Mesoscale Characteristic and Mechanism Analysis of a Heavy Flooding Rainstorm Process in Xijiang River Basin,Guangxi

Based on the Black-Body Temperature(TBB)data of FY-2C Stationary Meteorological Satellite from China Meteorological Agency(CMA) and the reanalysis dataset from the NCEP/NCAR reanalysis project,combining the data of hourly precipitation at 90 stations in Guangxi,the mesoscale characteristic and the mechanism of a heavy flooding rainstorm process happened in Xijiang River basin is analyzed by the 25-point smooth filter methods.Results show that the spatial and temporal characteristics of the mesoscale convective system that associated with the mesoscale rain mass has significant day variation,and the mesoscale rain mass often appear in the area of the center of low TBB and the lower TBB band,the sharp and dense TBB on the north of the low center and the area where the TBB curve is the larger;the evolution of the mesoscale vortex filtered from large scale SW stream has great impact on the maintaining and development of the mesoscale convective cloud mass over Xijiang River in South China,which is the direct causes for the heavy flooding rainstorm process;the low-level-jet give the rich moisture to the heavy rainfall and the convective instability and the strong vertical shear of horizontal wind are the important condition of the explosive and persistent heavy flooding rainstorm process.