Analysis of sustained rainstorm events over Hubei from July 7 to 15 in 2010

Using conventional observational data,NCEP 1°×1°reanalysis data,AWS precipitation data,radar data,satellite data and so on,the sustained rainstorm events over Hubeir province from July 7 to 15 in 2010 are comprehensively analyzed focusing on circulation background,formation mechanism,radar echo data and satellite cloud images etc.The conclusions are drawn that the short-wave troughs in the mid-and high-latitude continuously moving east-wards,stabilization and maintenance of both subtropical high over the west Pacific and shear in the mid-and low-level,and development of southwesterly low-level jet provide favorable large-scale circulation background for the occurrence of the sustained rainstorm events. Mesoscale echo clusters or echo bands and mesoscale convective cloud clusters result in the rainstorm events.Mesoscale convective echoes or cloud clusters generally emerge in the confluence areas of various synoptic scale systems, which have certain prediction significance for short-term rainstorm forecast. The convergence of water vapor takes place in the entire process of precipitation,and rainfall areas correspond to high air humidity center in low level. Mesoscale convective systems in the entire troposphere present an ascending movement, and the distribution of rainstorm is in dense areas with CAPE gradient continuously increasing, and frontal zone of θse in the low-level continuously strengthens and supply unstable condition which is advantageous for the occurrence of convective severe precipitation.