广西柳州2016年4月一次致灾冰雹天气过程分析

The Analysis of a Hail Weather on April 9th 2016 in Liuzhou,Guangxi

利用Micaps资料、地面加密自动观测资料、NCEP/NCAR的1°×1°每6h再分析资料以及新一代雷达资料,对2016年4月9日发生在柳州的一次强对流天气过程进行了分析。结果表明:(1)在高空冷涡槽后干冷平流及地面西南暖低压的影响下,中高层干冷,低层暖湿的不稳定层结为此次冰雹天气提供了有利的热力及动力条件,低层适当的水汽条件、高CAPE值以及较强的环境风垂直切变有利于强冰雹天气的发生;(2)地面中尺度辐合线及低层锋区的南压是这次强对流天气的触发因子;(3)适宜0℃层和﹣20℃层高度有利于强风暴云发展,为雹粒的形成、增长和降落提供了有利条件;(4)雷达回波分析表明,回波云中存在≥60d Bz的回波单体,回波区出现典型的冰雹回波特征,是判别有无冰雹天气的重要指标。

Based on the Micaps data, surface intensive observations data, and NCEP/NCAR 1.0×1.0 degree reanalysis （every 6 hours） data, and new generation radar data, severe convection weather on April 9th 2016 in Liuzhou of Guangxi was analyzed. The result shows： 1） Influenced by the dry and cold advection behind high- altitude cold vortex trough and southwest warm-core cyclone in the ground surface, the unstable stratification of dry and cold condition in upper-atmosphere and wet and warm condition in low atmosphere served as the advantageous thermal and dynamic conditions for the formation of this hail weather, and the adequate vapor condition, high CPAE value, and strong vertical shear of environmental wind in low level also catalyzed the forming of the strong hail weather. 2） The triggering mechanism of this severe convection weather is convergence line and low level frontal zone. 3） The the southward of the ground surface mid-level adequate altitude of 0℃ and -20℃ is advantageous for the development of the strong storm clouds, and it also created a favorable condition for the formation, growth, and falling of the hailstone. 4） According to the radar echo, the echo monomer （≥ 60dBZ） in the echo clouds and the typical hail echo feature appeared in the echo zone are the essential index for the judgement of hail weather.