青藏高原东侧初夏旱涝的季风环流分析

A Study on Monsoon Circulations of Drought and Wet Years on the East Side of Qinghai-Xizang Plateau in Early Summer

利用NCEP/NCAR1958—1999年5～6月各标准等压面层网格点资料,采用合成法和对比分析等方法,对初夏青藏高原季风和东亚季风环流异常进行了分析。结果表明:四川盆地初夏干旱的季风环流特征是高原季风偏弱,高原季风低压偏西,我国东部地区东亚季风偏弱,东亚季风槽偏南;而多雨年则反之。四川盆地初夏干旱年,极涡向亚洲大陆发展,强度偏强,东亚大槽偏强且稳定;而多雨的年份,极涡萎缩在极地区域,强度偏弱,东亚大槽偏弱。

By using NCEP/NCAR data from May to June 1958—1999, compositing and comparing methods, the anomaly circulations of QinghaiXizang Plateau monsoon and East Asian monsoon are analyzed. The results are as follows: The characteristics of Plateau monsoon and East Asian monsoon for drought and wet years in early summer are different. The Plateau monsoon was weak /strong in drought/wet years and its low pressure was far westward/eastward. East Asian monsoon in the east part of China was also weak /strong and its trough was far southward/northward. Polar vortex developed/shrank towards south/north in drought and wet years in Sichuan basin and deep trough of East Asia was strong/weak.