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Les simulations CMIP5 « near term » au Cerfacs : choix stratégiques et état d'avancement. CERFACS GIEC Team: Christophe Cassou, Emilia Sanchez-Gomez , Elodie Fernandez, Marie Pierre Moine, Laure Coquart, Yohan Ruprich-Robert , Laurent Terray … et nos collègues du CNRM .
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Les simulations CMIP5 « nearterm » au Cerfacs : choix stratégiques et état d'avancement CERFACS GIEC Team: Christophe Cassou, Emilia Sanchez-Gomez, Elodie Fernandez, Marie Pierre Moine, Laure Coquart, YohanRuprich-Robert, Laurent Terray … et nos collègues du CNRM Kickoff EPIDOM
Plan de la présentation • Les expériences décennales • le setup expérimental • le modèle CNRM-CM5 • Stratégies d’initialisation :nudgingde l’océan vers la réanalyse • Expériences du nudging: impact de l’initialisation • Résultats préliminaires pour les premières prévisions Kickoff EPIDOM
1. Les expériences décennales Initial conditions from the CONTROL exp. Experimental design (historic and scenario runs) SPIN UP CONTROL HISTORIC (15 members) Control (1000 yr) External forcing1850 Spin-up (300 yr) Historicrun (1850-2012) External forcing1850-2012 SCENARIO (2008-2100) Experimental design for decadalexperiment (novelty in CMIP5) Initial conditions takenfrom « observed » values!! 3-10 members per ensemble Evolutive external forcing Observations 10 yr experiments 2005 1965 1970 Every 5 years……. 1960 30 yr experiments 1980 2005 1960 Kickoff EPIDOM
1. Les expériences décennales: CMIP5 Summary of decadalexperiments in CMIP5 CORE: 3 membres « BONUS » Kickoff EPIDOM
1. Les expériences décennales: CMIP5 Work in progressat CERFACS: 10 yrsdecadalruns startedat 1st January of 1960, 1965, 1970, …, 2005 (10) startedat 1st January of 1960, 1965, 1970, …, 2005 (3, GHG, Vol. aero, cte) startedat 1st January of 1961, 1966, 1971, …, 2006 (10) 30 yrsdecadalruns startedat 1st January of 1960, 1980, 2005 (10) startedat 1st January of 1961, 1981, 2005 (10) Additionalexperiments 30yrs for 2005 initializedruns : Predictionwith 2010 Pinatubo (3) Predictionwith 2010 solar minimum (3) GHGs, Vol. aerocte (3) Full Initialisation : initial conditions fromnudgingexperiments Kickoff EPIDOM
1. Les expériences décennales : l’outil CNRM-CM5 (Voldoire et al. In preparation) Atmosphere ARPEGE-Climat, 1.4° , L31 Land surface scheme SURFEX 24h 24h 24h OASIS Sea Ice GELATO Ocean NEMO v3.2 ORCA1 L42 River routing TRIP 24h Kickoff EPIDOM
1. Les expériences décennales : l’outil SST versus LEVITUS (CNRM-CM5) SSS versus LEVITUS (CNRM-CM5) Kickoff EPIDOM
1. Les expériences décennales : l’outil Variability Modes : ENSO 2.8 – 3.5 yr 5yr 3yr Kickoff EPIDOM
1. Les expériences décennales : l’outil Variability Modes : PNA Kickoff EPIDOM
1. Les expériences décennales : l’outil Variability Modes : NAO Kickoff EPIDOM
1. Les expériences décennales : l’outil MeridionalOverturning Circulation MOC time seriesat 40°N Comparison to RAPID_ARRAY measures Kickoff EPIDOM
1. Les expériences décennales : l’outil Heat transport Kickoff EPIDOM
1. Les expériences décennales : l’outil SeaIceExtent (versus NOAA observations) MAX MIN 10e+9 m2 10e+9 m2 Kickoff EPIDOM
2. Stratégies d’initialisation Objective : To find ocean initial states compatibles at the same time with the model climatology and also with the observational state nudging Kickoff EPIDOM
2. Stratégies d’initialisation: nudging Sea surface restoring for T et S Nudging of NEMO (dkeytradmp, namtradmp) depth No damping in the mixed layer (1/ β) =0 To, So 3D observations The parameterβvaries with location Intermediate waters: β = 10 jours Deep ocean (800m): β = 360 jours Equatorial band: (1/ β) =0 Nearcoastlines(300km): (1/ β) =0 Over the equator the timescale are very short and the nudging can alter the oceanic currents Kickoff EPIDOM
2. Stratégies d’initialisation: nudging Sea surface restoring (namsbc_ssr) Heat flux: Feedback coefficient = -40W/m2/K feedback term. SSTobs= observations Heat flux at the surface Exemple:For a mixed layer of 50 m depth, this value corresponds to a relaxation of 2 months (2months are needed to Tk=1 = SSTobs) Fresh water flux: Feedback parameter = -167 mm/day Fresh water budget at the surface Feedback term. SSSobs= observations Kickoff EPIDOM
2. Stratégies d’initialisation: nudging Nudgingto the ECMWF oceanreanalysis NEMOVAR (ORCA1°) 1958 -2008 Several tests have been performed to set the optimal parameters for the nudging HISTNUD1freebetween(1°S – 1°N) HISTNUD15 free between(15°S – 15°N) Kickoff EPIDOM
2. Stratégies d’initialisation: nudging J/m2 NEMOVAR1 HISTNUD15 HISTNUD1 Annual time series of heat content averaged over the entire basins. The impact of nudgingdiffersfrom one basin to another. Kickoff EPIDOM
2. Stratégies d’initialisation: nudging The Impact of nudging on the Heat transport
2. Stratégies d’initialisation: nudging Comparison to RAPID_ARRAY measures Kickoff EPIDOM
3. L’impact de l’initialisation 10 yearsexperimentsinitialised on 1st January of 1960, 1965, …, 1990 from HISTNUD15 and HISTNUD1 GLOBAL SST HISTNUD15 HISTNUD1 0.08°C on average Kickoff EPIDOM
3. L’impact de l’initialisation Initial shock: First yearrun of 20deg isotherme between 2°S - 2°N PACIFIC OCEAN HISTNUD15 HISTNUD1 No nudging NEMOVAR1 Decadal15 depth Decadal1 longitude Kickoff EPIDOM
3. L’impact de l’initialisation Temperaturedifferencesbetween 2°S, 2°N for the 1st January and isotherme at 20deg PACIFIC OCEAN degC HISTNUD15 HISTNUD1 No nudging NEMOVAR1 degC degC Kickoff EPIDOM
3. L’impact de l’initialisation Zonal velocitydifferencesbetween 2°S, 2°N for the 1st January Contours: NEMOVAR1 PACIFIC OCEAN m/s m/s m/s Kickoff EPIDOM
3. L’impact de l’initialisation Initial shock: First yearrun of 20deg isotherme between 2°S - 2°N ATLANTIC OCEAN HISTNUD15 HISTNUD1 No nudging NEMOVAR1 Decadal15 Decadal1 Kickoff EPIDOM
3. L’impact de l’initialisation Temperaturedifferencesbetween 2°S, 2°N for the 1st January and isotherme at 20deg ATLANTIC OCEAN HISTNUD15 degC HISTNUD1 No nudging NEMOVAR1 degC degC Kickoff EPIDOM
3. L’impact de l’initialisation ATLANTIC OCEAN Zonal velocitydifferencesbetween 2°S, 2°N for the 1st January Contours: NEMOVAR1 m/s m/s m/s Kickoff EPIDOM
Résultats préliminaires pour les prévisions Unbiasedforecasts, SST and heat content 300m GLOBAL Heat Content GLOBAL SSTs NEMOVAR HISTNUD15 Atlantic OceanSSTs ACC SSTs Historicruns Kickoff EPIDOM
Résultats préliminaires pour les prévisions Anomalies of SSTsafterremoving the meansystematicbias ATLANTIC (35°S) SSTs GLOBAL SSTs PACIFIC (35°S) SSTs INDIAN (35°S) SSTs NEMOVAR1 HISTNUD15 Kickoff EPIDOM
Résultats préliminaires pour les prévisions Heat content 300m (anomalies) afterremoving the meansystematicbias GLOBAL HC300 ATLANTIC (35°S) HC300 NEMOVAR1 HISTNUD15 PACIFIC (35°S) HC300 AMO (35°S) HC300 Kickoff EPIDOM
Conclusions A nudgingmethodology to generate initial states has been presented. The nudging to T and S seems to alter somehow the ocean transports (heat and MOC) comparing to a non nudged simulation. Wheninitialisingfromnudgingexperiments, the model initial shockisenhanced as the nudging to oceanreanalysesis « stronger ». The initial shockisidentified as the generation of El Niño states due to the model heat release. Wheninitialisedfrom HISTNUD15, the model reaches the historicalrun in aproximately 3-4 yrs. The model drift has a regionalbehaviour, in particularthereis a strongwarming drift in the SouthernHemisphere (south out of 35°S) Kickoff EPIDOM
1. Les expériences décennales : l’outil Zonal meantemperature and salinitybias, Atlantic Ocean Differences CNRM-CM5 – LEVITUS climatology Kickoff EPIDOM