Analysis of the evolution of convective clouds during a rainstorm in 2015 over Hubei province

Conventional and intensive observation data,hourly rainfall data,FNL reanalysis data,as well as the Temperature of Black Body (TBB) observed by FY-2G satellite were used to analyze the environmental conditions and affecting mechanisms of convective clouds during a Meiyu rainstorm on July 14 to 15,2015 over Hubei province.The results show that the favorable conditions for the evolution of convective clouds are convective clouds located in front of the trough at 500 hPa,wind converging and small dew point depression at 850 hPa and warm advection maintaining between 500-850 hPa.When synoptic scale Warm Conveyor Belt (WCB) clouds develop from western Jiangnan area to the middle reaches of Yangtze River,and low-level warm shear lines appear over Hubei province,the precipitation will increase significantly.When WCB clouds obviously move eastward,rainstorm over Hubei province will terminate.When WCB is located over Hubei province,large positive items of both advection and convection of equivalent potential temperature will appear at 850 hPa,and the areas with large convection items will appear to the south of those with large advection items.Short-time heavy precipitation occurs predominantly in the rain-prevailing period,which is important to local rainstorms.There are four mechanisms influencing short-time rainstorms over Hubei province,including the western borders of convective clouds,center areas of deep convective clouds,"train effect" of convective cells and mergence of convective clouds.The number of rainstorms affected by the western borders of convective clouds and convective cells is relatively more,and the precipitation affected by center areas and mergence of convective clouds is relatively larger.