Modulation of land-sea thermal contrast on the energy source and sink of tropical cyclone activity and its annual cycle  

作　　者：YING Ming WU GuoXiong LIU YiMin SUN ShuQing 

机构地区：[1]Shanghai Typhoon Institute of China Meteorological Administration,Shanghai 200030,China [2]State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China

出　　处：《Science China Earth Sciences》2012年第11期1855-1871,共17页中国科学（地球科学英文版）

基　　金：supported jointly by the National Basic Research Program of China(Grant Nos. 2010CB950403,2012CB956003 and 2012CB417203);the National Natural Science Foundation of China (Grant Nos. 40925015 and41075071)

摘　　要：In general,the tropical cyclone(TC) activity is considered to be influenced by the heat content of underlying ocean,vertical shear of horizontal wind,vorticity in the low troposphere,moisture in the troposphere,and favorable condition for deep convection development.However,these factors by nature merely present the internal factors of either atmosphere or ocean which influence the TC activity.In fact,the energy budget of the Earth system and its variation,modulated by the land-sea thermal contrast,are the intrinsic reasons responsible for the variation of TC activity.Here we investigate the modulation of diabatic heating distribution associated with the land-sea thermal contrast on the distribution of TC activity energy source and sink as well as the seasonality.An accumulated energy increment index(AEI) is defined using the TC best track data,and the energy sources and sinks of TC activity are then diagnosed effectively and practically according to the distribution of AEI.Results show that the thermal contrast of land and ocean is the primary reason for asymmetric distribution of TC activity about the Equator as well as the zonally asymmetric distribution of TC activity.The energy sources of TC activity are dominated by condensation heating of deep convection or double-dominant heating,which includes the condensation heating and cooling of longwave radiation(LO),while the sink areas are dominated by LO.The large scale diabatic heating associated with land-sea thermal contrast results in more favorable conditions for TC activity over the west part of oceans than those over the east parts.Moreover,the intensity of interaction of different diabatic heating over the west and east parts of ocean is also affected by the zonal scale of the oceans,which induces the difference of TC activity over the western North Pacific(WNP) and North Atlantic(ATL).The favorable westerlies and anticyclonic vertical shear associated with the tropical zonally asymmetric diabatic heating also contribute to the most intense TC activity ovIn general,the tropical cyclone（TC） activity is considered to be influenced by the heat content of underlying ocean,vertical shear of horizontal wind,vorticity in the low troposphere,moisture in the troposphere,and favorable condition for deep convection development.However,these factors by nature merely present the internal factors of either atmosphere or ocean which influence the TC activity.In fact,the energy budget of the Earth system and its variation,modulated by the land-sea thermal contrast,are the intrinsic reasons responsible for the variation of TC activity.Here we investigate the modulation of diabatic heating distribution associated with the land-sea thermal contrast on the distribution of TC activity energy source and sink as well as the seasonality.An accumulated energy increment index（AEI） is defined using the TC best track data,and the energy sources and sinks of TC activity are then diagnosed effectively and practically according to the distribution of AEI.Results show that the thermal contrast of land and ocean is the primary reason for asymmetric distribution of TC activity about the Equator as well as the zonally asymmetric distribution of TC activity.The energy sources of TC activity are dominated by condensation heating of deep convection or double-dominant heating,which includes the condensation heating and cooling of longwave radiation（LO）,while the sink areas are dominated by LO.The large scale diabatic heating associated with land-sea thermal contrast results in more favorable conditions for TC activity over the west part of oceans than those over the east parts.Moreover,the intensity of interaction of different diabatic heating over the west and east parts of ocean is also affected by the zonal scale of the oceans,which induces the difference of TC activity over the western North Pacific（WNP） and North Atlantic（ATL）.The favorable westerlies and anticyclonic vertical shear associated with the tropical zonally asymmetric diabatic heating also contribute to the most in

关 键 词：land-sea thermal contrast tropical cyclone energy sources and sinks SEASONALITY 

分 类 号：P425.42[天文地球—大气科学及气象学] P46