青藏高原季风环流情况与中亚季风降水特征分析

Analysis on the Characteristics of Tibetan Plateau's Monsoon Circulation and Central Asia's Rainfall

为探究青藏高原季风环流与其西侧中亚局地环流之间的关系,以及环流对中亚降水的影响。利用NCEP/NCAR再分析资料和热带降水测量卫星（TRMM）的3B43逐月降水量资料,运用矢量合成法,分析青藏高原及周边区域500h Pa上空1979年1月～2013年12月的水平风场环流特征。结果表明,不存在以高原主体为中心的闭合环流,高原季风环流是其周边多个子季风系统共同影响的结果。进而对高原西侧中亚地区的气候特征进行分析,发现中亚地区是显著的季风区。里海作为大型水体,冬季为热源,夏季为热汇,对本地及下游地区的环流形势有重要影响;发现中亚地区以冬季降水为主。雨季期间中部腹地降水少,四周中亚西北里海区域,里海南侧区域,中亚东北高原西侧冬季迎风坡区域和高原西南区降水多。最后,利用旋转经验正交函数（REOF）把中亚分成5个有不同降水特征的区域。

In order to investigate the relationship between the monsoon circulation of Tibetan Plateau and the circulation of Central Asiand how the circulation impacts the precipitation on the NCEP/NCAR reanalysis data, method of vector composite the circulation character of he Tibetan plateau and surrounding area on the 500 hPa isobaric level in January 1979 to December 2013. The results show that the closed circulation centres on the main part of the Tibetan plateau is not exist. Plateau monsoon circulation is the result of several subsidiary monsoon systems effect around plateau. And then, we analyze Central Asia＇ s climate characteristicsthat Central Asia is a prominent monsoon area. The Caspian sea has a large water mass, is heat source in winter and heat sink in summer, has important influence on lower reaches＇ cir- culation. Combin with TRMM monthly precipitation data over 1998.01-2014.04, we can be sure that Central Asia often rain in winter. The interior of Central Asia is drought, all region around is moist. In the end, the rotated empirical or- thogonal function is used Central Asia into 5 rainfall regions.