一次孟加拉湾风暴影响下云南持续性暴雨天气诊断分析

应用MICAPS资料结合FY-2卫星云图,诊断分析了云南2004年5月18~20日的持续性暴雨天气过程,这次近50年来最强的暴雨过程主要影响天气系统是孟加拉湾风暴和700 hPa切变线及地面冷锋,冷空气侵入孟加拉湾风暴外围环流导致降水强烈发展。孟加拉湾风暴带来的充沛水汽输送和强烈的上升运动与高温高湿的不稳定大气为强降水发生发展提供了有利条件;高低空急流的建立及维持,强锋生区的持续触发作用,是本次连续性暴雨维持的重要原因。

Diagnostic Analysis of a Persistent Heavy Rainfall in Yunnan influenced by Bay of Bengal Tropical Cyclone

An analysis is made of a persistent heavy rainfall process in Yunnan occurred from 18 to 20 in May 2004 by means of MICAPS data and FY-2 satellite cloud pictures.It is found out that main influencing weather systems include the Bay of Bengal Tropical Cyclone,shear line on 700 hPa,and cold front on the ground.The incursion of clod air into the periphery circumfluence of the Bay of Bengal Tropical Cyclone resulted in the strong development of the precipitation system.The plentiful vapor and strong ascending motion brought by the Bay of Bengal Tropical Cyclone,as well as the unstable atmosphere of high temperature and high humidity,provided favorable conditions for the development of the heavy rainfall.The maintaining mechanisms of the heavy rainfall also include the establishment and maintenance of the upper-and lower-level jets,and the continual triggering of strong frontogenesis.