中文摘要：

利用常规观测资料、雷达回波资料、TBB卫星资料,WRF模式模拟输出的高时空分辨率结果对发生在2012年7月29-30日（＂7·29＂）宁夏北部地区的一次大暴雨过程的维持和演变进行详细分析。主要结论如下：（1）此次大暴雨过程与200 h Pa高空急流、500 h Pa短波槽及700 h Pa切变线发展和变化密切相关。（2）模式结果显示700 h Pa低涡及暖式切变线、低空急流形成是大暴雨形成的主要原因之一;低空急流从29日22：00形成,维持近7 h。（3）分析发现高层辐散明显早于低层的空气辐合,在低层空气辐合中心出现之后高空辐散继续加强,高空强辐散和低空强辐合导致明显的上升及700 h Pa低空急流形成和发展。（4）诊断分析显示ΔNBE的范围与1 h后强降水的落区有很好的对应关系,对流性降水阶段ΔNBE较大,不平衡特征明显,而在稳定性降水阶段大气质量场和流场之间的不平衡特征相对较小。（5）对此次暴雨的水汽输送分析表明水汽主要由偏南风低空急流输送,净水汽输送强度的变化与对流性降水阶段和稳定性降水阶段较为吻合。

英文摘要：

Based on the routine observation data,Yinchuan doppler radar data,FY-2E satellite TBB data and the output of high resolution in temporal and spatial from WRF model,the paper analyzed and discussed a rainstorm process,which happened from 29 to 30 July 2012（ ＂7·29 rainstorm process＂for short）. The main results are as follows：（ 1） The development of rainstorm is closely related to upper-level jet at 200 h Pa,short-wave trough at 500 h Pa,the shear line at 700 h Pa.（ 2） Eastward lowvortex,warm-type shear line and lowlevel jet（ LLJ） are the main reasons of rainstorm. The lowlevel jet（ LLJ） came into being at 20： 00 on 29 July,which maintained for about 7 hours.（ 3） Strong divergence at the right side of upper-level jet exit region,which occurred before the convergence in lowlevel and maintained,is crucial for the formation and maintenance of obviously upward motion and lowlevel jet.（ 4） The region of ΔNBE has a corresponding relationship with the rainfall region,which is large in convective precipitation stage,and quite small in stable precipitation stage because of the diferrent quasigeostrophic balance in two periods.（ 5） The water vapor transfer is mainly from the south wind of lowlevel jet,which is corresponded to the formation and development of the LLJ. The variation of net water vapor transport is consistent with the feature of convective precipitation and stable precipitation.