基于GPS-PWV的不同云系降水个例的综合分析

利用成都地基GPS观测网的观测数据,结合自动气象站资料计算出GPS遥感的大气可降水量(GPS-PWV)。按照降水性质,选取对流云降水和层状云降水个例,分析不同类型降水过程中GPS-PWV的变化特征。结果表明,对流云降水和层状云降水一般均发生在GPS-PWV的高值阶段。

Case Study of the Rainfall Processes in Different Cloud Systems Based on GPS-PWV Data in Chengdu Plain

The precipitable water vapor(PWV) are estimated from GPS data of a ground-based GPS network in Chengdu plain with help of the corresponding meteorological data from automatic weather stations.The variations of the derived GPS-PWV are analyzed for the process of convection and stratiform rainfalls.It shows that both in the convection and stratiform rainfall processes,precipitations always happened during the time where water vapor is rather high.In the process of convection rainfall,the local convergence of water vapor is the source of the growth of GPS-PWV.The GPS-PWV increased before the occurrence of precipitation,and condensed after heavy rains,for the value of GPS-PWV is lower than before.If the water vapor accumulated to a high-value afterwards,it usually indicates a new precipitation.During the whole process,fluctuation in GPS-PWV is significantly and frequently,and the intensity of rainfalls is highly correlated with the GPS-PWV.In the process of stratiform rainfalls,the growth of GPS-PWV comes from large-scale water vapor transport.The variation of GPS-PWV is slow comparatively.GPS-PWV remained at high level during participation and until a certain time afterwards,and then reduced gradually.Precipitation is systematic;there is no obvious relation between the intensity of rainfalls and the GPS-PWV.This contribution can optimize the use of the PWV derived from ground-based GPS networks for weather forecasts of different precipitation processes.