孟加拉湾热源对亚洲夏季风环流系统的影响

利用 1951—2000年NCEP/NCAR再分析逐日及月平均资料和我国 160个测站 1951—2000年月降水量资料,计算了夏季大气热源气候分布,分析了夏季孟加拉湾地区热源年际异常及亚洲季风环流系统的响应,以及夏季孟加拉湾地区热源与中国夏季降水的年际关系。结果表明:夏季亚洲季风区最强的热源中心位于孟加拉湾东北部一带。当孟加拉湾热源异常强 (弱 )时,南亚高压偏西 (东 ),西太平洋副热带高压位置偏东(西);印度夏季风偏强 (弱),东亚热带季风偏弱 (强 )。孟加拉湾热源异常对南亚高压、南亚季风、副热带高压的影响显著,对东亚热带季风的影响不显著。夏季孟加拉湾热源与同期长江以南、华南东部部分地区降水呈明显负相关,而与西南到华南西部地区降水呈明显正相关。

Influence of Heat Source over the Bay of Bengal on Asian Summer Monsoon Circulation and Summer Precipitation in China

Using the daily and monthly NCEP/NCAR reanalysis data from 1951 to 2000 and monthly precipitation of 160 stations in China in summer from 1951 to 2000, the climatic distribution of heat source are computed.the responses of the Asian monsoon circulation to the annual anomaly of the heat source over the Bay of Bengal in summer and the annual relationship between the heat source and the precipitation of China in summer are analyzed .The results show that the strongest heat source heating center was located over the north-east of the Bay of Bengal in summer.When the heat source over the Bay of Bengal was abnormally strong(weak),the southern Asian high extended westward(eastward),and the western Pacific subtropical high extended eastward(westward),and the Indian summer monsoon was stronger(weaker),and the eastern Asian tropical summer monsoon was weaker(stronger).The influence of the heat source anomalies over the Bay of Bengal was significant on the south Asian high and the south Asian summer monsoon and the western Pacific subtropical high,but not very significant on the eastern Asian tropical summer monsoon.There existed obviously negative correlation between the heat source over the Bay of Bengal and the precipitation of the south of the Yangtze River and the east of south China in summer,and obviously positive correlation between the heat source and the precipitation of the area from southwest in China to the west of south China.