A Modeling Study of Diurnal Rainfall Variations during the 21-Day Period of TOGA COARE  

作　　者：高守亭 崔晓鹏 Xiaofan LI 

机构地区：[1]Laboratory of Cloud-Precipitation Physics and Severe Storms （ LACS）,Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029 [2]Joint Center for Satellite Data Assimilation and NOAA/NESDIS/Center for Satellite Applications and Research, Camp Springs, Maryland, USA

出　　处：《Advances in Atmospheric Sciences》2009年第5期895-905,共11页大气科学进展（英文版）

基　　金：supported by the National Key Basic Research and Development Project of China (Grant No. 2009CB421505);the National Natural Sciences Foundation of China under Grant No. 40775031 and Grant No. GYHY200706020

摘　　要：The surface rainfall processes and diurnal variations associated with tropical oceanic convection are examined by analyzing a surface rainfall equation and thermal budget based on hourly zonal-mean data from a series of two-dimensional cloud-resolving simulations. The model is integrated for 21 days with imposed large-scale vertical velocity, zonal wind, and horizontal advection obtained from the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment （TOGA COARE） in the control experiment. Diurnal analysis shows that the infrared radiative cooling after sunset, as well as the advective cooling associated with imposed large-scale ascending motion, destabilize the atmosphere and release convective available potential energy to energize nocturnal convective development. Substantial local atmospheric drying is associated with the nocturnal rainfall peak in early morning, which is a result of the large condensation and deposition rates in the vapor budget. Sensitivity experiments show that diurnal variations of radiation and large-scale forcing can produce a nocturnal rainfall peak through infrared and advective cooling, respectively.The surface rainfall processes and diurnal variations associated with tropical oceanic convection are examined by analyzing a surface rainfall equation and thermal budget based on hourly zonal-mean data from a series of two-dimensional cloud-resolving simulations. The model is integrated for 21 days with imposed large-scale vertical velocity, zonal wind, and horizontal advection obtained from the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment （TOGA COARE） in the control experiment. Diurnal analysis shows that the infrared radiative cooling after sunset, as well as the advective cooling associated with imposed large-scale ascending motion, destabilize the atmosphere and release convective available potential energy to energize nocturnal convective development. Substantial local atmospheric drying is associated with the nocturnal rainfall peak in early morning, which is a result of the large condensation and deposition rates in the vapor budget. Sensitivity experiments show that diurnal variations of radiation and large-scale forcing can produce a nocturnal rainfall peak through infrared and advective cooling, respectively.

关 键 词：diurnal rainfall variation cloud-resolving simulation tropical oceanic convection TOGACOARE 

分 类 号：P732.6[天文地球—海洋科学]