鲁亚斌 李华宏 闵颖 王志云

摘要 利用常规观测资料与卫星、雷达等非常规观测资料，综合分析了2017年7月20日昆明主城区大暴雨过程的天气成因及中尺度对流系统特征。结果表明，500 hPa两高辐合区是此次暴雨过程的天气尺度影响系统；高能高湿的对流不稳定层结、适宜的垂直风切变是强对流天气形成的有利条件；在Q矢量散度辐合区内β中尺度对流系统（MCS）发生发展，短时强降水主要出现在MCS移动方前沿对流活跃的TBB等值线密集区，雨强变化与TBB等值线梯度变化密切相关；多普勒雷达显示，逆风区是强对流暴雨产生的直接影响系统，回波强度在35～45 dBz，最强达49 dBz，回波顶高超过10 km的区域对应着强烈雷暴，逆风区与短时强降水、雷暴天气有很好的对应关系。

关键词 强对流暴雨；天气成因；中尺度分析；昆明

中图分类号 S161.6文献标识码 A文章编号 0517-6611（2018）15-0145-06

Abstract Using conventional observation data and unconventional observational data such as satellites and radars， the weather causes of the heavy rainstorm process in the main city of Kunming on July 20， 2017 were analyzed and the features of the mesoscale convective system were comprehensively analyzed.The results showed that the 500 hPa two high convergence area was the weather scale effect system during the heavy rainstorm process；Convective instability stratification with high energy and high humidity， and suitable vertical wind shear were favorable conditions for the formation of strong convective weather.The mesoscale convective system （MCS） developed in the region of vector divergence convergence. The short-term heavy precipitation mainly occured in the convective active TBB isoline dense area at the front of the MCS mobile， and the change of rainfall intensity was closely related to the gradient change of TBB isoline.Doppler radar showed that the upwind region was a direct impact system for strong convective rainstorms；the echo intensity was 35 - 45 dBz， and the strongest was 49 dBz；the area where the echo top height exceeds 10 km corresponded to a strong thunderstorm. There was a good correspondence between short-term heavy precipitation and thunderstorm weather.

Key words Strong convective rainstorm；Weather origin；Mesoscale analysis；Kunming

強对流天气伴随雷暴、对流性大风、短时强降水、冰雹、龙卷等剧烈天气现象，其中短时强降水引发的暴雨是造成洪涝和滑坡、泥石流等地质灾害的重要气象诱因，强对流天气的预报预警一直以来都是天气预报业务的重点和难点。引发强对流的影响天气系统较为复杂，许美玲等[1]和张腾飞等[2]指出地面冷锋与700 hPa切变线共同作用是云南暴雨过程和强对流天气的重要类型，以往的研究揭示了冷锋切变的大尺度环流及水汽输送和中尺度特征[3-8]。据统计，造成云南短时强降水的天气类型中，冷锋切变型占绝大多数，其次是500 hPa两高辐合型，然而对两高辐合型暴雨中强对流和短时强降水的中尺度特征研究较少。……