact of convectve invigoraton due to aerosols on shallow clouds

NISHANT Nidhi*1; SHERWOOD Steven 2

1) UNSW Sydney, n.nidhi@student.unsw.edu.au; 2) UNSW Sydney

Convective invigoration effect is defined as the deepening of convective clouds with respect to increasing aerosol concentration. Past work suggests deep convective clouds will deepen and/or ascend faster as a result of increasing aerosol concentrations, an effect called “convective invigoration”. Inspite of the recent advances made in understanding convective invigoration by aerosols, the interaction between aerosol-invigorated deep cloud and shallow cloud still remains uninvestigated. The objective of this work is to understand the response of shallow clouds to convective invigoration during synoptic scale motions. The large scale motion chosen for this study is the Hadley Circulation associated with the Eastern Pacific Inter-Tropical Convective Zone, which has been found in a number of studies to exhibit a shallow meridional circulation (SMC). In this study we use the Weather Research and Forecasting (WRF 3.5.1) model and set up an idealised case in order to reproduce the circulation. SMC remains robust to the different resolutions of 20 km and 2 km (where cumulus schemes are used at 20 km but not at 2 km). We also compare the simulated SMC with ERA -Interim reanalysis dataset.

Later we investigate the potential affect of aerosols by adding a proxy effect of aerosols in the form of localised heating perturbations . To study the relative magnitudes of changes in the cloud cover and meteorological parameters due to aerosols, three simulations are performed. The first simulation is considered as a control in which there is no added heating perturbation, whereas the other two are perturbed cases in which localised heating perturbations are added - to latent heating in the cumulus and microphysics schemes at 20km and 2km resolutions respectively. The results of SMC simulation both from model and observational dataset, along with intercomparison of aerosol effect from base and perturbed runs, will be presented.

Page 160

S7.0a General meteorology - general

Submission ID: 287Presentng Author: Anthony Kiem

Session tme: THURSDAY 9:15 - 10:15

1

Spatal and temporal hydroclimatc variability in eastern Australia— quantfying the magnitude and spatal extent of East Coast Low (ECL) impacts

KIEM Anthony*1; TWOMEY Callum 2; LOCKART Natalie3 ; WILLGOOSE Garry4; KUCZERA George5

1) University of Newcastle, anthony.kiem@newcastle.edu.au; 2) University of Newcastle; 3) University of Newcastle; 4) University of Newcastle; 5) University of Newcastle

East Coast Lows (ECLs) are intense low-pressure systems which occur over eastern Australian coast. These systems are typically associated with gale force winds, large seas, storm surges, heavy rainfall and flooding. While these ECL impacts are mostly negative it is also important to realise that the rainfall associated with ECLs is very important for urban water security within the heavily populated eastern Australian seaboard. This study examines the impacts of all ECLs, and the various ECL sub-types, to determine the magnitude and spatial extent of ECL impacts on hydroclimatic variables (e.g. rainfall, streamflow, reservoir levels etc.). It is then shown how this information can be used to stochastically simulate daily rainfall such that the statistics important for catchment scale hydrology (e.g. clustering of extreme events, long-term persistence, frequency/duration/magnitude of wet and dry spells etc.) are realistically preserved. These simulated rainfall sequences, that incorporate the spatial and temporal hydroclimatic variability caused by ECLs and other climate phenomena, are important inputs into hydrological models used to determine current and future urban water security.

Page 161

S7.0a General meteorology - general

Submission ID: 126Presentng Author: AFM Kamal Chowdhury

Session tme: THURSDAY 9:15 - 10:15

2

A Stochastc Model for Rainfall Generaton with Long-term Variability – Calibraton to NARCliM Data at Catchments with Characteristc Infuence of

East Coast Lows

CHOWDHURY AFMKamal*1; LOCKART Natalie 2; WILLGOOSE Garry3 ; KUCZERA George4; PARANA_MANAGE Nadeeka5 ; KIEM Anthony6

1) University of Newcastle, afm.chowdhury@uon.edu.au; 2) The University of Newcastle; 3) The University of Newcastle; 4) The University of Newcastle; 5) The University of Newcastle; 6) The University of Newcastle

Underestimation of observed rainfall variability for longer timescales (e.g. monthly, annual and multi-year) is one of the major issues in rainfall simulation. In this study, we developed a Compound Distribution Markov Chain (CDMC) model for stochastic generation of daily rainfall. The model was calibrated to the 10 km resolution gridded data produced by NSW/ACT Regional Climate Modelling (NARCliM) project. The CDMC has two parameters for Markov Chain process (transition probabilities of wet-to-wet and dry-to-dry days) to simulate the rainfall occurrence and two parameters for a gamma distribution (calculated using mean and standard deviation of wet day rainfall) to simulate the rainfall amount. The key improvement of CDMC over previous Markov Chain rainfall models is stochastically sampling the mean and standard deviation of wet day rainfall from a bivariate normal distribution of log normally distributed mean and standard deviation values, while deterministic parameters were used for Markov Chain process. We have found that the CDMC is able to replicate both short term and long term rainfall variability in calibration at our study sites. This paper will compare the calibration of CDMC to NARCliM data at three locations of east coast Australia— one from the central NSW coast (Hunter River Catchment), one from the southern NSW coast (Bega River catchment) and one from the northern NSW coast (Richmond River catchment). The analysis of rainfall variability in these three locations is particularly important because the southern and northern catchments are subject to the least and the greatest impacts of East Coast Lows (ECLs) respectively, while ECLs are one of the major causes of rainfall in the central catchments. The findings of this study will be the basis for future work examining the influence of ECLs in urban water security of coastal NSW.

Page 162

S7.0a General meteorology - general

Submission ID: 30Presentng Author: Milton Speer

Session tme: THURSDAY 9:15 - 10:15

3

Meteorological conditons interactng with topography leading to the Brisbane and Lockyer Valley foods made QPF of catchment average rainfall

between 8 and 11 January 2011 extremely difcult

SPEER Milton*1

1) Climate Change Research Centre / UNSW, milton.speer@unsw.edu.au

The January 2011 Flood Event which impacted the Wivenhoe and Somerset dams can be characterized as a large (Annual Exceedance Probability [AEP] of 1 in 100) to rare (AEP of 1 in 2000 years) event. The 24-hour Quantitative Precipitation Forecasts (QPF) provided by the BoM is considered the primary forecast tool since they provide specific dam average rainfall forecast information.

There were three periods of rainfall that contributed significantly to the already saturated catchments resulting from rainfall earlier in January and in December. These 3 periods occurred on 9 January, the afternoon of 10 January and during 11 January. NWP derived single model rainfall underestimates rainfall amounts when model resolution is not representative of small scale physical processes and when topographical resolution is too coarse. Inconsistency in consecutive forecast amounts is also a problem for the single model approach. It has been shown that ensemble approaches can improve rainfall forecast guidance generally for a 24 hour period even when topographical influence is present. However, improved model guidance on shorter temporal scales of a few hours from a lead time of 24 h, and certainly for 3 and 5 day lead times, is still very much a research mode topic.

It will be shown that widespread rain cells over the catchment topography affected the underestimation of QPFs on 9 January, slow movement of rain cells over topography at the top of the catchment affected the underestimation of QPFs on 10 January, while a very narrow band of rain cells over the catchment topography on 11 January is consistent with an overestimation of QPF then. Wind velocity perpendicular to the topography, moist static stability, and the mountain height can be important for the occurrence of rain cell movement over topography. Some preliminary high temporal and horizontal resolution model rainfall results of a 24 h period during the event when the rain cells were slow moving will be shown.

Page 163

S7.0a General meteorology - general

Submission ID: 244Presentng Author: Laura O'Brien

Session tme: THURSDAY 9:15 - 10:15

4

Large Amplitude Rossby Waves and Extreme Weather

O'BRIEN Laura*1; REEDER Michael 2

1) Monash, laura.obrien@monash.edu; 2) Monash University

Rossby waves stir potential vorticity and this redistribution can play an essential role in the dynamics of the weather. These waves can grow in amplitude as they propagate along the wave guide and in certain cases are linked to extreme weather events in Australia such as heat waves (Parker et al, 2014), fire weather (Reeder et al, 2015) and the monsoon onset (Davidson et al, 2007). In this study we use Empirical Orthogonal Functions (EOFs) to identify large amplitude disturbances in the Indian Ocean. We analyse the generation, growth and subsequent attenuation of these waves and explore their connection to extreme weather events in Australia. In particular we use wave activity variables, jet stream position and links to climate modes to diagnose these elements.

References:

Parker, T. J., G. J. Berry, M. J. Reeder, 2014: The structure and evolution of heat waves in Southeastern Australia, J. Clim., 27, 5768-5785.

Reeder, M. J., T. Spengler, R. Musgrave, 2015: Rossby waves, extreme fronts, and wildfires in Southeastern Australia, Geophys. Res. Letters, accepted.

Davidson, N. E., K. J. Tory, M. J. Reeder, W. L. Drosdowsky, 2007: Extratropicaltropical interaction during onset of the Australian monsoon: reanalysis diagnostics and idealized dry simulations, J. Atmos. Sciences, 64, 10, 3475-3598.

Page 164

S7.0b General meteorology - general

Submission ID: 242Presentng Author: Hamish Ramsay

Session tme: FRIDAY 08:30 - 10:00

1

A new link between Indian Ocean sea surface temperatures and Australian tropical cyclone actvity

RAMSAY Hamish*1

1) Monash University, hamish.ramsay@monash.edu

The annual number of tropical cyclones (TCs) in the Australian region has a well-known statistical relationship with the El Niño-Southern Oscillation (ENSO), but the role of Indian Ocean sea surface temperatures (SST) remains relatively unexplored. Here we investigate a new link between SST variability in the sub-tropical to tropical South Indian Ocean (SIO) and Australian TC frequency, for the period 1969-2013. Preliminary analysis reveals a strong and highly statistically significant relationship between August-October SST anomalies in the subtropical SIO and the number of TCs in the Australian region during November to April. Composites of the Genesis Potential Index during peak TC season show that the Australian tropics is more (less) conducive to TC formation during low (high) SIO SST anomaly years. Work is ongoing to untie the confounding effects of ENSO, which phases with the SIO region of interest for sub-periods of the full time series examined, as well as the relevant physical mechanisms at play.

Page 165

S7.0b General meteorology - general

Submission ID: 167Presentng Author: Jennifer Fletcher

Session tme: FRIDAY 08:30 - 10:00

2

Marine cold air outbreaks in the Southern Ocean

FLETCHER Jennifer*1

1) Monash University, jennifer.fletcher@monash.edu

A comparison of marine cold air outbreaks (MCAOs) in the northern and southern hemispheres is presented, with attention to their seasonality, frequency of occurence, and strength as measured by a cold air outbreak index. MCAOs are more frequent in the northern hemisphere than the southern hemisphere in winter, but the reverse is true in summer. In agreement with previous results, southern hemisphere MCAOs are found to be weaker than those in the northern hemisphere, and the strongest events tend to occur in the high latitudes of the Pacific sector of the Southern Ocean.

The MCAO index is used to define MCAOs as discrete events which are categorized by strength, and it is found that the number of these events has only a slight annual cycle in the southern hemisphere. MCAO events occur throughout the year, but in warm seasons they are found to be smaller and weaker than in cold seasons. Strong MCAO events are found to have similar meteorological contexts in both hemispheres: occupying the cold air sector of mid-latitude cyclones which generally appear to be in their growth phase. Weak MCAO events in the southern hemisphere are found to be dynamically more similar to strong events in either hemisphere than to weak events in the northern hemisphere.

A strong relationship exists between frequency of occurrence of Southern Ocean MCAOs and the Southern Annular Mode, especially in autumn and winter. There is little relationship with ENSO because the seasonality in ENSO and MCAOs is mismatched. In the Southern Ocean, MCAOs are found to be important for sea ice growth. Anomalies in monthly mean MCAO frequency of occurrence are found to be highly correlated with anomalies in mean sea ice growth in the month that follows.

Page 166

S7.0b General meteorology - general

Submission ID: 209Presentng Author: Justn Peter

Session tme: FRIDAY 08:30 - 10:00

3

The efects of the thermodynamic environment on the statstcal propertes of convectve storms in SouthEast Queensland

PETER Justn*1; MANTON Michael 2; POTTS Rod3 ; MAY Peter4; COLLIS Scot5 ; WILSON Louise6

1) University of Southern Queensland, Justin.Peter@usq.edu.au; 2) School of Earth Atmopshere and Environment Monash University; 3) Centre for Australian Weather and Climate Research; 4) CAWCR; 5)

Argonne National Laboratory; 6) CSIRO MArine and Atmospheric Research

The primary goals of this study are to, (1) determine preferred geographical locations of convective storms, (2) examine the variability of thermodynamic profiles in Southeast Queensland and, (3) examine the concomitant changes in convective storm properties. The thermodynamic variability is analyzed by performing a cluster analysis on variables derived from radiosonde releases at Brisbane airport. The variables represented the shear, stability, near-surface (850 hPa) winds and water fluxes, and total column water of the atmosphere.

Three objectively defined regimes are found: a dry, stable regime with mainly westerly surface winds, a moist northerly regime and a moist trade wind regime. To obtain the statistics of convective storms, archived radar data obtained from the Marburg S-band radar is processed using the Thunderstorm Identification, Tracking and Nowcasting (TITAN) system. Convective storm statistics are then investigated stratified by sub-periods corresponding to the objectively defined regimes.

Convective storms are found to initiate and maintain along elevated topography. Probability distributions of convective storm size and rain rate are found to follow lognormal distributions with differing mean and variance among the regimes. On average, storm volume and height are smallest in the trade regime and storm mean rain rate largest in the westerly regime. However, westerly regime storms occur less frequently and have shorter lifetimes than northerly or trade wind storms. Thus, the conceptual model emerges that storms which form in the westerly regime are primarily driven by large scale forcing while those in the northerly and trade wind regimes are more responsive to the underlying surface forcing. The diurnal time series of precipitation area and rain rate exhibit early-morning and mid-afternoon maxima.

Page 167

S7.0b General meteorology - general

Submission ID: 140Presentng Author: Nadeeka Parana Manage

Session tme: FRIDAY 08:30 - 10:00

4

Statstcal Validaton of Dynamically Downscaled Climate Data for the Hunter Region of New South Wales, Australia

PARAN_MANAGE Nadeeka*1; LOCKART Natalie 2; WILLGOOSE Garry3 ; KUCZERA George4; KIEM Anthony5 ; CHOWDHURY AFMKamal6

1) The University of Newcastle, nadeeka.paranamanage@uon.edu.au; 2) The University of Newcastle; 3) The University of Newcastle; 4) The University of Newcastle; 5) The University of Newcastle; 6) The University of

Newcastle

This study performs statistical validation of downscaled climate data, concentrating on rainfall which is required for hydrology predictions used in reservoir simulations. The dataset used here was produced by the NARCliM (NSW/ACT Regional Climate Modelling) project which provided dynamically downscaled climate data at a 10km resolution for south-eastern Australia. NARCliM has produced twelve ensembles of simulations for current and future climates as well as three control run simulations driven by the NCEP/NCAR reanalysis for the 60 year period of 1950-2009. In this study, statistical testing results are presented for the three 60 year reanalysis datasets.

The validation has been performed for the Hunter region of Australia, located in the east coast of Australia, with a range of climate types (e.g. coastal, inland, rain shadow, ECL). The emphasis is on rainfall properties that are important for the correct simulation of hydrology and reservoir performance. The analysis used the time series of downscaled gridded rainfall data and ground based measurements for selected Bureau of Meteorology rainfall stations within the study area. The initial testing of the gridded rainfall focused on the autoregressive characteristics of time series, along with a correlation analysis performed at daily, fortnightly, monthly and annual time resolutions. We focus on autocorrelations as reservoir performance depends on long-term average runoffs and thus longer term correlations. The spatial variability of statistics of the gridded rainfall series was also calculated and plotted at the catchment scale. The NARCliM data were able to successfully reproduce the autocorrelations of observed rainfall at each time resolution, but the cross correlation analysis shows a poor agreement between NARCliM data and observed rainfall. The spatial variability plots show a possible link between the statistics and topography at the catchment scale.

Page 168

S7.0b General meteorology - general

Submission ID: 223Presentng Author: Steve Siems

Session tme: FRIDAY 08:30 - 10:00

5

SOUTHERN OCEAN PRECIPITATION AS OBSERVED AT MACQUARIE ISLAND

WANG Zhan1; SIEMS Steve* 2; MANTON Michael3 ; HUANG Yi4; HANDE Luke5

1) Monash University, Zhan.wang@monash.edu; 2) Monash University; 3) Monash University; 4) Monash University; 5) Karlsruhe Institute of Technology

Uncertainty in the cloud processes over the Southern Ocean have been identified as the likely source of large biases in the energy budget over the region. Over the past decade satellite-based studies have confirmed that the region has the highest fractional cloud cover on Earth with a heavy cloud concentration in the boundary layer. The uncertainty resides largely in the cloud microphysics, where supercooled liquid water is commonly been recorded from satellite products and has been observed in-situ at temperatures below -20C. Similarly the region has the highest frequency of precipitation. In this study we have developed a climatology of precipitation over Macquarie Island from the long term records of the Bureau of Meteorology. While previous efforts (Adams 2009; Jovanovich et al 2012) have noted the significant increase in precipitation over the past decades, this work focuses on the intensity and frequency of the events. Surface observations are compared against two CloudSat-based products and the ERA-I reanalysis product. While much of the precipitation is dominated by light precipitation or drizzle, common even at times far from frontal passages. Frontal passage are the common cause of heavy precipitation events, but ~20% of such events fail to be so classified. This research also considers two case studies in which heavy precipitation was observed at Macquarie Island.

Page 169

S7.0b General meteorology - general

Submission ID: 195Presentng Author: Anil Deo

Session tme: FRIDAY 08:30 - 10:00

5

EVALUATION of TMPA 3B42 TROPICAL CYCLONE PRECIPITATION ESTIMATES over NEW CALEDONIA

DEO Anil*1

1) University of Melbourne, deoa@student.unimelb.edu.au

Heavy rainfall associated with tropical cyclones has been related to disastrous natural hazards that have far-reaching impacts such as flooding, landslide and subsequent health and socio- economic problems. It thus becomes imperative to have accurate measurement of precipitation during such events which would aid in disaster mitigation and risk analysis. Such measurements, however, is not possible through surface based measurements over much of the globe, especially in remote and developing countries. The remote and developing island countries in the south west Pacific (SWP) region, which frequently experiences the drastic consequences of TC heavy precipitation, are no exception in terms of such constraints to accurately measure precipitation. As such precipitation estimates based on satellite remote sensing could be used to fill this gap over this region. To confidently use such products it is important to have its accuracy and limitations which could be achieved by evaluating them against “ground truth” gauge or calibrated radar data. The island of New Caledonia, situated in the SWP region, encompasses a relatively excellent gauge based measurements suitable for such evaluations. Using this data the popular Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) 3B42 precipitation estimates of tropical cyclones has been evaluated over the island. This presentation will explore some of the important findings of the evaluation study.

Page 170

S7.1 Past, Present and Future East Coast Low Actvity and Impacts

Submission ID: 173Presentng Author: Stuart Browning

Session tme: WEDNESDAY - 14:00 - 15:00

1

Long-Term Natural Variability Of East Coast Lows Over The Past Millennium

BROWNING Stuart*1; GOODWIN Ian 2

1) Marine Climate Risk Group Climate Futures and Department of Environmental Sciences Macquarie University Australia, stuart.browning@mq.edu.au; 2) Marine Climate Risk Group Climate Futures and

Department of Environmental Sciences Macquarie University Australia

A summary of the key findings of the ESCCI-ECL project on ‘Long-term natural variability and probability assessment of ECLs’ is presented. We have determined ECL frequency at event and seasonal resolution over the past 140-years from meteorological reanalysis data (ERA-Interim and Twentieth Century Reanalysis), and over the past 1200-years at decadal to multidecadal resolution from paleoclimate based reanalysis (PaleoR-MQ). Seasonal ECL frequency over the 1955-2012 period–determined by automated cyclone detection and tracking algorithms–is highly correlated to regional ocean-atmosphere circulation patterns. Correlation patterns are used to develop a statistical downscaling approach and estimate autumn-winter ECL frequency from seasonal reanalysis data over the 1871 to 2012 period, showing the 1950s and 1970s were likely the stormiest decades of the 20th century.

Documentary evidence suggests a close linkage between storm frequency and intensity, whereby the most intense events occur when large-scale conditions are also conducive to frequent events. PaleoR-MQ was developed by using paleoclimate data to constrain a climate model simulation and is used to understand Southern Hemisphere climate variability at decadal to multidecadal resolution from 800-2000 CE. Paleoclimate data are sourced from throughout the Southern Hemisphere and include tree ring records from Australia, Tasmania and South America, coral cores from the South Pacific, ice cores from Antarctica and a range of sedimentary evidence. Applying the ECL downscaling approach to PaleoR-MQ reveals the late Little Ice Age (1600-1900 CE) was likely the stormiest period of the past 1200-years, and most decades of the 19th century were at least as stormy as the 1970s. These ‘ultimate storm centuries’ in the Tasman Sea occurred in conjunction with persistently warm west Pacific sea surface temperatures and negative to neutral SAM.

Page 171

S7.1 Past, Present and Future East Coast Low Actvity and Impacts

Submission ID: 133Presentng Author: Ian Goodwin

Session tme: WEDNESDAY - 14:00 - 15:00

2

Coastal Response To Extreme East Coast Storm Climate Between 1600-1900 CE, Determined From A Coupled Climate Reconstructon And Coastal

Morphodynamic Approach

GOODWIN Ian*1; BROWNING Stuart 2; MORTLOCK Thomas3 ; BURKE Annete4

1) Macquarie University, Ian.Goodwin@mq.edu.au; 2) Macquarie University; 3) Macquarie University; 4) Macquarie University

A summary of the key findings of the ESCCI-ECL Project on ‘Coastal Response to Extreme East Coast Cyclones (ECC) over the past 500 years’ is presented. The highest extreme storm frequency or clustering of ECC occurred between ~1600 to 1900 CE, in association with large-scale shift in the modal wave climate, when compared to the past century. A sustained morphodynamic reorganisation of the east Australian coast occurred over a large latitudinal gradient from subtropical Queensland (S 25°) to mid-latitude Bass Strait (S 40°).

We investigate coastal evolution to extreme storm wave climate using a novel combination of methods, including: LIDAR DEM and field mapping of coastal geology; a decadal-scale climate reconstruction of sea-level pressure, marine windfields and ocean waves, and paleo-storm synoptic type and frequency, using a paleoclimate data assimilation approach; together with wave transformation and coastal planform modelling for paleo-wave directions, and historical bathymetry.

The methodology has illuminated the ‘ultimate’ storm impacts not seen in the past century, and defines the multi-decadal coastal system response and recovery to extreme storm sequences. Increased embaymentisation and anticlockwise rotation of embayed and barrier coast planform geometry; shifts in barrier-estuary-inlet configuration; and a ubiquitous foredune transgression, occurred between ~1600 to 1800 CE. This was in response to a poleward shift in the subtropics and increased frequency of tropical-origin storms. From 1800 to 1900 CE, an equatorward shift in the subtropics, and clustering of extratropical-origin storms drove an increase in the shoreface-littoral sediment budget and a clockwise coastline progradation. The 20th century decline in storm wave energy is a significant driver of modern shoreline behavior along the Australian east coast.

Page 172

S7.1 Past, Present and Future East Coast Low Actvity and Impacts

Submission ID: 142Presentng Author: Natalie Lockart

Session tme: WEDNESDAY - 14:00 - 15:00

3

Use of a stochastc rainfall generaton model calibrated to NARCliM data to simulate runof in the Lower Hunter for water security assessment

LOCKART Natalie*1; WILLGOOSE Garry 2; KUCZERA George3 ; KIEM Anthony4; CHOWDHURY AFMKamal5 ; PARANA_MANAGE Nadeeka6

1) The University of Newcastle, natalie.lockart@uon.edu.au; 2) The University of Newcastle; 3) The University of Newcastle; 4) The University of Newcastle; 5) The University of Newcastle; 6) The University of

Newcastle

Reanalysis and GCM climate projections are useful for understanding how climate change will affect future rainfall and evapotranspiration, and consequently the ability of water infrastructure to reliably supply water when and where it is needed. The NSW/ACT Regional Climate Modelling (NARCliM) project has produced 12 projections of high resolution spatially distributed climate data for three 20 year epochs (1990-2009, 2020-2039 and 2060-2079), as well as three 60 year reanalysis products for 1950-2009. While these datasets provide a snapshot of current and projected changes in climate, 20-60 years of data is not long enough to capture extremes of climate which can empty or fill reservoirs. However, we can use stochastic rainfall models to generate multiple sequences of rainfall, both historic and future, to capture the full range of climate variability. These rainfall sequences can then be input into hydrology models to determine the impact of climate change on future hydrology and urban water security. In a separate study we have developed a Compound Distribution Markov Chain (CDMC) model to stochastically simulate daily rainfall ensuring long term persistence. The CDMC model can be used to simulate East Coast Low (ECL) as well as non-ECL rainfall events. In this study we use the NARCliM reanalysis data and the CDMC model to generate multiple rainfall sequences. This data is then input into the SimHyd rainfall runoff model, calibrated to the Lower Hunter catchment, to generate streamflow. We will assess the validity of the simulated streamflow through a comparison with historic data. We will then assess the implications for water security in the Lower Hunter.

Page 173

S7.1 Past, Present and Future East Coast Low Actvity and Impacts

Submission ID: 53Presentng Author: Acacia Pepler

Session tme: WEDNESDAY - 14:00 - 15:00

4

East Coast Low Projectons from a Regional Climate Model Ensemble

PEPLER Acacia*1; DILUCA Alejandro 2; ALEXANDER Lisa3 ; EVANS Jason4; JI Fei5

1) University of New South Wales, a.pepler@student.unsw.edu.au; 2) University of New South Wales; 3) University of New South Wales; 4) University of New South Wales; 5) NSW Office of Environment and

Heritage

East Coast Lows (ECLs) cause a large proportion of severe weather along the east coast of Australia, and are also an important contributor to annual rainfall and water security. There is considerable interest in future projections of ECL frequency and impacts; however, small-scale systems such as cyclones can be poorly represented in global climate models.

The NSW ACT Regional Climate Modelling (NARCliM) project used an ensemble of global climate models and regional downscaling methods to produce high-resolution (50 km and 10 km) climate projections for southeast Australia. We combine this ensemble of future climate projections with an ensemble of several automated methods for identifying and tracking ECLs from gridded data that have been applied in recent papers, each of which has different strengths and sensitivities. Using this ensemble of projections we can assess the likely range of ECL trends, giving an indication of areas of model consistency, the major sources of uncertainty in projections, and the robustness of future changes.

Page 174

S7.2a High-Impact Weather in Research and Operatons

Submission ID: 264Presentng Author: Aurora Bell

Session tme: WEDNESDAY - 15:30 - 17:00

1

The Subjectve Evaluaton of a Convecton-Allowing High Resoluton NWP

BELL Aurora*1; SEED Alan 2

1) Bureau of Meteorology, abell@bom.gov.au; 2) Bureau of Meteorology

A convection-allowing high resolution model with a rapid update cycle (RUC) was evaluated during an 11 weeks experiment named “The Sydney 2014 Forecasting Demonstration Project”. The experiment had around 20 experienced participants (forecasters, managers and scientists), and simulated the operational environment with a focus on severe weather forecasting. The utility of the RUC model in the forecast process was assessed by different stakeholders. RUC output was used in the preparation of daily experimental human forecasts for convection outlooks. These forecasts were compared to similar predictions made without access to the RUC data. The talk will present the outcomes of the subjective evaluation of the RUC.

The model received higher rating on convective initiation, evolution, and mode. For initiation, mechanisms like dry lines and sea breezes and convective outflows were properly revealed by the RUC. For evolution, mechanisms like back building and propagation were surprisingly well described by the RUC while for the mode of convection, supercells and bowechoes were suggested by the structure of the rainfall pattern in the 10 minutes outputs.

The subjective evaluation was performed through individual interviews and group discussions. During the trial we identified a list of “themes” in the advantages and limitations of the RUC against other models. This helped us in comparing ideas across interviews. The RUC was unknown before to the forecasters so we couldn’t anticipate the themes before the trial. This generated a feeling of discomfort among some of the forecasters who were not used with such open trials but rather used to a very clear operational workflow.

Page 175

S7.2a High-Impact Weather in Research and Operatons

Submission ID: 168Presentng Author: Harald Richter

Session tme: WEDNESDAY - 15:30 - 17:00

2

How Good is Ensemble-based Calibrated Thunderstorm Probability Predicton over Australia?

RICHTER Harald*1

1) Bureau Research and Development, h.richter@bom.gov.au

“Calibrated Thunder” is an ensemble-based thunderstorm probability forecast approach first introduced at the Storm Prediction Center in the U.S. about a decade ago. It utilizes two predictors for electrified convection, the Cloud Physics Thunder Parameter (CPTP) and total model precipitation. The system has been run off two separate five member NWP lag ensembles: the experimental ACCESS-RUC (Rapid Update Cycle), a convection allowing model with a 1.5 km grid spacing (RUC) and ACCESS-R12, a currently operational model with a ~12 km grid spacing (AR12). The RUC-based system ran for a 3-month period (Sep-Nov 2014), the AR12-based system from September 2014 until February 2015. Calibrated Thunder has produced calibrated thunderstorm probabilities in 3-hourly increments across Australia for a range of lead times (out to 21 hours) and model validity times.

The first aim of this work is to (i) appraise the overall performance of Calibrated Thunder forecasts using a range of skill measures such as reliability diagrams and relative operating characteristics and to (ii) gauge the skill gain of Calibrated Thunder over the currently operational Bureau thunderstorm prediction system, the National Thunderstorm Forecast Guidance System (NTFGS).

Preliminary results indicate that both systems (based on the RUC and AR12) are reasonably reliable for the lower probabilities of thunderstorm occurrence. Over-forecasting occurs near the higher probabilities for the sample forecasts considered. Despite the inherent advantage of explicitly modelled convective storms, the Calibrated Thunder system performs better running off AR12 with the current default predictor thresholds for instability and rainfall. It will also be shown that Calibrated Thunder performs better than the current operational NTFGS system.

Page 176

S7.2a High-Impact Weather in Research and Operatons

Submission ID: 170Presentng Author: Jennifer Cato

Session tme: WEDNESDAY - 15:30 - 17:00

3

Link Between Warm Conveyor Belts and Fronts and the Impact on Extreme Rainfall

CATTO Jennifer*1

1) Monash University, jennifer.catto@monash.edu

The various dynamical features within extratropical cyclones have been shown to be very important for the precipitation produced by these systems. Warm conveyor belts (WCBs) and fronts are both strongly associated with total and extreme precipitation in the midlatitudes. Here we have brought together two automated feature detection methods to answer questions on the frequency of matching of fronts and WCBs, whether this depends on frontal type or height of WCB, and the impact this matching has on extreme precipitation events.

We find that WCBs and fronts are strongly related in the midlatitudes— annually 60% of WCBs are associated with cold fronts and around 50% associated with warm fronts, and a fairly large proportion associated with both together. The frequency of linked WCBs and fronts shows a strong seasonal cycle. In some regions warm fronts are more strongly linked to WCBs than cold fronts. To the east of Australia in particular, there are often WCBs not associated with fronts at all. Fronts that co-occur with a WCB are much more likely to produce an extreme precipitation event.

Page 177

S7.2a High-Impact Weather in Research and Operatons

Submission ID: 332Presentng Author: Robert Warren

Session tme: WEDNESDAY - 15:30 - 17:00

5

The Impact of Variatons in Upper-Level Shear on simulated supercell storms

1) WARREN, Robert*

1) Monash University, rob.warren@monash.edu

Numerous observational and numerical studies have highlighted the critical role that vertical wind shear plays in the organization of deep moist convection. However, the vast majority of this work has focused on shear in the lowest 6 km of the atmosphere. It has been suggested that upper-level storm-relative flow (a function both of the deep-layer shear and storm motion) is an important control on the precipitation distribution in supercell storms, giving rise to the familiar ‘classic', ‘low-precipitation' and ‘high-precipitation' morphologies. In the present study, the specific role of upper-level shear (that above 6 km) is isolated using idealized simulations. It is found that as upper-level shear increases; the simulated storms become larger, with more intense precipitation and associated stronger outflow winds. These changes (which are consistent across a range of model and environmental configurations) result from an increase in updraft mass flux, which leads to enhanced precipitation production and, in turn, stronger downdrafts. At the time of writing, work is ongoing to determine the mechanisms responsible for updraft intensification; however, preliminary results suggest that changes in the linear dynamic perturbation pressure forcing (associated with interactions between the updraft and upper-level shear) may be an important component. Findings from the completed investigation will be presented and discussed in the context of forecasting supercells and their associated hazards.

Page 178

S7.2a High-Impact Weather in Research and Operatons

Submission ID: 318Presentng Author: Mathew Mason

Session tme: WEDNESDAY - 15:30 - 17:00

6

Inference of Surface Wind Speeds During Tropical Cyclone Marcia Based on Damage Observatons

MASON Mathew*1; SMITH Daniel 2; HENDERSON David3

1) School of Civil Engineering University of Queensland, matthew.mason@uq.edu.au; 2) Cyclone Testing Station James Cook University; 3) Cyclone Testing Station James Cook University

The Fujita Scale, and subsequently the Enhanced Fujita Scale, were developed to enable maximum probable wind speed estimation following tornadoes where no formal measurements were possible. These scales rely on predetermined relationships between wind speed and resultant damage to, for example, buildings and foliage so localised maximum wind speeds can be estimated. More recently, these relationships have been coupled, along with detailed post-event damage survey information, into complex numerical models so that general storm characteristics as well as their localised intensities can be estimated. An example of this is the use of observed tree fall information after the 2011 Joplin tornado to estimate wind speeds throughout the impacted region (Lombardo et al., 2015). These concepts are not limited to use with localised wind events and may be applied to large-scale storms such as tropical cyclones.

Following the landfall of Tropical Cyclone Marcia in February 2015, a damage survey team from James Cook University, the University of Queensland and Risk Frontiers undertook a field survey of damage to buildings and foliage throughout the impacted regions of Rockhampton, Yeppoon and the surrounding areas. Aerial imagery was used to aid the characterisation of damage patterns, as too was observed damage to simple structures such as failed road signs. Estimates of probable maximum surface wind speed and direction have been made considering these data in conjunction with data recorded at AWS stations throughout the region. An analysis of tree-fall in areas North of Yeppoon, nearer to the landfall of TC Marcia, was also undertaken to estimate the probable maximum wind speed and storm structure. The analysis procedure, findings and limitations will be discussed.

Lombardo, F.T., Roueche, D.B., Prevatt, D.O. (2015) Comparison of near-surface wind speed estimation in the 22 May, 2011 Joplin, Missouri Tornado. J. Wind Eng. Ind. Aero. 138, pp87-97.

Page 179

S7.2b High-Impact Weather in Research and Operatons

Submission ID: 91Presentng Author: Michael Reeder

Session tme: THURSDAY 15:30 - 17:30

1

Rossby Waves, Extreme Fronts, and Bushfres in Southeastern Australia

REEDER Michael*1; SPENGLER Thomas 2; MUSGRAVE Ruth3

1) Monash University, michael.reeder@monash.edu; 2) University of Bergen; 3) University of California

The most catastrophic fires in recent history in southern Australia have been associated with extreme cold fronts. Here, an extreme cold front is defined as one for which the maximum temperature at 2 m is at least 17oC lower on the day following the front. An anticyclone, which precedes the cold front, directs very dry northerlies or northwesterlies from the interior of the continent across the region. The passage of the cold front is followed by strong southerlies or southwesterlies. European Centre for Medium range Weather Forecasts ERA-Interim reanalyses show that this regional synoptic pattern common to all strong cold fronts, and hence severe fire conditions, is a consequence of propagating Rossby waves, which grow to large amplitude and eventually irreversibly overturn. The process of overturning produces the low-level anticyclone and dry conditions over southern Australia, while simultaneously producing an upper-level trough and often precipitation in northeastern Australia.

Page 180

S7.2b High-Impact Weather in Research and Operatons

Submission ID: 165Presentng Author: Ghyslaine Boschat

Session tme: THURSDAY 15:30 - 17:30

2

Heat wave - SST relatonship: an example of non-reversibility in statstcal methods

BOSCHAT Ghyslaine*1; SIMMONDS Ian 2; COWAN Tim3 ; PURICH Ariaan4; PEZZA Alexandre5

1) University of Melbourne, ghyslaine.boschat@unimelb.edu.au; 2) University of Melbourne; 3) CSIRO Marine and Atmospheric Research; 4) CSIRO Marine and Atmospheric Research; 5) University of Melbourne

Our understanding of weather and climate events often relies on the use of statistical methods. Composite or correlation analyses, for instance, can be used to describe the physical variables involved in a phenomenon and how these may interact or connect with other regions of the globe. However, testing the significance or unravelling the causality in these hypothesized connections requires a combination of statistical approaches, and more importantly needs to be supported by an appropriate physical understanding of the climate system itself.

This paper illustrates some potential misunderstandings of the physical meanings associated with composite analyses, using a case study of heat waves and the potential role of the ocean during these events in South West Australia. Sea Surface Temperatures (SSTs) have been identified as factors contributing to heat wave development across many global regions. However, for Australian heat waves, the evidence provided so far by observations is limited and global climate models have difficulties simulating the observed SST patterns. In this study, we examine the global SST conditions observed during 25 summer heat waves in Perth over the 1979-2014 period. The composite results first point to the importance of the subtropical South Indian Ocean, where physically coherent SST dipole anomalies are observed and may form a necessary preconditioning for heat waves to occur in Perth. However, complementary and more quantitative analyses also show that this SST signal very frequently appears in summer without any heat wave necessarily (co-) occurring in Perth, which suggests that this signal is definitely not a sufficient precondition. These simple analyses for Perth heat waves may have interesting applications for other climate case studies. More generally, they highlight the necessity of combining different statistical approaches and rigorous tests before making appropriate physical interpretations of a climate connection.

Page 181

S7.2b High-Impact Weather in Research and Operatons

Submission ID: 76Presentng Author: Peter Steinle

Session tme: THURSDAY 15:30 - 17:30

3

The Value of High Resoluton NWP

STEINLE Peter*1; RENNIE Susan 2; SEED Alan3 ; XIAO Yi4

1) Bureau of Meteorology, p.steinle@bom.gov.au; 2) Bureau of Meteorology; 3) Bureau of Meteorology; 4) Bureau of Meteorology

As part of the Strategic Radar Enhancement Project, the Bureau of Meteorology developed a high resolution numerical weather prediction (NWP) system that assimilated radar data as well as the standard set of observations. This prototype system was run in real time during the spring of 2014 over eastern NSW. The move from the currently operational 4km downscaling predictions to a 1.5km fully assimilating system provides significant advantages, but also raises a number of interesting research questions.

The move from convection parametrization to explicit modelling of convection provides much more realistic structure to the predicted rainfall fields. There is generally an improvement in the timing and evolution of convective systems. However, calibrating the system to provide more realistic rainfall amounts becomes much more complicated, as now the full cloud dynamics routines require adjustment.

The use of a mesoscale assimilation system not only reduces spin-up, but also allows for more frequent forecasts, reducing the latency between analysis of observations and the forecast being available. Again there are challenges, this time regarding the low density of the observation network relative to the model grid as well as the best approach for analysing data at these small scales.

Despite a number of issues the new NWP system performed well. This talk will cover some of the successes of the system, and some of the improvements that are under way prior to operational implementation in 2017.

Page 182

S7.2b High-Impact Weather in Research and Operatons

Submission ID: 117Presentng Author: Will Thurston

Session tme: THURSDAY 15:30 - 17:30

4

Long-Range Spotng by Bushfre Plumes: The Efects of In-Plume Turbulence on Firebrand Trajectory

THURSTON Will*1; TORY Kevin 2; FAWCETT Robert3 ; KEPERT Jefrey4

1) Bureau of Meteorology, w.thurston@bom.gov.au; 2) Bureau of Meteorology; 3) Bureau of Meteorology; 4) Bureau of Meteorology

The lofting of firebrands from bushfires into a background atmospheric flow can lead to spotting downwind of the fire front. Spotting is a hazardous phenomenon because it leads to both unpredictable and accelerated fire spread, as winds aloft are often in a different direction from and faster than the near-surface winds. Here we attempt to address some of the uncertainty associated with the process of spotting by quantifying how the behaviour of bushfire plumes, in particular their turbulent nature, can influence the trajectories of potential firebrands.

We present large-eddy simulations of bushfire plumes under a range of background wind conditions and highlight the behaviour of the different plumes. The three-dimensional, time-varying wind fields from the plume simulations are then used to drive a Lagrangian particle transport model, in order to calculate the paths taken by potential firebrands. We expand on previous work by considering firebrands with a range of fall velocities and by calculating the trajectories of millions of potential firebrands, allowing distributions of particle landing position and flight time to be constructed. In addition, we also calculate trajectories for firebrands launched by steady-state plumes and compare them to the trajectories calculated using the corresponding time-varying plumes. This comparison allows us to assess the effect of the intra-plume turbulence on firebrand trajectory. Systematic studies such as this will eventually form the basis of inexpensive, physically sound parameterizations for spotting models.

Page 183

S7.2b High-Impact Weather in Research and Operatons

Submission ID: 162Presentng Author: Jussi Toivanen

Session tme: THURSDAY 15:30 - 17:30

5

Coupled fre-atmosphere simulatons

TOIVANEN Jussi*1

1) Monash University, jussi.toivanen@monash.edu

Bush fires destroy large areas of natural and urban land in Australia every year. It is therefore important to understand the behaviour of bush fires and their interaction with the atmosphere. We have developed a fire simulation code that can work either in an offline mode (no feedback to the atmosphere) or in a more computationally demanding coupled mode. In coupled fire-atmosphere simulations the atmospheric solver and the fire code exchange near ground observables (wind, temperature, surface heat flux and so forth) which allows us to study the complex behaviours resulting from the fire-atmosphere interactions. Our fire code couples with atmospheric solvers using the OASIS3-MCT coupler and can therefore be quite flexibly coupled with different atmospheric codes. Currently we use it together with a modified CM1 atmospheric solver to study fire whirls, fire tornadoes and fire interaction with bores and gravity currents. Work to couple our fire code with the ACCESS model is under way.

Page 184

S7.2b High-Impact Weather in Research and Operatons

Submission ID: 224Presentng Author: Dragana Zovko Rajak

Session tme: THURSDAY 15:30 - 17:30

6

The Generaton of Upper-Level Near-Cloud Turbulence in a Warm-Season Mesoscale Convectve System

ZOVKO RAJAK Dragana*1; LANE Todd 2

1) University of Melbourne, d.zovkorajak@student.unimelb.edu.au; 2) University of Melbourne

This study examines a case of an actual turbulence encounter that occurred in clear air outside a convective system on 3 June 2005 using observations and convection-permitting simulations. Turbulence occurs on the eastern edge of a nocturnal mesoscale convective system and large distances from regions of active convection (i.e., large reflectivity).

Comparison of a control simulation to one in which latent heating was eliminated shows that small Richardson numbers (Ri) supportive of turbulence occurred even in the simulation without latent heating. However, area with low Ri was larger in the control simulation and near the location of reported turbulence, which is due to the increase of wind shear associated with an anticyclonic convection-induced upper-level outflow.

Additional analysis shows that there are other regions further away from the turbulence reports that have widespread areas of simulated turbulence as well as lower Ri. Here, turbulence is related to Kelvin-Helmholtz instability that occurs in the strong shear layer below the outflow jet as well as gravity waves.

This work emphasizes the importance of cloud-environment interactions and gravity waves in the generation of turbulence large distances from active convection.

Page 185

S8. Emerging methods for weather observaton

Submission ID: 87Presentng Author: Elizabeth Ebert

Session tme: FRIDAY 08:30 - 10:00

1

Fire Weather and Air Quality Predicton in the Sydney Forecast Demonstraton Project

EBERT Elizabeth1; COPE Martn 2; WAIN Alan3 ; SMITH David4; LEE Sunhee5

1) Bureau of Meteorology, e.ebert@bom.gov.au; 2) CSIRO; 3) Bureau of Meteorology; 4) Bureau of Meteorology; 5) CSIRO

The Bureau of Meteorology conducted a 10-week Forecast Demonstration Project (FDP) in Sydney during spring 2014 to demonstrate new scientific capabilities aimed at improving the accuracy of forecasts and warnings in the 0-12 hour lead time. These included experimental high resolution (1.5km grid) rapid update cycle modelling using the ACCESS model (ACCESS RUC) and improvements to radar quality control enabling assimilation into the ACCESS RUC, visualisation, and quantitative rainfall products.

A collaboration project with the NSW Office of Environment and Heritage and NSW Rural Fire Service (RFS) used the ACCESS RUC model to drive CSIRO's Chemical Transport Model (CTM) to predict bushfire smoke and air quality for a 24-hour period. It also provided input to drive the Phoenix fire spread model run at RFS. Unrelated to the RUC but of significant interest to both users were non-operational 10-day ensemble predictions of meteorological variables and fire danger indices (Forest Fire Danger Index, FFDI and Grassland Fire Danger Index, GFDI) using the pre-operational ACCESS 24-member global ensemble. All experimental products were updated daily and made available through a registered user website.

The air quality system was first tested on the State Mine fire case from October 2013, with good results. During the FDP high resolution forecasts for several chemical constituents were available on a daily basis starting in early October 2014. Although forecasts of Air Quality Index (AQI) and particulate matter (PM2.5 and PM10) were not produced in real time, forecasts for the 10-week FDP period were rerun using full chemistry and post-processed to generate AQI and PM fields, allowing a thorough evaluation to be conducted.

Verification of ensemble FFDI forecasts from April-December 2014 showed that the ensemble mean were relatively unbiased and the forecast probabilities for FFDI exceeding 25 and 50 were statistically reliable and showed good discrimination.

Page 186

S8. Emerging methods for weather observaton

Submission ID: 200Presentng Co-Author: Alan Seed

Session tme: FRIDAY 08:30 - 10:00

2

Assimilaton of Doppler winds in high resoluton NWP

RENNIE Susan1; STEINLE Peter 2; SEED Alan*3 ; YI Xiao4; CURTIS Mark5

1) Bureau of Meteorology, s.rennie@bom.gov.au

The Strategic Radar Enhancement Project initiated a major upgrade to the Bureau of Meteorology’s radar quality control (QC) system. One objective was to enable the assimilation of radial velocity observations from Doppler radars. Ultimately, the assimilation of radar observations was trialled during the Sydney Forecast Demonstration Project. Over 10 weeks observations from 9 radars were assimilated. The observations were selected on the basis of classification by the radar QC system as precipitation or insect echo.

A statistical analysis of a comparison between the observations and model via first-guess departures indicates that the assimilated observations are of sufficient quality to provide wind information. Assimilated insect observations are shown to be comparable in quality to precipitation observations after observation processing. The use of insect echoes for wind estimation can substantially increase the number of observations assimilated, and provide information when it is not raining.

The effect of assimilating these radial winds is discussed. While radars can provide high resolution observations, their range is limited and the observations are often well above the surface. The impact of wind observations on the analysis are widely spread, and so tuning of the covariances may be needed to influence smaller-scale wind features in the model.

Page 187

S8. Emerging methods for weather observaton

Submission ID: 190Presentng Author: Bronwyn Dolman

Session tme: FRIDAY 08:30 - 10:00

3

Near Real-Time Rainfall Informaton Retrieved from Wind Profling Radars

DOLMAN Bronwyn*1; REID Iain 2

1) ATRAD Pty Ltd University of Adelaide, bdolman@atrad.com.au; 2) University of Adelaide ATRAD Pty Ltd

Wind profiling radars (WPR), particularly those operating near 50 MHz, are capable of retrieving rainfall information in the vertical column above the instrument. The rainfall drop size distribution (DSD) can be retrieved through a de-convolution process, and the rainfall integral parameters such as rain rate and liquid water content can then be calculated. The vertical evolution of rainfall in the descent from cloud to ground can be studied, and examination of all data in collaboration gives insight into the micro physical processes dictating rainfall events. This information can then be used observationally, and in numerical weather prediction models. WPRs operating at higher frequencies can also retrieve rainfall information, but must be used in conjunction with a second instrument capable of retrieving simultaneous clear-air information.

The de-convolution process involved in retrieving rainfall information typically involves extensive manual effort. Recent work on quality control has allowed this process to become more automated, and progress towards near real-time retrievals. This allows the WPR to act as a rain gauge, but in addition to rain-rate, can provide information on the microphysics throughout the vertical column, and the wind field. The Australian Government Bureau of Meteorology has recently installed a network of WPRs across Australia, where this technique can potentially be employed.

A 55 MHz WPR has operated in Darwin, Northern Australia, intermittently since 2006, and sampled multiple wet seasons. Similarly, a 55 MHz WPR, in conjunction with a prototype 449 MHz UHF WPR, have been operated out of Buckland Park, a field site belonging to the University of Adelaide, located 40 km north of the city. Data from selected events from both locations will be presented, in the context of progress towards real time rainfall retrievals, and how these data can be used to calibrate scanning weather radar data in rainfall events.

Page 188

S8. Emerging methods for weather observaton

Submission ID: 146Presentng Author: David Kinniburgh

Session tme: FRIDAY 08:30 - 10:00

4

The dynamics of pyro-tornadogenesis using a coupled fre-atmosphere model

KINNIBURGH David*1

1) Monash, david.kinniburgh@monash.edu

The Australian bushfires during 2003 that reached the outer suburbs of Canberra produced a series of pyro-cumulonimbus cells and the first recorded Australian pyro-tornado during the afternoon of 18 January. Here the dynamics of these pyro-tornadoes are investigated using the model CM1. Sensible and latent fluxes are specified at the lower boundary of the model through a parameterised representation of a bushfire based on the McArthur formula and coupled to the cloud model CM1. The coupled model is initialised using the sounding taken from Wagga Wagga, located 163 km west of Canberra along with an initial fire profile. The fire-spread model then receives the required atmospheric data and updates the burning area. The burning area data is then sent to CM1 as updated sensible and latent heat fluxes where the atmospheric conditions respond to this new source of surface heat and moisture, resulting in a fully coupled fire-atmosphere system. The resulting pyro-cumulonimbus and structure of the vertical vortices are consistent with previous literature. Spatial resolution dependencies are tested, and it is shown that the fundamental structure of the generated vortex is consistent for both: uniform grid spacing of 100 m, and non-uniform grid spacing with horizontal grid spacing of 25 m in the region of the parameterized fire. Passive tracer parcels are seeded into the domain such that they enter the vortex as it reaches tornadic strength. A vorticity budget is calculated along the forward trajectories of these parcels and results show that the dominant physical process in the formation of intense vertical vorticity is the vertical tilting and stretching of buoyancy-produced horizontal vorticity near the surface. The sensitivity of vortex generation to the availability of moisture is also tested, by removing the latent heat release of the fire.

Page 189

S8. Emerging methods for weather observaton

Submission ID: 54Presentng Author: William Gail

Session tme: FRIDAY 08:30 - 10:00

5

Advances in Post-Processing to Improve Forecast Accuracy

GAIL William*1; MYERS William 2; CHERESNICK Danny3

1) Global Weather Corporation, wb.gail@comcast.net; 2) Global Weather Corporation; 3) Global Weather Corporation

Global Weather Corporation (GWC: in Boulder, Colorado, USA) provides commercial weather forecast services using post-processing technology originally developed by the USA National Center for Atmospheric Research (NCAR). The technology incorporates newly developed techniques for dynamic model output statistics, consensus model combination, forward error correction, and nowcasting. Global and regional numerical weather prediction (NWP) model data, available from many of the world's national meteorological agencies, are a primary input to the system. The core engine computes forecasts at the locations of ground-based weather stations, enabling statistical tuning and weighted combining of the underlying NWP models, which replicates the process of the human forecaster. These point forecasts are used to adjust/combine global and regional NWP forecasts for generating intermediate grids with improved accuracy over all of the underlying NWP models. A nowcast step using radar data provides low-latency, fine spatial resolution precipitation adjustments. Space-time interpolation is then employed to achieve finer resolution than is available with the intermediate grids. The result is a global forecast, readily computed at an any latitude/longitude pair, with spatial resolution as fine as 1 km, sub-hour time resolution, and 15 day lead time. GWC's forecast is routinely more accurate than all of the underlying NWP models (using common statistical metrics such as MAE and RMSE for temperature, dew point, and wind speed) and has been assessed by a third party as consistently more accurate than other commercially-available forecasts for temperature.

Page 190

S8. Emerging methods for weather observaton

Submission ID: 78Presentng Author: Kevin Rogers

Session tme: FRIDAY 08:30 - 10:00

6

Measurement of temperature and wind felds in the atmospheric boundary layer using unmanned aerial vehicles

ROGERS Kevin*1; FINN Anthony 2

1) University of South Australia, kevin.rogers@mymail.unisa.edu.au; 2) University of South Australia

Atmospheric acoustic tomography is used to estimate the 2 or 3 dimensional spatial distributions of temperature and wind in the Atmospheric Boundary Layer. Some applications of these results are atmospheric research, boundary layer meteorology, theories of atmospheric turbulence and wave propagation through a turbulent atmosphere. Most atmospheric acoustic tomography trials in the past have been based on two dimensional horizontal arrays of mast mounted speakers and microphones. The tomographic technique described in this paper uses an Unmanned Aerial Vehicle flying over a horizontal array of ground based microphones. The temperature and wind profiles are estimated using tomographic inversion derived from the sound propagation time estimates between the Unmanned Aerial Vehicle and the microphones. This paper reports on initial field trials and the results from simulation studies using realistic atmospheres generated using Large Eddy Simulation. This technique may provide a capability to measure three dimensional temperature and wind fields that is not possible using any other technique.

Page 191

LIGHTNING LECTURES - ROOM B1 - TOPICS 2,3S2.0 General - Climate - Variability and ChangeSubmission ID: 280Presentng Author: Olivier GeofreySession: Lightning Lectures Room B1Session tme: Thursday 11:30 – 12:00Posters 1Poster #15

Tropical fngerprints of low and high sensitvites in CMIP5 models

GEOFFROY Olivier*1; SHERWOOD Steve 2

1) CCRC, o.geoffroy@unsw.edu.au; 2)CCRC UNSW

Climate sensitivity is a major source of uncertainty for climate change projections. Clouds, in particular tropical low clouds, are the first source of intermodel spread of climate sensitivity of climate models. Mechanisms at play in their changes are not well understood, due to their complex coupling with the tropical circulation. I will show some relationships between climate sensitivity and the structure of the circulation in the tropics, and discuss underlying mechanisms.

Page 192

LIGHTNING LECTURES - ROOM B1 – TOPICS 2,3S2.1 Regional climate projectons and applicatons

Submission ID: 110 Presentng Author: Kewei LyuSession: Lightning Lectures Room B1Session tme: Thursday 11:30 – 12:00Posters 1Poster #19

Comparing Forced and Internal Sea Level Signals at Regional Scales in CMIP5 Models

LYU Kewei*1; ZHANG Xuebin 2; CHURCH John3 ; HU Jianyu4; SLANGEN Aimee5

1) Centre for Australian Weather and Climate Research; CSIRO Oceans and Atmosphere Flagship Hobart; Xiamen University China; kewei.lyu@csiro.au; 2)Centre for Australian Weather and Climate Research; CSIRO

Oceans and Atmosphere Flagship Hobart; 3)Centre for Australian Weather and Climate Research; CSIRO Oceans and Atmosphere Flagship Hobart; 4)Xiamen University China; 5)Centre for Australian Weather and

Climate Research; CSIRO Oceans and Atmosphere Flagship Hobart

The regional sea level usually exhibits significant internal variability, obscuring sea level change due to external forcing and also causing large uncertainties for future projections. Here, two different methods are designed to measure the relative magnitude of the forced sea level change signal and the internal sea level variability at regional scales based on CMIP5 models. The same methodologies are also applied to surface air temperature for comparing the response differences between ocean and atmosphere. The first method is to determine the time when the climate change signal exceeds and thus emerges from the background internal variability, referred to as the Time of Emergence. The amplitude of internal variability is calculated from the CMIP5 models’ pre-industrial control run. We found that the emergence of regional sea level change, when all available contributions are included, is earlier than that of surface air temperature and exhibits little dependence on the emission scenarios. The second method is to quantify the ratio of forced variance due to external forcing (anthropogenic and natural) and total variance at regional scales. A variance analysis is used to partition the total variance into internally-generated and externally-forced parts from several CMIP5 models with multiple realization runs. The spatial patterns for the ratio of forced variance largely resemble those for the Time of Emergence, with larger forced variance ratios corresponding to earlier emergence times. Averaged globally, the ratio over a fixed time length is projected to increase continually with time under the business-as-usual scenario (RCP8.5). In contrast, under the medium emission scenario (RCP4.5) the forced variance ratio declines for the surface air temperature, but stabilizes for sea level by the end of this century, indicating a slower response of the latter to climate mitigation.

Page 193

LIGHTNING LECTURES - ROOM B1 – TOPICS 2,3S2.2 Reconciling climate change and variability on decadal scales

Submission ID: 275Presentng Author: Sonya FiddesSession: Lightning Lectures Room B1Session tme: Thursday 11:30 – 12:00Posters 1Poster #25

A New Perspectve on Australian Snow

FIDDES Sonya*1; PEZZA Alex 2

1)University of Melbourne, sonya.fiddes@unimelb.edu.au; 2)University of Melbourne

The Australian Alps have a unique climatological, ecological and hydrological environment and play a key role in water supply for southeastern Australia. Using resort observations we compile a new and robust snow accumulation data set. Both maximum snow depth and total snow accumulation have declined over the last 25 years. A significant decreasing trend was observed for the total number of light snow days, whereas the total number of heavy snow occurrences has remained constant. Maximum temperatures are highly related to all snow variables. It is suggested global warming is already impacting light snowfall events, while heavy events are less affected. Insights into daily snow melt trends are also able to be gained for the first time.

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LIGHTNING LECTURES - ROOM B1 – TOPICS 2,32.2 Reconciling climate change and variability on decadal scales

Submission ID: 265Presentng Author: James RicketsSession: Lightning Lectures Room B1Session tme: Thursday 11:30 – 12:00Posters 1Poster #27

Exploring Decadal Regimes with the Maronna Bivariate Test.

RICKETTS James*1

1) Victoria University, jim.ricketts@gmail.com

The presence of climate regime shifts at decadal scale is not controversial. The Pacific Decadal Oscillation (PDO), and North Atlantic Oscillation (NAO), for example, were identified in part from correlated rapid changes of climatic variables and biological data.

Methods used for detection of abrupt regional shifts are varied, and have come from a number of disciplines.

Jones (2012) is a comprehensive analysis of regime shifts over SE Australia, using the Maronna bivariate test. This homogeneity test, documented in Vives and Jones (2005), detects a time and degree of change with a given probability, and a test statistic, Ti0.

It assumes a fully stationary exemplar series, and a similar test series, which may have exactly one instance of a shift in the mean at a single time. The use of random data as a no-change control, so performing a univariate test, is in Vives and Jones (2005).

To use the test objectively, an algorithm was developed that returns lists of shift dates in a given time series. As a univariate test, it is repeated 100 times for each date, and the modal date of these having Pr <= 0.01 are retained. The algorithm first segments the time series into two, based on the modal dates, and then continues to divide these sub-segments similarly until no shifts are found. It then repeatedly revises these provisional shifts by serially combining consecutive segments, checking for shifts within until the list is stable.

This presentation will show results of the application of this test to global mean temperature data, and several zonally averaged temperature series. The evolution of the shifts within gridded observational data will be demonstrated.

Jones, R. N. (2012). “Detecting and Attributing Nonlinear Anthropogenic Regional Warming in Southeastern Australia.” J. Geophysical Research: Atmospheres (1984--2012) 117(D4).

Vives, B. and R. N. Jones (2005). Detection of Abrupt Changes in Australian Decadal Rainfall (1890-1989), CSIRO Atmospheric Research.

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LIGHTNING LECTURES - ROOM B1 – TOPICS 2,3S2.3 ENSO and ENSO impacts - past, present and futureSubmission ID: 141 Presentng Author: Andrew DowdySession: Lightning Lectures Room B1Session tme: Thursday 11:30 – 12:00Posters 1Poster #30

Potental for Seasonal Forecastng of Thunderstorm Risk

DOWDY Andrew*1

1)Bureau of Meteorology, a.dowdy@bom.gov.au

The possibility of producing seasonal forecasts of thunderstorms and associated impacts (such as heavy rainfall, hail, strong winds, tornados, lightning and fires) is examined. Surface-based convective available potential energy (CAPE), as an indicator of conditions favourable to thunderstorm formation, is obtained from ERA-Interim reanalyses and found to be significantly related to the El Niño-Southern Oscillation (ENSO) on seasonal time scales throughout many regions of the world. The relationship between thunderstorm activity (based on satellite lightning data for the time period 1995-2013) and ENSO shows strong similarities to the relationship between CAPE and ENSO in terms of its seasonal and spatial variability throughout the world. With a view towards potential operational applications, global maps are presented of seasonal anomalies (i.e., percentage difference to the seasonal mean) in thunderstorm activity for different phases of ENSO (El Niño, Neutral and La Niña), noting that ENSO can have some predictability up to a few months in advance. In addition to ENSO, a number of other large-scale modes of atmospheric and oceanic variability are examined in relation to thunderstorm occurrence (including the Northern Annular Mode, the Southern Annular Mode, the North Atlantic Oscillation, the Pacific-North American Pattern and the Indian Ocean Dipole mode). The significant relationships between thunderstorm activity and large-scale modes of variability suggest the possibility of developing a coarse-scale method for indicating the risk of lightning occurrence (i.e. suitable for application to global climate models, based on coarse spatial and temporal scales). This possibility is examined in relation to dry lightning and fuel moisture, noting that dry-lightning is a significant ignition source for a large proportion of the area burnt by fires throughout the world.

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LIGHTNING LECTURES - ROOM B1 – TOPICS 2,3S2.4 Reconstructon and modelling of past climates to improve understanding of climate processes and future change

Submission ID: 213 Presentng Author: Michael HutchinsonSession: Lightning Lectures Room B1Session tme: Thursday 11:30 – 12:00Posters 1Poster #39

Generic Estmaton of Monthly and Daily Solar Radiaton from Rainfall and Temperature

HUTCHINSON Michael*1; KESTEVEN Jennifer 2; EVANS Brad3

1)Australian National University, michael.hutchinson@anu.edu.au; 2)Australian National University; 3)Macquarie University

Solar radiation is a primary variable in ecosystem modelling but direct measurement of solar radiation has often been limited to a relatively small number of ground stations. This has led to the development of a variety of simple regression methods to estimate daily solar radiation from other more routinely measured meteorological variables, such as transformations of daily rainfall, daily temperature range and relative humidity. When used in conjunction with readily calculated extra-terrestrial solar radiation, such methods can provide acceptable estimates of daily solar radiation at particular locations (Lui and Scott 2001). The principal limitation of these methods is that they have coefficients that are location dependent. Using solar radiation observations we have developed new general formulations for estimating both monthly and daily solar radiation with coefficients defined in terms of long term mean rainfall occurrence and long term mean daily temperature range. Since spatial estimates of the latter are readily available for Australia, the method can be used to estimate monthly and daily solar radiation with acceptable accuracy across Australia for past, present and projected future climates. The prediction accuracy for the monthly estimates is around 5% while the prediction accuracy for the daily values is around 10-15%. The method therefore offers a viable alternative to direct measurements of solar radiation when such are unavailable. Gridded solar radiation estimates for Australia obtained with this method are being made generally available as part of ANUClimate spatial models for the eMAST facility of the Terrestrial Ecosystem Research Network.

eMAST 2015. Ecosystem Modelling and Scaling Infrastructure, Terrestrial Ecosystem Research Network. http://www.emast.org.au/

Lui, D.L. and Scott, B.J. 2001. Estimation of solar radiation in Australia from rainfall and temperature observations. Agricultural and Forest Meteorology 106: 41-59.

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LIGHTNING LECTURES - ROOM B1 – TOPICS 2,3S2.4 Reconstructon and modelling of past climates to improve understanding of climate processes and future change

Submission ID: 52 Presentng Author: Acacia PeplerSession: Lightning Lectures Room B1Session tme: Thursday 11:30 – 12:00Posters 1Poster #41

Zonal Winds and Southeast Australian Rainfall in Observatons and Models

PEPLER Acacia*1; ALEXANDER Lisa 2; EVANS Jason3

1)University of New South Wales, a.pepler@student.unsw.edu.au; 2)University of New South Wales; 3)University of New South Wales

The Great Dividing Range acts as a major divide in the climate of southeast Australia. Periods of enhanced westerly wind flow bring rain-bearing weather systems to much of southeast Australia during the cool season, but result in below-average rainfall along the east coast. Over the past several decades, there has been an observed southward shift in these westerlies, contributing to long-term cool season rainfall declines in much of southeast Australia.

While global climate models adequately represent the seasonality of zonal windflow across southeast Australia, the coarse resolution means the topography of the Great Dividing Range is poorly represented. We show that this has large impacts on their ability to represent the historical relationships between zonal windflow and rainfall variability. While regional downscaling is found to improve on these results through better representation of topographic features, particularly when applied to a poorly-performing model, they are also unable to fully correct for biases in the driving climate model. This suggests that both global and regional climate models may have difficulties in translating future trends in atmospheric circulation to their associated impacts.

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LIGHTNING LECTURES - ROOM B1 – TOPICS 2,3S2.4 Reconstructon and modelling of past climates to improve understanding of climate processes and future changeSubmission ID: 176 Presentng Author: Steven SherwoodSession: Lightning Lectures Room B1Session tme: Thursday 11:30 – 12:00Posters 1Poster #42

Atmospheric changes through 2012 as shown by iteratvely homogenised radiosonde temperature and wind data

SHERWOOD Steven*1; NISHANT Nidhi 2

1)UNSW, s.sherwood@unsw.edu.au; 2)UNSW

We present an updated version of the radiosonde dataset homogenised by Iterative Universal Kriging (IUKv2), now extended through February 2013, following the method used in the original version (Sherwood et al. 2008). This method, in effect, performs a multiple linear regression of the data onto a structural model that includes both natural variability, trends, and time-changing instrument biases, thereby avoiding estimation biases inherent in traditional homogenisation methods. One modification now enables homogenised winds to be provided for the first time. This, and several other small modifications made to the original method sometimes affect results at individual stations, but do not strongly affect broad-scale temperature trends.

Temperature trends in the updated data show three noteworthy features. First, tropical warming is equally strong over both the 1959-2012 and 1979-2012 periods, increasing smoothly and almost moist-adiabatically from the surface (where it is roughly 0.14 K/decade) to 300 hPa (where it is 0.25-0.3 K/decade over both periods), a pattern very close to that in climate model predictions. This contradicts suggestions that atmospheric warming has slowed in recent decades or that it has not kept up with that at the surface. Second, as shown in previous studies, tropospheric warming does not reach quite as high in the tropics and subtropics as predicted in typical models. Third, cooling has slackened in the stratosphere such that linear trends since 1979 are about half as strong as reported earlier for shorter periods.

Wind trends over the period 1979-2012 confirm a strengthening, lifting and poleward shift of both subtropical westerly jets; the northern one shows more displacement and the southern more intensification, but these details appear sensitive to the time period analysed. There is also a trend toward more easterly winds in the middle and upper troposphere of the deep tropics.

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LIGHTNING LECTURES - ROOM B1 – TOPICS 2,3S3.1 Climate and human health

Submission ID: 51Presentng Author: Mia GrossSession: Lightning Lectures Room B1Session tme: Thursday 11:30 – 12:00Posters 2Poster #55

Projectons of heatwaves using a Regional Climate Model ensemble for NSW and the ACT

GROSS Mia1; GREEN Donna* 2; ALEXANDER Lisa3 ; MACADAM Ian4

1)UNSW, mia.gross89@gmail.com; 2)UNSW; 3)UNSW; 4)UNSW

Climate change is increasing the occurrence of extremely hot temperatures in Australia. Increased temperatures affect a number of sectors, with the impacts on the human health sector being one of significant concern. The impacts on human health due to heat extremes are already apparent in Australia, with hundreds of additional deaths from heatwaves occurring in the south-east of the country during the summers of 2009 and 2013. To reduce the future human health burden, it is important to understand and predict these events. State-of-the art regional climate models suggest that the duration, frequency and intensity of heatwaves in Australia will increase. Evaluations of changes in such events enables health policy and planning initiatives to pro-actively adapt to these projected changes in extremes. The results presented here focus on the excess heat factor to analyse both recent simulations and future projections of various aspects of heatwaves for the New South Wales and Australian Capital Territory region. I used the NSW/ACT Regional Climate Modelling (NARCliM) project to evaluate a coarse and high-resolution domain for both raw and bias-corrected model output against recent observations. Further, projections for each of the heatwave aspects for the period 2060-2079 were made. Inferences on the health impacts were made based on the components of excess heat and heat stress included in the calculation of the excess heat factor. Overall, results indicated that bias-correction did not dramatically affect the indices, nor did the use of a higher-resolution dataset. Future projections indicated increases over the entire state in all heatwave aspects. In particular, a spatial pattern was found, in which coastal stations were projected to experience a greater increase in the length and frequency of heatwaves, and smaller increases in the intensity of events.

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LIGHTNING LECTURES - ROOM B1 – TOPICS 2,3SS3.1 Climate and human health

Submission ID: 84Presentng Author: Melissa HartSession: Lightning Lectures Room B1Session tme: Thursday 11:30 – 12:00Posters 2Poster: # 56

Forecastng Air Polluton Impacts from Hazard Reducton Burns

HART Melissa*1; JIANG Ningbo2

1) ARC Centre of Excellence for Climate System Science University of New South Wales, melissa.hart@unsw.edu.au; 2) NSW Office of Environment and Heritage

Hazard reduction burns are vital to reduce the severity of bushfires. The NSW 2021 Plan aims to increase the annual average area treated by hazard reduction activities by 45%, by 2016, in order to limit bushfire activity. However, if hazard reduction burns are undertaken during unfavourable meteorological conditions, they have the capacity to trigger extreme air pollution events. Air pollution events associated with bushfires have been associated with extreme health impacts, including increased hospital admissions and death.

This poster will provide an overview of the development of a tool for forecasting air pollution impacts caused by hazard reduction burns over the Greater Sydney region. Incorporated into the forecasting tool is an analysis of the meteorological controls on bushfire pollutant dispersion from historical fires, both prescribed and non-prescribed. This involves individual burn characteristics including: size, location and length of burn, and resultant air pollutant concentrations compared to background concentrations.

This forecasting tool is expected to improve planning of burn times to reduce extreme pollution risk to the community, while still allowing NSW land managers and fire agencies to carry out this vital work. It is envisaged that this tool will become part of the NSW Office of Environment and Heritage’s operational air quality forecasting framework (AQFF).

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LIGHTNING LECTURES - ROOM B1 – TOPICS 2,3SS3.3 EnergySubmission ID: 269Presentng Author: Willow HallgrenSession: Lightning Lectures Room B1Session tme: Thursday 11:30 – 12:00Posters 2Poster #59

The Impact of the El Nino Southern Oscillaton on Wind Resources in Australia and New Zealand

HALLGREN Willow*1; GUNTURU Bhaskar 2

1) Griffith University, whallgren@tpg.com.au; 2) King Abdullah University for Science and Technology (KAUST)

Australia has very good wind resources, and wind power accounts for over one-quarter of all renewable energy generated. Variability and intermittency are the biggest hurdles in the large scale deployment of wind power generation, impacting the economics of power generation and capacity planning. The El Nino Southern Oscillation (ENSO) has significant impacts on many weather variables including precipitation and solar radiation, and on the wind power resource in other parts of the world. To date, the impact of ENSO on Australia's wind resources has not been well studied. This study uses the Multivariate El-Nino Index and the a wind power density (WPD) field at an 80 m hub height constructed from MERRA data to explore the impact of ENSO on Australia's wind power resources. Composites of the WPD anomalies for days corresponding to El-Nino were calculated for Australia and New Zealand (a). Also calculated were (b) the variance of WPD associated with El Nino events, (c) the difference between the frequency of high wind events during El-Nino and the frequency during neutral conditions, and (d) the difference in the average magnitude between high wind events during El nino and the high wind events during neutral conditions. (c) and (d) are also calculated for low wind events (e,f),; (a)-(f) were calculated for La Nina events. Notable results for (a) were increases in the wind resource in the Top End, Tasmania, and NZ, and weak decreases elsewhere during El Ninos. Weak decreases were seen throughout most of Australia and NZ during La Ninas. The strongest increases in WPD variance (b) occurred in western and northern Australia, during La Ninas. Variance decreased most along the southern coast of Australia, and northern QLD during La Ninas. The changes in the frequency of both high and low wind events also was greatest during La Nina, with moderate increases of low wind throughout most of Australia and NZ. High wind frequency changes were generally weaker and patchier.

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LIGHTNING LECTURES - ROOM B2 – TOPICS 4, 5S4.1 Circulaton and Climate Variability in the Indian OceanSubmission ID: 315 Presentng Author: Helen PhillipsSession: Lightning Lectures Room B2Session tme: Thursday 11:30 – 12:00Posters 1Poster #46

Bio-Argo Floats Reveal Subsurface Structure of Southeast Indian Ocean Eddies

PHILLIPS Helen*1; PUMP Sylvia 2; DURAN Earl3 ; STRUTTON Pete4; TRULL Tom5

1)University of Tasmania, h.e.phillips@utas.edu.au; 2)University of Tasmania; 3)University of Tasmania; 4)University of Tasmania; 5)CSIRO

There is increasing recognition that eddies play an influential role in the productivity of open ocean waters, and that this influence depends on both eddy sources and the nature of their evolution. Eddies in the southeast Indian Ocean have been recognised, from satellite remote sensing of sea surface height and ocean colour, as particularly influential pathways for the westward transport of elevated biomass from the eastern boundary Leuuwin Current into the otherwise highly oligotrophic central South Indian Ocean. Further it has been hypothesized that processes at the base of the surface mixed layer within some of these eddies stimulate production and allow biomass to persist for much longer than would be expected from passive transport alone.

Here we present high-frequency profiles of temperature, salinity, biomass and oxygen concentrations in one anti-cyclonic and one cyclonic eddy in the South Indian Ocean. Satellite sea surface height data confirmed both profiling floats remained trapped within their respective eddies from winter to early summer 2012, sampling the upper 300 m of the water column 6-8 times per day. The eddies were larger than average for this region, with mean amplitude and radius of 18.1 (19.3) cm and 143 (97) km for the anticyclonic (cyclonic) eddy.

The total concentration of chlorophyll in the mixed layer remained relatively constant, although its vertical distribution changed over time: from September to October, it was evenly distributed throughout the mixed layer of both eddies; with the onset of spring warming, the chlorophyll became concentrated at greater depth with less chlorophyll at the surface. Satellite measurement of surface chlorophyll was 3-5 times lower than the float surface measurement throughout the record. There was no significant change in oxygen saturation state coincident with high phytoplankton concentration. No biological production was evident in either eddy. We discuss these and other results.

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LIGHTNING LECTURES - ROOM B2 – TOPICS 4, 5SS4.1 Circulaton and Climate Variability in the Indian OceanSubmission ID: 255Presentng Author: Craig SteinbergSession: Lightning Lectures Room B2Session tme: Thursday 11:30 – 12:00Posters 1Poster #47

Real-Time Marine Observing Systems in Australian Tropical Seas

RIGBY Paul1; STEINBERG Craig* 2; WILLIAMS David3 ; BRINKMAN Gary4; BRINKMAN Richard5 ; TONIN Hemerson6 ; Hughes David7

1)AIMS, p.rigby@aims.gov.au; 2)AIMS; 3)AIMS; 4)AIMS; 5)AIMS; 6)AIMS; 7)CSIRO

The well being and prosperity of Australia is strongly linked to the ocean, with most of the population living in highly urbanised centres along a narrow coastal strip. Infrastructure development and population growth along the coast will continue to place growing pressure on the marine environment and its natural resources, requiring a knowledge-based approach to the management of risks to these assets. Decision making around sea level rise, storms and extreme events, shipping and maritime operations, fisheries and aquaculture, and marine park zoning must be informed by an understanding of coastal ocean processes, their drivers, and ecosystem responses. This requires both coastal and open ocean observations.

Since 2007, these observations have been provided by the Integrated Marine Observing System (IMOS). IMOS is funded by the Australian Government and designed to be a fully-integrated national array of observing equipment to monitor the oceans and coastal marine environment around Australia, covering physical and biogeochemical variables. Near real time data delivered by IMOS comprises observations from a wide spectrum of platforms however the focus here is on the oceanographic moorings.

When data from ocean observing systems can be provided in near real-time, the operational aspects are possible and provide potential for a range of value added products to be developed. Here we provide 3 examples of co-invested partnerships that have facilitated the development of real-time ocean observing systems in the coastal and outer shelf, operated by the Queensland and Northern Australian moorings & National Reference Station sub-facilities of IMOS. These examples demonstrate the benefits of having a national collaborative approach to marine observing with a clear focus on open access to data. Increasingly the data uptake by modelling has matured through eReefs modelling of the Great Barrier Reef and other higher resolution efforts such as in Darwin Harbour.

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LIGHTNING LECTURES - ROOM B2 – TOPICS 4, 5S5.1 A review of Australian coastal upwellingSubmission ID: 253Presentng Author: Joshua ReinkeSession: Lightning Lectures Room B2Session tme: Thursday 11:30 – 12:00Posters 2Poster: #61

Coastal fronts and upwelling areas utlised by migratng humpback whales, Megaptera novaeanglia, on the Gold Coast, Australia

REINKE Joshua*1; LEMCKERT Charles 2; MEYNECKE Olaf3

1)Griffith University, joshua.reinke@griffithuni.edu.au

Humpback whales take part in an annual migration from polar feeding grounds in summer to tropical breeding grounds in winter. Large scale migration patterns are well known; however, small scale distribution and relationships with environmental conditions have received less attention. Protection from threats and predicting the effects of climate change requires knowledge of preferred habitat and reasons behind the preferences.

East Australian humpback whales travel from the Southern Ocean, along the east coast of Australia, to the Great Barrier Reef (or further) to breed. This environment is dominated by the East Australian Current, the western boundary current of the South Pacific Ocean, carrying warm water poleward from the tropics. This current, as well as strong northerly winds, is responsible for generating upwelling on the coast and providing nutrients. Sharp temperature changes are experienced at the border of the warm current and the cool upwelled waters.

This study investigates relationships between humpback whale distribution and environmental conditions on the Gold Coast, Australia. This area is used during the northern and southern migration and provides a rest stop for mothers and calves on the return journey. Whale distribution was recorded using boat and land based surveys. Environmental parameters included bathymetry, remote sensed sea surface temperature and chlorophyll a concentration, as well as their derived gradients. The conditions observed at the whales’ locations were compared with the average across the study area using paired sample t-tests.

First outcomes of the study suggest a preference for cooler waters and in areas with a strong temperature gradient. The higher productivity in upwelled water and fronts may provide a chance of opportunistic feeding, a rare occurrence on the prolonged journey. Following particular hydrodynamic features such as these, which generally run parallel to the shore, may also serve as a tool for navigation.

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LIGHTNING LECTURES - ROOM B2 – TOPICS 4, 5S5.2 Ocean mixing matersSubmission ID: 22Presentng Author: Paul HartlippSession: Lightning Lectures Room B2Session tme: Thursday 11:30 – 12:00Posters 2Poster: # 62

Observed Internal Tides on the contnental shelf of Eastern Australia

HARTLIPP Paul*1; ROBERTSON Robin 2; BELL Mathew3

1)UNSW Canberra, p.hartlipp@adfa.edu.au; 2)UNSW Canberra; 3)UNSW Canberra

Internal tides both affect the stratification and are affected by the stratification. Without stratification, internal tides do not exist. At the same time, internal tides induce mixing, which reduces the stratification. Observational temperature and velocity data from over 15 moorings from the Integrated Marine Observing System (IMOS) was used to investigate the internal wave and tidal fields off eastern Australia. Conditions differed between the coastal regions and the deep waters and with latitude in the coastal regions. In the deep basin, beams of semidiurnal internal tides appear to emanate from the continental shelf/slope break. On the continental shelf, the internal tidal situation is more complex, particularly in shallower waters. Typically, the water column on the continental shelf was predominantly represented by two layers. However, mixing events would occur on 5-7 day intervals, particularly in the shallow waters (< 100 m), and homogenize the water column. The water column would then restratify over the next few days until the next mixing event occurred. When the water column was relatively homogenous, internal tides would essentially be absent. As the water column stratified, they would reappear. Additionally, there was a strong overtide signal in the North-South velocities, with the high frequency energy exceeding both the diurnal and semidiurnal energies.

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LIGHTNING LECTURES - ROOM B2 – TOPICS 4, 5S5.2 Ocean mixing matersSubmission ID: 62Presentng Author: Andreas KlockerSession: Lightning Lectures Room B2Session tme: Thursday 11:30 – 12:00Posters 2Poster: #63

A regime diagram for ocean geostrophic turbulence

KLOCKER Andreas*1; MARSHALL DavidP 2; KEATING Shane3 ; READ PeterL4

1)University of Tasmania, andreas.klocker@utas.edu.au

A two-dimensional regime diagram for geostrophic turbulence in the ocean is constructed by plotting observation- based estimates of the nondimensional eddy radius and unsuppressed mixing length against a nonlinearity parameter equal to the ratio of the root-mean square eddy velocity and baroclinic Rossby phase speed. This regime diagram is then interpreted in terms of pertinent regime transition lines which refer to boundaries along which there is change in dynamical behaviour due to the dominance of different physical processes to either side of the transition.

For weak nonlinearity, as found in the tropics, the mixing length mostly corresponds to the stability threshold for baroclinic instability whereas the eddy radius corresponds to the Rhines scale; it is suggested that this mismatch is indicative of the inverse energy cascade that occurs at low latitudes in the ocean and the zonal elongation of eddies. At larger values of nonlinearity, as found at mid- and high-latitudes, the eddy length scales are much shorter than the stability threshold, within a factor of 2.5 of the Rossby deformation radius.

Finally implications for the construction of parameterizations of geostrophic eddies will be discussed, specifically for mixing length arguments which are used to express the eddy diffusivity as proportional to an eddy velocity multiplied by an eddy length scale.

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LIGHTNING LECTURES - ROOM B2 – TOPICS 4, 5S5.2 Ocean mixing matersSubmission ID: 136Presentng Author: Byju PookkandySession: Lightning Lectures Room B2Session tme: Thursday 11:30 – 12:00Posters 2Poster: #64

Areas of Re-emergence of Sea Surface Temperature Anomalies in the Global Oceans from Observatons and Model Simulatons.

POOKKANDY Byju*1; DOMMENGET Dietmar 2

1) Monash University, byju.pookkandy@monash.edu; 2) Monash University

Re-emergence is the mechanism through which Sea surface temperature (SST) anomalies formed in winter over a deep mixed layer are trapped beneath the shallow summer mixed layer and then re-entrained into the deepening mixed layer during the next fall or winter season. This persistence of winter-to-winter SST anomalies is mostly perceived in the midlatitude oceans, where the annual variability in mixed layer is deep. It thus provides a mechanism for long lead seasonal predictions.

We detect re-emergence areas of SST anomalies in the world oceans using ocean reanalysis datasets, CMIP model simulations and a single column mixed layer ocean model (KPP) coupled to ACCESS. It is revealed that re-emergence is far more widespread than previously thought. It not only exists through out the midlatitudes of the Southern and Northern hemisphere, but also in the subtropics and even in the tropics. We also find evidence for re-emergence from warm seasons to warm season and anti-correlation between cold and warm season SST anomalies. The CMIP and KPP model simulations show results consistent with the observations.

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LIGHTNING LECTURES - ROOM B2 – TOPICS 4, 5S5.3 Variability of physics and biogeochemistry in semi-enclosed and shelf seasSubmission ID: 235Presentng Author: Moninya RoughanSession: Lightning Lectures Room B2Session tme: Thursday 11:30 – 12:00Posters 2Poster: #66

Observaton impact in Australia’s Western Boundary Current

KERRY Colete1; ROUGHAN Moninya* 2; OKE Peter3 ; POWELL Brian4

1)UNSW Australia, c.kerry@unsw.edu.au; 2)UNSW Australia; 3)CSIRO; 4)University of Hawaii

The East Australian Current forms the western boundary current of the south pacific sub-tropical gyre. The vigorous current flows as a jet over the narrow shelf, shedding vast eddies at the highly variable separation point. These characteristics alone make it a dynamically challenging region to measure, model and predict.

In a first step toward improving our circulation models and our dynamical understanding of the circulation, we developed a high resolution re-analysis of the East Australian Current. In addition to the traditional data streams (SST, SSH and ARGO) we exploit the newly available IMOS observations in the region. These include velocity and hydrographic observations from the recently deployed EAC transport array, 1km HF radar measurements of surface currents near the EAC separation zone, more than 40,000 CTD casts on the shelf from ocean gliders, and 300 million velocity measurements from a network of shelf mooring arrays.

We use the ROMS (Regional Ocean Modeling System) 4D-Var assimilation tools to combine all of the available satellite, IMOS, and ARGO data streams with the model fields providing a reanalysis of the ocean state at 6km resolution over this period. This reanalysis provides our best estimate of the EAC/shelf exchange along the east coast to assist with a number of local studies. We define metrics that describe key dynamics of the EAC and its separation from the coast (e.g volume transport) and quantify how the observations contribute to our understanding of these circulation metrics. This allows us to assess the impact of particular data streams on our circulation estimates and provides information vital in assessing and improving the observing system design for Australia's western boundary current.

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LIGHTNING LECTURES - ROOM B2 – TOPICS 4, 5S5.3 Variability of physics and biogeochemistry in semi-enclosed and shelf seasSubmission ID: 160Presentng Author: Jennifer SkerratSession: Lightning Lectures Room B2Session tme: Thursday 11:30 – 12:00Posters 2Poster: #68

The eReefs marine model suite: tools for beter quantfying and understanding the Great Barrier Reef circulaton and water quality.

SKERRATT Jennifer1; BAIRD Mark* 2; MONGIN Matheiu3 ; ROBSON Barbara4; RIZWI Farhan5 ; WILD-ALLEN Karen6

1)CSIRO O&A, jennifer.skerratt@csiro.au; 2)CSIRO O&A; 3)CSIRO O&A; 4)CSIRO O&A; 5)CSIRO O&A; 6)CSIRO O&A

The Great Barrier Reef is under threat from catchment-derived human impacts and climate change. Through the eReefs Project , a suite of hydrodynamic, sediment, spectrally-resolved optical model and biogeochemical models have been developed. Here we describe the modelling system, including the ability to deploy relocatable high resolution embedded models, and the introduction of GBR-tailored biogeochemical processes such as carbon chemistry, corals, and improved seagrass and macroalgae models. We show results of the model together with comparisons to remote sensing, IMOS and NRS moorings and bottle observations to show how the model can be used to gain better understanding of carbon chemistry and biogeochemical dynamics close to the coast and on the reef. The biogeochemistry module of the eReef model is now run in near real time and historical model runs can be updated with model improvements and compared with observations. For further details and animation results from the near real time biogeochemistry see www.emg.cmar.csiro.au.

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LIGHTNING LECTURES - ROOM B2 – TOPICS 4, 5S5.4 The Global Infuence of the Southern Ocean and Antarctc SeasSubmission ID: 152 Presentng Author: Benoit PasquierSession: Lightning Lectures Room B2Session tme: Thursday 11:30 – 12:00Posters 2Poster #69

The plumbing of the global biological pump

PASQUIER Benoit*1; HOLZER Mark2

1) UNSW, b.pasquier@student.unsw.edu.au; 2) UNSW

We quantify the timescales and pathways that set the efficiency of the biological pump (the fraction of the phosphate inventory that is regenerated). We use a data-constrained phosphorus-cycling model embedded in a steady data-assimilated ocean circulation to quantify the pump’s leaks of preformed phosphate, its sources of regenerated phosphate, and the pathways with which the combined biogenic particle transport and the water circulation teleconnect different regions of the global euphotic zone. These pathways are quantified by a path density, which is the concentration of phosphate that was last utilized in a region A and that will reemerge into the euphotic zone of a region B, partitioned according to the A-to-B transit-time. Suitable integrals of this path density, computed efficiently by direct matrix inversions, yield the phosphate mass in transit, its flow rate, and its residence time in the aphotic zone. We find that a pump efficiency of (39 ± 2)% has dominant contributions from the Eastern Equatorial Pacific (25 ± 1)%, from the Southern Ocean (SO) (21 ± 1)%, and from the Eastern Equatorial Atlantic (EEqA) (12 ± 1)%. The pump’s 61% leak originates predominantly in the SO (75%) and in the SubPolar North Atlantic (17%). While the SO euphotic zone is a large leak of preformed phosphate, it is also the major receptor of phosphate reemerging from depth: The SO euphotic zone is the destination of (62 ± 6)% of the regenerated inventory and of (69 ± 5)% of the preformed inventory. The mean interior residence time of regenerated phosphate reemerging in the SO depends on where it was last utilized: 69 ± 1 years if last utilized in the SO and 500 ± 20 years if last utilized outside the SO. The transit-time distribution of the mass of regenerated phosphate last taken up in the EEqA and reemerging in the SO euphotic zone is bimodal, pointing to two distinct pathways which are quantified using the phosphate path density.

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LIGHTNING LECTURES - ROOM B3 – TOPICS 1,6,7,8S1.2 Forecastng, Characterising and Communicatng Extreme Weather and Climate EventsSubmission ID: 183 Presentng Author: Steefan ContractorSession: Lightning Lectures Room B3Session tme: Thursday 11:30 – 12:00Posters 1Poster #12

Investgatng The Efect Of Interpolaton On Daily Precipitaton And Extremes

CONTRACTOR Steefan*1

1) University of New South Wales, s.contractor@unsw.edu.au

Station-based daily precipitation data for Australia were obtained from the Global Historical Climatology Network-Daily dataset and gridded onto a 0.5°x0.5° latitude/longitude grid over the period 2004-2013. Around 5000 stations had available data over this period. Six gridding methods (Inverse Distance Weighting, Natural Neighbour, Barnes Optimal Interpolation, Bilinear, Bicubic and Kriging) were used to investigate the effect of interpolation on the resulting (1) daily and monthly grids and (2) precipitation indices that reflect more extreme events. Results are also compared with existing datasets available for Australia including datasets based on remote sensing. By highlighting the disagreement between various gridded datasets we aim to emphasize the uncertainty in interpreting trends in and variability of precipitation extremes based on such interpolated datasets. This presentation will outline the strengths and weaknesses of each interpolation method and discuss the parametric and structural uncertainties which can influence the assessment of precipitation extremes, an important consideration in model evaluation and communicating impacts of extremes.

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LIGHTNING LECTURES - ROOM B3 – TOPICS 1, 6, 7, 8S1.2 Forecastng, Characterising and Communicatng Extreme Weather and Climate Events

Submission ID: 125 Presentng Author: Daniel PazminoSession: Lightning Lectures Room B3Session tme: Thursday 11:30 – 12:00Posters 1Poster #14

Bushfre Danger in the Southern Hemisphere: Investgatng Seasonal Predictability and Circulaton Links

PAZMINO Daniel*1

1) University of Melbourne, danielpv@student.unimelb.edu.au

Bushfires cause great human, environmental and economic losses around the world. In the southern hemisphere, this problem is particularly severe in Australia where extensive research has been developed. Extreme bushfire seasons also occur in this hemisphere in several countries in South-America, which has generated lees documentation on this issue. Unfortunately, South-South research cooperation in this topic has not been very active. Regional climate in both continents is largely affected by climate modes of variability such as ENSO; which raises the question if there are common large-scale circulation patterns driving bushfire danger? If common patterns exist, what are the implications for seasonal predictability in both regions? This investigation aims to answers these questions with case studies in Victoria, Australia and Ecuador. Seasonal bushfire danger in these regions will be explored using the McArthur Forest Fore Danger Index (FFDI), since these two regions also share the eucalyptus as dominant specie in bushfire prone areas. This analysis will be conducted with weather station as well as reanalysis data from the 20th Century Reanalysis Project. Preliminary results for Victoria demonstrate that seasonal bushfire danger, measured as the spatially averaged cumulative sum of FFDI values in the season December-January-February, has increased 16% in the period 2000-2010 compared to the period 1919-1999.S2.0 General - Climate - Variability and Change

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LIGHTNING LECTURES - ROOM B3 – TOPICS 1, 6, 7, 8S7.0 General meteorology - generalSubmission ID: 247Presentng Author: Jenny AhnSession: Lightning Lectures Room B3Session tme: Thursday 11:30 – 12:00Posters 2Poster: #71

Aircraf Observatons of Microphysical Propertes of Winter-tme Low Alttude Cloud over The Sothern Ocean

AHN Jenny*1

1)Monash University, jenny.ahn@monash.edu

Cloud cover is the largest source of variability in defining the Earth’s albedo, and thus the Earth’s net energy budget. Over the Southern Ocean, the region of the globe with the highest fractional cloud cover, large biases exist in the energy budget and have been attributed to poor representations of the cloud cover. Large seasonal cycles in the effective radius and cloud droplet number concentration (CDNC) have been observed at part of the Southern Ocean Cloud Experiments (SOCEX I & II) of the 1990s, and were attributed to the dimethylsulphide (DMS) emissions of phytoplankton (i.e. the CLAW hypothesis, which has since come into question.) Satellite retrievals of these parameters suffer from uncertainty given the unique nature of the microphysics of SO clouds and the poor viewing angle during the winter months.

In this study we revisit the SOCEX observations of effective radius and CDNC using in-situ cloud microphysics observations taken from the Hydro Tasmania aircraft for two winter-time seasons (May-October, 2013 & 2014). Pristine (baseline) cloud conditions are explored as well as potential anthropogenic plumes in non-baseline conditions. In-situ observations are employed to evaluate Moderate Resolution Imagine Spectroradiometer (MODIS) satellite products, where available. A few limited flights were made to directly evaluate A-train observations (CloudSat, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) and MODIS).

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LIGHTNING LECTURES - ROOM B3 – TOPICS 1, 6, 7, 8Submission ID: 281Presentng Author: Duncan AckerleySession: Lightning Lectures Room B3Session tme: Thursday 11:30 – 12:00Posters 1Poster #49

The representaton of north Australian rainfall in CMIP5

ACKERLEY DUNCAN*1

1)Monash University, duncan.ackerley@monash.edu

As general circulation models (GCMs) are routinely used to make projections of future rainfall, it is important to assess whether the processes that cause precipitation are represented well. If those processes are poorly represented then it is important to identify and account for them in order to make the best projections. The work presented here identifies some of the features that are important for producing rainfall over northern Australia in a selection of CMIP5 models run under Atmospheric Model Intercomparison Project (AMIP) conditions (prescribed sea surface temperatures). The diurnal cycle of the low-level flow around the north-west Australian heat low is represented well; however, the nocturnal rearrangement of the flow leads to night-time convergence and then to convective rainfall. This forced convection is unlikely to occur in the real world; however, this forced nocturnal precipitation is an important contributor the modelled total precipitation in this region. Interestingly, the occurrence of such rainfall in these simulations (associated with convergence within the heat low overnight) may not be restricted to Australia. The models also produce precipitation too early in the day, which is associated with the early triggering of convection from surface heating.

Despite these errors in the timing of precipitation, the CMIP5 models assessed here are capable of representing the synoptic features responsible for initiating rain. Moreover, there is evidence that some of these systems have their origins in the mid-latitudes. Nevertheless, errors in the modelled seasonal mean precipitation appear to be associated with both the strength of the mean northerly flow onto the continent and the vertical mass flux over the continent. Furthermore, there is also evidence that it is ultimately the representation of convection in these models that is the important contributor to the precipitation biases identified, and not the synoptic features that initiate it.

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LIGHTNING LECTURES - ROOM B3 – TOPICS 1, 6, 7, 8S6.0 General – Tropical/Subtropical oceanographySubmission ID: 163Presentng Author: Michael GraySession: Lightning Lectures Room B3Session tme: Thursday 11:30 – 12:00Posters 1Poster #50

Surface Energy and Radiaton Budgets for a Subtropical Groundwater Dependent Ecosystem under Extreme Changes in Surface Conditons

GRAY Michael*1

1) UQ, m.gray@uq.edu.au

Subtropical sand islands have received little attention in regards to the measurement of surface-atmosphere exchanges of heat, moisture, and radiation. The state-of-the-art eddy covariance method was used to monitor surface-atmosphere energetics over a groundwater dependent swamp on Bribie Island in Southeast Queensland from December 2012 to February 2013.

The first stage of the measurement period was hot and unusually dry with the water table below the surface. This was followed by a bushfire, which led to a greater than 50 % decrease in upwelling shortwave radiation (mean daily maximums: pre-fire 99 Wm-2; post-fire 46 Wm-2), a 25 % increase in upwelling longwave radiation (503 Wm-2 to 629 Wm-2), and a subsequent 15 % decrease in net radiation (911 to 750 Wm-2). Sensible heat was more significant than latent heat in the energy balance of the pre-fire environment (mean daily maximums of 306 Wm-2 and 169 Wm-2 respectively); while post-fire this dominance increased (mean daily maximums of 457 Wm-2 and 90 Wm-2 respectively).

After two weeks of post-fire landscape recovery a significant rainfall event of 275 mm in three days inundated the swamp. This resulted in net radiation increasing to values similar to the pre-fire environment, caused primarily by a decrease in upwelling longwave radiation from 629 Wm-2 (post-fire) to 494 Wm-2. With water as the primary surface feature, the energy balance was dominated by latent heat (mean daily maximum 185 Wm-2) with sensible heat less than one-third the value of the pre-fire environment (mean daily maximum 105 Wm-2).

When considered on a landscape wide scale, these changes in surface energetics are likely to produce alterations in boundary layer characteristics, but the extent to which this occurs is as yet unknown. Future work on this case study will investigate these processes using the WRF model.

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LIGHTNING LECTURES - ROOM B3 – TOPICS 1, 6, 7, 8S6.3 Maritme Contnent: processes, weather and climateSubmission ID: 182Presentng Author: Martn BergemannSession: Lightning Lectures Room B3Session tme: Thursday 11:30 – 12:00Posters 1Poster #53

Meso-scale forcing of Maritme Contnent rainfall

BERGEMANN Martn*1; JAKOB Christan 2; LANE Todd3

1) Monash University, martin.bergemann@monash.edu; 2)Monash University; 3)University of Melbourne

An area that is particularly poorly represented in current numerical weather forecast and general circulation models (GCMs) is the Maritime Continent, where most models produce too much rain over the ocean areas and too little over land. One factor that contributes to difficulties in the representation of precipitation over the Maritime Continent area is the diurnal-cycle and thus precipitation due to land-sea interaction.

Coastal assciated precipitation is identified using an objective algorithm. The strength of this method is that it is based soley on rainfall.

The large-scale forcing under which the detected coastal associated rainfall over the Maritime Continent occurs is investigated and compared to the forcing for total rainfall. It is shown that coastal associated rainfall is much less dependent on the large-scale state of the atmosphere than total precipitation.

Parametrizations in GCMs are based on large-scale forcing variables. Since the objective algorithm shows that major portions of the Maritime Continent precipitation is related to land-sea interaction (meso-scale), we conclude that the Maritime Continent rainfall can not be well captured by GCMs. Thus, we propose a stochastic parametrisation scheme that is able to model rainfall occurring on meso-scales.

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LIGHTNING LECTURES - ROOM B3 – TOPICS 1, 6, 7, 8S7.2 High-Impact Weather in Research and OperatonsSubmission ID: 116Presentng Author: Will ThurstonSession: Lightning Lectures Room B3Session tme: Thursday 11:30 – 12:00Posters 2Poster: #78

Large-Eddy Simulatons of Pyro-Convecton and its Sensitvity to Environmental Conditons

THURSTON Will*1; TORY Kevin 2; FAWCETT Robert3 ; KEPERT Jefrey4

1)Bureau of Meteorology, w.thurston@bom.gov.au; 2)Bureau of Meteorology; 3)Bureau of Meteorology; 4)Bureau of Meteorology

Intense heating of air in the vicinity of a bushfire leads to deep ascent. If this ascent is deep enough to lift air above the lifting condensation level, cumulus or cumulonimbus clouds form in a process known as pyro-convection. There is abundant anecdotal evidence to suggest that pyro-convection may have a significant impact on fire behaviour by (i) amplifying burn and spread rates; (ii) enhancing spotting through plume intensification; and (iii) igniting new fires via pyrocumulonimbus lightning. Pyro-convection is also responsible for the transport of smoke and other aerosol into the stratosphere. Therefore a knowledge of the processes that lead to the generation of pyro-convection is an important component of being able to understand and predict fire behaviour, as well as the potential climatic influences of large fires.

Here we present idealised simulations of bushfire plumes using a cloud-resolving model, the UK Met Office Large-Eddy Model (LEM). The model is initialised with idealised temperature and moisture profiles representative of that associated with high fire-danger conditions. A bushfire plume is then generated by imposing a localised heat flux at the model surface. We explore the conditions under which the bushfire plume leads to pyro-convection and the sensitivity of that pyro-convection to variations in the environmental conditions and the heat and moisture flux. The implications of the observed changes in the pyro-convection are discussed in terms of their impact on fire behaviour, primarily through the potential to affect near-surface conditions in the vicinity of the fire and spotting potential via plume intensification.

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LIGHTNING LECTURES - ROOM B3 – TOPICS 1, 6, 7, 8S8. Emerging methods for weather observaton and PredictonSubmission ID: 181Presentng Author: Aurel GriesserSession: Lightning Lectures Room B3Session tme: Thursday 11:30 – 12:00Posters 2Poster: #81

A comparison of rainfall characteristcs between radar-based rainfall estmates and downscaled Global Climate Model output

GRIESSER Aurel*1; JAKOB DÕ_rte 2; SEED Alan3

1) Australian Bureau of Meteorology, a.griesser@bom.gov.au; 2) Australian Bureau of Meteorology; 3) Australian Bureau of Meteorology

Global Climate Models (GCMs) indicate that climate change may increase extreme rainfall intensity. This may increase the risk of flood and has implications for engineering design. In conjunction with the revision of the ‘Australian Rainfall and Runoff’ project, which formulates guidelines for infrastructure engineering and planning, dynamically downscaled GCM results were assessed using radar-based rainfall observations in an area around Sydney.

The radar data used was based on the Bureau of Meteorology’s Rainfields algorithm, which converts observed radar reflectivity to estimated rainfall on the ground. Measurements from rain gauges are ingested by the algorithm for calibration.

Two separate dynamically downscaled simulations were available: CSIRO’s Cubic Conformal Atmospheric Model (CCAM) (Thatcher and McGregor, 2009), and the Weather Research and Forecasting Model (WRF) as deployed by Evans and McCabe (2013). These models were run at a spatial resolution of 2km over the study region, and were driven by GCM data at boundaries. Gridded station data from the Australian Water Availability Project was also used for comparison.

Primary findings were:

Considerably more spatial variability is evident in radar-based rainfall compared to GCMs and AWAP. This implies that not all rainfall-producing mechanisms have been correctly simulated. This is important because changes in rainfall extremes are likely to be driven by changes in convective precipitation.

In the long-term mean, the current Rainfields algorithm underestimates rainfall relative to the gauge-based AWAP data, though broad-scale spatial features match well.

The frequency distribution of the radar-based rainfall differs markedly to those of the models and AWAP.

Shortcomings were identified in simulations which need to be considered when inferring potential impacts of climate change on rainfall extremes.

Radar-based rainfall estimates are a useful tool for assessing high-resolution dynamical models.

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LIGHTNING LECTURES - ROOM B3 – TOPICS 1, 6, 7, 8S8. Emerging methods for weather observaton and PredictonSubmission ID: 103Presentng Author: Murray HamiltonSession: Lightning Lectures Room B3Session tme: Thursday 11:30 – 12:00Posters 2Poster: #82

Discriminatng Super-cooled Liquid and Ice Partcles in Fog

CHAMBERS Thomas*1; HAMILTON Murray 2

1) University of Adelaide, thomas.chambers@student.adelaide.edu.au; 2) University of Adelaide

Various studies have shown that the Supercooled Liquid Water (SLW) content of Mixed Phase Clouds (MPC’s) is strongly linked to their formation and evolution, and influences the cloud radiative properties. This parameter is poorly constrained by conventional measurement techniques such as radar and lidar.

A polarsonde is a low cost, lightweight addition to a conventional radiosonde for measuring the SLW content of MPC, but it also can be mounted on a tower to study fog.

We present an analysis of polarsonde data from a tower installation at Summit Camp, Greenland spanning the months October and November 2013. Polarsonde data is compared with the output of a fog monitor (FM-100, Droplet Measurement Technologies Inc.), and independent measurements of temperature, relative humidity.

A good correlation is found between fog events identified by the polarsonde and by the fog monitor. There is also a correlation between the depolarisation of backscattered light measured by the polarsonde, and the particle sizes measured by the fog monitor. Together with Monte Carlo simulations of the scattering, which give the expected depolarisation for various particle shapes, this is evidence for the discrimination of SLW from ice crystals.

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LIGHTNING LECTURES - ROOM B3 – TOPICS 1, 6, 7, 8S8. Emerging methods for weather observaton and PredictonSubmission ID: 256Presentng Author: Harvey SternSession: Lightning Lectures Room B3Session tme: Thursday 11:30 – 12:00Posters 2Poster: #83

Increasing forecast accuracy in the context of a mult-model ensemble framework

STERN Harvey*1; DAVIDSON Noel2

1) University of Melbourne, hstern@unimelb.edu.au; 2) Bureau of Meteorology

The paper presents an assessment of weather forecasts that have been derived in the context of a multi-model ensemble framework.

Very long range day-to-day weather forecasts (out to Day-32) for Melbourne, Australia, derived by interpreting the output of the ECMWF ensemble control models, are also evaluated.

The evaluation is an update of an earlier assessment that was presented to the 2015 Annual M e e t i n g o f t h e A m e r i c a n M e t e o r o l o g y S o c i e t y [https://ams.confex.com/ams/95Annual/webprogram/Paper267305.html].

Results suggest that the ensemble approach to weather forecasting increases the accuracy of day-to-day weather predictions.

Reference: Stern H and Davidson N E (2015) Some aspects of the verification of weather forecasts for Melbourne, Australia. Harry R. Glahn Symposium, Phoenix, AZ, 4-8 Jan. 2015, Amer. Meteor. Soc.

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POSTERS 1 – THURSDAY 14:30 – 16:00S1.0 General - Communicatng our scienceSubmission ID: Presentng Author: David SchultzSession: Posters 1Session tme: Thursday 14:30-16:00Poster #1

1. Build Your Own Earth: Exploring Climate Model Output for Teaching and Research

SCHULTZ David*1, FAIRMAN Jonathan1 ANDERSON Stuart2 and GARDNER Sharon2

1) Centre for Atmospheric Science, School of Earth, Atmospheric and Environmental Sciences, University of Manchester 2) eLearning Team, Faculty of Engineering and Physical Sciences, University of Manchester

Build Your Own Earth was a vision that we had to engage students in understanding the controls on Earth’s climate. The vision was for students to build their own worlds by selecting various characteristics of a planet: distance from the Sun, tilt of the axis, location of continents, oceans and mountains, rotation rate, atmospheric composition, etc. Students would enter these characteristics on a web page, and then, after pushing the “Go” button, a climate model would run in the background and produce the climate on that world.

Unfortunately, such a vision is not possible with the speed of today’s computers. Even using a simplified climate model built for speed (FOAM: the Fast Ocean–Atmosphere Model) and with coarse resolution (each atmospheric grid box is 7.5º in longitude and 4.5º in latitude), our supercomputer will only run about 480 years of model climate in one day. Each model planet needs about 50–300 years of simulations to obtain a stable climate. Plus, with thousands of students submitting simulations in real time, our supercomputer would be inundated with requests. Instead, we preselected about 50 Earths, did the computer simulations already, and prepared plots of the simulation results for students to explore on BuildYourOwnEarth.com.

Earths are in three categories: Recent, Ancient, and Alien. Recent Earths include a Current Day (2015) simulation with 400ppm carbon dioxide. We also have a preindustrial control simulation, a simulation from 1975, and a simulation with no greenhouse gases. We also have simulations where we’ve changed the carbon dioxide concentrations (including some from our possible future), the amount of solar radiation received by the Earth, and orbital parameters of the Earth (axial tilt and eccentricity). Ancient Earths include snapshots from the past such as the Last Glacial Maximum (21,000 years ago), Miocene, Jurassic, Triassic, Carboniferous, Cambrian, and Ediacaran. Because the atmospheric carbon dioxide and methane concentrations are not well constrained, there is some uncertainty. Thus, we encourage students to not read these simulations as literal pasts, but as explorations of what changing ocean and land configurations can do to the climate when placed under the constraint of constant atmospheric composition. Alien Earths abstract the climate down to its essence. What is the effect of no continents on Earth (Aquaplanet)? What would the circulation look like during Snowball Earth (Iceplanet, which would be very much like Hoth from The Empire Strikes Back)? What would happen if we had a single continent on the equator? Or on the pole? What if the whole Earth was land except for a single ocean in the middle?

Build Your Own Earth was developed for the University of Manchester Coursera course “Our Earth: Its Climate, History, and Processes”, but will be implemented as a homework assignment and feature of the lecture content in the introductory Earth science course in the first semester of the next academic year. We also anticipate that the content will make excellent fodder for undergraduate research projects. The website is freely available for all to access and use.

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S1.0 General - Communicatng our science

Submission ID: 331 Presentng Author: Sonya WellbySession: Posters 1Session tme: Thursday 14:30-16:00Poster #2

2. Growing “Real-World-Ready” Scientsts: Using Undergraduate Higher Educaton to Train our Scientsts

WELLBY, Sonya*1, 2) ENGERER, Nicholas2

1) The ANU Fenner School of Environment and Society, sonya.wellby@gmail.com; 2) The ANU Fenner School of Environment and Society

The Fenner School of Environment and Society at the Australian National University offers later-year undergraduate students with the opportunity to enrol in a ‘Special Topic’—a semester-long course, offering the same number of units as a traditional subject, which allows a student to study subject matter not taught elsewhere at the university. The student and their supervisor jointly devise a learning plan and assessment items. This open, yet guided, structure makes it possible for the student and supervisor to explore new avenues of education not possible under the traditional style of higher education learning, whilst ensuring valuable skills conventionally acquired at the undergraduate level, such as self-directed learning and critical thinking, can still be taught.

This poster will explore how one student (presenting this poster) and supervisor duo worked to meet the student’s learning objectives, including developing the student’s understanding of meteorological phenomena that led to sudden changes in output from solar photovoltaic arrays in the Canberra region. As the student was particularly interested in any implications these events might have for the energy sector, the course was structured to enable her to initiate discussion with the public, industry, and policy-makers—as part of this, she presented a seminar, attended by representatives of the Bureau of Meteorology, ActewAGL, and an ACT parliamentarian. Additionally, the student acquired formal journal-article writing skills. This style of subject has the potential to expand learning beyond the classroom—the student has since engaged in the process of journal submission, and has continued to engage in public outreach activities relating to the research. This style of education has potential to broaden the traditional undergraduate skillset from inwardly-focussed knowledge acquisition, to that which is outward-looking and involves the student, scientific community, and public.

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S1.1 Educaton and outreachSubmission ID: 201 Presentng Author: Catherine GanterSession: Posters 1Session tme: Thursday 14:30-16:00Poster #3

3. Seasonal Climate Outlooks: an Upgraded Service for the Community

GANTER Catherine1; WATKINS Andrew*2; DUELL Robyn3 ; SHELLEY Luke4

1) Bureau of Meteorology, c.ganter@bom.gov.au; 2)Bureau of Meteorology; 3)Bureau of Meteorology; 4)Bureau of Meteorology

We present a case study for an upgraded operational service based upon user consultation and feedback. The Bureau's operational seasonal outlook service is a long established product, with the first rainfall outlook issued back in 1989. Originally this service was based on the statistical relationships between rainfall and the Southern Oscillation Index, with a later statistical model based on the two leading empirical orthogonal functions of sea surface temperature variability.

In 2010 to 2011, the Predictive Ocean Atmosphere Model for Australia (POAMA), the dynamical model run in the Bureau and developed in conjunction with CSIRO, was producing skill and reliability measures that exceeded those from the statistical model. The subsequent change in operations from a statistical to dynamical model involved a two-step process: firstly to change the model and educate this science; and secondly, an upgrade of the current service in terms of language, understanding, and layout to ensure the public could make the best use of the outlooks.

To rebuild the service, a 5-stage market research and user-centred design process took place, which included in-depth discussions with ‘VIP’ users, a survey of roughly 960 users, and focus groups consisting of stakeholders. These results helped guide upgrades to the service. Outlook text is notoriously difficult to understand, with survey results proving some insight into what did and didn’t work for communicating probabilistic outlooks. For instance, in a True/False question, 34% of respondents misunderstood 40% chance of exceeding median spring rainfall to mean the area “can expect less than 40% of its median rainfall for spring“. Further consultation was performed in the draft stages of the new website, including seeking feedback from the Managing Climate Variability Climate Champions. These consultation processes aided in providing an upgraded service better tailored to industry, government and emergency service decision making.

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S1.1 Educaton and outreach

Submission ID: 227 Presentng Author: Keith HuangSession: Posters 1Session tme: Thursday 14:30-16:00Poster #4

4. On-line and Switched On? Are High Tech Secondary Educaton Resources Efectve Learning Tools for Climate Science?

HUANG Keith*1; MAHARAJ Angela2

1) CCRC, keith.s.huang@gmail.com; 2)CCRC

Participation of Australian high school students in STEM subjects has seen a dramatic decrease in the recent decade, indicating declining interest in science. In the same time, previous studies have found a number of common climate science misconceptions amongst students internationally and in Australia. On the other hand, a good understanding of climate science is becoming increasingly imperative to enable current and future generations to make scientifically justifiable decisions. This calls for more effective education methods and resources.

Digital resources have been favoured in recent years in education to cater for the learning preferences of ‘Generation Z’ or ‘Digital Natives’. Few resources are thoroughly evaluated and even fewer actually target established misconceptions. It is important to evaluate and reflect on how to maximise effectiveness of resources for increasing both engagement and performance.

To address some of these issues, we surveyed more than 400 stage 5 students in four high schools in Sydney region before and after they attempted a newly developed interactive digital module on climate science. Together with the data collected within the online resource it appears that i) sampled students performed poorly in comparison to other populations in previous research using the same test items, regardless of school types and ii) misconceptions common in previous research were also present in this sample. The analysis also revealed that while the online resource failed to eliminate misconceptions it did generally improve student understandings significantly. These results suggest an insufficient level of climate science literacy amongst stage 5 secondary school students in NSW and while this digital tool demonstrated promising potential it needs to be further refined and specifically tailored in order to be effective to tackle misconceptions.

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S1.1 Educaton and outreach

Submission ID: 329 Presentng Author: Lea Kannar-LichtenbergerSession: Posters 1Session tme: Thursday 14:30-16:00Poster #5

5. Distncton with a Diference: Exploring the ECOSPHERES of the Galapagos and Lord Howe Islands with Controlled Tourism

KANNAR-LICHTENBERGER Lea1

1) leakannar@bigpond.com

My poster presentation will include (but will not be exclusive to) my exploration (including first hand research) and comparison of the islands of the Galapagos (Ecuador— Research Oct 2014) and Lord Howe Island (NSW Australia— Research on going);

This poster will be looking at the impact controlled tourism is having on native flora, fauna and aquatic ecologies. How they are influenced by the Anthropocene along with site specific evidence that question the effect on both these islands.

With waters rich in marine life and fluctuating ocean temperatures how does the life in these places cope with the increased tourism that their uniqueness attracts?

My investigation, which involves a studio art practice, looks to create awareness surrounding the alterations we make in nature to transform not only the flora but also social, ethical and cultural values in society. Through this I create metaphors for our connection to these changes and the Anthropocene through images that use cellular, geographical and habitational images.

This poster submission could also also take the form of/or include a display of sound (by headphones supplied) and moving images within the designated displayed area.

I hope to convey to the viewer through the recognizable what impact the current and increase in tourism will have on the uniqueness of these islands.

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S1.1 Educaton and outreach

Submission ID: 331 Presentng Co-Author: Angela MaharajSession: Posters 1Session tme: Thursday 14:30-16:00Poster #6

6. A Simple Climate Model for School and University Students, Researchers and Policy makers

SEN GUPTA Alex1; MAHARAJ Angela* 2; VANSEBILLE Erik3 ; SHERWOOD Steven4; ABRAMOWITZ Gab5

1) CCRC ARCCSS UNSW, a.sengupta@unsw.edu.au; 2)CCRC ARCCSS UNSW; 3)Imperial College London; 4)CCRC ARCCSS UNSW; 5)CCRC ARCCSS UNSW

Climate change has been flagged as the greatest challenge of our time and one that will require collaboration and ingenuity across numerous fields. However climate science and its workhorse, the climate model, is largely inaccessible to non-specialists. Furthermore, the various aspects of what is inherently an interdisciplinary issue are taught within silos of science, economics, engineering and social sciences. This poses a significant barrier to students trying to grapple with understanding climate system science and how it relates to impacts, climate policy or adaptation/mitigation solutions.

We have developed a simplified (energy-balance/ carbon cycle) climate model that is able to reproduce the globally averaged output from state-of-the-art climate models. The model is embedded in an easy to use graphical interface suitable for a wide range of users. At this stage, the user specifies time series of greenhouse gas emissions, solar intensity and other basic physical forcings, either from (i) pre-defined scenarios (including standard RCP scenarios), (ii) using a scenario builder or (iii) from externally imported data. The model then calculates a variety of output time series including, greenhouse gas concentrations, average temperature, sea-level and ocean pH. Future extensions will allow users to examine more output variables and tie emission to economics factors/population

Users can run multiple what-if scenarios to examine how different choices we make can affect important global characteristic. The simple interface makes it usable by school students and the general public (and even politicians!), while its ability to produce results comparable to those produced my complex climate models make it a suitable tool for research.

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S1.1 Educaton and outreach

Submission ID: 128 Presentng Author: Ben McNeilSession: Posters 1Session tme: Thursday 14:30-16:00Poster #7

7. How to engage the public with research using video

MCNEIL Ben*1

1) UNSW, b.mcneil@unsw.edu.au

The more we as scientists publish hyper-specialist manuscripts with jargon and complexity, the more we alienate the public and stifle cross-fertilisation of ideas, so important for discovery. Thinkable.org is a new web platform that uses video to break down the barriers between scientists and the public that allows on-going engagement and collaboration with research. By connecting scientists with their peers and the public using video as the knowledge medium, it gives a new level of transparency, trust and education to anyone wanting to be part of research. Here, I will give an overview of how scientists can use video to build on-going trusted connections with a wide audience that benefits all involved.

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S1.1 Educaton and outreach

Submission ID: 251Presentng Author: Laura O'BrienSession: Posters 1Session tme: Thursday 14:30-16:00Poster #8

8. Weather and Climate Schools Outreach Program: Proposal

O'BRIEN Laura1

1) Monash, laura.obrien@monash.edu

A group of early career researchers from the ARC Centre of Excellence for Climate System Science (ARCCSS) are proposing establishing a formal schools outreach program. The intent is to facilitate an efficient and easy way for teachers and scientists to arrange classroom sessions based on weather and climate. The group proposes a suite of experimental equipment and guidelines to be made available to the nodes of the ARCCSS and, an online system where teachers could easily request a particular scientist to visit their class. The expectation on scientists involved in the program would be to produce one presentation that could be distributed to multiple schools. The scientists would have access to equipment for fun experiments that could also be incorporated.

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S1.1 Educaton and outreach

Submission ID: 292 Presentng Author: Jen ParsonsSession: Posters 1Session tme: Thursday 14:30-16:00Poster #9

9. Scientsts and Mathematcians in Schools: inspiring the next generaton

PARSONS Jen*1

1) CSIRO, scientistsinschools@csiro.au

Scientists and Mathematicians in Schools (SMiS) is a successful national Australian program which has been in operation since 2007. Supported by a national coordinating team, state-based project officers match and support volunteer scientists, mathematicians and teachers in on-going, flexible and effective partnerships. The program encourages participation across the fields of science, technology, engineering and maths, and includes weather and climate professionals who work with primary and secondary school teachers and students. These weather and climate based partnerships show students a new way of looking at the world by learning weather observation skills and understanding forecasting, data collection, weather in Antarctica, and Australian weather and climate impacts on farming. Through interactions with ‘real scientists’, students receive insight into careers in meteorology and other physical sciences. This presentation brings together relevant examples from across Australia with program evaluation to explain the benefits of SMiS to teachers, scientists and students.

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S1.1 Educaton and outreach

Submission ID: 257 Presentng Author: Karen PearceSession: Posters 1Session tme: Thursday 14:30-16:00Poster #10

10. Tweetng the Heat and Blogging the Fog: A Science and Social Media Snapshot

PEARCE Karen*1

1) Bloom Communication, karen@bloomcommunication.com.au

The rise and rise of social media offers scientists and science communicators unprecedented opportunities to engage with the public and peers, and to promote their science. However, with so many channels, so much content and so many players, social media also throws up its fair share of challenges.

To ensure we are making the most of social media opportunities (and minimising the challenges) it is useful to characterise our current activities and attitudes when using these tools for science communication. To this end, a survey will be conducted across the Australian science community to develop a snapshot of social media use for science engagement in this country. The survey will seek to find out who is using social media, what social media they are using and how they are using it, and also what attitudes are held by scientists and science communicators about the value and success of social media for public engagement and promoting science.

This presentation will focus on the results obtained from respondents who have identified as working in weather and climate-related fields. They will respond to questions such as: Are they tweeters or bloggers? Who do they follow? Who follows them? What is their preferred social network? Do they think social media is worth the effort? How do employer rules affect social media use? What implications do these practices and attitudes have for effective science communication via social media?

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S1.1 Educaton and outreach

Submission ID: 124 Presentng Co-Author: Katherine TatersallSession: Posters 1Session tme: Thursday 14:30-16:00Poster #11

11. Integratng research infrastructure into educaton— bringing ocean observatons to the classroom

PROCTOR Roger1; HOENNER Xavier 2; MANCINI Sebasten3 ; TATTERSALL Katherine*4; EVERETT Jason5; SUTHERS Iain6; Steinberg Peter7; Doblin Martna8

1) UTAS-IMOS, roger.proctor@utas.edu.au; 2)UTAS-IMOS; 3)UTAS-IMOS; 4)UTAS-IMOS; 5)UNSW; 6)UNSW; 7)SIMS; 8)UTS

The Integrated Marine Observing System (IMOS, www.imos.org.au), established in 2007 as a component of the National Research Infrastructure Strategy, is collecting unprecedented volumes of multi-disciplinary oceanographic data in the ocean and on the continental shelf which is made freely available through the IMOS Ocean Portal (http://imos.aodn.org.au). IMOS frequently runs ‘data user workshops’ throughout Australia to introduce scientists and managers to the wealth of observations available at their fingertips.

For the past 3 years the Sydney Institute for Marine Science, in partnership with Macquarie University, the University of NSW, the University of Sydney and the University of Technology Sydney, has been running a Master’s degree course called Topics in Australian Marine Science (TAMS, http://sims.org.au/education/). This course is unique in that the core of the course is built around IMOS - understanding how different measurement platforms work and exploring the data that these platforms collect. Students combine attending seminars and lectures with hands on practicals and personal assignments, all built around access to IMOS data and the many tools available to visualise and analyse.

The course attracts a diverse class with many mature students (i.e. > 25 years old) from a range of backgrounds who find that the ease of discovering and accessing data, coupled with the available tools, enables them to easily study the marine environment without the need for high level computational skills. Since its inception the popularity of the course has increased with 38 students undertaking the subject in 2014.

The consensus from students and lecturers is that integrating ‘real’ observations into the classroom is beneficial to all, and IMOS is seeking to extend this approach to other university campuses.

The talk will describe the experiences from the TAMS course and highlight the IMOS approach to data discovery, availability and access through course examples.

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S1.2 Forecastng, Characterising and Communicatng Extreme Weather and Climate Events

Submission ID: 183 Presentng Author: Steefan ContractorSession: Posters 1Session tme: Thursday 14:30-16:00Poster #12

12. Investgatng The Efect Of Interpolaton On Daily Precipitaton And Extremes

CONTRACTOR Steefan*1

1) University of New South Wales, s.contractor@unsw.edu.au

Station-based daily precipitation data for Australia were obtained from the Global Historical Climatology Network-Daily dataset and gridded onto a 0.5°x0.5° latitude/longitude grid over the period 2004-2013. Around 5000 stations had available data over this period. Six gridding methods (Inverse Distance Weighting, Natural Neighbour, Barnes Optimal Interpolation, Bilinear, Bicubic and Kriging) were used to investigate the effect of interpolation on the resulting (1) daily and monthly grids and (2) precipitation indices that reflect more extreme events. Results are also compared with existing datasets available for Australia including datasets based on remote sensing. By highlighting the disagreement between various gridded datasets we aim to emphasize the uncertainty in interpreting trends in and variability of precipitation extremes based on such interpolated datasets. This presentation will outline the strengths and weaknesses of each interpolation method and discuss the parametric and structural uncertainties which can influence the assessment of precipitation extremes, an important consideration in model evaluation and communicating impacts of extremes.

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S1.2 Forecastng, Characterising and Communicatng Extreme Weather and Climate Events

Submission ID: 175 Presenter (non-author): Aurel GriesserSession: Posters 1Session tme: Thursday 14:30-16:00Poster #13

13. Communicatng the uncertainty in frequency estmates of climate extremes

JAKOB Doerte1; MARTIN David 2

1) Bureau of Meteorology, d.jakob@bom.gov.au; 2) Bureau of Meteorology

Risks from weather and climate extremes to governments, industries and communities are increasing and, at present, are not well quantified. Many weather and climate extremes have increased in frequency and/or intensity in recent decades with climate model projections showing that several trends are likely to continue (IPCC 2012). The analysis of historical records is complementary to the use of climate models in understanding the changing nature of extremes.

One way to characterise climate extremes is by using terciles, deciles or percentiles. This approach does not make assumptions about an underlying distribution (non-parametric). It has the advantage that the measure is straightforward to calculate and the results are easy to communicate. An alternative more complex approach is to fit an extreme value distribution to a series of extremes, say annual maxima. This approach involves selecting an appropriate distribution and testing its fit to the data. Users are provided with estimates of Annual Exceedance Probability (AEP), which is required for risk assessments.

Given that a combination of both approaches is required to serve all user needs, this study compares the estimates derived and the associated uncertainties, with the aim of developing a strategy for communicating differences in estimates derived using a non-parametric and a parametric approach. This is a problem that has not been widely considered and discussed.

The study considers data from sites included in the ACORN-SAT (Australian Climate Observations Reference Network— Surface Air Temperature) data if they have at least 100 years of record. Both temperature (Tmax & Tmin) and precipitation (daily rainfall) are assessed. To study the effect of record length we are considering two periods: a) 100 years (1911 to 2010) and b) a 30-year reference period (1981 to 2010).

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S1.2 Forecastng, Characterising and Communicatng Extreme Weather and Climate Events

Submission ID: 125 Presentng Author: Daniel PazminoSession: Posters 1Session tme: Thursday 14:30-16:00Poster #14

14. Bushfre Danger in the Southern Hemisphere: Investgatng Seasonal Predictability and Circulaton Links

PAZMINO Daniel*1

1) University of Melbourne, danielpv@student.unimelb.edu.au

Bushfires cause great human, environmental and economic losses around the world. In the southern hemisphere, this problem is particularly severe in Australia where extensive research has been developed. Extreme bushfire seasons also occur in this hemisphere in several countries in South-America, which has generated lees documentation on this issue. Unfortunately, South-South research cooperation in this topic has not been very active. Regional climate in both continents is largely affected by climate modes of variability such as ENSO; which raises the question if there are common large-scale circulation patterns driving bushfire danger? If common patterns exist, what are the implications for seasonal predictability in both regions? This investigation aims to answers these questions with case studies in Victoria, Australia and Ecuador. Seasonal bushfire danger in these regions will be explored using the McArthur Forest Fore Danger Index (FFDI), since these two regions also share the eucalyptus as dominant specie in bushfire prone areas. This analysis will be conducted with weather station as well as reanalysis data from the 20th Century Reanalysis Project. Preliminary results for Victoria demonstrate that seasonal bushfire danger, measured as the spatially averaged cumulative sum of FFDI values in the season December-January-February, has increased 16% in the period 2000-2010 compared to the period 1919-1999.S2.0 General - Climate - Variability and Change

Page 235

S2.0 General - Climate - Variability and ChangeSubmission ID: 280Presentng Author: Olivier GeofreySession: Posters 1Session tme: Thursday 14:30-16:00Poster #15

15. Tropical fngerprints of low and high sensitvites in CMIP5 models

GEOFFROY Olivier*1; SHERWOOD Steve 2

1) CCRC, o.geoffroy@unsw.edu.au; 2)CCRC UNSW

Climate sensitivity is a major source of uncertainty for climate change projections. Clouds, in particular tropical low clouds, are the first source of intermodel spread of climate sensitivity of climate models. Mechanisms at play in their changes are not well understood, due to their complex coupling with the tropical circulation. I will show some relationships between climate sensitivity and the structure of the circulation in the tropics, and discuss underlying mechanisms.

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S2.0 General - Climate - Variability and ChangeSubmission ID: 325 Presentng Author: Michael GroseSession: Posters 1Session tme: Thursday 14:30-16:00Poster #16

16. The Subtropical Ridge in CMIP5 Models, and Implicatons for Projectons of Rainfall in Southeast Australia

GROSE Michael*1; TIMBAL Bertrand 2; WILSON Louise3 ; BATHOLS Janice4; KENT David5

1) CSIRO, Michael.Grose@csiro.au

The subtropical ridge (STR) is the mean pressure ridge in the mid-latitudes, and is one of the key features affecting climate variability and change in southeast Australia. Changes to the STR and associated changes to rainfall in a warming climate are of strong interest, and the new Coupled Model Inter-comparison Project phase 5 (CMIP5) model archive provides new opportunities to examine this. Here we show that the STR is projected to strengthen and move pole-ward under global warming, contributing to reduced rainfall in the cool season in southeast Australia. This result is largely consistent among 35 models examined, and CMIP5 shows a greater increase in intensity relative to position than CMIP3 did. We show that the simulation of the STR in the CMIP5 is similar to that of the previous CMIP3 in many respects, including the underestimation of both the historical trends in the STR intensity and the correlation between inter-annual STR intensity and southeast Australian rainfall. These issues mean we still have reduced confidence in regional rainfall projections for southeast Australia and suggest that CMIP5 rainfall projections for this region in April to October may be underestimates.

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S2.0 General - Climate - Variability and Change

Submission ID: 39 Presentng Author: Ben HagueSession: Posters 1Session tme: Thursday 14:30-16:00Poster #17

17. Heatwaves and Their Impact on Wheat Yields in Australia

HAGUE Ben*1; BRAGANZA Karl 2; SMALLEY Robert3

1) University of Melbourne, bhague@student.unimelb.edu.au; 2) Bureau of Meteorology; 3) Bureau of Meteorology

Extreme heat and frost events are known to have potentially detrimental effects on cereal production in Australia. By developing a list of both single-day extreme temperature events and more prolonged heatwave events for state, national and key agriculture areas from the early 20th Century to Present, we investigate the economic costs of heatwaves on wheat production. As wheat is generally most affected by heat events that exceed a certain temperature threshold, we analyse extreme heat events from this perspective as well as a percentile-based approach. The role of rainfall in determining the wheat yield is also explored— in particular, the effect of co-incident extremes in both temperature and rainfall observations.

We then apply our findings gained from this historical perspective to forecast projected future impacts on Australia’s wheat yields under a variety of climate change scenarios.

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S2.0 General - Climate - Variability and Change

Submission ID: 65 Presentng Author: Blair TrewinSession: Posters 1Session tme: Thursday 14:30-16:00Poster #18

18. 2014 – the world’s hotest year on record

TREWIN Blair*1

1) Bureau of Meteorology, b.trewin@bom.gov.au

The global mean temperature for 2014 was warmest on record, according to all major international data sets. The combined figure reported by the World Meteorological Organization was 0.57°C above the mean for the 1961-1990reference period and 0.02°C above the previous record set in 2010. Ocean temperatures were especially warm, with the global average exceeding the previous annual record by 0.05°C. The exceptional warmth occurred despite the lack of a clear-cut El Niño event in 2014.

Land temperatures were especially warm across Europe, resulting in the warmest year on record for the continent by a substantial margin. It was also the warmest year on record for countries including the United Kingdom, the Netherlands, Germany, Denmark and Norway. It was also very warm in parts of subtropical South America, where a major heatwave in October resulted in all-time record high temperatures in numerous centres in Brazil, Paraguay and Argentina. The only substantial area with 2014 temperatures significantly below normal was the central United States and adjacent areas of Canada.

There were major rainfall contrasts in South America. Argentina had its wettest year on record with major floods (which also impacted Paraguay) in the Parana basin in mid-year. Further northeast, severe drought affected the Sao Paulo region in Brazil, before expanding to cover much of the country later in the year. Severe drought also affected the western United States, particularly California. Heavy monsoon rainfall produced widespread flooding across parts of south Asia resulted in widespread devastation in Kashmir during September.

Tropical cyclone activity was generally below normal across the globe, with the North Atlantic having an especially quiet year, although the Northeast Pacific was active. The Arctic sea ice minimum was above its 2012 record low but still well below the post-1979 average, while Antarctic sea ice extent reached record high levels later in the year.

Page 239

S2.1 Regional climate projectons and applicatons

Submission ID: 110 Presentng Author: Kewei LyuSession: Posters 1Session tme: Thursday 14:30-16:00Poster #19

19. Comparing Forced and Internal Sea Level Signals at Regional Scales in CMIP5 Models

LYU Kewei*1; ZHANG Xuebin 2; CHURCH John3 ; HU Jianyu4; SLANGEN Aimee5

1) Centre for Australian Weather and Climate Research; CSIRO Oceans and Atmosphere Flagship Hobart; Xiamen University China; kewei.lyu@csiro.au; 2)Centre for Australian Weather and Climate Research; CSIRO

Oceans and Atmosphere Flagship Hobart; 3)Centre for Australian Weather and Climate Research; CSIRO Oceans and Atmosphere Flagship Hobart; 4)Xiamen University China; 5)Centre for Australian Weather and

Climate Research; CSIRO Oceans and Atmosphere Flagship Hobart

The regional sea level usually exhibits significant internal variability, obscuring sea level change due to external forcing and also causing large uncertainties for future projections. Here, two different methods are designed to measure the relative magnitude of the forced sea level change signal and the internal sea level variability at regional scales based on CMIP5 models. The same methodologies are also applied to surface air temperature for comparing the response differences between ocean and atmosphere. The first method is to determine the time when the climate change signal exceeds and thus emerges from the background internal variability, referred to as the Time of Emergence. The amplitude of internal variability is calculated from the CMIP5 models’ pre-industrial control run. We found that the emergence of regional sea level change, when all available contributions are included, is earlier than that of surface air temperature and exhibits little dependence on the emission scenarios. The second method is to quantify the ratio of forced variance due to external forcing (anthropogenic and natural) and total variance at regional scales. A variance analysis is used to partition the total variance into internally-generated and externally-forced parts from several CMIP5 models with multiple realization runs. The spatial patterns for the ratio of forced variance largely resemble those for the Time of Emergence, with larger forced variance ratios corresponding to earlier emergence times. Averaged globally, the ratio over a fixed time length is projected to increase continually with time under the business-as-usual scenario (RCP8.5). In contrast, under the medium emission scenario (RCP4.5) the forced variance ratio declines for the surface air temperature, but stabilizes for sea level by the end of this century, indicating a slower response of the latter to climate mitigation.

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S2.1 Regional climate projectons and applicaton

Submission ID: 108 Presentng Author: Bhupendra RautSession: Posters 1Session tme: Thursday 14:30-16:00Poster #20

20. Rainfall Changes over Southwestern Australia in Observatons and Select CMIP-5 Simulatons

RAUT Bhupendra*1; JAKOB Christan 2; HOANG Lam3 ; REEDER Michael4

1) School of Earth Atmosphere & Environment Monash University, bhupendra.raut@monash.edu; 2) Australian Research Council Centre of Excellence for Climate System Science, School of Earth Atmosphere &

Environment Monash University; 3) Australian Research Council Centre of Excellence for Climate System Science School of Earth Atmosphere & Environment Monash University; 4) Australian Research Council

Centre of Excellence for Climate System Science School of Earth Atmosphere & Environment Monash University

A sharp reduction in winter rainfall over coastal Southwestern Australia occurred in 1970s along with a gradual increase in summer rainfall over the inland region. A k-means algorithm was used to cluster the rainfall patterns in the Australian Water Availability Project (AWAP) data, and their association with southern annular mode (SAM) and ENSO was studied (Raut et. al., 2014). It was found that the rainfall changes are mainly due to the changing frequency of raining fronts in winter and troughs in summer. The reduction in winter rainfall (coastal) and the increase in summer rainfall (inland) are both related to the predominantly positive phase of SAM during the neutral ENSO phase.

In present study, a selection of CMIP-5 simulations for historical runs are clustered and validated against the AWAP clusters. For the RCP4.5 and RCP8.5 scenarios for the period 2006-2055, each day is binned into the closest historical cluster centroid in Euclidean space and their statistics are compared with the historical clusters. The CMIP-5 models reproduce the coastal and the inland rainfall patterns with varying skill. CMIP-5 simulations underestimate the frequency of frontal rain over the coast and over-estimate the frequency of trough over the inland region. For both RCP4.5 and RCP8.5 emission scenario, the frequency of the light rain days increased and frequency of the fronts decreased. The decrease is more evident in the frequency of strong fronts.

References:

Raut, B.A., Jakob, C., and Reeder, M.J., 2014: Rainfall Changes over Southwestern Australia and Their Relationship to the Southern Annular Mode and ENSO. J. Climate, 27, 5801–5814.

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S2.1 Regional climate projectons and applicaton

Submission ID: 130 Presentng Co-Author: Andrea Tascheto*Session: Posters 1Session tme: Thursday 14:30-16:00Poster #21

21. The impacts of Tasman Sea warming on regional precipitaton extremes

ROBERTS James1; SENGUPTA Alex 2; UMMENHOFER Caroline3 ; MCGREGOR Shayne4; TASCHETTO Andrea*5

1) The University of Auckland/ARC Centre of Excellence for Climate System Science/Climate Change Research Centre UNSW, jrob916@aucklanduni.ac.nz; 2) ARC Centre of Excellence for Climate System

Science/Climate Change Research Centre; 3) Department of Physical Oceanography Woods Hole Oceanographic Institution; 4) ARC Centre of Excellence for Climate System Science/Climate Change Research

Centre UNSW; 5) ARC Centre of Excellence for Climate System Science/Climate Change Research Centre UNSW

A high resolution, multi-member global climate model is analysed to examine future precipitation change in southern Australia. In this study, changes in seasonal rainfall extremes and means are examined over three regions in southern Australia, namely Tasmania, south western Australia and mid-latitude East Coast. Model output is from the atmospheric component of the EC-Earth Earth System-Model, run at a resolution of approximately 25km. It includes six ensemble members for a present day (2002-2006) and future (2094-2098) climate. The present day simulation is forced with daily high-resolution sea surface temperature (SST) data provided by the NOAA National Climatic Data Center. Future SSTs were created by adding the present day SST field to the mean change of a 17-member ensemble based on the RCP4.5 scenario simulated by the ECHAM5 model. Preliminary findings show significant increase in cold season rainfall over Tasmania and the Tasman Sea, (mean, 95th and 99th percentile extremes) combined with a significant decrease in cold season rainfall over eastern mid-latitudes and south western Australia. These changes are presented aside variables most attributed to affecting precipitation; i.e. changes in mean sea level pressure at mid-latitudes, zonal and meridional wind vectors and SSTs. The intensification of precipitation in the Tasmanian region is likely caused by the combined effect of east Australian current advecting poleward, causing Tasman Sea warming, and an increase in westerly winds of the Southern Annular Mode, driven by a steepened mid-latitude sea level pressure gradient.

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S2.1 Regional climate projectons and applicaton

Submission ID: 143 Presentng Author: Karuru WamahiuSession: Posters 1Session tme: Thursday 14:30-16:00Poster #22

22. Infuence of domain locaton, spatal extent, and resoluton in resolving coastal precipitaton from cold-fronts in the southwest of Western Australia

WAMAHIU Karuru*1; ANDRYS Julia 2; KALA Jatn3 ; LYONS Thomas4

1) Murdoch University Environmental and Conservation, k.wamahiu@murdoch.edu.au; 2) Murdoch University Environmental and Conservation Science; 3) Murdoch University Environmental and Conservation

Science; 4) Murdoch University Environmental and Conservation Science

High resolution (5 km) regional climate simulations for the south western West Australia (SWWA) using the Weather Research and Forecasting model (WRF) have shown that the model is able to simulate the daily, seasonal, and annual variations of temperature and precipitation well, including extreme events (Andrys et al. 2015). However the location and resolution of the inner model domain is critical in fully representing frontal rainfall along the southern coastal region. This study carries out a detailed analysis of the influence of domain size and proximity to the coast on coastal precipitation due to frontal processes over SWWA. We show that the domain location and extent can be equally important to the choice of model physics options, something that is often over-looked.

References:

Andrys, J., T. J. Lyons, and J. Kala, 2015: Multidecadal Evaluation of WRF Downscaling Capabilities over Western Australia in Simulating Rainfall and Temperature Extremes. J. Appl. Meteor. Climatol., 54, 370–394. doi: http://dx.doi.org/10.1175/JAMC-D-14-0212.1

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S2.1 Regional climate projectons and applicaton

Submission ID: 188 Presentng Author: Xuebin ZhangSession: Posters 1Session tme: Thursday 14:30-16:00Poster #23

23. Dynamical Downscaling Of Climate Changes With A High-Resoluton OGCM

ZHANG xuebin*1

1) CSIRO, xuebin.zhang@csiro.au

Global climate models provide useful information about large-scale climate changes. Nonetheless, global climate models usually have coarse resolutions, mostly due to computational resource constraint. Consequently, meso-scale ocean features are nearly missing in climate models, however they can be critical for studies like boundary currents, eddies, near-shore processes and biogeochemical processes. Dynamical downscaling provides a feasible alternative to explore detailed regional features.

In this CSIRO Ocean Downscaling Strategic Project, we are working a framework to downscale future climate change signals simulated by CMIP5 models with a high-resolution (0.1x0.1 degree) eddy-resolving ocean general circulation model - OFAM3. The study period is from 1979 to 2100. During the historical period from 1979 to 2013, the OFAM3 is driven by atmospheric forcing from reanalysis product. During the future period from current to 2100, atmospheric changes simulated by CMIP5 models are added to drive the OFAM3. The ocean state changes relative to the historical period are treated as the downscaled ocean climate changes.

Some preliminary results, possible application of products from this CSIRO strategic project on coastal regions will be discussed.

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S2.1 Regional climate projectons and applicaton

Submission ID: 217 Presentng Author: Huqiang ZhangSession: Posters 1Session tme: Thursday 14:30-16:00Poster #24

24. How Much Rainfall Projecton Uncertainty in CMIP5 Can Be Atributed to SST Warming Intensity/Paterns: ACCESS1.3 Experiments

ZHANG Huqiang*1; ZHAO Yong 2; MOISE A.3 ; COLMAN R.4; HANSON L.5 ; YE H.6

1) Bureau of Meteorology, h.zhang@bom.gov.au

In this study, we assess the contribution from different SST warming intensity and patterns in the CMIP5 models leading to the uncertainty in their projected changes in rainfall at regional and global scales. We have conducted experiments by forcing ACCESS1.3 (one of the CMIP5 models) with different SST anomalies from 9 models to estimate how much the scatter among the CMIP5 models can be reproduced by this AMIP-type SST experiments. Preliminary results from this study will be presented.

Page 245

S2.2 Reconciling climate change and variability on decadal scales

Submission ID: 275 Presentng Author: Sonya FiddesSession: Posters 1Session tme: Thursday 14:30-16:00Poster #25

25. A New Perspectve on Australian Snow

FIDDES Sonya*1; PEZZA Alex 2

1)University of Melbourne, sonya.fiddes@unimelb.edu.au; 2)University of Melbourne

The Australian Alps have a unique climatological, ecological and hydrological environment and play a key role in water supply for southeastern Australia. Using resort observations we compile a new and robust snow accumulation data set. Both maximum snow depth and total snow accumulation have declined over the last 25 years. A significant decreasing trend was observed for the total number of light snow days, whereas the total number of heavy snow occurrences has remained constant. Maximum temperatures are highly related to all snow variables. It is suggested global warming is already impacting light snowfall events, while heavy events are less affected. Insights into daily snow melt trends are also able to be gained for the first time.

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S2.2 Reconciling Climate Change and Variability on Decadal Scales

Submission ID: 230 Presentng Co-Author: Scot PowerSession: Posters 1Session tme: Thursday 14:30-16:00Poster #26

26. Inability of CMIP5 models to simulate recent strengthening of the Walker Circulaton: implicatons for projectons

KOCIUBA Greg1; POWER Scot*2

1) Bureau of Meteorology, g.kociuba@bom.gov.au; 2) Bureau of Meteorology

Here we examine changes in the strength of the Walker Circulation (WC) in observations and 35 CMIP5 climate models. 78% of the models show a weakening of the WC over the 20th century, consistent with the observations and previous studies using CMIP3 models. However, the observations also exhibit a strengthening in the last three decades (i.e. from 1980-2012), that is statistically significant at the 95% level. The models, on the other hand, show no consensus on the sign of change, and none of the models show a statistically significant strengthening over the same period. The reasons for the inconsistency between models and observations will be discussed.

In the 21st century projections, the WC weakens in the vast majority of models under the four emissions scenarios considered, consistent with results obtained previously using CMIP3 models. However, the inconsistency between modelled and observed trends over the last three decades reduces confidence in the model projections.

Reference:

Kociuba, G., and S.B. Power, 2015: Inability of CMIP5 Models to Simulate Recent Strengthening of the Walker Circulation: Implications for Projections. J. Climate, 28, 20-35.

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SS2.2 Reconciling climate change and variability on decadal scales

SUBMISSION ID: 265SUBMITTER: James RicketsSUBMITTER EMAIL: jim.rickets@gmail.comSUBMITTER CAREER LEVEL: Postgrad studentPRESENTATION PREFERENCE: Oral

27. Exploring Decadal Regimes with the Maronna Bivariate Test.

RICKETTS James*1

1) Victoria University, jim.ricketts@gmail.com

The presence of climate regime shifts at decadal scale is not controversial. The Pacific Decadal Oscillation (PDO), and North Atlantic Oscillation (NAO), for example, were identified in part from correlated rapid changes of climatic variables and biological data.

Methods used for detection of abrupt regional shifts are varied, and have come from a number of disciplines.

Jones (2012) is a comprehensive analysis of regime shifts over SE Australia, using the Maronna bivariate test. This homogeneity test, documented in Vives and Jones (2005), detects a time and degree of change with a given probability, and a test statistic, Ti0.

It assumes a fully stationary exemplar series, and a similar test series, which may have exactly one instance of a shift in the mean at a single time. The use of random data as a no-change control, so performing a univariate test, is in Vives and Jones (2005).

To use the test objectively, an algorithm was developed that returns lists of shift dates in a given time series. As a univariate test, it is repeated 100 times for each date, and the modal date of these having Pr <= 0.01 are retained. The algorithm first segments the time series into two, based on the modal dates, and then continues to divide these sub-segments similarly until no shifts are found. It then repeatedly revises these provisional shifts by serially combining consecutive segments, checking for shifts within until the list is stable.

This presentation will show results of the application of this test to global mean temperature data, and several zonally averaged temperature series. The evolution of the shifts within gridded observational data will be demonstrated.

Jones, R. N. (2012). “Detecting and Attributing Nonlinear Anthropogenic Regional Warming in Southeastern Australia.” J. Geophysical Research: Atmospheres (1984--2012) 117(D4).

Vives, B. and R. N. Jones (2005). Detection of Abrupt Changes in Australian Decadal Rainfall (1890-1989), CSIRO Atmospheric Research.

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S2.3 ENSO and ENSO impacts - past, present and future

Submission ID: 149 Presentng Author: Jaclyn BrownSession: Posters 1Session tme: Thursday 14:30-16:00Poster #28

28. Simulatng current and future teleconnectons of ENSO to north-eastern Australia.

DONOVAN Elizabeth*1; BROWN Jaclyn 2; MCINTOSH Peter3 ; RISBEY James4; POOK Michael5

1) Bureau of Meteorology, elizabeth.donovan@utas.edu.au; 2) CSIRO; 3) CSIRO; 4) CSIRO; 5) CSIRO

North-eastern Australian rainfall variability is dominated by El Niño Southern Oscillation. Wet years are associated with La Niña and dry years with El Niño, as evidenced by the strong correlation between precipitation and the Nino3.4 index. Climate change may alter the strength of this teleconnection through changes in features such as the south pacific convergence zone, local positions of troughs, surrounding sea surface temperatures, or even ENSO flavour.

To understand potential changes to the Queensland-ENSO relationship in the future we rely on projections from climate models. Such an assessment requires that the climate model is firstly able to simulate the historical ENSO rainfall teleconnection patterns. Here we test this relationship in the ACCESS1-0 climate model and find that the teleconnection is not evident. AMIP-style runs are able to capture the teleconnection, so we infer that the coupling biases are introducing this error. We find that the teleconnection breakdown is due to the poor simulation of the western Pacific including the SPCZ, ocean temperature variability and surface winds. We explore more robust methods for estimating changes in QLD rainfall in climate models.

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S2.3 ENSO and ENSO Impacts - Past, Present and FutureSubmission ID: 115 Presentng Author: Jaclyn BrownSession: Posters 1Session tme: Thursday 14:30-16:00Poster #29

29. How Increasing Ocean Resoluton Alters ENSO Dynamics

BROWN Jaclyn*1; MATEAR Richard 2; CHAMBERLAIN Mathew3

1) CSIRO, jaci.brown@csiro.au; 2) CSIRO; 3) CSIRO

As computing power increases, our climate models can be run at higher resolutions, usually improving our ability to simulate climate features such as El Niño Southern Oscillation. With CMIP6 ahead and many modelling groups developing 1/10th degree models, it is interesting to find out what might be gained from higher resolution to interpret how/why our models alter in the way they simulate ENSO. The dynamics of ENSO is a complex interplay of many features including the structure and strength of the thermocline, barriers layers, and mixed layer heat budgets in the east. Changes to any of these due to higher resolution can change the way that ENSO is simulated.

We analyse output of two ocean-only models: the only differences between the models is the horizontal and vertical resolution. Forced ocean models are studied rather than coupled climate models to identify the gains from ocean resolution rather than those from made from reducing the coupling biases. The coarser model has a horizontal resolution of 1° by 1/3° in longitude and latitude, the finer scale model is 1/10th degree in both horizontal directions. The size of the friction coefficients applied also varies to account for the differing ability of the models to resolve eddies.

We explore three major paradigms of ENSO: the heat budget in the eastern equatorial Pacific, the warm water volume and energetics of the thermocline, and the role of barrier layers in altering the impact of westerly wind events. The way ENSO develops and progresses according to each of these paradigms is altered in complex ways that can here be completely attributed to an increase in ocean resolution. We describe these different ENSO behaviours in relation to changes to primary features due to higher resolution including an increase in thermocline sharpness, greater prevalence of barrier layers, and increased complexity and strength of ocean currents.

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SS2.3 ENSO and ENSO impacts - past, present and future

Submission ID: 141 Presentng Author: Andrew DowdySession: Posters 1Session tme: Thursday 14:30-16:00Poster #30

30. Potental for Seasonal Forecastng of Thunderstorm Risk

DOWDY Andrew*1

1)Bureau of Meteorology, a.dowdy@bom.gov.au

The possibility of producing seasonal forecasts of thunderstorms and associated impacts (such as heavy rainfall, hail, strong winds, tornados, lightning and fires) is examined. Surface-based convective available potential energy (CAPE), as an indicator of conditions favourable to thunderstorm formation, is obtained from ERA-Interim reanalyses and found to be significantly related to the El Niño-Southern Oscillation (ENSO) on seasonal time scales throughout many regions of the world. The relationship between thunderstorm activity (based on satellite lightning data for the time period 1995-2013) and ENSO shows strong similarities to the relationship between CAPE and ENSO in terms of its seasonal and spatial variability throughout the world. With a view towards potential operational applications, global maps are presented of seasonal anomalies (i.e., percentage difference to the seasonal mean) in thunderstorm activity for different phases of ENSO (El Niño, Neutral and La Niña), noting that ENSO can have some predictability up to a few months in advance. In addition to ENSO, a number of other large-scale modes of atmospheric and oceanic variability are examined in relation to thunderstorm occurrence (including the Northern Annular Mode, the Southern Annular Mode, the North Atlantic Oscillation, the Pacific-North American Pattern and the Indian Ocean Dipole mode). The significant relationships between thunderstorm activity and large-scale modes of variability suggest the possibility of developing a coarse-scale method for indicating the risk of lightning occurrence (i.e. suitable for application to global climate models, based on coarse spatial and temporal scales). This possibility is examined in relation to dry lightning and fuel moisture, noting that dry-lightning is a significant ignition source for a large proportion of the area burnt by fires throughout the world.

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SS2.3 ENSO and ENSO impacts - past, present and futureSubmission ID: 229 Presentng Author: Scot PowerSession: Posters 1Session tme: Thursday 14:30-16:00Poster #31

31. ENSO in a warmer world: clearer than ever before

POWER scot*1; DELAGE Francois 2; CHUNG Christne3 ; KOCIUBA Greg4; KEAY Kevin5

1) Bureau of Meteorology, s.power@bom.gov.au; 2)Bureau of Meteorology; 3)Bureau of Meteorology; 4)Bureau of Meteorology; 5)bureau of meteorology

The El Niño-Southern Oscillation (ENSO) drives substantial variability in rainfall, severe weather, agricultural production, ecosystems and disease in many parts of the world. As further human-forced changes in the earth’s climate system appear inevitable, the possibility exists that the character of ENSO and its impacts might change over the coming century. While this issue has been investigated many times during the last 20 years, there was, until very recently, very little consensus on future changes in ENSO, apart from an expectation that ENSO will continue to be a dominant source of year-to-year variability. This has now changed. Why? The main reason is the unexpected presence of robust, non-linear changes in precipitation anomalies during El Niño years. This nonlinear response is, surprisingly and amazingly, large enough and robust enough to overwhelm uncertain projected changes in the amplitude of ENSO-driven surface temperature variability. Some of the implications of this discovery will be described. If time, projected changes in Modoki El Ninos evident in the latest generation of climate models will also be outlined.

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SS2.3 ENSO and ENSO impacts - past, present and futureSubmission ID: 254 Presentng Author: Harun RashidSession: Posters 1Session tme: Thursday 14:30-16:00Poster #32

32. Mechanisms of ENSO Phase Locking Bias in the ACCESS Coupled Models

RASHID Harun*1; HIRST Anthony 2

1) CSIRO Oceans and Atmosphere, harun.rashid@csiro.au; 2) CSIRO Oceans and Atmosphere

The mechanisms of coupled model bias in seasonal ENSO phase locking are investigated using versions 1.0 and 1.3 of the ACCESS coupled models. The two ACCESS models are mostly similar in construction except for some differences, the most notable of which are in the cloud and land surface schemes used in the models. ACCESS1.0 simulates a realistic seasonal phase locking, with the ENSO variability peaking in December as in observations. On the other hand, the simulated ENSO variability in ACCESS1.3 peaks in March, a bias shown to be shared by many other CMIP5 models. To explore the mechanisms of this model bias, we contrast the atmosphere-ocean feedbacks associated with ENSO in both ACCESS model simulations and also compare the key feedbacks with those in other CMIP5 models.

We find evidence that the ENSO phase locking bias in ACCESS1.3 is primarily caused by incorrect simulations of the shortwave feedback and the thermocline feedback in this model. The bias in the shortwave feedback is brought about by unrealistic SST-cloud interactions leading to a positive cloud feedback bias that is largest around March, in contrast to the strongest negative cloud feedback found in ACCESS1.0 simulations and observations at that time. The positive cloud feedback bias in ACCESS1.3 is the result of a dominant role played by the low-level clouds in its modeled SST-cloud interactions in the tropical eastern Pacific. Two factors appear to contribute to the dominance of low-level clouds in ACCESS1.3: the occurrence of a stronger mean descending motion bias and a larger mean SST cold bias during March-April in ACCESS1.3 than in ACCESS1.0. A similar association is found between the positive cloud feedback bias and the biases in spring-time mean descending motion and SST for a group of CMIP5 models that show a seasonal phase locking bias similar to ACCESS1.3. The thermocline feedback also significantly differs in the two models, reinforcing the phase locking bias in ACCESS1.3.

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SS2.3 ENSO and ENSO impacts - past, present and future

Submission ID: 123Presentng Author: Alison TheobaldSession: Posters 1Session tme: Thursday 14:30-16:00Poster #33

33. Trends and Variability in Precipitaton-Bearing Synoptc Circulaton, Snowy Mountains, Australia

THEOBALD Alison*1; MCGOWAN Hamish 2

1)University of Queensland, a.theobald@uq.edu.au; 2)University of Queensland

The hydroclimate of the Snowy Mountains, south-east Australia (SEA) is highly variable. Inflows generated from precipitation falling in the region provide critical water resources for hydro-power generation and are a major source of environmental flows, supporting agriculture in the Murray-Darling Basin (MDB).

Positioned at a junction between the influence of tropical and extra-tropical synoptic scale weather systems, the hydroclimate is sensitive to change in the mid-latitude westerly wind belt, the dominant driver of precipitation in winter, and tropical moisture advection, particularly during the warmer months.

A multi-decade (1958-2012) objective climatology of precipitation-bearing synoptic weather systems is developed from re-analysis data and regional precipitation data.

Trend analyses show declining frequency of inflow-generating precipitation days (days on which __‚10 mm is observed), whilst the precipitation they generate has increased. In line with climate change projections, we conclude that precipitation intensity has increased.

Historically a cool-season (April_–ÐOctober) dominated precipitation regime is observed. However evidence is presented of a decline in precipitation during autumn and spring months - important for crop sowing in the MDB and replenishment of water storages. Change in annual precipitation distribution is evident with a shift towards greater precipitation during warmer months.

Results indicate synoptic type frequency varies according to ENSO phase, in line with dominant moisture pathways. Preliminary trend analyses of atmospheric variables during precipitation days associated with ENSO phases are presented.

Seasonal changes have implications for filling of water storages and agriculture. Also, effects of increasingly intense precipitation, e.g. erosion and flooding, may have major impacts in SEA. Ongoing research will quantify combined effects of drivers of variability in synoptic circulation responsible for precipitation.

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SS2.3 ENSO and ENSO impacts - past, present and futureSubmission ID: 26Presentng Author: Guojian WangSession: Posters 1Session tme: Thursday 14:30-16:00Poster #34

34. Increasing frequency of extreme El Nino events due to greenhouse warming

CAI Wenju1; WANG Guojian* 2

1)CSIRO, Wenju.Cai@csiro.au; 2)CSIRO

El Niño events are a prominent feature of climate variability with global climatic impacts. The 1997/98 episode, often referred to as ‘the climate event of the twentieth century, and the 1982/83 extreme El Niño, featured a pronounced eastward extension of the west Pacific warm pool and development of atmospheric convection, and hence a huge rainfall increase, in the usually cold and dry equatorial eastern Pacific. Such a massive reorganization of atmospheric convection, which we define as an extreme El Niño, severely disrupted global weather patterns, affecting ecosystems, agriculture, tropical cyclones, drought, bushfires, floods and other extreme weather events worldwide. Potential future changes in such extreme El Niño occurrences could have profound socio-economic consequences. Here we present

climate modelling evidence for a doubling in the occurrences in the future in response to greenhouse warming.We estimate the change by aggregating results from climate models in the Coupled Model Intercomparison Project phases 3 (CMIP3) and 5 (CMIP5) multi-model databases, and a perturbed physics ensemble. The increased frequency arises from a projected surface warming over the eastern

equatorial Pacific that occurs faster than in the surrounding ocean waters, facilitating more occurrences of atmospheric convection in the eastern equatorial region.

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SS2.3 ENSO and ENSO impacts - past, present and futureSubmission ID: 102Presentng Author: Mei ZhaoSession: Posters 1Session tme: Thursday 14:30-16:00Poster #35

35. Variatons of Near-Surface Salinity in the Tropical Pacifc Associated with ENSO

ZHAO mei*1; HENDON Harry 2; YIN Yonghong3 ; ALVES Oscar4

1) R&D branch Bureau of Meteorology, m.zhao@bom.gov.au; 2)R&D branch Bureau of Meteorology; 3)Bureau of Meteorology; 4)Bureau of Meteorology

Interannual variation of upper-ocean salinity in the tropical Pacific and its relation to ENSO is investigated using the Bureau of Meteorology PEODAS ocean reanalyses 1980-2012. Along the equator, interannual variations of temperature tend to be largest along the thermocline and maximize in the eastern Pacific whereas for salinity the largest variations are near the surface (above ~50 m) and largely confined to the western Pacific fresh pool. Empirical orthogonal function (EOF) analysis of temperature and salinity in the equatorial-depth plane (0-250m) reveals the systematic co-evolution of salinity with temperature during ENSO. Mature El Niño (La Niña) conditions are associated with eastward (westward) displacements of the western Pacific fresh pool and warm pool. The strong asymmetry of El Niño/La Niña temperature anomalies is equally expressed in the fresh pool salinity anomalies (less relative eastward shift during La Niña). The occurrence of extreme El Niño conditions during 1982/83 and 1997/98, when the strong positive temperature anomaly extended to the South American coast, is also well depicted in near-surface salinity by an additional eastward extension of the fresh pool to just east of the dateline. Systematic freshening of the western Pacific fresh pool in advance of El Niño during the recharge phase, which might contribute to subsequent evolution of El Niño, is also revealed and is shown to result largely from anomalous E-P. Additional implications of the variation of salinity for the ENSO cycle, including its role in the variation of the barrier layer, and the possible impacts of recent trends of near-surface salinity on ENSO behaviour will be discussed.

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2. Climate - Variability and Change

SS2.3 ENSO and ENSO impacts - past, present and future

Submission ID: 278Presentng Author: Jens ZinkeSession: Posters 1Session tme: Thursday 14:30-16:00Poster #36

36. Coral record of southeast Indian Ocean heat waves with intensifed Western Pacifc temperature gradient

ZINKE Jens*1; HOELL Andrew 2; LOUGH JaniceM.3 ; FENG Ming4; KURET AntonJ.5 ; CLARKE Harry6 ; Ricca Vincenzo7 ; McCulloch MalcolmT.8

1)Curtin University of Technology, jen.zinke@gmail.com; 2)University of California Santa Barbara; 3)Australian Institute of Marine Science; 4)CSIRO; 5)UWA School Earth and Environment ARC CoE for Coral

Reef Studies; 6)UWA School Earth and Environment ARC CoE for Coral Reef Studies; 7)UWA School Earth and Environment; ARC CoE for Coral Reef Studies; 8)UWA School of Earth and Environment; ARC Centre of

Excellence for Coral Reef Studies

Marine heat waves (1-3) of increasing intensity which cause widespread mass coral bleaching events are threatening the integrity and functional diversity of corals reefs. Here, we demonstrate the role of inter-ocean coupling in escalating thermal stress on reefs in the poorly studied southeast Indian Ocean (SEIO), through a robust 215 year (1795-2010) geochemical proxy sea surface temperature (SST) record. The emergent long-term SST trends and inter-annual to multi-decadal variability in our proxy record highlight the key role of an increased WPG(4-5), often in concert with strong La Niña’s, in triggering extreme warm events in the SEIO. We trace the cause of historical heat waves to large heat flux changes associated with an increased WP (4,5) as a result of the western Pacific warming faster than the central Pacific. We show that the magnitude of the WPG varies independently between individual El Niño and La Niña events (4-5) resulting in modification of the large-scale tropical circulation and precipitation fields (4,5) affecting the energy and heat flux terms, warm water ocean advection through the coastal waveguide and sea-level pressure in the SEIO and ultimately the magnitude of SEIO marine heat waves. Thus, the independent variability of the WPG from ENSO is of pivotal importance for Indo-Pacific climate connectivity and their impacts on the environment and human society. Better understanding of the zonal SST gradient in the western Pacific is expected to improve projections of the future activity of SEIO heatwaves and their ecological impacts on the important coral reef ecosystems of Western Australia.

1. Feng, M. et al.Sci. Rep. 3, 1277 (2013).

2. Moore et al., PLoS ONE 7, (2012).

3. Zinke, J. et al. Nature Communications 5, doi:10.1038/ncomms4607 (2014).

4. Hoell, A., Funk, C. J. of Clim. 26, 9545-9562 (2013).

5. Hoell, A. et al. Climate Dynamics, doi: 10.1007/s00382-014-2083-y (2014).

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S2.4 Reconstructon and modelling of past climate

Submission ID: 83 Presentng Author: Duncan AckerleySession: Posters 1Session tme: Thursday 14:30-16:00Poster #37

37. Evaluatng mid-Holocene precipitaton over Australasia and the Maritme Contnent in climate models.

ACKERLEY Duncan*1

1) Monash University, duncan.ackerley@gmail.com

This work presents the initial assessment of model simulations of the mid-Holocene over the Australasian and Maritime Continents (taken from the Paleoclimate Modelling Intercomparison Project, PMIP) in relation to those available data. The mid-Holocene (6 ka) encompasses a period after sea level stabilisation (around 8-7.5 ka) and before the onset of strong ENSO-related variability (post 4 ka). There is some evidence of possibly drier conditions over northern Australia with increased coastal dune activity, along with slightly wetter conditions over Borneo and Papua New Guinea. Weakening of the Southern Hemisphere mid-latitude westerlies (relative to the early Holocene) is also likely to have occurred, as evidenced by drier conditions in Western Tasmania and Victoria. The modelled results from the mid-Holocene simulations indicate that conditions were approximately 1-6% drier over much of continental Australia than at present. There is also evidence of slightly wetter conditions (1-3%) over the northern tip of Australia and parts of Papua New Guinea and Borneo. There are also differences in the seasonal cycle of precipitation and circulation in these models in response to the changes in the orbital parameters in the mid-Holocene relative to present day. The precipitation in the early half of the monsoon season (October, November and December–OND) is typically 10% higher in the mid-Holocene simulations. Conversely, the precipitation is typically more than 10% lower in the late half of the monsoon period (January, February and March–JFM). The increase in OND precipitation and decrease in JFM implies that the monsoon onset and retreat may have been earlier than at present (in response to the insolation forcing), and therefore it is important to assess the changes over the whole monsoon period (October to March) instead of just the summer months (December, January and February).

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S2.4 Reconstructon and modelling of past climate

Submission ID: 187 Presentng Author: Kathryn AllenSession: Posters 1Session tme: Thursday 14:30-16:00Poster #38

38. Towards cool season temperature reconstructons in southeastern Australia

ALLEN Kathryn*1; EVANS Robert 2; NICHOLS Scot3 ; COOK Edward4; BAKER Patrick5

1) University of Melbourne, Kathryn.Allen@unimelb.edu.au; 2) Silviscan Pty Ltd; 3) University of Melbourne; 4) Lamont-Doherty Earth Observatory; 5) University of Melbourne

There are very few tree-ring reconstructions of temperature for the cooler months of the year in temperate regions. Essentially this is due to the shutdown of trees over the cooler months, and the resulting lack of a strong relationship with climate over the cool months. New evidence suggests, however, that some of the Tasmanian conifers, although forming annual rings, do not fully shut down over the cool season months. Athrotaxis selginoides and Phyllocladus aspleniifolius are two such species. Indeed, in a number of locations, tree ring-width chronologies based on these species exhibit their strongest response to temperature in the late winter and early spring months. Using the Tasmanian tree-ring network, we have developed the first annually-resolved maximum and mean temperature reconstructions for the cool season (July— October) for southeastern Australia. Our reconstructions are based on a point-to-point nested regression method and currently limited to the 1710— 2007CE period. PC1 of both reconstruction contains ~83% variance and has a significant relationship with the intensity of the subtropical ridge (STR). A trend since in the PC time series from the middle of the 20th century is evident. PC2 contains ~9%of the variance and has a weak but significant correlation with the Southern Annular Mode (SAM). Development of additional chronologies from species with a cool season signature in their rings is currently underway and can be expected to improve the quality and length of our reconstructions

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S2.4 Reconstructon and modelling of past climates to improve understanding of climate processes and future change

Submission ID: 213 Presentng Author: Michael HutchinsonSession: Posters 1Session tme: Thursday 14:30-16:00Poster #39

39. Generic Estmaton of Monthly and Daily Solar Radiaton from Rainfall and Temperature

HUTCHINSON Michael*1; KESTEVEN Jennifer 2; EVANS Brad3

1)Australian National University, michael.hutchinson@anu.edu.au; 2)Australian National University; 3)Macquarie University

Solar radiation is a primary variable in ecosystem modelling but direct measurement of solar radiation has often been limited to a relatively small number of ground stations. This has led to the development of a variety of simple regression methods to estimate daily solar radiation from other more routinely measured meteorological variables, such as transformations of daily rainfall, daily temperature range and relative humidity. When used in conjunction with readily calculated extra-terrestrial solar radiation, such methods can provide acceptable estimates of daily solar radiation at particular locations (Lui and Scott 2001). The principal limitation of these methods is that they have coefficients that are location dependent. Using solar radiation observations we have developed new general formulations for estimating both monthly and daily solar radiation with coefficients defined in terms of long term mean rainfall occurrence and long term mean daily temperature range. Since spatial estimates of the latter are readily available for Australia, the method can be used to estimate monthly and daily solar radiation with acceptable accuracy across Australia for past, present and projected future climates. The prediction accuracy for the monthly estimates is around 5% while the prediction accuracy for the daily values is around 10-15%. The method therefore offers a viable alternative to direct measurements of solar radiation when such are unavailable. Gridded solar radiation estimates for Australia obtained with this method are being made generally available as part of ANUClimate spatial models for the eMAST facility of the Terrestrial Ecosystem Research Network.

eMAST 2015. Ecosystem Modelling and Scaling Infrastructure, Terrestrial Ecosystem Research Network. http://www.emast.org.au/

Lui, D.L. and Scott, B.J. 2001. Estimation of solar radiation in Australia from rainfall and temperature observations. Agricultural and Forest Meteorology 106: 41-59.

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S2.4 Reconstructon and modelling of past climates to improve understanding of climate processes and future changeSubmission ID: 79 Presentng Author: Joelle GergisSession: Posters 1Session tme: Thursday 14:30-16:00Poster #40

40. Drought variability in the Southern Hemisphere: insights from recent advances in palaeoclimatology

GERGIS Joelle*1; HENLEY Benjamin 2

1) University of Melbourne, jgergis@unimelb.edu.au; 2) University of Melbourne

This study presents an analysis of three recently published palaeoclimate rainfall reconstructions from the Southern Hemisphere regions of south-eastern Australia (SEA), southern South Africa (SAF) and southern South America (SSA). We provide a first comparison of rainfall variations in the three regions over the past two centuries, with a focus on identifying synchronous wet and dry periods. The 1837–1842, 1902–1905, and 1911–1914 and the post-1970 periods were identified in at least two regions across the hemisphere as being dry, while above average rainfall conditions were identified during the 1805–1810, 1828–1830, 1886–1894 and 1947–1963 periods. An investigation of the 20th century relationship between regional rainfall and the large-scale climate circulation features of the Pacific, Indian and Southern Ocean regions revealed that Indo–Pacific variations of the El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) dominate rainfall variability in SEA and SAF, while the high latitude Southern Annular Mode (SAM) exerts a greater influence in the SSA region.

An assessment of the stability of the regional rainfall–climate circulation modes over the past two centuries revealed a number of non-stationarities, the most notable of which occurs during the early 19th century at around 1820. This corresponds to a time when the influence of SEA, SAF and SSA rainfall–ENSO relationships weaken and there is a strengthening of the influence of SAM. We provide evidence for the long-term association of El Niño (La Niña) and negative (positive) SAM conditions from the three mid-latitude regions of SEA, SAF and SSA. The rainfall reconstructions compared here offer long term estimates of past rainfall variability which can now be used as a basis for the detection and attribution of mid-latitude anthropogenic climate change and its impact on future Southern Hemisphere hydroclimatic variability.

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S2.4 Reconstructon and modelling of past climates to improve understanding of climate processes and future change

Submission ID: 52 Presentng Author: Acacia PeplerSession: Posters 1Session tme: Thursday 14:30-16:00Poster #41

41. Zonal Winds and Southeast Australian Rainfall in Observatons and Models

PEPLER Acacia*1; ALEXANDER Lisa 2; EVANS Jason3

1)University of New South Wales, a.pepler@student.unsw.edu.au; 2)University of New South Wales; 3)University of New South Wales

The Great Dividing Range acts as a major divide in the climate of southeast Australia. Periods of enhanced westerly wind flow bring rain-bearing weather systems to much of southeast Australia during the cool season, but result in below-average rainfall along the east coast. Over the past several decades, there has been an observed southward shift in these westerlies, contributing to long-term cool season rainfall declines in much of southeast Australia.

While global climate models adequately represent the seasonality of zonal windflow across southeast Australia, the coarse resolution means the topography of the Great Dividing Range is poorly represented. We show that this has large impacts on their ability to represent the historical relationships between zonal windflow and rainfall variability. While regional downscaling is found to improve on these results through better representation of topographic features, particularly when applied to a poorly-performing model, they are also unable to fully correct for biases in the driving climate model. This suggests that both global and regional climate models may have difficulties in translating future trends in atmospheric circulation to their associated impacts.

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S2.4 Reconstructon and modelling of past climates to improve understanding of climate processes and future changeSubmission ID: 176 Presentng Author: Steven SherwoodSession: Posters 1Session tme: Thursday 14:30-16:00Poster #42

42. Atmospheric changes through 2012 as shown by iteratvely homogenised radiosonde temperature and wind data

SHERWOOD Steven*1; NISHANT Nidhi 2

1)UNSW, s.sherwood@unsw.edu.au; 2)UNSW

We present an updated version of the radiosonde dataset homogenised by Iterative Universal Kriging (IUKv2), now extended through February 2013, following the method used in the original version (Sherwood et al. 2008). This method, in effect, performs a multiple linear regression of the data onto a structural model that includes both natural variability, trends, and time-changing instrument biases, thereby avoiding estimation biases inherent in traditional homogenisation methods. One modification now enables homogenised winds to be provided for the first time. This, and several other small modifications made to the original method sometimes affect results at individual stations, but do not strongly affect broad-scale temperature trends.

Temperature trends in the updated data show three noteworthy features. First, tropical warming is equally strong over both the 1959-2012 and 1979-2012 periods, increasing smoothly and almost moist-adiabatically from the surface (where it is roughly 0.14 K/decade) to 300 hPa (where it is 0.25-0.3 K/decade over both periods), a pattern very close to that in climate model predictions. This contradicts suggestions that atmospheric warming has slowed in recent decades or that it has not kept up with that at the surface. Second, as shown in previous studies, tropospheric warming does not reach quite as high in the tropics and subtropics as predicted in typical models. Third, cooling has slackened in the stratosphere such that linear trends since 1979 are about half as strong as reported earlier for shorter periods.

Wind trends over the period 1979-2012 confirm a strengthening, lifting and poleward shift of both subtropical westerly jets; the northern one shows more displacement and the southern more intensification, but these details appear sensitive to the time period analysed. There is also a trend toward more easterly winds in the middle and upper troposphere of the deep tropics.

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S4.1 Circulaton and Climate Variability in the Indian Ocean

Submission ID: 29 Presentng Author: Lea Kannar-LichtenbergerSession: Posters 1Session tme: Thursday 14:30-16:00Poster #43

43. There Be Dragons: Human Impact on the Unique Environments of the Galapagos and Lord Howe Islands

KANNAR-LICHTENBERGER Lea *1

1) leakannar@bigpond.com

My proposal is an exploration (including first hand research) and comparison of aspects of life relating to the islands of the Galapagos (Ecuador— Research Oct 2014) and Lord Howe Island (NSW Australia— Research April 2015). These islands have waters rich in marine life whist the annual ocean temperatures fluctuate significantly. They are also home to unique terrestrial and aquatic species that have either become extinct or now struggled to re-establish a foot hold on the landscape through various means including controlled breeding or restricted human access.

I am exploring the impact of controlled Tourism in its current form and how the Anthropocene may be considered with regard to both the aquatic and terrestrial flora and fauna on these islands; further extrapolating how future water temperature changes could impact on current marine life.

My investigation, which involves a studio art practice, looks to create awareness surrounding the alterations we make in nature that transforms not only the flora and fauna but also social, ethical and cultural values towards them. Through this I create metaphors for our connection to these changes and the Anthropocene. Through a visual reflection on the microscopic and macroscopic I use cellular, geographical and habitational images.

This will be a visual exploration of the island waters utilising various media from, sound to film to photography giving my perspective relating to this research. These will include but will not be limited to merging the imagery with Human DNA strands to reflect the influence of humans on the natural environment.

My investigations look to highlight what is currently occurring in these areas by raising questions relating to the existing aquatic balance and explore the impact of changes to the fundaments of life

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S4.1 Circulaton and Climate Variability in the Indian Ocean

Submission ID: 237 Presentng Author: Viviane MenezesSession: Posters 1Session tme: Thursday 14:30-16:00Poster #44

44. Interannual Variability In The South Indian Ocean Countercurrent: Dominance Of The Quasi-Biennial Band

MENEZES Viviane*1; PHILLIPS Helen 2

1) Institute for Marine and Antarctic Studies (IMAS) University of Tasmania, vivianev@utas.edu.au; 2) Institute for Marine and Antarctic Studies (IMAS) University of Tasmania

The South Indian Countercurrent (SICC) is a major current of the surface circulation in the Indian Ocean.It flows between 20S and 30S all the way across the basin from Madagascar to Western Australia, where it merges with the Leeuwin Current. Despite its importance, few studies have examined the temporal variability of the SICC especially across interannual time scales. To fill this gap in knowledge, four different datasets are analyzed: AVISO (1993-2012); the eddy-resolving OFAM3 model (1993-2010); the GLORYS2V3 reanalysis (1993-2012) and SODA (1871-2010). Zonal components (u) are used as indexes of the SICC strength: for altimetry data, u is the absolute geostrophic zonal velocity; for the other data, u is the zonal transport between 0/200m. By using Singular Spectrum Analysis and the Maximum Entropy Method, the datasets were projected into 4 subjectively chosen temporal period (T) band-limited time intervals defined as: up to annual (T<1.2 yr), quasi-biennial (QB) (1.2 -3 yr), ENSO (3-7yr) and quasi-decadal (7-10 yr). We find that the QB band dominates the interannual variability of u, explaining 13-14% of the global variances, followed by the ENSO band (5-6%). In the SICC domain, the QB band accounts for 40%-70% of the low frequency variance (T>1.2 yr), with the ENSO band explaining 18%-22%. A wavelet analysis of the QB in the SICC region shows that this band is characterized by two spectral peaks: a stronger well-defined peak around 1.5-1.8 yr and a weaker one centered at 2.5 yr, which occurs mostly in the western sub-basin. There, the 1.5-1.8 yr peak dominates from 1994 to 2005, while the 2.5 yr peak dominates from 2005 onwards. The QB signals present decadal modulations. The QBs are characterized by westward propagating waves in both u and sea surface height, which may represent interannual Rossby waves. The QB is being investigated in relation to the QBO(QB Oscillation) and IOD(Indian Ocean Dipole) since IOD is well know to have a biennial signature.

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S4.1 Circulaton and Climate Variability in the Indian Ocean

Submission ID: 222 Presentng Author: Charitha PataratchiSession: Posters 1Session tme: Thursday 14:30-16:00Poster #45

45. Surface Circulaton and Upwelling paterns around Sri Lanka and Formaton of the Sri Lanka Dome

PATTIARATCHI Charitha*1; WIJERATNE Sarath 2

1) The University of Western Australia, chari.pattiaratchi@uwa.edu.au; 2) The University of Western Australia

Sri Lanka occupies a unique location within the equatorial belt in the northern Indian Ocean with the Arabian Sea on its western side and the Bay of Bengal on its eastern side and experiences bi-annually reversing monsoon winds. Elements of the dynamics of the surface circulation and coastal upwelling in the waters around Sri Lanka using satellite imagery and numerical simulations using the Regional Ocean Modelling System (ROMS) are presented. The model was run for 3 years to examine the inter-annual, seasonal and shorter term (~10 days) variability. The results reproduced correctly the reversing current system, between the equator and Sri Lanka, in response to the changing wind field: the eastward flowing Southwest Monsoon Current (SMC) during the Southwest (SW) monsoon transporting 11.5 Sv and the westward flowing Northeast Monsoon Current (NMC) transporting 9.6 Sv during the Northeast (NE) monsoon, respectively. A recirculation feature located to the east of Sri Lanka during the SW monsoon, the Sri Lanka Dome, is shown to result from the interaction between the SMC and the Island of Sri Lanka. Along the eastern and western coasts, during both monsoon periods, flow is southward converging along the south coast. During the SW monsoon the Island deflects the eastward flowing SMC southward whilst along the east coast the southward flow results from the Sri Lanka Dome recirculation. The major upwelling region, during both monsoon periods, is located along the south coast resulting from southward flow converging along the south coast and subsequent divergence associated with the offshore transport of water. The location of the flow convergence and hence the upwelling centre was dependent on the relative strengths of wind driven flow along the east and west coasts: during the SW (NE) monsoon the flow along the western (eastern) coast was stronger migrating the upwelling centre to the east (west).

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S4.1 Circulaton and Climate Variability in the Indian OceanSubmission ID: 315 Presentng Author: Helen PhillipsSession: Posters 1Session tme: Thursday 14:30-16:00Poster #46

46. Bio-Argo Floats Reveal Subsurface Structure of Southeast Indian Ocean Eddies

PHILLIPS Helen*1; PUMP Sylvia 2; DURAN Earl3 ; STRUTTON Pete4; TRULL Tom5

1)University of Tasmania, h.e.phillips@utas.edu.au; 2)University of Tasmania; 3)University of Tasmania; 4)University of Tasmania; 5)CSIRO

There is increasing recognition that eddies play an influential role in the productivity of open ocean waters, and that this influence depends on both eddy sources and the nature of their evolution. Eddies in the southeast Indian Ocean have been recognised, from satellite remote sensing of sea surface height and ocean colour, as particularly influential pathways for the westward transport of elevated biomass from the eastern boundary Leuuwin Current into the otherwise highly oligotrophic central South Indian Ocean. Further it has been hypothesized that processes at the base of the surface mixed layer within some of these eddies stimulate production and allow biomass to persist for much longer than would be expected from passive transport alone.

Here we present high-frequency profiles of temperature, salinity, biomass and oxygen concentrations in one anti-cyclonic and one cyclonic eddy in the South Indian Ocean. Satellite sea surface height data confirmed both profiling floats remained trapped within their respective eddies from winter to early summer 2012, sampling the upper 300 m of the water column 6-8 times per day. The eddies were larger than average for this region, with mean amplitude and radius of 18.1 (19.3) cm and 143 (97) km for the anticyclonic (cyclonic) eddy.

The total concentration of chlorophyll in the mixed layer remained relatively constant, although its vertical distribution changed over time: from September to October, it was evenly distributed throughout the mixed layer of both eddies; with the onset of spring warming, the chlorophyll became concentrated at greater depth with less chlorophyll at the surface. Satellite measurement of surface chlorophyll was 3-5 times lower than the float surface measurement throughout the record. There was no significant change in oxygen saturation state coincident with high phytoplankton concentration. No biological production was evident in either eddy. We discuss these and other results.

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SS4.1 Circulaton and Climate Variability in the Indian OceanSubmission ID: 255Presentng Author: Craig SteinbergSession: Posters 1Session tme: Thursday 14:30-16:00Poster #47

47. Real-Time Marine Observing Systems in Australian Tropical Seas

RIGBY Paul1; STEINBERG Craig* 2; WILLIAMS David3 ; BRINKMAN Gary4; BRINKMAN Richard5 ; TONIN Hemerson6 ; Hughes David7

1)AIMS, p.rigby@aims.gov.au; 2)AIMS; 3)AIMS; 4)AIMS; 5)AIMS; 6)AIMS; 7)CSIRO

The well being and prosperity of Australia is strongly linked to the ocean, with most of the population living in highly urbanised centres along a narrow coastal strip. Infrastructure development and population growth along the coast will continue to place growing pressure on the marine environment and its natural resources, requiring a knowledge-based approach to the management of risks to these assets. Decision making around sea level rise, storms and extreme events, shipping and maritime operations, fisheries and aquaculture, and marine park zoning must be informed by an understanding of coastal ocean processes, their drivers, and ecosystem responses. This requires both coastal and open ocean observations.

Since 2007, these observations have been provided by the Integrated Marine Observing System (IMOS). IMOS is funded by the Australian Government and designed to be a fully-integrated national array of observing equipment to monitor the oceans and coastal marine environment around Australia, covering physical and biogeochemical variables. Near real time data delivered by IMOS comprises observations from a wide spectrum of platforms however the focus here is on the oceanographic moorings.

When data from ocean observing systems can be provided in near real-time, the operational aspects are possible and provide potential for a range of value added products to be developed. Here we provide 3 examples of co-invested partnerships that have facilitated the development of real-time ocean observing systems in the coastal and outer shelf, operated by the Queensland and Northern Australian moorings & National Reference Station sub-facilities of IMOS. These examples demonstrate the benefits of having a national collaborative approach to marine observing with a clear focus on open access to data. Increasingly the data uptake by modelling has matured through eReefs modelling of the Great Barrier Reef and other higher resolution efforts such as in Darwin Harbour.

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S6.0 General - Tropical/Subtropical OceanographySubmission ID: 286 Presentng Author: Michael MurphySession: Posters 1Session tme: Thursday 14:30-16:00Poster #48

48. The Trade Wind Regime of eastern Australia and its Inversion

MURPHY Michael1; SIEMS Steven 2; MANTON Michael3

1) Monash University, michael.j.murphy@monash.edu; 2) Monash University; 3) Monash University

Despite their prevalence along much of the coastline, the basic characteristics of the trade wind regime of eastern Australia and its associated temperature inversion remain unclear. Describing the trades in this region is especially important as it is on the western flank of a subtropical high pressure system, far from the source areas of the trades, where studies have been limited. The trade winds and their associated temperature inversion along the coast of eastern Australia are examined with an emphasis on seasonal and regional variations, using available upper-level wind and radiosonde observations over 1960-2010 and 1976-2010, respectively. The trade wind regime prevails during austral winter in the deep tropics and late summer in the subtropics with its poleward fringe in southeastern Queensland. A low-level temperature inversion is a common feature across the region with highest frequency in winter and summer in the deep tropics and subtropics, respectively. Thermodynamic properties of the inversion follow a distinct annual cycle that peaks in winter, with strongest amplitude in the deep tropics. Inversion base height is largely independent of these other properties with a strong annual cycle across the region, peaking in autumn. Seasonality in the frequency of the trade winds is strongly influenced by the latitude of the subtropical ridge (STR) across much of the region, while interannual variability is closely related to the intensity of the STR throughout the winter. Seasonality in the frequency and thermodynamic properties of the inversion follow that of the STR with the strongest relationships in the deep tropics, and only a weak relationship with inversion base height. Interannual variability in inversion frequency is moderately related to the local sea surface temperature. Significant positive and negative trends are found in the frequency of winds from the east and southeast, respectively, at most stations equatorward of the subtropics.

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S6.0 General – Tropical/Subtropical oceanographySubmission ID: 281Presentng Author: Duncan AckerleySession: Posters 1Session tme: Thursday 14:30-16:00Poster #49

49. The representaton of north Australian rainfall in CMIP5

ACKERLEY DUNCAN*1

1)Monash University, duncan.ackerley@monash.edu

As general circulation models (GCMs) are routinely used to make projections of future rainfall, it is important to assess whether the processes that cause precipitation are represented well. If those processes are poorly represented then it is important to identify and account for them in order to make the best projections. The work presented here identifies some of the features that are important for producing rainfall over northern Australia in a selection of CMIP5 models run under Atmospheric Model Intercomparison Project (AMIP) conditions (prescribed sea surface temperatures). The diurnal cycle of the low-level flow around the north-west Australian heat low is represented well; however, the nocturnal rearrangement of the flow leads to night-time convergence and then to convective rainfall. This forced convection is unlikely to occur in the real world; however, this forced nocturnal precipitation is an important contributor the modelled total precipitation in this region. Interestingly, the occurrence of such rainfall in these simulations (associated with convergence within the heat low overnight) may not be restricted to Australia. The models also produce precipitation too early in the day, which is associated with the early triggering of convection from surface heating.

Despite these errors in the timing of precipitation, the CMIP5 models assessed here are capable of representing the synoptic features responsible for initiating rain. Moreover, there is evidence that some of these systems have their origins in the mid-latitudes. Nevertheless, errors in the modelled seasonal mean precipitation appear to be associated with both the strength of the mean northerly flow onto the continent and the vertical mass flux over the continent. Furthermore, there is also evidence that it is ultimately the representation of convection in these models that is the important contributor to the precipitation biases identified, and not the synoptic features that initiate it.

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S6.0 General – Tropical/Subtropical oceanographySubmission ID: 163Presentng Author: Michael GraySession: Posters 1Session tme: Thursday 14:30-16:00Poster #50

50. Surface Energy and Radiaton Budgets for a Subtropical Groundwater Dependent Ecosystem under Extreme Changes in Surface Conditons

GRAY Michael*1

1) UQ, m.gray@uq.edu.au

Subtropical sand islands have received little attention in regards to the measurement of surface-atmosphere exchanges of heat, moisture, and radiation. The state-of-the-art eddy covariance method was used to monitor surface-atmosphere energetics over a groundwater dependent swamp on Bribie Island in Southeast Queensland from December 2012 to February 2013.

The first stage of the measurement period was hot and unusually dry with the water table below the surface. This was followed by a bushfire, which led to a greater than 50 % decrease in upwelling shortwave radiation (mean daily maximums: pre-fire 99 Wm-2; post-fire 46 Wm-2), a 25 % increase in upwelling longwave radiation (503 Wm-2 to 629 Wm-2), and a subsequent 15 % decrease in net radiation (911 to 750 Wm-2). Sensible heat was more significant than latent heat in the energy balance of the pre-fire environment (mean daily maximums of 306 Wm-2 and 169 Wm-2 respectively); while post-fire this dominance increased (mean daily maximums of 457 Wm-2 and 90 Wm-2 respectively).

After two weeks of post-fire landscape recovery a significant rainfall event of 275 mm in three days inundated the swamp. This resulted in net radiation increasing to values similar to the pre-fire environment, caused primarily by a decrease in upwelling longwave radiation from 629 Wm-2 (post-fire) to 494 Wm-2. With water as the primary surface feature, the energy balance was dominated by latent heat (mean daily maximum 185 Wm-2) with sensible heat less than one-third the value of the pre-fire environment (mean daily maximum 105 Wm-2).

When considered on a landscape wide scale, these changes in surface energetics are likely to produce alterations in boundary layer characteristics, but the extent to which this occurs is as yet unknown. Future work on this case study will investigate these processes using the WRF model.

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S6.1 The Indo-Pacifc Warm PoolSubmission ID: 171 Presentng Author: Ghyslaine BoschatSession: Posters 1Session tme: Thursday 14:30-16:00Poster #51

51. A new ‘energetc’ approach into the variability and trends of the Hadley circulaton and energy transports to the high southern lattudes

BOSCHAT Ghyslaine*1; SIMMONDS Ian 2

1) University of Melbourne, ghyslaine.boschat@unimelb.edu.au; 2) University of Melbourne

The Hadley circulation is a major atmospheric overturning and is responsible for most of the energy transport from the low tropics to the extratropics. It consists of ascent of equatorial air associated with high-rainfall regimes, a poleward mass transport in the upper atmosphere and subsidence over extensive subtropical ‘dry zones’. Understanding the variations in the strength and extent of this large-scale circulation bears obvious societal importance for Australia and other global climates. However there is, as yet, no clear consensus on the mechanisms controlling the current and future behaviour of the cell.

This work provides new perspectives on the variability and trends of the Hadley circulation, by exploring its structure within an energy (rather than a mass) framework. In this approach, spatial contrasts in the meridional transport of energy and its components are determined at different vertical levels, and for both hemispheres. This decomposition is performed using updated 6-hourly reanalysis data, which allows us to calculate seasonal means but also account for the role of transient eddy activity in the subtropics and midlatitudes. This interactive perspective presents the opportunity to integrate the climatology, variability and trends of the Hadley circulation into a broader and (perhaps) more comprehensive picture. Our analysis also reveals the important interannual signals associated with the meridional heat transports on to the Antarctic continent.

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S6.1 The Indo-Pacifc Warm Pool

Submission ID: 156 Presentng Author: Ian WatersonSession: Posters 1Session tme: Thursday 14:30-16:00Poster #52

52. Drivers Of Australian Climate Change Based On Paterns Of Trends Among CMIP5 Models

WATTERSON Ian*1

1) CSIRO, ian.watterson@csiro.au

Australian climate is expected to warm over the coming century, driven by the global-scale warming that is expected as a consequence of rising greenhouse gas concentrations. Likewise, changes in rainfall and other quantities over Australia, as simulated by CMIP5 global climate models, tend to be proportional to the global warming— consistent with the ‘pattern scaling’ approximation. However, the patterns of ‘trend per degree’ vary considerably across an ensemble of 40 models, leading to the range in projections, which is particularly large for rainfall. Patterns of change have often been linked to modes of interannual variability, such as ENSO and SAM. Watterson (Climatic Change, 2012) found that a simple index of the change in the central Pacific sea surface temperature relative to that in the Indian Ocean correlated strongly with the Australian rainfall trends across the CMIP3 models. The same holds for CMIP5, but combining the ‘Pacific-Indian dipole’ index with that for average equatorial temperatures improves the correlation to 0.87. This combined SST index is closely related to the first EOF of the equatorial temperature trends. Furthermore, a simple index representing the SAM-like trend in southern hemisphere mean-sea level pressure relates well to southern Australian rainfall, particularly in winter.

These three indices of trend - global warming, equatorial SST, and SAM - can be used to interpret much of the range of the projections of Australian temperature, rainfall and other variables. If the uncertainty in the future index values could be narrowed, from the range within the CMIP5 ensemble, then the projections could potentially be narrowed also. An approach based on the skill of simulating the present climate is explored here, with some success. The implications for projections of Australian rainfall trends are considered.

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S6.3 Maritme Contnent: processes, weather and climateSubmission ID: 182Presentng Author: Martn BergemannSession: Posters 1Session tme: Thursday 14:30-16:00Poster #53

53. Meso-scale forcing of Maritme Contnent rainfall

BERGEMANN Martn*1; JAKOB Christan 2; LANE Todd3

1) Monash University, martin.bergemann@monash.edu; 2)Monash University; 3)University of Melbourne

An area that is particularly poorly represented in current numerical weather forecast and general circulation models (GCMs) is the Maritime Continent, where most models produce too much rain over the ocean areas and too little over land. One factor that contributes to difficulties in the representation of precipitation over the Maritime Continent area is the diurnal-cycle and thus precipitation due to land-sea interaction.

Coastal assciated precipitation is identified using an objective algorithm. The strength of this method is that it is based soley on rainfall.

The large-scale forcing under which the detected coastal associated rainfall over the Maritime Continent occurs is investigated and compared to the forcing for total rainfall. It is shown that coastal associated rainfall is much less dependent on the large-scale state of the atmosphere than total precipitation.

Parametrizations in GCMs are based on large-scale forcing variables. Since the objective algorithm shows that major portions of the Maritime Continent precipitation is related to land-sea interaction (meso-scale), we conclude that the Maritime Continent rainfall can not be well captured by GCMs. Thus, we propose a stochastic parametrisation scheme that is able to model rainfall occurring on meso-scales.

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S6.3 Maritme Contnent: Processes, Weather, and ClimateSubmission ID: 93 Presentng Author: Hanh NguyenSession: Posters 1Session tme: Thursday 14:30-16:00Poster #54

54. Sensitvity of the ACCESS regional forecast model statstcal rainfall propertes to resoluton

NGUYEN Hanh*1; PROTAT Alain 2; WHIMPEY Michael3

1) Bureau of Meteorology, h.nguyen@bom.gov.au; 2) Bureau of Meteorology; 3) Bureau of Meteorology

We assess the representation of the statistical rainfall properties over Darwin using different regional high-resolution versions of the ACCESS model using the dual-polarization CPOL radar observation as a reference.

Results from the coarser resolution (horizontal resolution of 12km, 50 height levels with a 37.5km top) show that while the model reasonably well reproduces the accumulated daily rainfall amount albeit tending to slightly overestimate it, the mean rain rate is too weak, compensated by too large a rain frequency of occurrence. In terms of intensity the model tends to perform worse in the dry regimes but improves in the wet regimes, especially during the active monsoon regime, where most of the monsoonal precipitation is produced. Probability distribution functions of daily rain rates reveal that while there are very little differences amongst regimes, marked discrepancies are found between model and observations. The model overestimates light rain rates, underestimates moderate to heavy rain rates and produces spurious very heavy rain rates that are not observed at all by the radar. The evaluation of the diurnal cycle of rainfall properties also reveals a general underestimate of rain rates compensated by an overestimated rain frequency over the whole cycle, resulting in an overestimated amplitude and a wrong timing of the diurnal cycle. In all regimes, the overestimation of total domain daily rainfall and rain frequency is found to be due to an overestimation of low rain rates produced by the model convective scheme while the underestimation of mean rain rate is due to an underestimate of high rain rates and high rain rates frequency by the model convective scheme.

Using higher horizontal resolutions (4km and 1.5km) of the ACCESS model, we expect to gain further insights into the respective performances of convective parameterization and explicit convection at different model resolutions relative to the CPOL observations.

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POSTERS 2 – FRIDAY 14:00 – 15:30S3.1 Climate and human health

Submission ID: 51Presentng Author: Mia GrossSession: Posters 2Session tme: Friday 14:00 - 15:30Poster #55

55. Projectons of heatwaves using a Regional Climate Model ensemble for NSW and the ACT

GROSS Mia1; GREEN Donna* 2; ALEXANDER Lisa3 ; MACADAM Ian4

1)UNSW, mia.gross89@gmail.com; 2)UNSW; 3)UNSW; 4)UNSW

Climate change is increasing the occurrence of extremely hot temperatures in Australia. Increased temperatures affect a number of sectors, with the impacts on the human health sector being one of significant concern. The impacts on human health due to heat extremes are already apparent in Australia, with hundreds of additional deaths from heatwaves occurring in the south-east of the country during the summers of 2009 and 2013. To reduce the future human health burden, it is important to understand and predict these events. State-of-the art regional climate models suggest that the duration, frequency and intensity of heatwaves in Australia will increase. Evaluations of changes in such events enables health policy and planning initiatives to pro-actively adapt to these projected changes in extremes. The results presented here focus on the excess heat factor to analyse both recent simulations and future projections of various aspects of heatwaves for the New South Wales and Australian Capital Territory region. I used the NSW/ACT Regional Climate Modelling (NARCliM) project to evaluate a coarse and high-resolution domain for both raw and bias-corrected model output against recent observations. Further, projections for each of the heatwave aspects for the period 2060-2079 were made. Inferences on the health impacts were made based on the components of excess heat and heat stress included in the calculation of the excess heat factor. Overall, results indicated that bias-correction did not dramatically affect the indices, nor did the use of a higher-resolution dataset. Future projections indicated increases over the entire state in all heatwave aspects. In particular, a spatial pattern was found, in which coastal stations were projected to experience a greater increase in the length and frequency of heatwaves, and smaller increases in the intensity of events.

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SS3.1 Climate and human health

Submission ID: 84Presentng Author: Melissa HartSession: Posters 2Session tme: Friday 14:00 - 15:30Poster: # 56

56. Forecastng Air Polluton Impacts from Hazard Reducton Burns

HART Melissa*1; JIANG Ningbo2

1) ARC Centre of Excellence for Climate System Science University of New South Wales, melissa.hart@unsw.edu.au; 2) NSW Office of Environment and Heritage

Hazard reduction burns are vital to reduce the severity of bushfires. The NSW 2021 Plan aims to increase the annual average area treated by hazard reduction activities by 45%, by 2016, in order to limit bushfire activity. However, if hazard reduction burns are undertaken during unfavourable meteorological conditions, they have the capacity to trigger extreme air pollution events. Air pollution events associated with bushfires have been associated with extreme health impacts, including increased hospital admissions and death.

This poster will provide an overview of the development of a tool for forecasting air pollution impacts caused by hazard reduction burns over the Greater Sydney region. Incorporated into the forecasting tool is an analysis of the meteorological controls on bushfire pollutant dispersion from historical fires, both prescribed and non-prescribed. This involves individual burn characteristics including: size, location and length of burn, and resultant air pollutant concentrations compared to background concentrations.

This forecasting tool is expected to improve planning of burn times to reduce extreme pollution risk to the community, while still allowing NSW land managers and fire agencies to carry out this vital work. It is envisaged that this tool will become part of the NSW Office of Environment and Heritage’s operational air quality forecasting framework (AQFF).

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S3.2 Drought: from monitoring and land surface mo

Submission ID: 215Presentng Author: EunPa LimSession: Posters 2Session tme: Friday 14:00 - 15:30Poster #57

57. Understanding the contrast of Australian springtme rainfall of 1997 and 2002 in the frame of two favors of El Niño

Dry conditions over Australia are generally thought to be linearly related to the strength of El Niño. However, Australia received near normal springtime rainfall during the record strong El Niño in 1997 whereas it suffered from severe drought, especially in the east, during the weak El Niño of 2002. This study is aimed to investigate the causes and predictability of the different springtime rainfall responses over Australia for El Niño in 1997 and 2002. Statistical reconstruction of the rainfall anomalies and forecasts produced from the Australian Bureau of Meteorology’s dynamical seasonal forecast system (POAMA) demonstrated that the eastward and westward shifts of the maximum SST warming of El Niño contributed to the near normal and dry responses of Australian spring rainfall in 1997 and 2002, respectively. Hence, the contrasting rainfall responses were largely predictable. However, the dry conditions in 2002 were significantly enhanced by the occurrence of the record strength negative phase of the Southern Annular Mode (SAM), which could only be predicted with the use of realistic atmospheric initial conditions in the atmosphere-ocean coupled configuration of POAMA. Therefore, predictability of the 2002 drought over eastern Australia was strongly constrained by the predictability of the SAM despite the high predictability of the drier than normal condition of 2002 spring, stemming from the anomalous central Pacific warming of 2002 El Niño.

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S3.3 Energy

Submission ID: 296 Presentng Author: Nicholas EngererSession: Posters 2Session tme: Friday 14:00 - 15:30Poster #58

58. Simulatng City-Wide Distributed Photovoltaic Producton under Critcal Collectve Ramp Events

ENGERER Nicholas*1

1) The ANU Fenner School of Environment and Society, nicholas.engerer@anu.edu.au

Ongoing research work at The Australian National University has identified the meteorological origins of critical ramp events in collective photovoltaic (PV) array power output in Canberra, Australia using data collected from 150+ distributed PV systems. These critical events are defined by a 60% change in the total power output from all measured systems (with respect to the clear-sky potential) over a time frame of no more than 60 minutes. Now, by using information about the locations and installed capacity of 12,500+ PV systems installed in the Canberra region, it is possible to produce full-scale city-wide simulations of the entire fleet of microgenerators. Using a scalable approach via the clear-sky index for photovoltaics (KPV), data from the monitored PV systems are used to model the total power output of the entire Canberra metropolitan region. Results from this modelling will focus on key critical ramp events which fall in repeatable meteorological categories. This includes negative ramp events from thunderstorms and northwest cloud bands, and positive ramp events from fog dissipation and exiting cold fronts. The research presentation will focus on modelling results, with an emphasis on simulation videos depicting these events, as well as providing estimates of the 'true' power and energy losses/gains which occur during these meteorological scenarios.

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SS3.3 EnergySubmission ID: 269Presentng Author: Willow HallgrenSession: Posters 2Session tme: Friday 14:00 - 15:30Poster #59

59. The Impact of the El Nino Southern Oscillaton on Wind Resources in Australia and New Zealand

HALLGREN Willow*1; GUNTURU Bhaskar 2

1) Griffith University, whallgren@tpg.com.au; 2) King Abdullah University for Science and Technology (KAUST)

Australia has very good wind resources, and wind power accounts for over one-quarter of all renewable energy generated. Variability and intermittency are the biggest hurdles in the large scale deployment of wind power generation, impacting the economics of power generation and capacity planning. The El Nino Southern Oscillation (ENSO) has significant impacts on many weather variables including precipitation and solar radiation, and on the wind power resource in other parts of the world. To date, the impact of ENSO on Australia's wind resources has not been well studied. This study uses the Multivariate El-Nino Index and the a wind power density (WPD) field at an 80 m hub height constructed from MERRA data to explore the impact of ENSO on Australia's wind power resources. Composites of the WPD anomalies for days corresponding to El-Nino were calculated for Australia and New Zealand (a). Also calculated were (b) the variance of WPD associated with El Nino events, (c) the difference between the frequency of high wind events during El-Nino and the frequency during neutral conditions, and (d) the difference in the average magnitude between high wind events during El nino and the high wind events during neutral conditions. (c) and (d) are also calculated for low wind events (e,f),; (a)-(f) were calculated for La Nina events. Notable results for (a) were increases in the wind resource in the Top End, Tasmania, and NZ, and weak decreases elsewhere during El Ninos. Weak decreases were seen throughout most of Australia and NZ during La Ninas. The strongest increases in WPD variance (b) occurred in western and northern Australia, during La Ninas. Variance decreased most along the southern coast of Australia, and northern QLD during La Ninas. The changes in the frequency of both high and low wind events also was greatest during La Nina, with moderate increases of low wind throughout most of Australia and NZ. High wind frequency changes were generally weaker and patchier.

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S3.4 Urban climate

Submission ID: 68 Presentng Author: Mathew AdamsSession: Posters 2Session tme: Friday 14:00 - 15:30Poster #60

60. Assessing Fine-Scale Urban Temperature Projectons based on Building Densites

ADAMS Mathew*1

1) Office Of Environment and Heritage NSW Government, matthew.adams@environment.nsw.gov.au

Cities create their own microclimates through influencing the surrounding atmosphere and interacting with climate processes. The most striking characteristic of an urban microclimate is the urban heat island (UHI) effect. Going forward, the UHI effect will only be exacerbated by projected global temperature increases and growing urbanization. Collectively, these phenomena indicate a significant majority of the future urban population will endure average maximum temperatures several degrees warmer than those currently experienced in adjacent rural areas today.

Global and regional climate model projections based on physical processes give a good basis for planners and policy makers to prepare for such future changes in temperature. However, most models cannot accurately define the UHI effect, due to coarse resolutions (10-300 km grid cells) and the use of simple and static land use layers. This paper presents higher resolution (1km) results from regional climate modelling using “Present” and “Future” land use layers for Sydney based on present and projected dwelling densities. The land use layers account for differing building density/structure and more accurately capture urban canopy model parameters for Australian climates. Temperature projection improvements, as compared to observational data, are assessed based on modelling using the “Present” land use layer. If a substantial improvement is demonstrated, the “Future” land use layer will be applied to a 12 member regional climate model ensemble to project future temperature changes for Sydney’s urban area.

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S5.1 A review of Australian coastal upwellingSubmission ID: 253Presentng Author: Joshua ReinkeSession: Posters 2Session tme: Friday 14:00 - 15:30Poster: #61

61. Coastal fronts and upwelling areas utlised by migratng humpback whales, Megaptera novaeanglia, on the Gold Coast, Australia

REINKE Joshua*1; LEMCKERT Charles 2; MEYNECKE Olaf3

1)Griffith University, joshua.reinke@griffithuni.edu.au

Humpback whales take part in an annual migration from polar feeding grounds in summer to tropical breeding grounds in winter. Large scale migration patterns are well known; however, small scale distribution and relationships with environmental conditions have received less attention. Protection from threats and predicting the effects of climate change requires knowledge of preferred habitat and reasons behind the preferences.

East Australian humpback whales travel from the Southern Ocean, along the east coast of Australia, to the Great Barrier Reef (or further) to breed. This environment is dominated by the East Australian Current, the western boundary current of the South Pacific Ocean, carrying warm water poleward from the tropics. This current, as well as strong northerly winds, is responsible for generating upwelling on the coast and providing nutrients. Sharp temperature changes are experienced at the border of the warm current and the cool upwelled waters.

This study investigates relationships between humpback whale distribution and environmental conditions on the Gold Coast, Australia. This area is used during the northern and southern migration and provides a rest stop for mothers and calves on the return journey. Whale distribution was recorded using boat and land based surveys. Environmental parameters included bathymetry, remote sensed sea surface temperature and chlorophyll a concentration, as well as their derived gradients. The conditions observed at the whales’ locations were compared with the average across the study area using paired sample t-tests.

First outcomes of the study suggest a preference for cooler waters and in areas with a strong temperature gradient. The higher productivity in upwelled water and fronts may provide a chance of opportunistic feeding, a rare occurrence on the prolonged journey. Following particular hydrodynamic features such as these, which generally run parallel to the shore, may also serve as a tool for navigation.

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S5.2 Ocean mixing matersSubmission ID: 22Presentng Author: Paul HartlippSession: Posters 2Session tme: Friday 14:00 - 15:30Poster: # 62

62. Observed Internal Tides on the contnental shelf of Eastern Australia

HARTLIPP Paul*1; ROBERTSON Robin 2; BELL Mathew3

1)UNSW Canberra, p.hartlipp@adfa.edu.au; 2)UNSW Canberra; 3)UNSW Canberra

Internal tides both affect the stratification and are affected by the stratification. Without stratification, internal tides do not exist. At the same time, internal tides induce mixing, which reduces the stratification. Observational temperature and velocity data from over 15 moorings from the Integrated Marine Observing System (IMOS) was used to investigate the internal wave and tidal fields off eastern Australia. Conditions differed between the coastal regions and the deep waters and with latitude in the coastal regions. In the deep basin, beams of semidiurnal internal tides appear to emanate from the continental shelf/slope break. On the continental shelf, the internal tidal situation is more complex, particularly in shallower waters. Typically, the water column on the continental shelf was predominantly represented by two layers. However, mixing events would occur on 5-7 day intervals, particularly in the shallow waters (< 100 m), and homogenize the water column. The water column would then restratify over the next few days until the next mixing event occurred. When the water column was relatively homogenous, internal tides would essentially be absent. As the water column stratified, they would reappear. Additionally, there was a strong overtide signal in the North-South velocities, with the high frequency energy exceeding both the diurnal and semidiurnal energies.

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S5.2 Ocean mixing matersSubmission ID: 62Presentng Author: Andreas KlockerSession: Posters 2Session tme: Friday 14:00 - 15:30Poster: #63

63. A regime diagram for ocean geostrophic turbulence

KLOCKER Andreas*1; MARSHALL DavidP 2; KEATING Shane3 ; READ PeterL4

1)University of Tasmania, andreas.klocker@utas.edu.au

A two-dimensional regime diagram for geostrophic turbulence in the ocean is constructed by plotting observation- based estimates of the nondimensional eddy radius and unsuppressed mixing length against a nonlinearity parameter equal to the ratio of the root-mean square eddy velocity and baroclinic Rossby phase speed. This regime diagram is then interpreted in terms of pertinent regime transition lines which refer to boundaries along which there is change in dynamical behaviour due to the dominance of different physical processes to either side of the transition.

For weak nonlinearity, as found in the tropics, the mixing length mostly corresponds to the stability threshold for baroclinic instability whereas the eddy radius corresponds to the Rhines scale; it is suggested that this mismatch is indicative of the inverse energy cascade that occurs at low latitudes in the ocean and the zonal elongation of eddies. At larger values of nonlinearity, as found at mid- and high-latitudes, the eddy length scales are much shorter than the stability threshold, within a factor of 2.5 of the Rossby deformation radius.

Finally implications for the construction of parameterizations of geostrophic eddies will be discussed, specifically for mixing length arguments which are used to express the eddy diffusivity as proportional to an eddy velocity multiplied by an eddy length scale.

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S5.2 Ocean mixing matersSubmission ID: 136Presentng Author: Byju PookkandySession: Posters 2Session tme: Friday 14:00 - 15:30Poster: #64

64. Areas of Re-emergence of Sea Surface Temperature Anomalies in the Global Oceans from Observatons and Model Simulatons.

POOKKANDY Byju*1; DOMMENGET Dietmar 2

1) Monash University, byju.pookkandy@monash.edu; 2) Monash University

Re-emergence is the mechanism through which Sea surface temperature (SST) anomalies formed in winter over a deep mixed layer are trapped beneath the shallow summer mixed layer and then re-entrained into the deepening mixed layer during the next fall or winter season. This persistence of winter-to-winter SST anomalies is mostly perceived in the midlatitude oceans, where the annual variability in mixed layer is deep. It thus provides a mechanism for long lead seasonal predictions.

We detect re-emergence areas of SST anomalies in the world oceans using ocean reanalysis datasets, CMIP model simulations and a single column mixed layer ocean model (KPP) coupled to ACCESS. It is revealed that re-emergence is far more widespread than previously thought. It not only exists through out the midlatitudes of the Southern and Northern hemisphere, but also in the subtropics and even in the tropics. We also find evidence for re-emergence from warm seasons to warm season and anti-correlation between cold and warm season SST anomalies. The CMIP and KPP model simulations show results consistent with the observations.

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S5.3 Variability of physics and biogeochemistry in semi-enclosed and shelf seasSubmission ID: 309 Presentng Author: Carlos RochaSession: Posters 2Session tme: Friday 14:00 - 15:30Poster #65

65. Biogeochemical modeling of SE Australia - a PhD proposal

ROCHA Carlos*1 1) UNSW, c.vieirarocha@student.unsw.edu.au

The inclusion of biogeochemistry into a hydrodynamic model poses itself as an exciting opportunity while also involving significant challenges. The interest in marine biogeochemical models arise from the need to better understand and quantify the biological processes involved in the cycling of nutrients and carbon in the oceans. This proposal aims at achieving a realistic simulation of the nitrogen cycling and related lowest trophic levels of the marine ecosystem present off southeastern Australia, with special focus on the specific dynamics created by the East Australian Current and its important eddy field.

The project is divided into four main components: assess the latitudinal differences observed in high chlorophyll-a patterns; understand the process of entrainment of enriched continental shelf waters into eddies and the consequent biogeochemical response; provide insight into the implications of the interaction of cold-core and warm-core eddies with the shelf and finally the simulation of BGC dynamics in future scenarios.

The main tools will be a nitrogen-based (NPZD) biogeochemical module coupled to a high resolution (2-4km) regional oceanic circulation model (ROMS). We will make use of data collected during the INV03_2015 campaign on board of the RV Investigator, from 2nd June to 18th June 2015. This campaign is of special interest as it sampled diverse physical, biological and chemical parameters of a quasi-geostrophic cold-core eddy and on a smaller frontal eddy detaching from the shelf. The results of this research will shed new insight into the dynamics of EAC eddies and their biogeochemical processes and function with potential applications to fisheries and larval connectivity and survival.

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S5.3 Variability of physics and biogeochemistry in semi-enclosed and shelf seasSubmission ID: 235Presentng Author: Moninya RoughanSession: Posters 2Session tme: Friday 14:00 - 15:30Poster: #66

66. Observaton impact in Australia’s Western Boundary Current

KERRY Colete1; ROUGHAN Moninya* 2; OKE Peter3 ; POWELL Brian4

1)UNSW Australia, c.kerry@unsw.edu.au; 2)UNSW Australia; 3)CSIRO; 4)University of Hawaii

The East Australian Current forms the western boundary current of the south pacific sub-tropical gyre. The vigorous current flows as a jet over the narrow shelf, shedding vast eddies at the highly variable separation point. These characteristics alone make it a dynamically challenging region to measure, model and predict.

In a first step toward improving our circulation models and our dynamical understanding of the circulation, we developed a high resolution re-analysis of the East Australian Current. In addition to the traditional data streams (SST, SSH and ARGO) we exploit the newly available IMOS observations in the region. These include velocity and hydrographic observations from the recently deployed EAC transport array, 1km HF radar measurements of surface currents near the EAC separation zone, more than 40,000 CTD casts on the shelf from ocean gliders, and 300 million velocity measurements from a network of shelf mooring arrays.

We use the ROMS (Regional Ocean Modeling System) 4D-Var assimilation tools to combine all of the available satellite, IMOS, and ARGO data streams with the model fields providing a reanalysis of the ocean state at 6km resolution over this period. This reanalysis provides our best estimate of the EAC/shelf exchange along the east coast to assist with a number of local studies. We define metrics that describe key dynamics of the EAC and its separation from the coast (e.g volume transport) and quantify how the observations contribute to our understanding of these circulation metrics. This allows us to assess the impact of particular data streams on our circulation estimates and provides information vital in assessing and improving the observing system design for Australia's western boundary current.

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S5.3 Variability of physics and biogeochemistry in semi-enclosed and shelf seasSubmission ID: 284 Presentng Co-Author: Amandine SchaeferSession: Posters 2Session tme: Friday 14:00 - 15:30Poster #67

67. Investgatons into seasonal variability on the contnental shelf adjacent to the East Australian Current

WOOD Julie1; SCHAEFFER Amandine* 2; ROUGHAN Moninya3 ; TATE Peter4 1) UNSW, julie.e.wood@gmail.com; 2) UNSW; 3) UNSW; 4) Sydney Water

Seasonality has been shown to be an important timescale driving variability in the waters of many continental shelves around the world. In addition it has been shown that the East Australian Current warms and strengthens in the Austral summer. However, its highly dynamic nature results in variability in separation and eddy shedding which may have an a-seasonal impact on continental shelf waters. We investigate seasonality on the narrow continental shelf of south-eastern Australia, adjacent to the East Australian Current, using at least 3 years of moored in situ temperature and velocity observations, in combination with wind observations from 2 locations upstream and downstream of the East Australian Current (EAC) separation z o n e .

Our results show that the local winds are mostly bimodal throughout the year and thus do not drive a seasonal response in the circulation. The seasonal cycle in the temperature accounted for up to 49% of variability upstream of the EAC separation zone and 66% downstream. The same annual harmonic found that only 6% (3%) of the variability in the along-shelf velocity in 100 m (140 m) of water upstream (downstream) of the separation was explained by the seasonal cycle.

The strong summertime cross-shelf temperature gradient upstream of the separation zone results in seasonally strengthened vertical shear in the along-shelf velocities, likely enhanced by the mesoscale pressure gradient.

Downstream of the separation zone, the episodic influence of eddies and the EAC prevents any seasonality in the vertical structure of the flow despite similar seasonality in the stratification. These finding indicate that seasonality plays only a minor role in the circulation of waters on the continental shelf of south eastern Australia.

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S5.3 Variability of physics and biogeochemistry in semi-enclosed and shelf seasSubmission ID: 160Presentng Author: Jennifer SkerratSession: Posters 2Session tme: Friday 14:00 - 15:30Poster: #68

68. The eReefs marine model suite: tools for beter quantfying and understanding the Great Barrier Reef circulaton and water quality.

SKERRATT Jennifer1; BAIRD Mark* 2; MONGIN Matheiu3 ; ROBSON Barbara4; RIZWI Farhan5 ; WILD-ALLEN Karen6

1)CSIRO O&A, jennifer.skerratt@csiro.au; 2)CSIRO O&A; 3)CSIRO O&A; 4)CSIRO O&A; 5)CSIRO O&A; 6)CSIRO O&A

The Great Barrier Reef is under threat from catchment-derived human impacts and climate change. Through the eReefs Project , a suite of hydrodynamic, sediment, spectrally-resolved optical model and biogeochemical models have been developed. Here we describe the modelling system, including the ability to deploy relocatable high resolution embedded models, and the introduction of GBR-tailored biogeochemical processes such as carbon chemistry, corals, and improved seagrass and macroalgae models. We show results of the model together with comparisons to remote sensing, IMOS and NRS moorings and bottle observations to show how the model can be used to gain better understanding of carbon chemistry and biogeochemical dynamics close to the coast and on the reef. The biogeochemistry module of the eReef model is now run in near real time and historical model runs can be updated with model improvements and compared with observations. For further details and animation results from the near real time biogeochemistry see www.emg.cmar.csiro.au.

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S5.4 The Global Infuence of the Southern Ocean and Antarctc SeasSubmission ID: 152 Presentng Author: Benoit PasquierSession: Posters 2Session tme: Friday 14:00 - 15:30Poster #69

69. The plumbing of the global biological pump

PASQUIER Benoit*1; HOLZER Mark2

1) UNSW, b.pasquier@student.unsw.edu.au; 2) UNSW

We quantify the timescales and pathways that set the efficiency of the biological pump (the fraction of the phosphate inventory that is regenerated). We use a data-constrained phosphorus-cycling model embedded in a steady data-assimilated ocean circulation to quantify the pump’s leaks of preformed phosphate, its sources of regenerated phosphate, and the pathways with which the combined biogenic particle transport and the water circulation teleconnect different regions of the global euphotic zone. These pathways are quantified by a path density, which is the concentration of phosphate that was last utilized in a region A and that will reemerge into the euphotic zone of a region B, partitioned according to the A-to-B transit-time. Suitable integrals of this path density, computed efficiently by direct matrix inversions, yield the phosphate mass in transit, its flow rate, and its residence time in the aphotic zone. We find that a pump efficiency of (39 ± 2)% has dominant contributions from the Eastern Equatorial Pacific (25 ± 1)%, from the Southern Ocean (SO) (21 ± 1)%, and from the Eastern Equatorial Atlantic (EEqA) (12 ± 1)%. The pump’s 61% leak originates predominantly in the SO (75%) and in the SubPolar North Atlantic (17%). While the SO euphotic zone is a large leak of preformed phosphate, it is also the major receptor of phosphate reemerging from depth: The SO euphotic zone is the destination of (62 ± 6)% of the regenerated inventory and of (69 ± 5)% of the preformed inventory. The mean interior residence time of regenerated phosphate reemerging in the SO depends on where it was last utilized: 69 ± 1 years if last utilized in the SO and 500 ± 20 years if last utilized outside the SO. The transit-time distribution of the mass of regenerated phosphate last taken up in the EEqA and reemerging in the SO euphotic zone is bimodal, pointing to two distinct pathways which are quantified using the phosphate path density.

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S5.5 Waves, storms surges and tsunamis

Submission ID: 114 Presentng Author: Ying ZhaoSession: Posters 2Session tme: Friday 14:00 - 15:30Poster #70

70. Wave Operatonal Consensus Forecasts

ZHAO Ying*1 1) Bureau of Meteorology, yzhao@bom.gov.au

The Wave Operational Consensus Forecast (Wave OCF) system combines an ensemble of local and international numerical wave models and produces improved forecasts of significant wave height, peak wave period, 10 m wind direction and wind speed for selected wave buoy sites around the Australian coast. The OCF methodology uses wave observations from the past 30 days to remove systematic bias from each of the model forecasts, and then combines them into a weighted consensus in which models with more accurate forecasts in the previous 30 day training period receive greater weight. Previous studies have shown that the skill of consensus forecasts of significant wave height, peak period and wind speed is better than the skill of any individual component model.

Wave OCF was operationally implemented in the Bureau of Meteorology in 2011. In the current operational suite, six wave models are incorporated to produce 3 hourly consensus forecasts up to 7 days ahead. This poster presents verification statistics for 24h and 72h forecasts on significant wave height using data between 2012 and 2014. Performances of Wave OCF wave height forecasts at thresholds < 2 m, between 2 m and 4 m, above 4 m are evaluated across all available buoys. It shows that the reliability of the significant wave height forecasts has been considerably improved through the use of OCF techniques. Finally, suggestions for future improvements to surface wind forecasts, especially wind direction in the Wave OCF system are presented.

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S7.0 General meteorology - generalSubmission ID: 247Presentng Author: Jenny AhnSession: Posters 2Session tme: Friday 14:00 - 15:30Poster: #71

71. Aircraf Observatons of Microphysical Propertes of Winter-tme Low Alttude Cloud over The Sothern Ocean

AHN Jenny*1

1)Monash University, jenny.ahn@monash.edu

Cloud cover is the largest source of variability in defining the Earth’s albedo, and thus the Earth’s net energy budget. Over the Southern Ocean, the region of the globe with the highest fractional cloud cover, large biases exist in the energy budget and have been attributed to poor representations of the cloud cover. Large seasonal cycles in the effective radius and cloud droplet number concentration (CDNC) have been observed at part of the Southern Ocean Cloud Experiments (SOCEX I & II) of the 1990s, and were attributed to the dimethylsulphide (DMS) emissions of phytoplankton (i.e. the CLAW hypothesis, which has since come into question.) Satellite retrievals of these parameters suffer from uncertainty given the unique nature of the microphysics of SO clouds and the poor viewing angle during the winter months.

In this study we revisit the SOCEX observations of effective radius and CDNC using in-situ cloud microphysics observations taken from the Hydro Tasmania aircraft for two winter-time seasons (May-October, 2013 & 2014). Pristine (baseline) cloud conditions are explored as well as potential anthropogenic plumes in non-baseline conditions. In-situ observations are employed to evaluate Moderate Resolution Imagine Spectroradiometer (MODIS) satellite products, where available. A few limited flights were made to directly evaluate A-train observations (CloudSat, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) and MODIS).

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S7.0 General meteorology - general

Submission ID: 216 Presentng Author: Francisco LangSession: Posters 2Session tme: Friday 14:00 - 15:30Poster #72

72. Common Characteristcs and Propagaton of Wind Directon Shifs in the Nocturnal Boundary Layer

LANG Francisco*1; BELUSIC Danijel 2; SIEMS Steven3

1)Monash University, francisco.lang@monash.edu; 2)Monash University; 3)Monash University

Nocturnal boundary layers are characterized by stable conditions where very weak winds dominate the atmosphere and generate high variability of wind direction. We studied the main characteristics of abrupt wind direction changes at four micrometeorological stations located in a large area with homogeneous and flat terrain. The stations were organized in a Y-shaped network, with one central tower and three satellite towers. Solitary events of wind direction shift were defined and detected at the central tower. The events were defined as wind direction shifts larger than 60° that occurred during the nighttime. There were 130 extracted events in the period from 24 March to 19 June 2013. Changes in temperature, wind and turbulence were analyzed for each event. The distribution of changes at the central tower shows that the temperature has a tendency to decrease for large wind direction shifts, with negative temperature changes occurring in 74% of the events. Other variables do not show a clear tendency to decrease or increase when a change in wind direction occurs. The three satellite stations were used along with the central tower to study the propagation of events. The events were classified according to the distance of propagation or their spatial persistence into four classes: the events appearing only at the central tower were grouped in one category, those that appear at two stations in the second category, and so on. The analysis of propagation categories shows that the temperature changes are smaller when an event is only detected at the central tower (±0.2 °C) and larger when events reached one or more satellite stations. The analysis reveals that sudden wind direction shifts have a tendency to develop with passage of a cold microfront; however, abrupt direction changes are not systematically related with changes of other variables. Largest changes in temperature and wind speed appear to be associated with the spatial extent or length of propagation of events.

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S7.0 General meteorology - general

Submission ID: 319 Presentng Author: Mathew WheelerSession: Posters 2Session tme: Friday 14:00 - 15:30Poster #73

73. Seamless Precipitaton Predicton Skill Comparison between Two Global Models

WHEELER Mathew*1

1)Bureau of Meteorology, m.wheeler@bom.gov.au

The skill with which two coupled ensemble prediction systems are able to predict precipitation over a range of time scales is analysed. The two systems are the Bureau’s POAMA (T47) system, and the ECMWF (T319) monthly system. The goal is to understand the relative predictability across a broad range of time scales, from those relevant to short-term weather forecasts to those relevant to seasonal forecasts. To facilitate comparison across a seamless range of scales, the verification is performed using data averaged over time windows equal in length to the lead time. In addition to actual skill, potential skill is computed by taking one ensemble member as “reality” and computing the skill with which the other members can forecast that member.

Overall, ECMWF shows higher actual skill than POAMA across all time scales and in both the tropics and extratropics. ECMWF is particularly more skilful than POAMA in the tropics for the short lead times. Consistent between the two systems, however, is that as both lead time and averaging window are simultaneously increased, the near-equatorial (10°S-10°N) skill remains approximately constant, whereas it drops in all other latitude bands. As a result, both systems show much higher skill in the tropics than extratropics beyond the 1 week time scale, with much of this skill concentrated in the equatorial Pacific.

Potential skill in both systems is, as expected, almost everywhere higher than their actual skill. Interestingly, POAMA potential skill is similar to ECMWF actual skill, suggesting that POAMA has appropriate spread. Within-model comparisons of potential and actual skill show greatest differences for POAMA in the tropics, especially for the short lead times, and greatest differences for ECMWF in the southern hemisphere high latitudes and subtropics. The implication is that POAMA has greatest room for improvement in the tropics, whereas for ECMWF it is the southern hemisphere that is most deserving of attention.

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S7.0 General meteorology - general

Submission ID: 161 Presentng Author: Xiaoxi WuSession: Posters 2Session tme: Friday 14:00 - 15:30Poster #74

74. Performance Assessment of PME Probability Matched Precipitaton Forecast and New Calibrated Precipitaton Forecast

WU Xiaoxi *1

1) Bureau of Meteorology, X.WU@BOM.GOV.AU

The Poor Man’s Ensemble (PME) precipitation forecast system, is run operationally by Bureau National Operations Centre (BNOC) was upgraded on the 11th of June 2014. The upgraded system uses a new method to calibrate daily precipitation forecasts. These new calibrated precipitation forecasts along with the existing probability matched precipitation forecast are routinely delivered to the Next Generation Forecasting and Warning System (NextGenFWS) and registered users. The precipitation forecasts provide essential forecast guidance to forecasters via the NextGenFWS.

The domain of the daily PME system covers -45.25S to -4.75N, 109.75E to 160.25E, with a grid spacing of 0.5 degree. The operational PME system runs four times daily for basetimes 00, 06, 12, 18Z (UTC) and generates daily precipitation forecasts for lead times out to 8 days.

Calibrated daily precipitation forecasts and probability matched precipitation forecasts are compared to real-time analysis of rain gauge measurements (Ebert, E.E. and J.L. McBride 1997). These analyses are on a 0.25-degree latitude/longitude grid which has been spatially averaged onto the PME grid for verification (Mills, G.A., G.Weymouth etc 1997). The precipitation verification uses a tool called “RAINVAL” developed by Beth Ebert in the Bureau. The verification measurements include a variety of statistical methods.

References

Ebert, E.E. and J.L. McBride, 1997: Methods for verifying quantitative precipitation forecasts: Application to the BMRC LAPS model 24-hour precipitation forecasts: BMRC Techniques Development Report No. 2, Bureau of Meteorology Research Centre, Melbourne, 87 pp.

Mills, G.A., G. Weymouth, D. Jones, E.E. Ebert, M. Manton, J. Lorkin and J. Kelly, 1997: A national objective daily rainfall analysis system: BMRC Techniques Development Report No. 1, Bureau of Meteorology Research Centre, Melbourne, 30 pp.

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S7.1 Past, Present and Future East Coast Low Actvity and Impacts

Submission ID: 63 Presentng Author: Alejandro Di LucaSession: Posters 2 Session tme: Friday 14:00 - 15:30Poster #75

75. Using QuikSCAT wind data to evaluate some propertes of ECLs as derived from reanalysis products

DILUCA Alejandro*1; EVANS Jason 2; ARGÜESO Daniel3

1) Climate Change Research Centre University of New South Wales Sydney Australia., a.diluca@unsw.edu.au; 2)Climate Change Research Centre University of New South Wales Sydney Australia.; 3)ARC Centre of

Excellence for Climate System Science University of New South Wales Sydney Australia. Climate Change Research Centre University of New South Wales Sydney Australia.

The new generation of high-resolution reanalyses (ERA-Interim, CFSR, JRA55 and NASA-MERRA) provide a great opportunity to perform more detailed analyses of East Coast Lows (ECLs) compared to former low-resolution products. However, in a recent study, Di Luca et al. (2015) have shown that when looking at ECLs as derived from mean sea level pressure fields at their native grid mesh (about 50 km grid spacing), the various high-resolution reanalyses provide very different climatologies of the frequency, intensity and size of ECL events.

In an attempt to determine which reanalysis, if any, gives a better description of ECL events we use 10-m winds as derived from the Quick Scatterometer (QuikSCAT) satellite product. This data is available over a 0.25ë latitude Õ‹ longitude grid mesh every 6 hours.

The evaluation is performed by comparing ECL composites of 10-m winds as derived from reanalyses and from the QuikSCAT product. The composites are constructed by averaging over all the identified ECLs in individual reanalysis. Several ECL's properties such as their intensity and size can then be evaluated and used to decide on the performance of the various reanalyses.

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S7.2 High-Impact Weather in Research and Operatons

Submission ID: Presentng Author: Joshua SoderholmSession: Posters 2Session tme: Friday 14:00 - 15:30Poster #76

76. A Modifed Global Climate Simulaton Model

PRAKHOVA Sofya*1, REHBOCK Volker2, SULEIMANOV Igor3,

1) Department of Mathematcs and Statstcs, sofya.prakhova@postgrad.curtn.edu.au; 2) Curtn University, Department of Mathematcs and Statstcs; 3) Curtn University, Department of Mathematcs, Ufa State

Petroleum Technical University

External forces can have a big impact on our climate and may even lead to extreme events (e.g., a flare which occurred in March 1989, when power was knocked out across most of the Quebec province in Canada).

In this work we used the new approach for modelling insolation from the authors’ earlier work which allows for direct modelling of space activity and incorporated it into the global climate model C-GOLDSTEIN.

Simulation results indicate that the obtained monthly latitudinal temperature distributions are in a good agreement with the actual temperature maps. Also, the average accuracy of modelling the insolation within the global climate model has been increased by 2%. Most importantly, the new types of experiments can now be performed with the C-GOLDSTEIN model, such as the investigation of consequences of random temporal variations of insolation due to solar flares on temperature etc.

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S7.2 High-Impact Weather in Research and Operatons

Submission ID: 82 Presentng Author: Joshua SoderholmSession: Posters 2Session tme: Friday 14:00 - 15:30Poster #77

77. Coastal Convectve Interactons Experiment - Preliminary Findings

SODERHOLM Josh*1

1) UQ, joshua.soderholm@uqconnect.edu.au

The Coastal Convective Interactions Experiment aims to quantify the presence long-term “hotspots” _ in hail storm activity for the South East Queensland and explore the role of the sea breeze as a driver in this variability. Severe storm activity in this region has resulted in some of Australia’s most costly natural disasters, including the $1.1B insured losses from the 27-11-2014 hail storm. The experiment integrates a high resolution, 18 year radar-derived hail storm climatology with an intensive, multi year field campaign to provide an innovative perspective on the often over-looked sea breeze interaction phenomena. Furthermore, an Australian first application of mobile dual-polarised radar and mobile Doppler scanning lidar was utilised for the field campaign in conjunction with observations from the CAWCR CP-2 radar research facility and a mobile sounding system. Preliminary findings from both the climatological and observational components demonstrate the significance and underlying storm-scale mechanisms of sea breeze - storm interactions.

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S7.2 High-Impact Weather in Research and OperatonsSubmission ID: 116Presentng Author: Will ThurstonSession: Posters 2Session tme: Friday 14:00 - 15:30Poster: #78

78. Large-Eddy Simulatons of Pyro-Convecton and its Sensitvity to Environmental Conditons

THURSTON Will*1; TORY Kevin 2; FAWCETT Robert3 ; KEPERT Jefrey4

1)Bureau of Meteorology, w.thurston@bom.gov.au; 2)Bureau of Meteorology; 3)Bureau of Meteorology; 4)Bureau of Meteorology

Intense heating of air in the vicinity of a bushfire leads to deep ascent. If this ascent is deep enough to lift air above the lifting condensation level, cumulus or cumulonimbus clouds form in a process known as pyro-convection. There is abundant anecdotal evidence to suggest that pyro-convection may have a significant impact on fire behaviour by (i) amplifying burn and spread rates; (ii) enhancing spotting through plume intensification; and (iii) igniting new fires via pyrocumulonimbus lightning. Pyro-convection is also responsible for the transport of smoke and other aerosol into the stratosphere. Therefore a knowledge of the processes that lead to the generation of pyro-convection is an important component of being able to understand and predict fire behaviour, as well as the potential climatic influences of large fires.

Here we present idealised simulations of bushfire plumes using a cloud-resolving model, the UK Met Office Large-Eddy Model (LEM). The model is initialised with idealised temperature and moisture profiles representative of that associated with high fire-danger conditions. A bushfire plume is then generated by imposing a localised heat flux at the model surface. We explore the conditions under which the bushfire plume leads to pyro-convection and the sensitivity of that pyro-convection to variations in the environmental conditions and the heat and moisture flux. The implications of the observed changes in the pyro-convection are discussed in terms of their impact on fire behaviour, primarily through the potential to affect near-surface conditions in the vicinity of the fire and spotting potential via plume intensification.

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S7.2 High-Impact Weather in Research and OperatonsSubmission ID: 77 Presentng Co-Author: Will ThurstonSession: Posters 2Session tme: Friday 14:00 - 15:30Poster #79

79. Modelling The Fire Weather Of The Blue Mountains Fires Of October 2013

FAWCETT Robert1; CHING Simon* 2; THURSTON William3 ; TORY KevinJ4; KEPERT Jefrey5

1) Bureau of Meteorology, r.fawcett@bom.gov.au; 2) Bureau of Meteorology; 3) Bureau of Meteorology; 4) Bureau of Meteorology; 5 )Bureau of Meteorology

We will exhibit state-of-the-art high-resolution numerical weather prediction simulations for three different periods in October 2013, with a specific focus on the Blue Mountains in eastern New South Wales and the weather on the 13th, 17th and 23rd of October 2013. The simulations have been performed using the Australian Community Climate and Earth-System Simulator (ACCESS), and involve a sequence of nested limited-area model runs embedded in the ACCESS global model runs, with a finest grid spacing of 440 metres.

NSW fire fighters attended 1167 bush and grass fires in the four weeks of October 2013, but the most intensive fire activity was between the 13th and the 26th when there were 627 incidents and 164,054 hectares burnt. The afternoon of the 17th proved to be one of the most destructive few hours in the past decade, with more than 200 houses destroyed across the Blue Mountains region. Notable fires within the Blue Mountains region included the State Mine Fire (area 54,862 hectares, perimeter 461 km) and the Mt York Road Fire (9,383 hectares, 99 km). [1]

The simulations show a marked cool change crossing New South Wales on the 13th, with subsequent ones on the 17th and the 23rd. In the vicinity of the State Mine Fire, the simulations across the three days show bands of coherent wind direction variability ahead of the cool changes, taking the form of lines of convergence and divergence in the 10-metre simulated winds. This variability could potentially lead to broadening of fire fronts, and consequently faster fire propagation. In addition, several interesting features present in the simulations for the 17th, including a dry slot, a complex wind change and fine-scale wind-direction fluctuations, will be discussed.

[1] Bush Fire Bulletin Vol. 36 No. 2 (2014), NSW Rural Fire Service

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S7.2 High-Impact Weather in Research and Operatons

Submission ID: 113 Presentng Author: Danielle UdySession: Posters 2Session tme: Friday 14:00 - 15:30Poster #80

80. Identfcaton Of Flood Producing Atmospheric Circulaton Paterns In The Brisbane River Basin, Australia

UDY Danielle*1

1) University of Queensland, danielle.udy@uqconnect.edu.au

Flooding from extreme precipitation causes billions of dollars in damage annually worldwide and often results in loss of human life. Floods result from a combination of factors, especially atmospheric conditions causing extreme precipitation and antecedent catchment conditions. Improved understanding of this relationship can enhance flood-forecasting and potentially reduce damage through early warning of flood conditions. This study compares synoptic and upper atmosphere characteristics with the flood record in the Brisbane River Basin in Southeast Queensland, Australia. Using spatial and magnitude flood thresholds, 104 flood events were identified over the past 55 years (1958-2013) and were classified by their key synoptic circulation patterns. A comparison of synoptic (mean sea level pressure patterns) and statistical (principal component analysis and cluster analysis) classification techniques found that the statistical method provided groupings of events with common atmospheric conditions that improved predictive capability of flood impact over the manual synoptic classification. In contrast, the synoptic classification offered little information on flood behavior. Based on the statistical classification, three atmospheric variables (temperature 500 hPa, total column water and 500 hPa potential vorticity) are recommended for exploration as potential predictive criteria for future flood events. In accordance with previous studies, antecedent soil moisture conditions, 48-hour cumulative rainfall and inter-annual and inter-decadal variability (i.e. El Niño Southern Oscillation) were also identified as important predictive factors. Trends were also identified in the predictive atmospheric variables suggesting changes in regional climate patterns over the last 55 years. This work provides a foundation for the development of empirical regional flood prediction tools.

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S8. Emerging methods for weather observaton and PredictonSubmission ID: 181Presentng Author: Aurel GriesserSession: Posters 2Session tme: Friday 14:00 - 15:30Poster: #81

81. A comparison of rainfall characteristcs between radar-based rainfall estmates and downscaled Global Climate Model output

GRIESSER Aurel*1; JAKOB DÕ_rte 2; SEED Alan3

1) Australian Bureau of Meteorology, a.griesser@bom.gov.au; 2) Australian Bureau of Meteorology; 3) Australian Bureau of Meteorology

Global Climate Models (GCMs) indicate that climate change may increase extreme rainfall intensity. This may increase the risk of flood and has implications for engineering design. In conjunction with the revision of the ‘Australian Rainfall and Runoff’ project, which formulates guidelines for infrastructure engineering and planning, dynamically downscaled GCM results were assessed using radar-based rainfall observations in an area around Sydney.

The radar data used was based on the Bureau of Meteorology’s Rainfields algorithm, which converts observed radar reflectivity to estimated rainfall on the ground. Measurements from rain gauges are ingested by the algorithm for calibration.

Two separate dynamically downscaled simulations were available: CSIRO’s Cubic Conformal Atmospheric Model (CCAM) (Thatcher and McGregor, 2009), and the Weather Research and Forecasting Model (WRF) as deployed by Evans and McCabe (2013). These models were run at a spatial resolution of 2km over the study region, and were driven by GCM data at boundaries. Gridded station data from the Australian Water Availability Project was also used for comparison.

Primary findings were:

Considerably more spatial variability is evident in radar-based rainfall compared to GCMs and AWAP. This implies that not all rainfall-producing mechanisms have been correctly simulated. This is important because changes in rainfall extremes are likely to be driven by changes in convective precipitation.

In the long-term mean, the current Rainfields algorithm underestimates rainfall relative to the gauge-based AWAP data, though broad-scale spatial features match well.

The frequency distribution of the radar-based rainfall differs markedly to those of the models and AWAP.

Shortcomings were identified in simulations which need to be considered when inferring potential impacts of climate change on rainfall extremes.

Radar-based rainfall estimates are a useful tool for assessing high-resolution dynamical models.

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S8. Emerging methods for weather observaton and PredictonSubmission ID: 103Presentng Author: Murray HamiltonSession: Posters 2Session tme: Friday 14:00 - 15:30Poster: #82

82. Discriminatng Super-cooled Liquid and Ice Partcles in Fog

CHAMBERS Thomas*1; HAMILTON Murray 2

1) University of Adelaide, thomas.chambers@student.adelaide.edu.au; 2) University of Adelaide

Various studies have shown that the Supercooled Liquid Water (SLW) content of Mixed Phase Clouds (MPC’s) is strongly linked to their formation and evolution, and influences the cloud radiative properties. This parameter is poorly constrained by conventional measurement techniques such as radar and lidar.

A polarsonde is a low cost, lightweight addition to a conventional radiosonde for measuring the SLW content of MPC, but it also can be mounted on a tower to study fog.

We present an analysis of polarsonde data from a tower installation at Summit Camp, Greenland spanning the months October and November 2013. Polarsonde data is compared with the output of a fog monitor (FM-100, Droplet Measurement Technologies Inc.), and independent measurements of temperature, relative humidity.

A good correlation is found between fog events identified by the polarsonde and by the fog monitor. There is also a correlation between the depolarisation of backscattered light measured by the polarsonde, and the particle sizes measured by the fog monitor. Together with Monte Carlo simulations of the scattering, which give the expected depolarisation for various particle shapes, this is evidence for the discrimination of SLW from ice crystals.

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S8. Emerging methods for weather observaton and PredictonSubmission ID: 256Presentng Author: Harvey SternSession: Posters 2Session tme: Friday 14:00 - 15:30Poster: #83

Increasing forecast accuracy in the context of a mult-model ensemble framework

STERN Harvey*1; DAVIDSON Noel2

1) University of Melbourne, hstern@unimelb.edu.au; 2) Bureau of Meteorology

The paper presents an assessment of weather forecasts that have been derived in the context of a multi-model ensemble framework.

Very long range day-to-day weather forecasts (out to Day-32) for Melbourne, Australia, derived by interpreting the output of the ECMWF ensemble control models, are also evaluated.

The evaluation is an update of an earlier assessment that was presented to the 2015 Annual M e e t i n g o f t h e A m e r i c a n M e t e o r o l o g y S o c i e t y [https://ams.confex.com/ams/95Annual/webprogram/Paper267305.html].

Results suggest that the ensemble approach to weather forecasting increases the accuracy of day-to-day weather predictions.

Reference: Stern H and Davidson N E (2015) Some aspects of the verification of weather forecasts for Melbourne, Australia. Harry R. Glahn Symposium, Phoenix, AZ, 4-8 Jan. 2015, Amer. Meteor. Soc.

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S8. Emerging methods for weather observatonSubmission ID: 234 Presentng Author: Carly TozerSession: Posters 2Session tme: Friday 14:00 - 15:30Poster #84

84. Establishing the Hierarchy of Infuence of Drivers of Seasonal Rainfall Variability in South Australia

TOZER Carly*1

1) University of Newcastle, Carly.tozer@uon.edu.au

A key challenge in the development of skilful seasonal rainfall forecasts is the identification of the atmospheric and oceanic processes that drive the rainfall variability. Seasonal rainfall forecasts for South Australia (SA) currently have low predictive skill and we hypothesise that this is because the key drivers of SA’s rainfall variability have yet to be fully identified and therefore are not adequately represented in the forecast models. Previously, much of the focus in Australia has been on determining the causes of seasonal and annual rainfall variability in eastern and Western Australia, with little research conducted on SA’s rainfall variability. Therefore the aim of this this study is to identify relationships between a host of potential climate drivers and seasonal rainfall across South Australia. A threshold method is used that accounts for the inherently non-linear nature of the links between large scale climate phenomena and hydroclimatic variability. The work is then extended by using a novel method for climate predictor selection to both identify the key combination of drivers that explain the most seasonal rainfall variability in different regions of SA and to determine the hierarchy of importance of the key drivers. This will provide a set of metrics against which dynamical forecasting schemes can be tested and may also lead to the development of new statistical forecasting schemes.

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A

Abbs, Deborah · 44Abellan, Esteban* · 57Abramowitz, Gab · 19, 227Abramowitz, Gab* · 83ACKERLEY, DUNCAN* · 36, 215, 258, 270Adams, Mathew* · 281Ahn, Jenny* · 214, 292Alexander, Lisa · 26, 78, 174, 198, 200, 262, 276Alexander, Lisa* · 77Alexander, LisaV. · 27Allen, Kathryn · 66Allen, Kathryn* · 259Allie, Stuart* · 66Alroe, Joel · 108Alves, Oscar · 61, 256Anderson Stuart · 222Andrade_Torres, Ednildo · 89Andrys, Julia · 243Arblaster, Julie · 25Arg’_eso, Daniel · 45, 95ARGÜESO, Daniel · 43, 296Arguesso, Daniel · 40Austn, Emma* · 79

B

Badlan, Rachel* · 153Baird, Mark* · 121, 210, 289Baker, Patrick · 66, 259Baltais, Simon · 67Barnes-Keoghan, Ian · 25Barr, Cameron · 37Barria, Pilar* · 38Bathols, Janice · 237Bedin, Tim* · 10Bell, Aurora* · 175Bell, Mathew · 206, 283Belusic, Danijel · 293Bennet, John · 75, 92Benthuysen, Jessica · 99Benthuysen, Jessica* · 112Bergemann, Martn* · 217, 274Berry, Gareth · 136, 159Bhend, Jonas · 40, 76Bluteau, Cynthia* · 114Boetger, Daniel* · 115Book, JefreyW. · 100Boschat, Ghyslaine* · 181, 272Braganza, Karl · 238Brieva, Daniel* · 109Brinkman, Gary · 204, 268Brinkman, Richard · 99, 100, 112, 204, 268Brown, Jaclyn · 63, 249Brown, Jaclyn* · 47, 80, 145, 250Brown, Josephine · 145Browning, Stuart · 172

Browning, Stuart* · 171Brzezinski, Mark · 125Burke, Annete · 172Burston, Joanna* · 149Burton, Andrew · 21Bye, John* · 50, 134

C

Cai, Wenju · 34, 64, 128, 147, 156, 255Cai, Wenju* · 53callaghan, jef · 69Carson, Greg · 66Cato, Jennifer* · 177Chamberlain, Mathew · 250Chambers, Thomas* · 220, 303Cheresnick, Danny · 190Ching, SimonE* · 300Chowdhury, AFMKamal · 168, 173Chowdhury, AFMKamal* · 162Chua, Zhi-Weng · 35Chung, Christne · 59, 252Church, John · 41, 193, 240Churchill, Jim · 149Clarke, Hamish* · 32Clarke, Harry · 62, 257Coleman, Richard · 105Colin, Maxime* · 142Collis, Scot · 167Colman, R. · 245Colman, Robert · 25Contractor, Steefan* · 212, 233Cook, Edward · 66, 259Cope, Martn · 186Courtney, Joe* · 21, 152Cowan, Tim · 181COWLEY Rebecca · 101Cravigan, Luke* · 108Curran, Mark · 37Curts, Mark · 187

D

Dalla_Pozza, Ramona · 37Dargaville, Roger · 86Dargaville, Roger* · 71Davidson, Noel · 221, 304Day, Ken · 37de_Jong, Pieter* · 89Delage, Francois · 51, 59, 252Deo, Anil* · 170Dias, Fr’©d’©ric · 132DiLuca, Alejandro · 45, 46, 174DiLuca, Alejandro* · 43, 296Ditus, AndreaJ.* · 27Doblin, Martna · 18, 232Dobrohotof, Peter · 39

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Dolman, Bronwyn* · 188Dommenget, Dietmar · 208, 285Donat, Markus* · 26Donovan, Elizabeth* · 63, 249Dowdy, Andrew · 40Dowdy, Andrew* · 150, 196, 251Duc, Hiep* · 91Duell, Robyn · 13, 224Duran, Earl · 203, 267Duran, Earl* · 104Durand, Gael · 126

E

Earl, Nick* · 29Ebert, Elizabeth · 186Ekstrom, Marie · 40ENGERER, Nicholas · 223Engerer, Nicholas* · 85, 279England, Mathew · 81, 118, 128Erwin, Tim · 10Evans, Brad · 197, 260Evans, Jason · 32, 40, 45, 46, 174, 198, 262, 296Evans, Jason* · 42Evans, JasonP. · 43Evans, Robert · 66, 259Everet, Jason · 18, 232Ewenz, Cacilia* · 92Ewenz, Caecilia · 75

F

Fahey, Thomas · 92FAIRMAN Jonathan · 222Falter, Jim · 119Fawcet, Robert · 183, 218, 299Fawcet, RobertJB · 300Feikema, Paul · 23Feng, Ming · 62, 99, 257Feng, Ming* · 103, 124Fiddes, Sonya* · 74, 194, 246Field, Emily* · 70Finn, Anthony · 191Fischer, Mat* · 49Flack, Anna · 37, 73Fletcher, Jennifer* · 166Folland, Chris · 51Fraedrich, Klaus · 50Frankcombe, Leela · 106Franzke, Christan · 31Freund, Mandy* · 68Frey, Wiebke · 157

G

Gail, William* · 190Gallant, Ailie · 34, 94, 96Gallant, Ailie* · 84Gamble, Felicity · 8

Ganachaud, Alex · 47Ganter, Catherine* · 13, 54, 224Gardner Sharon · 222GEOFFROY, Olivier* · 192, 236Gergis, Joelle · 51, 68Gergis, Joelle* · 261Gharib Choobary, Saeedeh · 93Gharib, Saeedeh · 75Giannakis, Dimitrios · 148Goldie, James* · 78Gontz, Allen · 67Gonzalez, Max · 11Goodwin, Ian · 171Goodwin, Ian* · 172Grabowski, Wojciech* · 154Gray, Michael* · 216, 271Green, Donna · 78Green, Donna* · 72, 200, 276Griesser, Aurel* · 219, 302Grose, Michael* · 40, 76, 237Gross, Mia · 77, 200, 276Guan, DrHuade* · 93Guan, Huade* · 75Gunn, Andrew* · 127Gunturu, Bhaskar · 202, 280

H

Hague, Ben* · 238HAKEEM, SHAIK* · 138Hallgren, Willow* · 202, 280Hamilton, Murray · 220, 303Hande, Luke · 169Hanson, L. · 245Hart, Melissa · 95Hart, Melissa* · 201, 277Hartlipp, Paul · 113Hartlipp, Paul* · 116, 206, 283Harvey, Mike · 108Hassim, Muhammad · 157Heady, Craig · 10Henderson, David · 179Hendon, Harry · 25, 61, 137, 146, 256Henley, Benjamin · 261Henley, Benjamin* · 51Herold, Nicholas · 77Herold, Nicholas* · 28Herzfeld, Mike · 121Hille, Ron · 152Hirst, Anthony · 60, 253Hoang, Lam · 241Hoang, Lam* · 136Hoell, Andrew · 62, 257Hoenner, Xavier · 18, 232Hofmann, Peter · 40Holzer, Mark · 211, 290Holzer, Mark* · 125Hope, Pandora · 35, 52Hope, Pandora* · 25Horenko, Illia · 31HORII, Takanori · 107Hu, Jianyu · 193, 240

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Huang, Jing* · 90Huang, Keith* · 12, 225Huang, Yi · 169Hughes, David · 204, 268Hutchinson, Michael* · 197, 260Huva, Robert · 71Huva, Robert* · 86

I

Irving, Damien · 9Irving, Damien* · 30Ivey, Greg · 100Ivey, Gregory · 114

J

Jacobs, Stephanie* · 94Jakob, Christan · 141, 159, 217, 241, 274Jakob, DÕ_rte · 219, 302Jakob, Doerte* · 234Jamandre, Carlo* · 95Ji, Fei · 46, 174Jiang, Ningbo · 201, 277Jiang, Ningbo* · 46Jin, Fei-Fei · 33Johnson, Robert* · 122Jones, Emlyn · 121Jones, Katherine · 119Jones, Nicole · 100, 114Jones, Nicole* · 119Jones, Roger* · 48Jourdain, Nicolas · 47Jourdain, Nicolas* · 126Jourdain, NicolasC. · 156

K

Kala, Jatn · 243Kannar-Lichtenberger, Lea · 20, 226Kannar-Lichtenberger, Lea* · 264Karoly, David · 51, 68Karoly, DavidJ. · 27Katzfey, Jack · 39, 42Kay, Merlinde · 87, 88Keatng, Shane · 207, 284Keatng, Shane* · 117Keay, Kevin · 59, 252Kelly, Brian · 79Kennedy, John · 51Kent, Chris · 75Kent, David · 237Kepert, Jefrey · 183, 218, 299Kepert, JefreyD · 300Kerry, Colete · 209, 287Kesteven, Jennifer · 197, 260Keywood, Melita · 108Kiem, Anthony · 37, 79, 151, 162, 168, 173Kiem, Anthony* · 73, 161

King, Malcolm* · 139Kinniburgh, David* · 189Kiperstok, Asher · 89Kiss, Andrew* · 106Klocker, Andreas* · 207, 284Kociuba, Greg · 59, 247, 252Kuczera, George · 161, 162, 168, 173Kumar, Vickal · 157Kumar, Vinod · 75Kuret, AntonJ. · 62, 257

L

Lane, Todd · 139, 141, 153, 157, 158, 185, 217, 274Lane, Todd* · 143Lang, Francisco* · 293Lau, Rex · 44Lavender, Sally · 44Law, Clif · 108Lawson, Sarah · 108Lazos, Dimitris* · 87Lee, Sunhee · 186Lemckert, Charles · 109, 205, 282Lenton, Andrew · 41lesommer, julien · 118, 126Lewis, Sophie · 25, 84Lewis, SophieC. · 27Li, Yue* · 156Lim, Eun-Pa · 146Lim, Eunpa* · 25Ling, Fiona · 66Lisonbee, Joel · 52Lockart, Natalie · 161, 162, 168Lockart, Natalie* · 173Lough, JaniceM. · 62, 257Loughran, Tammas* · 56Lowe, Ryan · 100, 119Lowry, Andrew · 26Lucas, Chris · 146Lyons, Thomas · 243Lyu, Kewei* · 193, 240

M

Macadam, Ian · 200, 276Macdonald, Helen · 100Magee, Andrew* · 151Maharaj, Angela · 12, 19, 225, 227Maher, Nicola · 26Mallet, Marc · 108Maloney, Eric · 146Mancini, Sebasten · 18, 232Manton, Michael · 135, 167, 169, 269Margvelashvili, Nugzar · 121Marshall, DavidP · 207, 284Martn, David · 25, 234Mason, Mathew* · 179Matear, Richard · 145, 250Mathiot, Pierre · 126May, Peter · 167

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McAllister, Felicity · 99McCulloch, MalcolmT. · 62, 257McGowan, Hamish · 58, 254McGregor, Helen* · 55McGregor, John · 39McGregor, Shayne · 242McGregor, Shayne* · 33McInnes, Kathleen* · 41McIntosh, Peter · 63, 249McNeil, Ben* · 16, 129, 228Menezes, Viviane* · 102, 265Meynecke, Olaf · 205, 282Moise, A. · 245Moise, Aurel · 76Moise, Aurel* · 7molines, jean-marc · 118Molloy, Suzie · 108Moncrief, Mitchell · 143Mongin, Matheiu · 210, 289Mongin, Mathieu · 121Monselesan, Didier · 31, 41Morgan, Adam* · 22Mortlock, Thomas · 172Moss, Patrick* · 67Mullen, Clare* · 23Murphy, Michael · 269Murphy, Michael* · 135Musgrave, Ruth · 180Myers, William · 190

N

Narsey, Sugata* · 140Ng, Benjamin* · 147Nguyen, Hanh · 150Nguyen, Hanh* · 146, 275Nguyen, Kim · 39, 44Nicholls, Neville · 34Nichols, Scot · 66, 259Nikurashin, Maxim · 127Nishant, Nidhi · 199, 263Nishant, Nidhi* · 160

O

O'Brien, Laura · 17, 229O'Brien, Laura* · 132, 164O'Grady, Julian · 41O'Kane, Terence* · 31Oke, Peter · 105, 124, 209, 287Olivares, Gustavo · 108Olson, Roman* · 45Osbrough, Stacey · 76

P

Palmer, Martn* · 11Paran_Manage, Nadeeka* · 168Parana_Manage, Nadeeka · 162, 173

Parsons, Jen* · 14, 230pasquier, benoit* · 211, 290Pataratchi, Chari · 99Pataratchi, Charitha* · 110, 131, 266Pazmino, Daniel* · 213, 235Pearce, Karen* · 15, 231Peel, Murray · 38Pepler, Acacia · 54Pepler, Acacia* · 174, 198, 262Pequignet, Anne-Christne* · 100Perkins, David · 79Perkins, Sarah · 56Perkins, SarahE. · 43Peter, Justn* · 167Petherick, Lynda · 67Pezza, Alex · 194, 246Pezza, Alexandre · 181Phatak, Aloke · 44Phillips, Helen · 102, 104, 265Phillips, Helen* · 203, 267Pilo, Gabriela* · 105Pitman, Andy · 95Pook, Michael · 63, 249Pookkandy, Byju* · 208, 285Pots, Rod · 167Powell, Brian · 209, 287Power, Scot · 51power, scot* · 59, 69, 247, 252PRAKHOVA Sofya* · 297Prasad, Abhnil* · 88Prideaux, Alex · 67Proctor, Roger · 18, 232Protat, Alain · 141, 144, 153, 157, 275Pugh, Tim · 7Pump, Sylvia · 203, 267Purich, Ariaan · 181Purich, Ariaan* · 128

R

Rafer, Tony · 39Rafer, Tony* · 44Rainville, Luc · 115Ramsay, Hamish* · 165Rashid, Harun* · 60, 155, 253Rauniyar, Surendra* · 144Raut, BhupendraA.* · 241Rayner, Peter · 86Read, PeterL · 207, 284Reeder, Michael · 136, 164Reeder, Michael* · 159, 180Reeder, MichaelJ. · 241REHBOCK Volker · 297Reid, Iain · 188Reinke, Joshua* · 205, 282Rennie, Susan · 182, 187Ribbe, Joachim · 109Ricca, Vincenzo · 62, 257Rich, Jane · 79Richter, Harald* · 176Rickets, James* · 195, 248Rigby, Paul · 99, 204, 268

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Riley, Mat · 46Risbey, James · 31, 63, 76, 249Ristovski, Zoran · 108Rizwi, Farhan · 121, 210, 289Roberts, James* · 242Roberts, Jason · 37, 73Robertson, Robin · 115, 116, 206, 283Robertson, Robin* · 113, 130Robson, Barbara · 121, 210, 289Rocha, Carlos* · 123, 286Rogers, Cassandra* · 96Rogers, Kevin* · 191Roughan, moninya · 120, 288roughan, moninya* · 111, 209, 287Rykova, Tatana · 105

S

Saheli, Alireza · 131Salmanidou, Dimitra · 132Santoso, Agus · 53, 147schaefer, amandine* · 120, 288Schiller, Andreas · 124Schofeld, Robyn* · 157SCHULTZ David* · 222Scorgie, Yvonne · 46Seed, Alan · 175, 182, 219, 302Seed, Alan* · 187Sen_Gupta, Alex · 47, 156Sen_Gupta, Alex* · 19, 227SenGupta, Alex · 81, 242Shelley, Luke · 13, 224Shelton, Kay · 159Sherwood, Steve · 192, 236Sherwood, Steven · 19, 78, 142, 160, 227Sherwood, Steven* · 199, 263Shirvill, James · 23Shulmeister, James* · 65Siems, Steve* · 169Siems, Steven · 135, 269, 293Simmonds, Ian · 30, 181, 272Simmons, Craig · 75Skerrat, Jennifer · 121, 210, 289Slangen, Aimee · 193Slangen, AimÕ©e · 240Slawinska, Joanna* · 148Sloss, Craig · 67SLOYAN Bernadete · 101Sloyan, Bernadete · 99Smalley, Robert · 238Smith, Daniel · 179Smith, David · 186Soderholm, Josh* · 298Spagnol, Simon · 99Speer, Milton* · 163spence, paul · 118, 126Spengler, Thomas · 180Stafeld, Josh · 23Steinberg, Craig · 100, 112Steinberg, Craig* · 99, 204, 268Steinberg, Peter · 18, 232Steinle, Peter · 187

Steinle, Peter* · 182Stern, Harvey* · 221, 304stewart, kial* · 118Stewart, Philip · 67Straton, Rachel · 137Struton, Pete · 203, 267Struton, Peter · 119SULEIMANOV Igor · 297Suthers, Iain · 18, 120, 232

T

Talbot, Nick · 108Tapper, Nigel · 94, 96Tascheto, Andrea* · 81, 242Tascheto, AndreaS. · 156Tate, Peter · 288Tatersall, Katherine* · 18, 232Taylor, David · 149Thatcher, Marcus · 44, 90Thatcher, Marcus* · 39Theobald, Alison* · 58, 254Thurston, Will* · 183, 218, 299Thurston, William · 300Timbal, Bertrand · 10, 40, 42, 74, 146, 237Timmermann, Axel · 33Toivanen, Jussi* · 184Tonin, Hemerson · 112, 204, 268Tory, Kevin · 183, 218, 299Tory, KevinJ · 300Tozer, Carly · 37, 73Tozer, Carly* · 305Trewin, Blair · 54Trewin, Blair* · 52, 239Trull, Tom · 203, 267Twomey, Callum · 161

U

Udy, Danielle* · 301Ummenhofer, Caroline · 81, 242

V

van_Rensch, Peter* · 34Vance, Tessa · 37, 73vanSebille, Erik · 19, 47, 227Verdon-Kidd, Danielle · 151Verdon-Kidd, Danielle* · 98Vergés, Adriana · 47Vincent, Claire* · 158

W

Wain, Alan · 186Waite, Jared · 75Walsh, Kevin · 38, 147Wamahiu, Karuru* · 243

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Wang, Changlong · 71Wang, Guojian · 53Wang, Guojian* · 64, 255Wang, Guomin · 25Wang, Yang · 10Wang, Zhan · 169Ward, Jason · 108Warren, Robert* · 178waterman, stephanie · 118Watkins, Andrew · 13, 23, 224Watkins, Andrew* · 8Waterson, Ian* · 35, 273WELLBY, Sonya* · 223Wheeler, Mathew · 139Wheeler, Mathew* · 141, 294Whimpey, Michael · 275White, Dana · 120Wijeratne, Sarath · 131, 266WIJFFELS Susan · 101Wijfels, Susan · 99, 141Wild-Allen, Karen · 121, 210, 289Wilks, Jessica · 152Willgoose, Garry · 161, 162, 168, 173Williams, David · 99, 204, 268Wilson, Louise · 76, 167, 237Wood, Julie · 288WU, Xiaoxi* · 295

X

Xiao, Yi · 182

Y

Ye, H. · 245Yi, Xiao · 187Yin, Yonghong · 61, 256young, celeste* · 24Young, Leigh · 23

Z

Zhang, Fuqing · 143Zhang, Huqiang* · 82, 245Zhang, Liang · 82Zhang, Xuebin · 41, 124, 193, 240zhang, xuebin* · 244zhao, mei* · 61, 256Zhao, Ying* · 291Zhao, Yong · 245Zhong, Aihong · 133Zhu, Hongyan* · 137Zhu, Xiuhua · 50Zinke, Jens* · 62, 257Zovko Rajak, Dragana* · 185

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