2011年8月宁夏连日强对流天气监测预警技术分析

Technologies for Monitoring and Early Warning of Severe Convection Weather in Ningxia in August 2011

2011年8月21—25日宁夏发生了连日分散性强对流天气,综合多种探测资料,对其进行监测预警技术和可预报性分析,初步提炼出冰雹、短时强降水分级监测预警指标。强对流天气发生在稳定的西高东低环流背景下,属于典型的高层干冷、中低层暖湿的前倾槽配置;0℃层高度平稳,-20℃层高度的显著降低与冰雹发生有较好的对应关系,0℃层与-20℃层高度差减小至1 500 m以下时,降雹概率较大;进行回波强度比较时必须选取与雷达站距离相当的点,回波强度相同时,持续时间越长,降水量越大;回波强度与持续时间一定时,垂直液态水含量越大,可降水率越大,降水越强;对冰雹尺寸反映较敏感的是垂直液态水含量。中气旋可作为冰雹形成的一个监测指标。阵风锋雷达回波是产生雷雨大风天气的标志。

A continuous scattered severe convection weather occurred in Ningxia Hui Autonomous Region, China during 21 -25 August,2011. In this paper, the technologies for monitoring and early warning of severe convection weather were analyzed, and the indicators of grading early-warning were explored by analyzing the sounding data during the convectional process. The results indicated that, under the circulation high in the west but low in the east, a convectional process with a typical forward tilting trough configuration that it was dry and cold at high alti- tude but warm and moist at middle and low level occurred. There was a close relationship between a hail process and a stable 0 ~C -layer altitude and a significant decrease of - 20℃ -layer altitude, and the occurring probability of hail was high when the altitude difference between 0℃-layer altitude and -20 ℃ layer altitude was below 1 500 m. The spots selected to compare the radar echo intensity must be equidistant. The longer the duration is, the higher the precipitation will be. The more the vertical liquid water socyclone can be regarded as a monitoring indicator of hail wind. content is, the higher the precipitation rate will be. Meformation. The gust front is the signal of thunderstorm