成都双流机场一次多雷暴天气的雷达回波分析

Echo Analysis of An Multiple Thunderstorms Process in Chengdu Shuangliu Airport

成都双流机场在 2 0 0 0年 7～ 8月有 35天内出现 2 3次雷暴 ,经过天气形势的分析 ,发现该次多雷暴天气中局地性热雷暴和系统性雷暴各占一半左右。通过对这两类雷暴的雷达回波的特征进行比较分析 ,得出热雷暴和系统性雷暴在回波参数、时空分布、初生源地、移动路径以及演变过程都存在明显的差异。系统性雷暴在雷达回波上表现为形成与移动是有组织的、有系统的多单体的集合 ,各个单体的生消过程构成了雷暴的生命史 ,因而系统性雷暴的生命时间大大超过了对流单体的生命时间。在消散单体的下沉冷空气外流和前方低空暖湿气流汇合作用下 ,新单体得以生成与发展 ,雷暴的发展与维持主要是通过这种机制。

Twenty three thunderstorms occurred for twenty successive days from July to August,2000.The weather situations are analyzed.Results show that they comprise 11 local heat thunderstorms and 12 systemic thunderstorms.The characteristic of the two kinds of thunderstorms echo have been analyzed and compared.It shows that there are obvious difference in their echo parameters、spatial and temporal distribution、original source、movement and evolution.The systemic thunderstorm are complex of organizational and systemic multiple cell.The life span of the thunderstorm consist of life span of every cell,so lifetime of them greatly longer than that of anyone convection cell.New cell is created and developed over confluence of cold downdraught and front warm current.The thunderstorms have been developed and maintained by means of this mechanism.