湖南“6.19”暴雨过程的中尺度特征分析

Characteristics of the Mesoscale System in 6.19 Heavy Rain Process in Hunan Province

针对2010年6月19～20日湖南一次大范围暴雨过程,利用常规观测资料、FY-2E卫星TBB资料、NCEP1°×1°格点资料及WRF模式输出的高分辨率资料,采用数值模拟和诊断分析相结合的方法,综合分析了此次暴雨过程.结果表明：东移短波槽及低层低涡是此次暴雨的主要影响系统;卫星资料分析显示,α中尺度对流云团前部不断有β中尺度扰动分裂和发展;WRF模式模拟结果表明,此次大范围暴雨过程是多尺度系统影响的结果,在有利的大尺度环流背景下,激发了中小尺度对流系统的活动,导致强降水带中出现了多个中尺度扰动和与此对应的中尺度雨团有组织的活动,是暴雨发生的主要原因;中尺度雨团对应着强上升气流柱、正涡度柱和低层强辐合、高层强辐散的散度结构.

Based on a heavy rain process in Hunan during 19-20 June 2010,the high spatial-temporal data on Temperature of Black Bold observed by FY-2E satellite,NCEP 1° × 1°grid data and the high-resolution output from WRF model are used to analyze the structure and evolution of the mesoscale systems.The major conclusions as follows：East short-wave trough and low-level vortex are the main influencing systems of the rainstorm process.Analysis of satellite data shows that the meso-β scale system generated and developed from the meso-α scale convective cloud cluster front.The result of WRF model simulation is consistent with the fact,the multiscale systems lead to the wide range of torrential rain process.In situation of favorable large scale circulation,mesoscale convective systems are activated,and result in many mesoscale disturbances and mesoscale rain clusters regular motion,that is the main cause for rainstorm process.The strong development of the mesoscale rain clusters are supported by the favorable mesoscale dynamic configuration,which corresponding to the strong updrafts column,a positive vorticity column coupled with strong lower-level convergence and upper-level divergence.