东亚大气环流由冬向夏的转变时间及其特征  

Transition of East Asian general circulation from winter to summer and its features

作　　者：何金海[1] 祁莉[1] 刘丹妮[1] 朱占云[1] 

机构地区：[1]南京信息工程大学气象灾害省部共建教育部重点实验室,南京210044

出　　处：《气象科学》2010年第5期591-596,共6页Journal of the Meteorological Sciences

基　　金：国家自然科学基金资助项目(40905044;41075068);国家重点基础研究发展计划(973计划)项目(2010CB950401)

摘　　要：利用NCEP/NCAR再分析数据集及CMAP降水资料分析了东亚大气环流由冬转夏的可能时间及其特征。结果表明,3月底4月初,东亚与西太平洋对流层纬向热力差异由东暖西冷转为东冷西暖,对流层低层大陆高压东移,使得纬向气压梯度发生逆转。与此同时,对流层低层偏南风建立,经向垂直环流也发生季节逆转。同时,3月底4月初华南已出现持续性降水雨带。所有这些特征都表明东亚大气环流可能在3月底4月初已经由冬季型开始转为夏季型。NCEP/NCAR reanalysis dataset and CMAP rainfall data are used to analyze the transition of East Asian general circulation from winter to summer and its features.The results show that in late March the thermal difference of troposphere between the East Asia and West Pacific has turned from warm in east and cold in west to warm in west and cold in east.The anticyclone over the land in lower troposphere shifts eastward,leading to the reversal of related pressure contrast.At the same time,the southerly sets up in lower troposphere.The corresponding vertical circulation also has its seasonal transition done.Moreover,it has continuous rain over the south of Jiangnan region and to the north of South China in late March.All these features indicate that the East Asian general circulation has transited from winter status to summer status.

关 键 词：东亚大气环流 冬转夏的时间 特征 东亚副热带季风 

分 类 号：P434.1[天文地球—大气科学及气象学]