鄂尔多斯市一次副热带高压边缘暴雨天气过程分析

Analysis of a Heavy Rainfall on Edge of Subtropical High Pressure in Ordos

2016年8月14日20时至15日02时,内蒙古鄂尔多斯市南部出现了一次大暴雨过程,最大小时雨量达到84.4mm。文章利用常规气象观测资料、NCEP再分析资料、FY-2E卫星TBB资料以及雷达资料对本次过程进行分析。结果表明:(1)西太平洋副热带高压西北边缘的暖湿气流与低层切变线的共同作用导致了本次强降水;(2)水汽的输送与辐合、低层增温、增湿等为本次过程提供了有利的动力、水汽条件;(3)鄂尔多斯市南部上空被<-70℃的对流云系覆盖,雷达反射率因子达到55dBz以上,速度图中观测到有明显的风场辐合,是本次过程的中尺度特征。

On August 14th,2016,there was a heavy rainstorm in the southern of Ordos,Inner Mongolia.The maximum of hourly rainfall reached 84.4mm.The process was analyzed by using the conventional meteorological observational data,NCEP reanalysis data,TBB data of FY-2Eand radar data.The major results were as following:(1) The combination of warm and humid airflow on the northwestern edge of the Western Pacific subtropical high pressure and the shear line of lower layer led to this strong precipitation.(2)Profitable dynamic and vapor conditions were provided to this process by transport and convergence of water vapor,,warming and humidification in lower layers,etc.(3)The mesoscale characteristics of this process were as follows.The south of Ordos was covered by convective clouds that the temperature was lower than-70℃.The radar reflectivity factor was exceed 55dBz.We could observe obvious convergence of wind field in the velocity map.