安徽夏季中γ尺度对流云的雷达回波特征

Summer Meso-γ Scale Convective Cloud's Radar Echo Characteristics in Anhui

探讨夏季不同类型降水系统中对流性降水云的结构、降水形成机制,旨在为人工影响天气提供技术途径。利用合肥新一代天气雷达(CINRAD)监测到的13933个中γ尺度对流云体,按5种天气类型对其生命史、基本反射率、回波顶高、回波厚度、垂直累积液态水含量进行了统计分析。结果表明:在5种天气系统中,对流云生命史在1小时之内的占统计总数的90%～95%;对流单体云的厚度一般都有2～5km,最大厚度也有超过10km的。副高外围及副高控制时,对流云单体的云顶高度70%以上都超过了0℃层;在华北低槽、沿海低槽、南支槽影响时,云顶高度大部分出现在0℃层以下或0℃层附近。这为指挥人工增雨作业提供了很好的指标。

For the sake of providing technical methods for precipitation modification, the structure and precipitation formation mechanism of precipitating convection clouds of different types in summer are investigated. Based on 13933 meso-γ scale convection clouds observed by New Generation Weather Radar （CINRAD） in Hefei, the life time, primary reflection rate, echo top height, echo thickness and vertical integrated liquid water are statistically analyzed according to 5 kinds of synoptic systems. The results about the 5 kinds of synoptic systems declared that the life time of convection clouds less than 1 hour accounted for a major percentage of 90 % - 95 % of the total sample, and the thickness of convective cell clouds are often 2- 5km with maximum over 10km. Under controlling of subtropical high and its outer circle, the height of cloud top of 75 % convective cells exceeded 0℃ layer. But under the influence of low troughs and southern branch trough, the height of most cloud top is below or near 0℃ layer. Top heights of convection cloud cells are mainly near or below 0℃ level when they are affected by the low trough of North China, the low trough along coast and the south branch trough. These results are helpful for the operation of artificial enhancement of rain.