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The Concordiasi Project

Part of THORPEX-IPY Cluster

WWRP, THORPEX, WCRP POLAR PREDICTION WORKSHOP

Oslo, 6-8 October 2010

by Florence Rabier, Concordiasi project leader

and Eric Brun

CNRM/GAME : Météo-France and CNRS

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Concordiasi main objectives

� A better use of satellite data, including IASI on board MetOp for analyses, forecasts and reanalyses over polar regions

� Improving our understanding of the interactions between ozone depletion, stratospheric clouds and dynamics

� A contribution to the design of a cost-effective long-termmonitoring system of the Antarctic atmosphere

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Concordiasi: the international team

Participating Institutes:� CNES, CNRS (LMD, LGGE, LA), Météo-France � NSF, Purdue University, NCAR, University of Colorado, University of

Wyoming� Alfred Wegener Institute, UK Met Office� Polar institutes: IPEV, PNRA, USAP, BAS� ECMWF, BSRN

Collaborating institutes: � NWP centres (Australia…), NASA/GMAO, UCLA, ….

� Overview of Concordiasi: “The Concordiasi project i n Antarctica”Rabier et al, Bulletin of the American Meteorologica l Society, January 2010.

� Website www.cnrm.meteo.fr/concordiasi/

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Experimental design

� Surface-based

o extra radiosoundings at Concordia (Dome C), Dumont d’Urville and Rothera

o 45-m instrumented tower, snowfall and accumulation observations, BSRN data and HAMSTRAD radiometer at Concordia

o Ozonesondes over some Antarctica polar stations

� Stratospheric superpressure balloons with meteorological sensors, ozone sensors, particle counters, GPS receivers, driftsondes carryingdropsondes

� Modelling: global and fine-scale models, chemical-transport models

� .... and satellites !

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The Concordiasi Project

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Improvement of the assimilation of satellite observations in Météo-France global meteorological model ARPEGE

Assimilation experiment over sea-ice and land with more satellite data infrared & microwave

Color : additional IR data

Additional data (IR and MW)

Number of obs between 300 and 900Comparison(RMS) to

Radiosoundings for area : 65°S –

South Pole

Enhanced assimilation of satellite dataBouchard et al, MWR, May 2010.

Black : without additional data

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Assimilation experiment with more satellite data over sea-ice and Antarctica:

Obs – model for a period of 20 days duringaustral winter 2007

Obs : AIREP (airborne data) between 20°S and 50°S

Predictability studies, effects on lower latitudes

Improving assimilation over polar areas can also improve forecasts at lower latitudes

Bouchard et al, MWR, May 2010.

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Data at Concordia

Time Period : from the 15 September 2008 to 30 November 2008 and 19 November 2009 to 13 December 2009

Observations: � 2008 : Radiosounding at DomeC (75°S ; 123°E) in order to have 2 observations

per day, at 0UTC and 12UTC. Complementary launch at the same time of IASI overpass.

� 2009 : As 2008 + Surface measurements (vertical profile of the snow temperature and BSRN data) at the time of the sounding.

Meteorological conditions : around 60% clear sky

� First outcome: models too warm at surface

An exceptional location to validate

satellite data assimilation

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Model improvement

Statistics at Concordia and diagnostic of model performance: model too warm atSurface (C.Genthon, LGGE)

Lead to an improvement at ECMWF Change in albedo over permanent snow effective in 2008. Decreased warm bias(G. Balsamo, ECMWF)

before

after

difference

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Work on snow modelling at Meteo-FranceImpact on IASI simulation over Antarctica

E. Brun, E. Bazile, V. Guidard

Histogram O-B for IASI surface channel 921 Cloudy channel diagnostic

In red, before snow modelling changes (albedo, roughness, thermal properties)

In blue and green, after changes: more data can be assimilated!

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Current step: launching stratospheric balloons from Mc Murdo

Launch site:� Flattened area,� 2 Jamesways with

power, and some heating

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Balloon system characteristics

18 superpressure balloons from CNES

All with meteorological sensorsat gondola level (temperature, pressure)

12 with driftsondes from NCAR (50 dropsondes in each)

6 with innovative instruments: ozone sensors, particle counters, GPS receivers

� Accurate wind speed forecast is a criticalissue for balloons launchings !

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Launch preparation from McMurdo

CNES Courtesy

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Lagrangian structures of the flow and data assimilation

Trajectories will be used to better understand the control exerted by the vortex on the motion of air parcels

(R. Mechoso, UCLA)

Use of the Concordiasi flight-level observations directly in the assimilation

(A. Tangborn, GMAO) Current past and forecasted trajectory of PSC16 balloon from September 11 to October 6

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Dropsondes to calibrate the assimilation and for predictability studies

Localized singular vectors are computed at ECMWF(Alex Doerenbecher)Computed October the 3rd

for droppings the 4 th

Most of the sondes are dropped when coinciding MetOp overpasses

(calibration of IASI retrievals, validation of AVHRR winds..)

Part of the dropsondes are deployed in sensitive areas

�A unique test-bed for targeting in polar regions

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Original targetting tools to optimize the launching of the dropsondes (A. Doerenbecher, Météo-France)

local time

Scheduled possible launches from 28 September 2010

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Successful dropsondes on September the 28th.

O : dropsondes

O: radiosoundings

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Real-time assimilation of balloonsobservations and dropsondes

(ECMWF)

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Ozone depletion, polar stratospheric clouds and stratospheric dynamics

Interannual variability of ozone depletion depends on the activity of stratospheric waves and the presence of polar stratospheric clouds

Documentation of ozone loss along trajectories with meteorological

(P, T, Wind), chemical (Ozone) and microphysical observations.

(A. Hertzog, T. Desher, L. Avallone)

Validation of Chemical-Transport model

and Stratospheric ozone assimilation.

(L. El Amraoui)

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Particle counter (T. Deshler, U. Wyoming)

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Ozone depletion (L. Avallone, U. Colorado)Lagrangian real-time observations

���� Unique records of O3 loss rates

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Ozone depletion (A. Hertzog, LMD)Lagrangian real-time observations

Colors: date since the launching of Balloon PSC16

� Concordiasi already got a unique lagrangian record of a total ozone depletion

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GPS radio-occultation onboard one balloon(from J. Haase, Purdue University)

GPS radio occultation is used to obtain high-resolution atmospheric profiles of refractivity

Radio signals pass through the atmosphere from GPS satellite to GPS receiver

� As it travels, the signal encounters atmospheric layers of varying density

� The density changes cause the signal to refract and delay slightly

� A doppler shift is associated with the overall delay seen in the signal and can be converted into an atmospheric refractivity value at a geometrically determined tangent point to the Earth

r(tan)

TOA

GPSReceiver

GPSSatellite

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Use of the detailed multi-layer snow model Crocusto study snow-atmosphere interactions over the Plateau

Radiative balance (short and long-wave)

turbulent fluxes (sensible and latent heat)

Snow /rain precipitation

Temperature

Density

Liquid Water content

Snow grains

Ground thermal fluxWater run-off

wind compaction

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Dome C: a very convenient siteto study snow-atmosphere interactions

BSRN radiation station (ISAC-CNR)

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Good performance of detailed snow models in off-line mode...

Input data from BSRN (ISAC-CNR) and LGGE

2010 January 20th. to 31st

Offline simulation with Crocus snow modelSurface Temperature : Observation from emitted LW

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Reasonable simulation of snow surface temperature:fully coupled AROME/Crocus, 10-day simulation

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... and realistic simulation of internal snow temperaturein coupled mode AROME/Crocus

-33 cm

-63 cm

-103 cm

Snow temperature observation by Laurent Arnaud (LGGE)

-23 cm

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Outlook

Concordiasi 2008 and 2009 field campaigns: data hav e started to be used in studies over the Antarctic Plateau

���� improved assimilation of IASI and other sounders ov er snow and ice

���� improved snow scheme at ECMWF and Météo-France

Ongoing balloon campaign is already very successful :

In September-November:

- 600 dropsondes (already 87 )

- 18 balloons providing « AIREP-like » continuous data (already 11)

- already a unique record of lagrangian ozone deplet ion

- additional radiosoundings at Concordia, Dumont d’U rville and Rothera

� A unique data set :

- to calibrate/validate the assimilation of satellite data (sounders, polar winds…),

- to diagnose gravity-wave activity

- to better understand ozone depletion and quantify l oss rates

- to assess the potential of targeting in polar regio ns

- to study the extreme boundary-layer and snow-atmosp here interactions