午夜欧美大片免费观看,欧美激情综合五月色丁香,亚洲日本在线视频观看,午夜精品福利在线

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.