新疆短时强降水天气系统环流配置及雷达回波特征

Circulation Configuration of Synoptic System and Radar EchoCharacteristics of Short-time Heavy Rainfall in Xinjiang

利用2010—2018年新疆105个国家站、1240个区域自动站逐时降水资料及8部多普勒天气雷达资料,从预报业务应用角度提出新疆短时强降水过程定义并遴选468次短时强降水过程,分析短时强降水影响系统环流配置和雷达回波特征。结果表明新疆短时强降水的影响系统主要有中亚低槽(涡)、西西伯利亚低槽(涡)、西北低空急流。造成新疆短时强降水的对流风暴主要有合并加强型、列车效应型和孤立对流单体型,其中合并加强型最多,占45.1%,孤立对流单体型占34.8%,列车效应型最少,占20.2%,且各区域对流风暴的影响比例也有一定差异。南疆短时强降水过程中多普勒雷达最大反射率因子强度(Z max)、强回波中心顶高(D max)、回波顶高(ET)、最大垂直累积液态水含量(VIL)预警阈值小于北疆,且伊犁州最大,阿克苏最小,伊犁州短时强降水以低质心回波为主,其他区域则为低质心和高质心回波。

Based on the hourly precipitation observation data of 105 national stations and 1240 regional stations and 8 Doppler weather radars data in Xinjiang from 2010 to 2018,from the perspective of operational forecasting,the definition of short-term heavy precipitation process in Xinjiang was proposed and 468 short-term heavy precipitation processes were selected,and circulation configuration of influence system and radar observation characteristics were analyzed.The results show that there were four kinds of influence systems including the central Asia trough(vortex),the west Siberian trough(vortex)and low level northwest jet stream.The convective storms resulting in short-term heavy rainfall were combined enhancement type,train effect type and isolated convective cell type,and the combined enhancement type was 45.1%,isolated convective cell type was 34.8%,and the train effect type was 20.2%,respectively.The parameter thresholds of the maximum reflectivity factor intensity(Z max),the maximum height of the strong echo(D max),the maximum height of the echo top(ET)and the maximum vertical accumulated liquid water content(VIL)observed by Doppler radar during short-term heavy precipitation processes in southern Xinjiang were less than those in northern Xinjiang,and in Yili prefecture they were largest and in Aksu they were smallest.The short-term heavy precipitation in Yili prefecture was dominated by low centroid echo,while in other regions it was dominated by low centroid and high centroid echo.