The prevention of rainstorm disaster is very significant to the security of social economy,ecological environment and human life.Based on the PWV obtained from the Hunan ground-based CORS network (72 stations),along with the atmospheric thermodynamic conditions (temperature and pressure),this study analyzes the time series and plane dynamic variation of PWV before and after a rainstorm occurring April 3-4,2015,in northern Hunan province.Some regular patterns of change characteristics of water vapor field are summarized.The results show that higher PWV values,which indicate a high probability of a storm,is a necessary condition for rain.Second,when PWV has reached 48 mm,it will be very likely to rain within an hour after the PWV begins to descend.Third,the intensity and duration of precipitation is determined by the peak value (50 mm) and dropping rate (increment) of PWV.Fourth,the variation range of PWV and the atmospheric thermodynamic conditions will determine the hourly precipitation density to a large degree.Lastly,the plane dynamic variation of PWV can accurately predict the actual falling zone of future precipitation.%基于72个湖南连续运行参考站(CORS)反演得到的可降水量(PWV),针对2015-04-03～04-04湘北地区一次局地暴雨,结合温度和气压等大气热动力条件,分析湖南省PWV时间序列及其平面动态分布变化,并总结此次暴雨过程中水汽场变化规律.研究结果表明,作为降水的必要条件,PWV峰值越大降水概率越高,当PWV突破48 mm并首次降低时,随后1h内会出现降水;当PWV持续增强达到峰值50mm之后再次下降时,PWV增量变化很大程度上决定着雨势的大小及降雨持续时长;气温和气压等热动力条件也对雨势预测有一定的指示作用;PWV分布变化可对实际降水范围(落区)趋势作出较为准确的预测.
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