春季强降水过程的多普勒天气雷达图像特征剖析

对2004年4月25日出现在华北的一次大范围较强降雨过程进行了分析,介绍了多普勒天气雷达径向速度PPI图像和垂直风廓线(VWP)产品的应用技术,根据这两种产品可以判断冷、暖平流,以及各个高度层风的辐合、辐散,综合这些特征进一步判断气流上升或下沉,从而可以推断降水的生消。通过对此次降水个例的分析,探讨了春季强降雨过程的雷达图像特征,发现在降水发生、发展和消亡的不同时段垂直风廓线产品和径向速度图像都有非常明显地体现,为今后预报春季大面积降水提供一定的参考和依据。

Analysis of Characteristics of Doppler Weather Radar Images during a Precipitation Process in Spring

A large-scale heavy rainfall process occurred in North China on 25 April 2004 is analyzed,and the methods of using Doppler weather radar radial velocity PPI and vertical velocity profile(VWP) are introduced.Based on the two radar products,the situation of cold and thermal advection,convergence and divergence at different altitudes can be identified comprehensively and then either ascending or descending air can be identified,so to deduce the occurrence of rainfall.Meanwhile,according to the analyses of this rainfall case,some Doppler weather radar image characteristics during heavy rainfall in spring are discussed.It is found out that there are obvious characteristics in the two radar products at the different stages of rainfall development(formation,development,and dissipation),which provides some reference for rainfall forecasting in spring.