空心台风“麦德姆”(2014)引发的江西局地暴雨过程分析

Analysis of Local Torrential Rain Caused by the Hollow Typhoon “Matmo”

利用常规气象观测资料、NCEP再分析资料、雷达资料,从环流特征、水汽条件、动力条件以及冷空气侵入作用等方面,对2014年台风"麦德姆"登陆后的空心结构及其引发的7月24日德安县局部特大暴雨过程进行分析。结果发现,高层南亚高压东风急流形成的高空辐散流场的变化,以及下垫面和地形的影响导致了台风减弱为热带风暴,并出现空心结构;冷空气与热带风暴的东北象限发生作用,使热带风暴外围德安县附近大气垂直层结处于非常不稳定状态,地面中尺度辐合线的形成与维持,使低层辐合加强和对流加强,在东风急流带来充足的水汽辐合条件下引发了特大暴雨。

Using conventional weather data, NCEP reanalysis data and Nanchang Doppler radar data, the hollow structure of typhoon ＂Matmo＂ after its landing and local torrential rainfall occurred on July 24 2014 over De′an county in Jiangxi Province are analyzed in terms of circulation characteristics, vapor condition and the intrusion of cold air. The results showed that the hollow structure of typhoon ＂Matmo＂ was caused by the change of high-level divergence flow field from south Asia easterly jet, the underlying surface and the topography. The interactions between the cold air and the northeast circulation of typhoon greatly strengthened the atmosphere instability over De′an. The formation and maintenance of meso-scale convergence line led to intensify low-level convergence and strong convection. In addition, enough vapor convergence from easterly jet caused this heavy torrential rainfall.