强降雪天气中GPS可降水量与地面空气湿度的综合分析

Comprehensive Analyses on GPS Precipitable Water Vapor and Surface Humidity Parameters during Severe Snowfall Weather

利用2008-2010年河北省石家庄市地基GPS反演的可降水量资料和常规天气资料,对可降水量在强降雪天气过程中的演变趋势进行了分析。结果表明,回流降雪过程出现前24h,可降水量存在一个极大值,而且这个值越大,对应的过程降水量就越大;在降雪开始前,可降水量经过长时间的酝酿,持续高于月均值;降雪过程结束后,可降水量缓慢下降,这与高空槽降水结束后可降水量呈现迅速下降的趋势不同。与地面温度露点差和水汽压不同的是,GPS可降水量反映的是垂直气柱中的大气水汽总量,因而对降雪过程有较好的指示意义。

Based on the precipitation water vapor retrieved from ground-based GPS and meteorological data in Shijiazhuang city from 2008 to 2010,the evolution trends of precipitable water vapor during severe snowfall processes are studied.The results show that the precipitable water vapor exist a maximum value in 24 h before the return-flow snowfall weather occurring,this value is bigger,and corresponding precipitation is bigger too.Before the snowfall beginning,the precipitable water vapor goes through a long brewing period,and its value is consistent higher than the monthly average.After the snowfall,the precipitable water vapor decreases decline slowly;on the contrary,the trend of precipitable water vapor appearing rapid decrease is different after the precipitation from the upper trough has stopped.The precipitable water vapor from GPS is different with the depression of dew point and vapor pressure.For reflecting all the water vapor in the vertical atmosphere column,the precipitable water vapor from GPS has a good indication to snowstorm process.