利用ERA-Interim再分析资料优化地基GNSS水汽三维层析

摘要

利用ERA-Interim再分析资料对地基GNSS水汽层析中几个关键技术进行优化.首先利用ERA-Interim提供的大气产品建立同时顾及时间及地表温度参数的区域性大气加权平均温度模型;然后根据ERA-Interim提供的高垂直分辨率的水汽产品,分析“水汽层层顶”随时间变化的规律;最后提出一种新的划分垂直方向层析网格的方法.选取我国香港地区的12个CORS站2014-06的观测数据进行试算,结果表明,与探空资料相比,6 km高度以下优化后的层析结果相比传统层析结果精度提高了12％,在6 km高度以上提高了17％.%In this paper,several key techniques of ground-based GNSS water vapor tomography are optimized using ERA-Interim reanalysis data.First,a regional atmospheric weighted mean temperature model is established using atmospheric products provided by ERA (each-re-analysis)-Interim.We give the humidity conversion factor,which varies with time and surface temperature.Then,based on the high vertical resolution water vapor products provided by ERA-Interim,we analyze the law of the change of water vapor stratification roof with time,and propose a new method to divide the vertical grid.Data from 12 CORS stations in Hong Kong,China in June,2014 are selected for trial.The experimental results show that compared with conventional tomographic results,the precision of the optimized tomography results is 12％ higher in areas under 6 km and 17％ higher in areas greater than 6 km.