“2011.6.18”湖北大暴雨成因分析

Analysis on Heavy Rainstorm in Hubei Province on 18 June 2011

利用常规观测和地面自动站资料、NCEP 1°×1°再分析资料、FY-2E卫星云图,以及武汉和荆州多普勒雷达资料,针对2011年6月17-18日湖北中东部地区一次大暴雨过程进行了天气动力学诊断和中尺度分析,结果表明:(1)暴雨是在有利的大尺度背景条件下,在特定的地域触发产生的,干冷、暖湿空气在江汉平原和鄂东剧烈交汇触发了这次大暴雨过程。(2)中尺度对流云团有3种类型:即单一云团型、合并型和急剧发展型。中尺度对流云团的大小与其生命史相关,尺度越大,生命史越长,在多个α中尺度对流云团之间的新生云团发展最为迅速,降水强度也最大。(3)呈气旋性转动的中尺度回波团和由低层较强的偏北风急流与偏南风急流辐合作用产生的中尺度复合体是此次暴雨过程雷达回波的主要表现形式;(4)地形对暴雨的强度以及落区等起到重要的作用,长江中游地区由于特定地形形成了三支明显的气流,由这三支气流组成的中尺度辐合系统促进了中尺度对流云团的形成和发展,云团F的加强和发展与地形作用密切相关。

Using the conventional observation and surface station data,NCEP 1°×1 ° reanalysis data,FY-2E satellite cloud image,Wuhan and Jingzhou Doppler radar data,the heavy rainstorm in Hubei Povince on 17-18 June 2011 was analyzed for the Dynamic diagnosis and mesoscale weather analyses.The obtained results are as follows：（1） The heavy rainstorm is produced in the large scale background and the special region.This heavy rainstorm is triggered by severe intersection of cold dry air from the north and warm moist air in the south of Jianghan plain and the eastern part of Hubei Province.（2） Mesoscale convective clouds have three types： A single cloud,combined cloud and the rapid development cloud.The greater the cloud scale,the longer the life history.The new cloud development around the α mesoscale convective cloud is the most rapidly,and rainfall is the largest.（3） Mesoscale echo group,which rotation is cyclonic,and mesoscale complex which is produced by a strong north wind and low-level south wind jet streams in cooperation with the scale of this rainstorm complex process,are the main forms of the radar echo.（4） Terrain for the intensity of rainstorm and the zones play the important roles.The middle reach of the Yangtze River region due to specific topographic effects formed three airflow.Mesoscale convergence system which is composed by the airflow plays an important role in the formation and development of mesoscale convective clouds.The strengthening and development of the F-cloud is closely related to the terrain.