中文摘要：

2012 年7 月29 日13 时至30 日03 时河西走廊中部遭遇暴雨袭击,利用常规高空和地面资料、区域加密雨量站资料、FY -2 静止卫星云图以及6 h 一次1° × 1°的NCEP 再分析资料,对此次暴雨发生前后的天气环流背景及影响系统、物理量特征和卫星云图以及中尺度系统的发生发展进行了天气学综合诊断分析.结果表明：此次暴雨发生在非常有利的大尺度天气背景下,高、低层均为“东高西低”的流场配置,影响的环流系统是巴尔喀什湖冷槽,暴雨发生时高层辐散、低层辐合,形成了强烈的抽吸作用;对流层内出现强烈的上升运动,中低层流场的配置有利于水汽的输送和汇聚;500 hPa垂直螺旋度的分布与天气系统和强降水有很好的对应关系,700 hPa 柴达木暖性低涡及地面中尺度系统为不稳定能量的储存和暴雨提供了动力条件,从兰州至河西的强暖湿平流的发展为暴雨提供了热力条件;暴雨发生期间有多个中尺度对流云团在该区域上空活动,表明暴雨过程中存在明显的中小尺度系统.

英文摘要：

For the process of the rainstorm occurred in central Hexi Corridor from 13：00 29 to 03：00 30 July 2012,based on the conventional aerological sounding and surface data,intensive regional rainfall data,FY - 2 satellite cloud imagery and NCEP reanalysisdata at 1° ×1° spatial and 6 hours temporal resolution,the weather circulation pattern,the influence system,physical parameters characteristics,satellite cloud imagery and mesoscale system of the rainstorm before and later were analyzed by the synoptic diagnosticmethod. The results showed that the rainstorm occurred in the context of favorable large scale weather conditions. The flow field presented the pattern of “high in the east and low in the west”in high and low layer of the sky,and the Balkhash Lake cold trough broughtout the occurrence of the rainstorm. When the rainstorm happened,an intensive pumping action formed due to the upper layer divergence and lower layer convergence,at the point the strong ascending motion appeared in the troposphere,so the flow field pattern wasfavorable for the transport and gather of moisture. The 500 hPa vertical distribution of helicity was corresponding with the weather system and strong precipitation. The 700 hPa Qaidam warm vortex and the mesoscale weather system on ground provided dynamic conditions for unstable energy storage and the rainstorm,and the development of strong warm advection from Lanzhou to Hexi Corridor offered thermal conditions. Furthermore,the mesoscale and microscale weather systems were obvious during the period of the torrentialrain.