Analysis on the Applicability of a K-value Model Used for Water Vapor Conversion in Western China

Abstract

This paper makes use of the sounding data of 43 sounding stations located in western China from 2016 to 2019 and takes the PWV-ZWD (precipitable water vapor and Zenith wet delay) conversion coefficient K calculated via numerical integration as the reference value to study the applicability of using a K-value model for PWV-ZWD conversion in western China. Six groups of stations with similar latitude and increasing altitude difference were selected to identify how the K-value model varies with elevation. Also, the K-value model was employed to invert the PWV of eight sounding stations in 2019 to verify the usability of the model. As shown by the results, the establishment of the regional model has contributed to the improvement of model accuracy; the K-value model assumes a higher accuracy in flatter terrains; there is a <3mm deviation between the PWV inverted using the K-value model and that provided by the sounding stations, with the deviation being positively correlated with the PWV value inverted using the K-value model.