梅汛期100hPa南亚高压特征与江苏梅雨关系研究

STUDY ON CONNECTION BETWEEN SOUTH ASIA HIGH CHARACTER OF 100 HPA IN PLUM FLOOD SEASON AND JIANGSU PLUM RAIN

关键词:  南亚高压  特征指数  江苏梅雨

Key words:  South Asia High  character index  Jiangsu plum rain

摘要:

通过2002～2005年南亚高压特征指数、高空槽变化过程分析,讨论了南压高压对江苏梅雨期和主要降水落区的影响。并结合近15年南亚高压特征指数,探讨了不同梅雨年型的特征指数区域分布关系。同时利用2002～2005年45年NCEP100hPa高度场资料,分析了不同梅雨年型高空环流形势差异。得出:(1)南亚高压特征指数变化和西风槽移动与江苏梅期(入梅、出梅、梅期、梅雨量和落区)特征有密切关系。(2)梅雨期100hPa南亚高压的平均特征对梅期特征和梅雨年型有很好的对应关系。6～7月和梅雨期间南亚高压脊线和东伸指数平均值对梅雨强度指数具有一定的预报指示意义。

Abstract:

Through analyzing the change of south Asia high character index and upper air trough,the impact of South Asia High on Jiangsu plum rain and main precipitation area are discussed.Together with 15 years of South Asia High character index,the distribution of South Asia High character index in different plum rain patterns are studied.In the meantime,using altitude field data from 2002 to 2005 and 45 years of NCEP data on 100 hPa,the 100 hPa circulation difference of different plum rain patterns is analyzed.Some results are gained.(1) There is close relation between the change of south Asia high character index,trough in the westerlies and plum rain date character(the beginning,ending dates and lasting days of plum rain,rainfall and area of rain).(2) The total circulation field on 100 hPa and average character of South Asia High have some links with plum rain duration and plum rain type.The average values of South Asia High ridge line and eastward advancing index in June and July and during the plum rain have some indication for the forecasting plum rain intensity index.