暴雨预报中潜热能场的应用

Application of Potential Energy Field to Heavy Rainfall Forecast

利用能量天气学原理,统计了3种天气类型的暴雨过程中潜热能场的水平分布特征。对1999年8月11日出现在山东省的大范围暴雨天气过程(99.8),分别就潜热能场水平分布特征、潜热能场垂直分布特征、能量锋生特征进行了分析。结果表明,潜热能场对暴雨预报有较好的指示作用,仅仅是能量高值区并不一定能产生大降水,当较强的能量锋区(或冷空气)与高能轴交汇、能量锋生函数负值区域移入当地,低层辐合条件较好时,预示强降水将要发生。"99.8"大暴雨主要发生在能量锋区与高能轴线交汇的地方,进而沿高能轴右侧向锋区密度较大地区移动,高能轴顶端的右前方、冷槽的后部也是强降水易发生的地区。

The horizontal distributing characteristics of potential energy in three types of heavy rainfall are studied on the basis of energy synoptic principles. The heavy rain process on 11 August 1999 in Shandong Province is analyzed in aspects of horizontal and vertical potential energy and energy frontogenesis characteristics. The result shows that potential energy plays a good indicative role in heavy rain forecasting. The appearance of only high energy value does not mean heavy rainfall; but when the more powerful energy frontal zone and negative energy frontogenetical function zone move to the area and the convergence condition in the lower layer is favorable at the same time, severe precipitation is likely to occur. The heavy rain of August 1999 occurred at the front of the energy frontal zone, and the vertical distribution of potential energy can indicate the movement of cold air.