一次中-β尺度局地大暴雨对流系统的雷达回波特征

CINRAD Radar Echo Features of a Mesoscale-β Local Heavy Rainfall Convective System

利用新一代天气雷达产品对2006年6月18日永定一次中-β尺度大暴雨对流系统的雷达回波特征进行分析,探讨短时大暴雨的回波特征。结果表明:有利的大尺度环流、充足的水汽条件和较强的上升运动是产生强降水有利的天气背景。新一代天气雷达资料分析表明,强降水是由局地发展的对流回波加强合并产生的;中低层冷平流的入侵触发了强对流的产生,对流单体有明显的典型的液态强降水系统特征;逆风区及良好的垂直运动使对流单体发展加强,强降水区域尺度较大,与回波移向一致产生"列车效应",同时系统移动较慢,导致了强降水的持续。

Radar echo feature of a heavy rainfall event is discussed on the basis of analyzing NEXRAD products during the mesoscale-β heavy rainfall convective system event in June 18th, 2006 occurred in Yongding City. Conclusion is drawn as follows： large-scale circulation, ample water vapor and stronger ascending movement are advantageous weather background of severe rainfall. The results show that severe rainfall is led by local convective echoes strengthening and integrating; lower-middle layer cold advection triggers the strong convection. And convective cells show typical features of severe precipitation system. Converse wind region and good vertical movement strengthens the development of convective cells. The server larger-scale rainfall area moves along the same direction as echoes do, which cause so-called ＂train domino effect＂. Furthermore, system moves slowly, which helps severe rainfall continue.