The Meso-Scale Analysis of “6.18” Severe Rainfall Event in Hunan Province

[Objective]The aim was to analyze the mesoscale and small scale system that influenced the strong rainfall in Hunan from June 18 to 20 in 2010. [Method] By dint of regular observation material and rainfall in regional automatic station, TBB of FY-2C geostationary meteorological satellite, characteristics and causes of one heavy rainfall event in Hunan Province on 18-20 June 2010 were studied. [Result] The rainstorm happened under the southwest warm and wet torrent at the edge of subtropical high when the ground cold air intruded, which triggered the release of unstable energy. The water vapor from Bay of Bengal and South China Sea sent abundant water vapor to south China. The water vapor strengthened, which synchronized with the rainstorm. The ground mesoscale convergence line and the mesoscale low pressure intensified the rainstorm. Changes of pressure field reflected the changes of rainfall and indicated the location and movement of heavy rainfall. [Conclusion] The study provided theoretical basis to understand the rainstorm formation mechanism and improve disaster prevention capacity.