Abstract: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.