地基GPS反演大气可降水量在暴雨中的演变特征

The Evolution Characteristics of PWV in a Rainstorm Process Based on GPS

根据四川GPS观测网的数据资料,利用GAMIT软件解算和反演大气可降水量,并与地面经验公式计算结果对比,发现由经验公式求解得到的大气可降水量与GAMIT求解的大气可降水量存在显著差异。通过对四川省都江堰地区2013年的一次强降雨过程中,附近4个GPS站点的求解可降水量与实际降水量对比发现:4个GPS站点记录数据均呈现出大气可降水量在暴雨发生前有缓慢上升趋势,随后达到峰值;在暴雨发生时出现轻微下降趋势;暴雨结束后迅速达到低谷。可见,GPS反演出的大气可降水量在暴雨天气过程中与实际降水量有一定的对应关系,对暴雨的临近预报具有较好的指示意义。

We use the Sichuan GPS observation network data and the GAMIT software to calculate and inverse the atmospheric perceptible water vapor（PWV）, and compare the calculation result with that of the calculation of the from the ground experience formula. Our result shows that there is significant difference between PWV and GAMIT which are obtained by empirical formula. Through the data of a strong rainfall in Dujiangyan in 2013, there are differences between the precipitation quantity calculated from 4 GPS sites in its vicinity and the actual precipitation. Comparison shows that PWV increase slowly before the rainstorm, after the peak appears in a storm, a slight downward trend appears. When the storm ends, the peak value quickly reaches. It can be seen that there is a certain relationship between the precipitation evolution from the date of GPS and the actual precipitation in the rainstorm. The differences have a good indication for the impending forecast.