江苏南部两次暴雨-大暴雨过程分析

2011年6月10日(简称"11·06")和2017年6月10日(简称"17·06")在江苏南部出现了两次暴雨-大暴雨过程,本文利用常规观测资料、FNL再分析资料和雷达资料等,对两次过程进行了分析,结果表明:异常的高低纬度环流形势配合,为强降水的发生提供了有利的环流背景.两次过程代表站的物理量场差异较大:"17·06"...

Analysis of Two Heavy Rainstorms in Southern Jiangsu

On 10June 2011(for short,Process 1106)and on 10June 2017(Process 1706),there occurred two rainstorms in the south of Jiangsu Province.With the conventional observational and FNL reanalysis data and radar data,the two processes are analyzed.The results show that the anomalous high and low latitudinal circulation conditions provided a favorable circulation background for the occurrence of the heavy precipitation.There were great differences between the two processes in the physical quantity fields of the representative stations:the maximum divergence of Process 1706was about twice as big as that of Process 1106;the maximum vertical velocity and maximum water vapor flux divergence of Process 1706 were about 1.8and 1.3times as big as that of Process 1106;and the large values were maintained for a long time.Both processes were characterized by strong tropical precipitation in the warm region;but the strong echo of 1106was dispersing,the extensional height was low,the intensity was weak,and there was no obvioustrain effect"of strong echoes.The strong echoes of Process 1706arranged closely;the extension height was high,the intensity was obviously strong;and thetrain effect"of strong echo was obvious.The change of helicity was generally ahead of that of precipitation,which was predictable and can be used as a predictor of the start,maintenance,and ending of large-area precipitation in short-time forecasting(nowcasting).The change of the bottom height of the high wind zone in VWP(Vertical Wind Profiles)products was helpful to judge the changing trend of precipitation around the radar station.