Objectif
THE PROPOSED RESEARCH WILL INCLUDE THE FOLLOWING STEPS:
DEVELOPMENT AND VALIDATION OF THE COUPLED MODEL.
THE COUPLING BETWEEN THE ATMOSPHERIC MODEL AND THE OCEANIC MIXED-LAYER AND SEA-ICE MODELS COMES ESSENTIALLY FROM THE RADIATIVE AND TURBULENT FLUXES AT THEIR COMMON INTERFACE. SUCH FLUXES ARE COMPUTED BY THE PARAMETERIZATION SCHEMES OF THE ATMOSPHERIC MODEL. PARAMETERIZATION SCHEMES ARE BASED ON PHYSICAL THEORIES BUT APPLY GENERALLY SIMPLIFYING ASSUMPTIONS AND USE SOME PARAMETERS WHICH ARE ADJUSTED EMPIRICALLY. IN ORDER TO OBTAIN AS FAR AS POSSIBLE SATISFACTORY VALUES OF THE SURFACE FLUXES WE SHALL TRY TO ADJUST SUCH PARAMETERS OR DEVELOP IF NECESSARY MORE ELABORATE PARAMETERIZATION SCHEMES, IN PARTICULAR FOR THE COMPUTATION OF BOUNDARY LAYER, CLOUD COVER AND THEIR INTERACTIONS WITH RADIATIVE TRANSFER.
DEVELOPMENT OF A COMMON INTERFACE TO COUPLE THE DIFFERENT MODELS.
THE ATMOSPHERIC MODEL AND THE OCEAN MIXED-LAYER AND SEA-ICE MODELS HAVE DIFFERENT GRIDS AND DIFFERENT TIME-STEPS. THEIR COUPLING WILL REQUIRE THE REALIZATION OF A COMMON INTERFACE THAT WILL ALLOW COMMUNICATION AND EXCHANGE OF THE NEEDED DATA BETWEEN THE MODELS.
VALIDATION OF THE COUPLED 3-D MODEL.
THE COUPLED MODEL WILL BE TESTED IN SIMULATIONS OF THE PRESENT CLIMATE. SIMULATIONS ON SEVERAL ANNUAL CYCLES WILL BE NEEDED TO REACH A STATE OF STATISTICAL EQUILIBRIUM. THESE EXPERIMENTS WILL ALLOW TO CHECK IF THE COUPLING BETWEEN THE PARAMETERIZATIONS OF THE DIFFERENT MODELS DOES NOT LEAD TO UNDESIRABLE FEEDBACKS. IF NECESSARY THE PARAMETERIZATION SCHEMES WILL BE MODIFIED TO OBTAIN A SATISFACTORY EVOLUTION AND AN EQUILIBRIUM AS CLOSE AS POSSIBLE TO THE OBSERVED CLIMATE.
APPLICATION OF THE 3-D MODEL TO DETAILED CLIMATIC RECONSTRUCTIONS.
AFTER ITS VALIDATION OF THE 3-D COUPLED MODEL WILL BE APPLIED TO DETAILED RECONSTRUCTIONS OF REGIONAL CLIMATE FOR CONDITIONS DIFFERENT FROM THE PRESENT ONES. THESE SIMULATIONS WILL BE CHOSEN IN ORDER TO SIMULATE MORE PRECISELY THE GEOGRAPHICAL VARIATIONS CORRESPONDING TO SOME OF THE MORE REMARQUABLE SITUATIONS IDENTIFIED BY THE LONG TERM SIMULATIONS OF THE 2-DIMENSIONAL MODEL.
USE OF THE COUPLED MODEL FOR SEASONAL FORECASTING EXPERIMENTS.
WE PLAN TO TEST FIRST THE POTENTIALITIES OF THE MODEL ON WELL-DOCUMENTED SITUATIONS OBSERVED DURING THE PAST 6 YEARS FOR WHICH GLOBAL ANALYSES ARE AVAILABLE AT ECMWF. WE SHALL PERFORM FORECASTING EXPERIMENTS ON THE SITUATIONS CORRESPONDING TO THE MORE SIGNIFICANT CLIMATIC ANOMALIES. A COMPARISON OF THE ANOMALIES SIMULATED BY THE MODEL TO THE OBSERVED ONES BY MEANS OF OBJECTIVE SCORES WILL ALLOW AN EVALUATION OF THE PREDICTIVE CAPACITY OF THE MODEL ON A SEASONAL SCALE.
Thème(s)
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31054 Toulouse
France