Mesoscale characteristics analysis of a heavy rainstorm processon July 1st 2008 in Zhaotong

Applying meteorology and physical diagnosis methods,the large scale environment characteristics of a heavy rainstorm have been analyzed from 30 June 2008 to 1 July 2008 in Zhaotong;Then applying the space-time echo data of Doppler radar and the satellite cloudy images of FY-2C and the rainfall data of regional automatic station,the mesoscale characteristics have been analyzed.The results show that:① This process has the favorable conditions of large scale,the MCS's producing the rainstorm were in the front area of the upper trough where the upper level divergence-lower level convergence provided a favorable large-scale dynamic background for MCS's development.② The process has the haracteristics of big intensity,happened suddenly,small time scale,concentration of rainfall duration of approximate 3—5 h,the surface rainfall obviously showed meso-scale spatial and temporal distribution features.③ Viewed from the stratification characteristics of temperature and humidity,a SW-NE stretched lower level warm and moist tongue was obviously seen before the occurrence of the rainstorm and the tongue fed the rainfall area with plentiful and sufficient moisture.The differential advection induced by the dry/cold advection at the upper level superposing on the warm/moist advection at the low level strengthened the local instability of atmospheric stratification within the rainstorm area.④ After analyzing of satellite cloudy images and Doppler radar echo data,found that there was seperated construction of meso-β scale convective system in the large-scale environmental wind field,But the meso-β scale convective system consists of 2 mesoscale cloudse convective and has the characteristics of oval structure,the flow field convergence of mesoscale clouds corresponded with strong echo band,and it showed typically the 人 in the strong stage of radar echo.