Abstract:The atmospheric water vapor conversion factor K is an important parameter in the progress of retrieving precipitable water vapor(PWV) from the zenith wet delay(ZWD) of the GPS. In this paper, four years of atmospheric water vapor conversion factor K values are calculated using radiosonde profiles derived from 19 radiosonde stations distributed in southwest China. The Emardson model is refined using K values from 2011 to 2013; finally, two refined K factor models are developed: the Emardson-I model(elevation independent) and the Emardson-H model(elevation dependent). These two new models are validated using 2014 K values. The results are:(1) Emardson-H model yields more accurate and stable results than Emardson-I model for predicting the K factor; (2) the performance of the Emardson-H model is significantly better than the Emardson-I model in high-altitude areas, indicating that elevation is an important factor for the K value calculation in these areas. In addition, the two new models are used for retrieving GPS-PWV at Lhasa station, with results showing that the Emardson-H model has excellent performance in retrieving GPS-PWV, and both models can achieve GPS-PWV retrieval precision of better than 2 mm.
HUANG Liangke,WU Pituan,WANG Haoyu et al. Refining the GPS Atmospheric Water Vapor Conversion Factor Model over Southwest China[J]. jgg, 2019, 39(3): 256-261.