The Validation of WET Zenith Delay of Ground GPS Stations Based on Jason-2 AMR

The wet zenith delay(WZD) can be estimated by ground GPS stations as well as satellite altimeter. The Jason-2 altimeter has been an operational satellite, which provides the sea surface height with several centimeters, and have the high accuracy of measuring the WZD using a Microwave Radiometer (AMR). In this paper, we estimate the wet zenith delay (WZD) of 79 ground GPS stations using Jason-2 AMR from 2013 to 2016. The GPS stations are distributed in seven regions around the world. The distance between these GPS stations and the footprints of Jason-2 AMR was less than 150km. In the processing of GPS data, the GAMIT/GLOBK software with the VMF1 mapping function was used to achieve the GPS WZD. The results showed that the bias of the AMR and the GPS WZD was stable between the distance of 23km to 98km. The overall bias of GPS WZD was $+5.68\pm 21.96\mathrm{mm}$. Land still has a lot of influence to the AMR though new algorithm has reduced the variance within 25 km of coastline. Because of the variability of water vapor, the comparison between the GPS WZD and AMR was greatly high when the distance was more than 100km.

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