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利用MICAPS资料、多普勒雷达资料和NCEP资料,对2010年8月10日08：00-11日08：00（北京时）毛乌素沙地南部边缘地带一次大暴雨过程的中-γ尺度特征及成因进行了分析。结果表明,强降水发生时,在多普勒气象雷达速度场上可观测到西南低空急流的生成和增强,以及西南低空急流左侧中-γ尺度气旋式辐合的生成和维持,并在反射率因子图上出现〉50dBz的强回波区;暴雨过程中单站要素表现为气压持续降低并出现≥4.0m·s-1的最大风速（南风）;伴随强降水的开始,暴雨区主要受水平平流项和水平辐散项作用,600hPa以下对流层低层的涡度收支增大,800～700hPa达6×10-9s-2;受水平平流项作用,350～100hPa维持涡度收支负值,在150hPa附近达-6×10-9s-2;视热源Q1的垂直廓线显示,伴随暴雨区最强降水即将开始时,主要受局地变化项和垂直输送项作用,Q1在780～300hPa形成正值层;受水平平流项作用,Q1在300～220hPa形成负值层,大气热力强迫作用有利于上升运动加强和云团发展;Q1的累积分布显示,临近暴雨发生时,暴雨区靠近上游生成Q1〉20J·kg-1·s-1的大值中心,而且暴雨区视水汽汇Q2〉10J·kg-1·s-1。“,”The MICATP data.tif,Doppler radar data and NCEP data are used to analyze the meso-γscale characteristic and cause in heavy rainstorm process in the south border of Maowusu sandy land on 10-11August 2010.The result show that,when the severe precipitation occurring,the development and enhancement of the southwesterly low-level jet,the development and maintenance of meso-γ-scale cyclone convergence on the left side of the southwesterly low-level jet are observed from velocity field of Doppler radar as well as strong echoes more than 50dBz.Continuous decrease of barometric pressure,continuous southerly wind with maximum speed more than or close to 4.0m·s-1 are observed during the rainstorm process.The analysis of vorticity budget show that,when the heavy rainstorm beginning,the dominant factors are horizontal advection and horizontal divergence terms,the vorticity budget bellow 600hPa in the rainstorm area,which reached 6×10-9s-2 on 800~700hPa.Due to horizontal advection item,the vorticity maintained on 350~100hPa,which reached-6×10-9s-2nearby 150hPa level.The analysis of apparent heat source(Q1)indicat that,when the heavy precipitation beginning,the dominant factors are local chang and vertical advection terms,Q1forms the positive heating layer from 780to 300hPa;the dominant factor is horizontal advection term,Q1forms the negative cooling layer from 300to 220hPa.The atmospheric thermal forcing is favorable for the ascending movement and the cloud cluster development.The accumlated distribution of apparent heat source(Q2)showed that,as the approach of heavy rainstorm occurrence,large value center is more than 20J·kg-1·s-1 near the upstream region of heavy rainstorm area,the Q2is greater than 10J·kg-1·s-1 in rainstorm area.