江苏省汛期强降水过程的延伸期预报试验

针对汛期延伸期降水预报问题,根据大气低频振荡特性,运用低频天气图预报方法,通过分析关键区低频天气系统(低频气旋和低频反气旋)的活动特征,建立低频系统与强降水过程间的对应关系,通过低频系统的活动特征来预报降水过程。在2011年7—9月江苏省延伸期强降水过程预报试验中,低频天气图预报方法的预报效果较好,且预报时效为10~30 d,可以在延伸期业务预报中加以应用。此外,还运用模式统计降尺度方法预报降水落区,为强降水过程的发生提供背景依据和参考信息,具有一定的实用意义。

A range-extended forecast expreiment for severe rainstorm process of Jiangsu in flood season

According to the character of atmospheric low-frequency oscillation and using 700 hPa geopotential height data,this paper aimed at forecast of heavy precipitation processes in Jiangsu Province. By using the method of low-frequency weather map,the active characteristics of the low-frequency cyclones and anticyclones were analyzed, and forecast of the precipitation processes was based on its active characteristics. The forecast results were good in Jiangsu Province from July to September 2011 and its forecast validity could be extended to 10-30 d. The method of low-frequency weather map can be apply to precipitation process in medium-range and long-range forecasts. Moreover,the rainfall areas are predicted by downscaling techniques,which could provide reference information for practical forecasting.