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

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.