区域GPS网实时计算可降水量的若干问题

SOME PROBLEMS ABOUT REAL-TIME RETRIEVING PWV FROM LOCAL GPS NETWORK

目前地基GPS气象学测得的可降水量 (PWV )精度好于 2mm ,但在利用区域GPS网实时计算每个测站上空的PWV时 ,要涉及到很多常规GPS资料处理时所忽略的问题 ,如需考虑数据处理软件和计算方式的选择、站坐标的确定和约束、轨道的使用方法、网外辅助站最佳数量的确定、海潮对实时计算PWV的影响以及实时应用于气象服务时的端部效应等问题。利用上海GPS综合应用网获取的 2 0 0 2年 6、7月份长江三角洲地区入梅前后的数据 ,分析了利用区域性的GPS网实时计算高精度的PWV时要解决的各种问题 。

From ground-based GPS, we can obtain PWV (Precipitable Water Vapor) with the accuracy of 2mm. However, when using local GPS network to retrieve absolute PWV over every station in real time, some problems must be considered. Reasonable computation software and method should be chosen. Station coordinates must be well determined and suitable constrain should be given. In order to guarantee the absolute value of PWV, reasonable remote assistant stations with the range more than 500 km should be combined. In this paper, these problems have been studied. And how to use the predicted orbit is also introduced. The effect of ocean tide on real-time retrieving PWV, and the end effect problem of real application in weather forecast are also discussed. In this paper,these problems are analyzed by processing the data from Shanghai Comprehensive GPS Application Network. Preferable data process techniques are provieled, so PWV with high precision can be obtained from local GPS network.