江淮流域强暴雨过程对阻高和副高逐日变化的响应关系

江淮流域是我国暴雨频发的地区之一，而乌拉尔山阻塞高压和西太平洋副热带高压是北半球两个主要的大气环流系统.本文统计分析了1971~2003年期间乌山阻塞高压和西太平洋副高的逐日强度变化特征，研究了乌山阻塞高压和西太平洋副高对江淮流域强暴雨过程的响应关系.结果表明，江淮流域多数强暴雨过程发生在乌山阻高的减弱期，在乌山阻高的建立和加强期较少有持续性暴雨发生.乌山阻高的突然减弱是江淮流域强暴雨过程发生的强信号之一.同时，西太平洋副热带高压的加强西伸登陆是江淮流域强暴雨过程发生的必要条件之一.

The ural blocking high anomalous daily variation impact on the heavy rainfall in the yangtze river basin and Huai River basin

Heavy rainfall and severe flood events occurred frequently in the Yangtze River Basin and Huai River Basin. Its reason is multidisciplinary. The Ural blocking high (UBH) and the western Pacific subtropical high are two major atmosphere circulation systems in northern hemisphere. The high impacts of UBH and the western Pacific subtropical on heavy rainfall in the Yangtze River Basin and Huai River Basin are investigated in this paper. The Ural (0°~100°E, 45°~65°N) blocking high strength indices of daily variation characteristics during 1991-2003 are analyzed. We discovered that the most of heavy rainfall events in the Yangtze River valley and the Huai River valley occurred in the weakening period of the stronger UBH, the heavy rainfall events are less during establishment and strengthening period of UHB. The weakening of UBH is resulted from stronger cold mass activity frequently, therefore stronger UHB sudden weakening is one of weather signals of heavy rainfall that would be occurring in the Yangtze River Basin and Huai River Basin. And the strengthening and landing westward of the western Pacific subtropical high has great impact on the heavy rainfall area.