Overview of Coupled Model Intercomparison Project (CMIP)

and IPCC AR5 ActivitiesRonald J Stouffer

Karl Taylor, Jerry Meehl and many others

June 2009

Outline

• Background– Review AR4– Initialization– Variability

• Overview of CMIP5/AR5 design– Long term experiments– Near term experiments

• Questions

Land physicsand hydrologyOcean circulation

Atmospheric circulation and radiation

Land physicsand hydrology

Ocean ecology andBiogeochemistry

Atmospheric circulation and radiation

Allows Interactive CO2

Ocean circulation

Plant ecology andland use

Climate Model (AOGCM)

Earth System Model (ESM)

Sea Ice

Sea Ice

An Earth System Model (ESM) closes the carbon cycle

About 18 groups using 24 models participated.More than 1000 papers written using CMIP3 databaseDownloads continue at very high rate

CMIP3/AR4

Initialization: How is this done? Implications for you

• Modelers make a long Pre-industrial control-Typically 1850 or 1860 conditions

• Perturbation runs start from control- Model related to real years only through radiative forcing- Solar, volcanoes, human emissions, land use, etc.

• Each ensemble member an equally likely outcome• Do not expect wiggles to match – model vs obs

Model vs. Observed Global Mean Surface Temperature Anomalies

ModelObs-JonesObs-GISS

Year

oK

Global surface temperatureo C

US Surface Temperatureo C

DC Surface Temperatureo C

Natural Variability

• Natural variability confounds or “hides” the global warming signal.

• Smaller space scales and shorter time scales exhibit more natural variability

• Signal to noise ratio much lower for smaller space and time scales

• Temperature has a relative large signal to noise ratio, precipitation is much smaller S/N ratio

Human activities are very likely the cause of the warming of last 100 years.

Black line: temperature observation from thermometers.Pink shade: Climate model simulations using all past radiative forcings.Blue shade: Climate model simulation using only natural forcings (solar, volcanoes).

IPCC WGI SPM 2007

Human activities are likely to be the cause of the warming over last 100 years on each continent.

IPCC WGI SPM 2007

CMIP5 Background

• Process started in 2005 Aspen meeting• Lots of groups with input

– IPCC WG1, 2, 3 authors– Various WCRP and IGBP committees– Lots of individuals

• Strategy adopted by WGCM in Paris in September 2008

Long Term Experiments

Core

Tier 1

Tier 2

Core: ≥1718 yrsTier 1: ≥1727 yrsTier 2: ≥2038 yrs

Long Term ExperimentsOverview

• AOGCM – control/historical/projections– Physical climate models

• ESM – control/historical/projections– AOGCM + closed carbon cycle

• Lots of runs for “understanding”

CMIP5 Long Term ExperimentsAOGCM Core (concentration driven)

• Control– 500+ years

• Historical– ~1850 to 2005

• Projection– 2006 to 2100– RCP4.5 (stabilization near 2100)– RCP8.5 (GHG continue to increase)

• AMIP – Atmosphere-land model, obs SST + sea ice– 1979 to 2008

1850 2005 2100

Runs for UnderstandingCore

• AOGCM or ESM– 1% CO2 increase to 2X (140 years)

• TCR

– 4XCO2 switch-on (150 years)• Equilibrium climate sensitivity

• Atmosphere-land– Hansen style

• 1XCO2• 4XCO2

Long Term ExperimentsAOGCM Tier 1

• Historical– More ensemble members– Natural, GHG-only forcing, other?

• Projection– RCP2.X (GHG continue to decrease) 2006 to 2100– RCP6.0 (stabilization near 2100) 2006 to 2100– RCP4.5 2101 to 2300

• AMIP– More ensemble members

• PMIP – see PMIP protocol; AOGCM or ESM– 6KBP– LGM

Long Term ExperimentsAOGCM Tier 2

• Historical– Ensemble natural and GHG-only forcings– Ensemble individual forcings

• Projection– RCP2.X 2101 to 2300– RCP8.5 2101 to 2300

• PMIP – see PMIP protocol; ESM or AOGCM– Last 1000 yrs (850 to 1850)

Long Term ExperimentsESM Core

• All AOGCM long term runs plus• Control with pCO2 free

– 500+ years

• Historical – emission driven– ~1850 to 2005

• Projection – emission driven– RCP8.5 (2006 to 2100)

GFDL’s Long Term Experiment Plans

• CM3 using GHG concentrations and aerosol emissions– Study aerosol-cloud interactions and impact on

climate and climate change

• ESM2M and ESM2G– Study carbon cycle feedbacks in climate change– Study impact of increasing carbon on ecosystems– Study impact of using differing ocean vertical

coordinates on simulation and response

CMIP5 Near Term Experiments

Core

Tier 1

Core: 480 yrsTier 1: ≥1700 yrs

Foci• Regional information• Short lived species• Decadal Prediction

Near Term - Core• 10 year hindcasts

– Initialized at 1960, 1965, 1970 …– 3+ ensemble members

• 30 year forecasts– Initialized at 1960, 1980, 2005– 3+ ensemble members

1960 1965 1970 198519801975 200019951990 2005 2010 2030

Near Term – Tier 1

• Increase ensemble size to 10+• Hindcast without volcanoes • Runs initialized in 200X

– 2001, 2002, 2003, 2004, 2006, 2007, 2008, …

• Prediction with Pinatubo-like event in 2010

Near Term – Tier 1

• Investigate role of short live species• Investigate alternative initialization methods• 100 yr control and 1% run (if not doing long

term experiments with same model)

Near Term – Tier 1Time Slice Experiments

• Time periods– AMIP (1979-2008) and 2026-2035– Overlap with decadal prediction exps

• High atmospheric resolution• Atmospheric chemistry experimentsStudy regional impactsStudy extreme events

GFDL’s Near Term Experiment Plans

• CM2.1 using Coupled Data Assimilation with ensemble filter techniques– Investigate predictability on decadal time scales

• High resolution atmosphere-land-only models in time slice mode (25km)– Investigate regional climate change– Study extreme events (hurricanes)

• Potentially use high resolution coupled models – Study importance of resolution on predictability

CMIP5/AR5 Data Serving

• Distribution data paradigm– Earth System Grid (ESG) software

• PCMDI still a gateway to data• Several new gateways

– BMRC, MPI, NCAR, GFDL, …

• Archive expected to be more than 1 PB• CMIP panel oversight

– Variable list

GFDL Data Serving

• Node on PCMDI’s network (ESG) of data servers for CMIP5– Also provides an independent path to GFDL data

• Currently serving 10’s of TB to external users– Potentially 100’s of CMIP5/AR5 TB available

Thank you

Questions?

Runs for UnderstandingTier 1

• ESM-only– CO2 increases for bio, CO2 constant for radiation

• 1% or historical+RCP4.5• AOGCM or ESM

– Ensemble 4XCO2 switch-on (5 years)• Atmosphere-land

– CFMIP simulator – observed SSTs, sea ice• See CFMIP protocol

– Aqua planet– Hansen

• Future run with sulfate at year 2000

Runs for UnderstandingTier 2

• ESM-only– CO2 increases for bio, CO2 constant for radiation

• 1% or historical+RCP4.5

• AOGCM or ESM– AC&C chemistry protocol

• Atmosphere-land– CFMIP simulator – +4C increase SSTs

• See CFMIP protocol