广西百色2013-03-12―14冰雹天气过程分析

Weather Process of the Hailstorm on March, 12-14,2013 in Baise,Guangxi

利用常规气象资料和新一代天气雷达资料,对广西百色市2013-03-12―14的一次典型持续性冰雹天气过程进行分析。结果表明:1)有利于百色市冰雹天气发生的环流特征是:受西南暖低压控制,地面持续升温;百色地区低空存在西南风急流,积聚足够的不稳定能量;中高层有切变线和南支槽扰动,促发不稳定能量的释放。2)百色市冰雹天气发生的物理量场特征是:沙氏指数(SI)<-2℃;对流有效位能(CAPE)>500 J/Kg;中高层存在位势不稳定的现象,且Δθse850-500>10℃;有"上干下湿"的水汽条件;环境垂直速度达到(-30^-10)×10-3 h Pa/s;0~6 km的垂直风切变>20 m/s,是有利于冰雹天气发生的环境条件。3)有利于冰雹天气发生的雷达回波特征是:在PPI上有超过60d Bz的强回波中心,在强中心附近常常有"三体散射"、钩状回波;RHI显示上,回波顶高一般要超过-20℃区,并且出现有界弱回波区和"穹窿"回波。回波单体的一些属性也有助于对冰雹天气的判断,如当冰雹天气来临时,垂直累积液态水含量出现跃增。4)在冰雹天气的预报和识别上,应该在传统的中尺度天气分析基础上,结合新一代天气雷达监测手段,才能较好地提高服务水平。

By using the regular meteorological data and the CINRAD data, an analysis on a classical and persistent hailstorm process was made, which happened in Baise region from 12-14, March, 2013. The result shows that： 1） Circulation that was in favor of the hailstorm occurring in Baise region was as follows： the surface temperature soared as the southwest warm low controlled the region; the southwest jet stream existed at low level over the Baise region, accumulating enough unstable energy. Turbulent of the shear line and the south-branch trough at middle high triggered the releasing of unstable energy. 2） The characteristics of the physical field that lead to happening of hail weather were as follows： the Showalter Index（SI） -2℃; CAPE500 J/Kg; unstable potential existed in middle high, as well as Δθse 850-50010℃; moisture condition was ＂dry at high level and wet at low level＂; vertical velocity in the circumstance reached（-30--10）×10^-3 h Pa/s;wind shear between 0~6 km was bigger than 20 m/s; 3） Characteristics of echo for the hailstorm were： in the PPI display, reflectivity of the core was bigger than 60 d Bz, with the TBSS and hook shape echo nearby the core; in the RHI display, echo top exceeded the level of-20℃, with the occurrence of WER or vault. Some properties of the echo would also help to estimate the hailstorm weather, such as： the VIL soared rapidly when the hailstorm was coming. 4）For the hailstorm prediction and identification, the nowcast technics of CINRAD should be applied, based on the traditional mid-scale synoptic analysis, as to improve the service level.