Modelling and Validation of the Precipitable Water Vapour from Zenith Wet Delay using Radiosonde and GNSS Data in the Central Arabian Peninsula

Abstract

In this study, radiosonde observations for the period 1985 to 2016 from four sites in Saudi Arabia (Riyadh, Abha, Hail, and Dammam) were used to calculate the Zenith Wet Delay (ZWD) and Precipitable Water Vapour (PWV). Using the Asken & Nordius [1] approach (PWV =1/k ZWD), correlation analyses between these two variables (in mm) were carried out using data from1986-2012 for each site individually and for the combined data from all sites. The values of the conversion constant between the two variables were determined and found to lie between 0.171 and 0.178. The site-specific model and the regional developed model were used to predict the PWV values for the period between 2013 and 2016 and for the entire study period (1986 to 2016). The predictability of these models against the three datasets was excellent. The mean bias error (MBE) and root mean square error (RMSE) for the three datasets were, respectively, between 0.02mm and 0.53mm and between 1.51mm and 3.71mm.