2006年7月阳泉市两次致灾冰雹天气过程分析

Analysis of Twice Weather Processes of Disaster-causing Hail in Yangquan City in July of 2006

2006年7月山西省阳泉市出现两次致灾冰雹天气过程。分析了天气预报业务中常用的实际观测资料、卫星云图资料、太原多普勒雷达资料,尝试对同类天气的短时和临近预报进行总结,得出预报指标和可用的概念。经分析发现:夏季午后致灾冰雹发生时,当日08时是典型的降雹环流形势,500 hPa有低于-12℃的冷中心,存在高层干冷,低层暖湿的大气层结,有正的对流有效位能,本地地面总能量达到高能(≥60℃)。当对流云发展时,卫星云图上云顶亮温低于-40℃,多普勒雷达探测到回波强度在45 dBz以上,强回波(≥45dBz)高度在8 km以上,强回波面积≥15 km×15 km,对流回波发展为典型的冰雹云特征,垂直液态含水量(VIL)≥40 kg/m2,强回波对应径向速度场的逆风区(风辐合)或模糊区(风突变引起)。

The weather processes of disaster-causing hail occurred twice in Yangquan City of Shanxi Province in July of 2006.The routine data,satellite nephogram and Doppler radar data usually used in weather forecasting operation were analyzed to try to summarize the short-term forecasting and nowcasting of this kind of weather.And the forecasting indices and usable concepts were obtained.The analysis results showed that it was a typical circulation situation of hail at 8 o＇clock when disaster-causing hail occurred in summer afternoon.There was a cold centre of lower than-12 ℃ at 500 hPa.It was dry and cold at high level and warm and humid at lower level in atmosphere.The convective available potential energy was positive and the total energy of local ground reached to be higher（≥ 60 ℃）.In the developmental process of convective clouds,black body temperature on satellite nephogram was lower than-40 ℃.Doppler radar echo intensity was more than 45 dBz,the height of strong echo（≥45 dBz） was over 8 km.The area of strong echo was more than 15 km × 15 km.The convective echo turned to show the typical features of hail cloud.The vertical liquid water content（VIL） was more than 40 kg/m^2.Strong echo regions corresponded to adverse wind regions（wind convergence） or vague regions（wind abrupt） of radial velocity field.