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Les simulations CMIP5 « near term » au Cerfacs : choix stratégiques et état d'avancement Kickoff EPIDOM CERFACS GIEC Team: Christophe Cassou, Emilia Sanchez-Gomez,

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Presentation on theme: "Les simulations CMIP5 « near term » au Cerfacs : choix stratégiques et état d'avancement Kickoff EPIDOM CERFACS GIEC Team: Christophe Cassou, Emilia Sanchez-Gomez,"— Presentation transcript:

1 Les simulations CMIP5 « near term » au Cerfacs : choix stratégiques et état d'avancement Kickoff EPIDOM 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 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

2 Kickoff EPIDOM Les expériences décennales le setup expérimental le modèle CNRM-CM5 Stratégies dinitialisation : nudging de locéan vers la réanalyse Expériences du nudging: impact de linitialisation Résultats préliminaires pour les premières prévisions Plan de la présentation

3 Experimental design (historic and scenario runs) Spin-up (300 yr) SPIN UP Control (1000 yr) External forcing 1850 CONTROL HISTORIC (15 members) Historic run ( ) External forcing Initial conditions from the CONTROL exp. Experimental design for decadal experiment (novelty in CMIP5) SCENARIO ( ) Observations yr experiments Every 5 years…… yr experiments 3-10 members per ensemble Evolutive external forcing Initial conditions taken from « observed » values!! 1. Les expériences décennales Kickoff EPIDOM

4 1. Les expériences décennales: CMIP5 Summary of decadal experiments in CMIP5 CORE: 3 membres « BONUS »

5 Kickoff EPIDOM 1. Les expériences décennales: CMIP5 Work in progress at CERFACS: 10 yrs decadal runs started at 1st January of 1960, 1965, 1970, …, 2005 (10) started at 1st January of 1960, 1965, 1970, …, 2005 (3, GHG, Vol. aero, cte) started at 1st January of 1961, 1966, 1971, …, 2006 (10) 30 yrs decadal runs started at 1st January of 1960, 1980, 2005 (10) started at 1st January of 1961, 1981, 2005 (10) Additional experiments 30yrs for 2005 initialized runs : Prediction with 2010 Pinatubo (3) Prediction with 2010 solar minimum (3) GHGs, Vol. aero cte (3) Full Initialisation : initial conditions from nudging experiments

6 Kickoff EPIDOM 1. Les expériences décennales : loutil Land surface scheme SURFEX Atmosphere ARPEGE-Climat, 1.4°, L31 Ocean NEMO v3.2 ORCA1 L42 24h River routing TRIP 24h Sea Ice GELATO 24h OASIS CNRM-CM5 ( Voldoire et al. In preparation )

7 Kickoff EPIDOM 1. Les expériences décennales : loutil SST versus LEVITUS (CNRM-CM5) SSS versus LEVITUS (CNRM-CM5)

8 Kickoff EPIDOM 1. Les expériences décennales : loutil Variability Modes : ENSO 5yr 3yr 2.8 – 3.5 yr

9 Kickoff EPIDOM 1. Les expériences décennales : loutil Variability Modes : PNA

10 Kickoff EPIDOM 1. Les expériences décennales : loutil Variability Modes : NAO

11 Kickoff EPIDOM 1. Les expériences décennales : loutil Meridional Overturning Circulation MOC time series at 40°N Comparison to RAPID_ARRAY measures

12 Kickoff EPIDOM 1. Les expériences décennales : loutil Heat transport

13 Kickoff EPIDOM 1. Les expériences décennales : loutil Sea Ice Extent (versus NOAA observations) MAXMIN 10 e +9 m 2

14 2. Stratégies dinitialisation Kickoff EPIDOM Objective : To find ocean initial states compatibles at the same time with the model climatology and also with the observational state nudging

15 2. Stratégies dinitialisation: nudging Kickoff EPIDOM Nudging of NEMO ( dkey tradmp, namtradmp ) No damping in the mixed layer (1/ β) =0 Sea surface restoring for T et S Intermediate waters: β = 10 jours Deep ocean (800m): β = 360 jours depth T o, S o 3D observations The parameter β varies with location Equatorial band: (1/ β) =0 Near coastlines (300km): (1/ β) =0 Over the equator the timescale are very short and the nudging can alter the oceanic currents

16 2. Stratégies dinitialisation: nudging Kickoff EPIDOM Sea surface restoring ( namsbc_ssr ) Exemple: For a mixed layer of 50 m depth, this value corresponds to a relaxation of 2 months (2months are needed to T k=1 = SSTobs) Heat flux: Heat flux at the surface feedback term. SST obs = observations Feedback coefficient = -40W/m2/K Fresh water flux: Fresh water budget at the surface Feedback term. SSS obs = observations Feedback parameter = -167 mm/day

17 2. Stratégies dinitialisation: nudging Kickoff EPIDOM Nudging to the ECMWF ocean reanalysis NEMOVAR (ORCA1°) Several tests have been performed to set the optimal parameters for the nudging HISTNUD1 free between (1°S – 1°N) HISTNUD15 free between (15°S – 15°N)

18 2. Stratégies dinitialisation: nudging Kickoff EPIDOM Annual time series of heat content averaged over the entire basins. The impact of nudging differs from one basin to another. J/m2 NEMOVAR1 HISTNUD15 HISTNUD1

19 2. Stratégies dinitialisation: nudging The Impact of nudging on the Heat transport

20 2. Stratégies dinitialisation: nudging Kickoff EPIDOM Comparison to RAPID_ARRAY measures

21 3. Limpact de linitialisation Kickoff EPIDOM 10 years experiments initialised on 1st January of 1960, 1965, …, 1990 from HISTNUD15 and HISTNUD1 GLOBAL SST HISTNUD15 HISTNUD1 0.08°C on average

22 3. Limpact de linitialisation Kickoff EPIDOM Initial shock: First year run of 20deg isotherme between 2°S - 2°N HISTNUD15 HISTNUD1 No nudging NEMOVAR1 Decadal15 Decadal1 PACIFIC OCEAN longitude depthdepth

23 3. Limpact de linitialisation Kickoff EPIDOM HISTNUD15 HISTNUD1 No nudging NEMOVAR1 Temperature differences between 2°S, 2°N for the 1st January and isotherme at 20deg degC PACIFIC OCEAN

24 3. Limpact de linitialisation Kickoff EPIDOM PACIFIC OCEAN Zonal velocity differences between 2°S, 2°N for the 1st January Contours: NEMOVAR1 m/s

25 3. Limpact de linitialisation Kickoff EPIDOM Initial shock: First year run of 20deg isotherme between 2°S - 2°N HISTNUD15 HISTNUD1 No nudging NEMOVAR1 Decadal15 Decadal1 ATLANTIC OCEAN

26 3. Limpact de linitialisation Kickoff EPIDOM HISTNUD15 HISTNUD1 No nudging NEMOVAR1 Temperature differences between 2°S, 2°N for the 1st January and isotherme at 20deg degC ATLANTIC OCEAN

27 3. Limpact de linitialisation Kickoff EPIDOM ATLANTIC OCEAN Zonal velocity differences between 2°S, 2°N for the 1st January Contours: NEMOVAR1 m/s

28 Résultats préliminaires pour les prévisions Kickoff EPIDOM Unbiased forecasts, SST and heat content 300m NEMOVAR HISTNUD15 GLOBAL Heat Content GLOBAL SSTs Atlantic Ocean SSTs Historic runs ACC SSTs

29 Résultats préliminaires pour les prévisions Kickoff EPIDOM Anomalies of SSTs after removing the mean systematic bias NEMOVAR1 HISTNUD15 GLOBAL SSTs ATLANTIC (35°S) SSTs PACIFIC (35°S) SSTs INDIAN (35°S) SSTs

30 Résultats préliminaires pour les prévisions Kickoff EPIDOM Heat content 300m (anomalies) after removing the mean systematic bias NEMOVAR1 HISTNUD15 GLOBAL HC300 ATLANTIC (35°S) HC300 PACIFIC (35°S) HC300 AMO (35°S) HC300

31 Conclusions Kickoff EPIDOM A nudging methodology 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. When initialising from nudging experiments, the model initial shock is enhanced as the nudging to ocean reanalyses is « stronger ». The initial shock is identified as the generation of El Niño states due to the model heat release. When initialised from HISTNUD15, the model reaches the historical run in aproximately 3-4 yrs. The model drift has a regional behaviour, in particular there is a strong warming drift in the Southern Hemisphere (south out of 35°S)

32 Kickoff EPIDOM 1. Les expériences décennales : loutil Zonal mean temperature and salinity bias, Atlantic Ocean Differences CNRM-CM5 – LEVITUS climatology


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