广东一次暴雨的数值模拟及诊断研究

Numerical Simulation and Diagnosis of Mesoscale Heavy Rain in Guangdong Province

运用中尺度数值模式MM5对2009年6月17～18日广东一次暴雨天气过程进行了数值模拟,结合天气形势和卫星云图对此次过程进行了分析。结果表明,500hPa南支槽、850hPa切变线是造成此次强降水天气过程的两大系统,他们的有利配置是这次强降水预报的着眼点。高层西风急流在此次暴雨过程中起到了至关重要的作用。200hPa高空急流强辐散"抽吸作用",中低层切变线南压,使得低层暖湿气流沿切变线向上爬升,从而产生强烈的上升运动,为强降水天气的发生发展提供有利的背景条件。850hPa水平螺旋度中心与影响系统的发展、移动有很好的对应关系,水平螺旋度的分布与强降水落区有一定的联系。

A heavy rainfall event in Guangdong Province on 17-18 June 2009 was simulated bythe mesoscale numerical model MM5 and was analyzed with the synoptic charts and satellite imagine.The results indicated that WEBTISR at 500 hPa and Shear line at 850 hPa was the focus of forecast.Upper-tropospheric westerly jet played an important role in this heavy rainfall.Strong divergence by westerly Jet at 200 hPa provided favorable conditions for the development of the heavy rainfall.The analysis of helicity also revealed that horizontal helicity at 850 hPa keep in touch with heavy rain region.