Objectif
UNDERSTANDING THE FEEDBACKS IN THE CLIMATE SYSTEM : ATMOSPHERE, OCEAN, CRYOSPHERE.
THIS STUDY CORRESPONDS TO THE FIRST STEP OF THE JOINT PROJECT TO DEVELOP A SIMPLE CLIMATE MODEL, WHICH WILL BE USED TO STUDY THE LONG-TERM VARIABILITY OF THE CLIMATIC SYSTEM.THE SCIENTISTS INVOLVED IN THIS PROPOSAL BELONG TO TWO LABORATORIES : THE LABORATOIRE DE METEOROLOGIE DYNAMIQUE DU CNRS AND THE LABORATOIRE D'OCEANOGRAPHIE DYNAMIQUE ET CLIMATOLOGIE DU CNRS.
WE CONSIDER THE DESIGN OF AN ATMOSPHERIC BIDIMENSIONAL MODEL, WHICH, IN THE LAST STAGES OF THE PLANNED RESEARCH, WILL BE COUPLED TO MODELS OF THE OTHER PARTS OF THE CLIMATIC SYSTEM (DEVELOPED IN THE OTHER LABORATORIES TAKING PART TO THIS PROJECT.).ALTHOUGH THE ATMOSPHERIC DYNAMICS HAS A VERY SHORT TIME SCALE,IT PLAYS AN IMPORTANT ROLE AT VERY LONG TIME SCALES SINCE IT COMPETES WITH THE OCEAN TO TRANSPORT THE HEAT AND MOISTURE FROM THE EQUATOR TO THE POLES, AND DETERMINES THE MASS BALANCE OF THE ICECAPS THROUGH PRECIPITATION OF SNOW AND MELTING OF THE ICE.
WE WOULD DEVELOP A BIDIMENSIONNAL VERSION OF THE LMD GENERAL CIRCULATION MODEL, OBTAINED BY ZONALLY AVERAGING THE PRIMITIVE EQUATIONS AND BY KEEPING THE SAME PHYSICAL PARAMETERIZATIONS. THIS WILL DIVIDE THE COMPUTER TIME NEEDED FOR A GIVEN INTEGRATION BY A FACTOR OF APPROXIMATELY 100.
WE WILL PARAMETERIZE THE MERIDIONAL TRANSPORT OF HEAT AND MOISTURE BY THE BAROCLINIC ACTIVITY AT MID LATITUDES. TO ALLOW A RIGOROUS APPROACH OF THIS PROBLEM WE FIRST INTEND TO STUDY THE BEHAVIOUR OF THE TRIDIMENSIONAL ATMOSPHERIC MODEL WHEN SUBMITTED TO ZONAL BOUNDARY CONDITIONS (WHICH MEANS TO SIMULATE THE CLIMATE OF AN OCEANIC PLANET OR OF AN OCEANLESS PLANET).THESE SIMULATIONS WILL SERVE AS REFERENCE CASES TO BE REPRODUCED BY THE BIDIMENSIONNAL MODEL.
Champ scientifique
Thème(s)
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91190 Gif-sur-Yvette
France