Abstract:

A Global Positioning System (GPS) experimental station network including nine GPS stations in Fangshan district of Beijing was used for a study on GPS tomography grid. Effects of vertical stratification on the water vapor tomography results were analyzed in terms of methods of a vertically uniform and a non-uniform stratification. The results show that GPS water vapor tomography results obtained by two vertical stratification methods are reliable, and they are consistent with observed water vapor from radiosonde stations. However, tomography grid of vertically non-uniform stratification is more accurate compared with the observed atmospheric water vapor distribution, and the results are more precise compared with that of vertically non-uniform stratification, especially for GPS stations with less altitude differences. Thus, the vertically non-uniform stratification method should be chosen for these stations, although two methods both can provide references for the GPS tomography grid in Beijing.

Key words:  GPS meteorology, Tomography, Atmospheric water vapor, Vertical stratification