Features of Precipitable Water Vapor(P_(wv)) Data/GPS During the Summer Rainstorm Processes in Chongqing

Based on precipitable water vapor(Pwv) data obtained from ground-based GPS network in Chongqing,the evolution characteristics of Pwv during rainstorm weather processes occurred in early summer and midsummer were analyzed.Results show that the value of Pwv was different in rainy day and no rain day,and in early summer,Pwv often increased rapidly in 20-35 hours before rainstorm occurrence with the increasing rate of 0.9-1.6 mm/h.while in midsummer,the value of Pwv increased relatively slow in 10-25 hours before rainstorm occurrence with the increasing rate of 0.4-1.0 mm/h.Rainstorm often occurred when Pwv decreased from its peak to trough in both early summer and midsummer,but occurrence time of rainstorm was often different from each other.