The effect of topography on GPS troposphere tomography technique

Tropospheric water vapor is a key parameter in meteorology studies. Because of its irregular spatiotemporal distribution, modeling this parameter is a challenging subject. Global Positioning System (GPS) troposphere tomography is a new and powerful technique to assess the spatiotemporal distribution of water vapor in this layer. The efficiency of this method is dependent on different factors such as accuracy of GPS derived tropospheric slant wet delays, correct reconstruction of the signal paths and topography of the area. In this paper, the effect of considering the topography of the area in troposphere tomography model is analyzed. For this purpose, the tomography is done using GPS tropospheric delays and ray tracing technique based on Eikonal equations in different weather conditions. Finally, the modeled water vapor profiles are validated using radiosonde observations and ERA-I data. Comparison between the obtained results and radiosonde observations shows that considering the topography of the area reduces the Root Mean Square Error (RMSE) from 0.98 gr/m3 to 0.62 gr/m3. This assessment shows the importance of considering the topography in the troposphere tomography model, especially in the mountainous areas.

کلیدواژه ها:

Troposphere ، Tomography ، Topography ، GPS