融合 ECMWF 格网数据的水汽层析精化方法.

Objectives：GNSS tomography technique is one of the most important methods to obtain the three‐dimensional water vapor information. However, due to lack of enough initial prior information in the process of building the tomography model, the design matrix of tomography model is unstable and the tomographic result is poor, which has become an urgent problem to be resolved.Methods: First of all, the grid data derived from European Center for Medium‐Range Weather Forecasting (ECMWF) is used to calculate the initial value of water vapor density in every voxel of interest area. And then, sophisticating the traditional tomography modeling using the calculated initial water vapor values. Finally, the influence of weightings of different equations in tomography model on tomographic result is also considered.Results: Comparing to the traditional methods, the proposed approach can enhance the accuracy of tomographic result by 41.2%, and its root mean squared error (RMSE) decreases from 1.82 g/m³ to 1.07 g/m³ . Additionally, the mean absolute error (MAE), Bias and standard deviation (STD) also show a better performance than those of the traditional methods.Conclusions: The purpose is to improve the accuracy of tomographic water vapor profiles and used to sophisticate the established tomography model. [ABSTRACT FROM AUTHOR]