Transition from the Southern Mode of the Mei-yu Front Cloud System to Other Leading Modes  

作　　者：QIN Danyu LI Bo HUANG Yong 

机构地区：[1]Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites,China Meteorological Administration [2]Institute of Satellite Meteorology, National Satellite Meteorological Center,China Meteorological Administration [3]School of Atmospheric Physics, Nanjing University of Information Science and Technology [4]Anhui Institute of Meteorology Science

出　　处：《Advances in Atmospheric Sciences》2014年第4期948-961,共14页大气科学进展（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant No. 40975023);the Special Promotion Program for Meteorology (Grant No. GYHY201406011 and No. GYHY201106044);the National High Technology Research and Development Project of China (Grant No. 2012AA120903)

摘　　要：Based on normalized six-hourly black body temperature （TBB） data of three geostationary meteorological satellites,the leading modes of the mei-yu cloud system between 1998 and 2008 were extracted by the Empirical Orthogonal Function （EOF） method,and the transition processes from the first typical leading mode to other leading modes were discussed and compared.The analysis shows that,when the southern mode （EOF1） transforms to the northeastern mode （EOF3）,in the mid-troposphere,a low trough develops and moves southeastward over central and eastern China.The circulation pattern is characterized by two highs and one low in the lower troposphere.A belt of low pressure is sandwiched between the weak high over central and western China and the strong western North Pacific subtropical high （WNPSH）.Cold air moves southward along the northerly flow behind the low,and meets the warm and moist air between the WNPSH and the forepart of the low trough,which leads to continuous convection.At the same time,the central extent of the WNPSH increases while its ridge extends westward.In addition,transitions from the southern mode to the dual centers mode and the tropical-low-influenced mode were found to be atypical,and so no common points could be concluded.Furthermore,the choice of threshold value can affect the number of samples discussed.Based on normalized six-hourly black body temperature （TBB） data of three geostationary meteorological satellites,the leading modes of the mei-yu cloud system between 1998 and 2008 were extracted by the Empirical Orthogonal Function （EOF） method,and the transition processes from the first typical leading mode to other leading modes were discussed and compared.The analysis shows that,when the southern mode （EOF1） transforms to the northeastern mode （EOF3）,in the mid-troposphere,a low trough develops and moves southeastward over central and eastern China.The circulation pattern is characterized by two highs and one low in the lower troposphere.A belt of low pressure is sandwiched between the weak high over central and western China and the strong western North Pacific subtropical high （WNPSH）.Cold air moves southward along the northerly flow behind the low,and meets the warm and moist air between the WNPSH and the forepart of the low trough,which leads to continuous convection.At the same time,the central extent of the WNPSH increases while its ridge extends westward.In addition,transitions from the southern mode to the dual centers mode and the tropical-low-influenced mode were found to be atypical,and so no common points could be concluded.Furthermore,the choice of threshold value can affect the number of samples discussed.

关 键 词：black body temperature mei-yu front cloud system leading modes mode transition 

分 类 号：P441[天文地球—大气科学及气象学]