2008年桂林冰冻雨雪灾害天气多普勒雷达资料分析

Analysis on Icy Rain and Snow Freezing Disaster Weather Event with Doppler Weather Radar Data in Guilin

利用多普勒雷达，对2008年1～2月的低温冻害和雨雪天气进行分析：桂林处于雨雪区域边缘，冻害天气有自己本地特点。（1）反射率上呈现出零度层亮度带，表明对于处于南方的桂林来说，冷空气势力很强；（2）径向速度图上有环型零速度圈、速度模糊区、牛眼。表明大气低层有急流，高层有大风区。高层的“S”型零速度线表明有强暖平流有利于产生逆温；（3）VWP风廓线图上，有风向的突变，突变区的位置对降水的形态有一定指示意义，较低的突变层对冻雨有利。高层的西南风过于强大，低层的东北风无法向上突破，这也是这次过程逆温迟迟没有遭到破坏，造成桂林以冻雨为主的灾害的另一原因。

Bases on the Doppter radar data during early year of 2008 in Guilin, the characteristics of the chilling icy rain and snow freezing disaster weather event are analyze there are many local characteristics of the freezing disaster because Guilin city d. Results show that locates at the edge of the icy rain and snow area. （1） PPI showed a large range symmetrical flaky reflectivity with flat top. And 0℃ bright belt occurred in higher beams, which indicate there was strong cold air over Guilin. （2） On VPPI, ＂O＂ line crossed through the radar station and showed a structure like ＂ S＂ . The wind veered with height from NE to W, until SW with warm advection in lower layer, which is benefit to shape the inversion layer. （3） The wind direction were discontinuous in the vertical direction. The start and end time of precipitation was closely related to the wind direction and the low catastrophic layer is favorite to the icy rain. Besides it is another reason for the icy rain disaster that the SW wind at upper was too strong to let the NE wind at lower move up and the inversion layer lasted for a long time .