天山山区中部一次局地暴雨成因分析

利用常规气象资料、NCEP 1°×1°再分析资料、FY-2C卫星云图及多普勒雷达资料对2010年6月22~23日发生在新疆天山山区的一次短时大暴雨天气过程进行分析。结果表明：（1）高空急流及南亚高压双体型,中层＂2脊1槽＂,南北锋区同相位叠加,低层的急流及明显的风场辐合,冷锋快速东移,为此次暴雨发生提供了较好的环流背景;（2）双通道为研究区输入了一定的水汽,中高层强水汽辐散使低层大面积水汽向研究区辐合,形成较大的水汽通量,导致整层的空气接近饱和,从而为此次暴雨天气提供了强有利的水汽条件;（3）对流云带发展强盛并在本地区上空长时间停留,强回波区的稳定少动,逆风区的出现,是产生短时大暴雨的关键原因,说明此次天气主要是由中小尺度对流系统引起。

Cause of a Local Rainstorm in Central Tianshan Mountain

Based on the conventional meteorological data,NCEP reanalysis data with 1° × 1° spatial resolution,TBB product of FY-2C,Doppler radar data,the short- term rainstorm weather process which occurred in central Tianshan Mountain was analyzed from 22 to 23 June 2010. The results showed that the jet stream and South Asia High in upper level,the‘two ridge and one trough＇circulation field and the same phase overlay of northern and southern frontal zone in middle level,the jet stream and obvious wind field convergence in low level and the rapid moving easterly of cold front on surface provided better circulation background for the formation and maintenance of this rainstorm. The abundant water vapor transported to the research area through the western and southeastern water vapor channels. And the strong divergence in middle- upper level pushed large area water vapor in lower level to the study area,and that formed great water vapor flux,which led the moist air in whole level to approach saturation. All of the above offered advantageous water vapor conditions for the rainstorm process. In additional,the vigorous developing of convective cloud band,which stopped over the central Tianshan Mountain for long period,and the appearance of adverse wind regions played key roles for the short- time rainstorm formation. It means that the meso- and micro- scales convection system caused the rainstorm process in central Tianshan Mountain.