GPS Water Vapor Estimation Using Interpolated Surface Meteorological Data from Australian Automatic Weather Stations

The existing GPS tracking networks established primarily for surveying, geodesy and navigation purposes may also be used for meteorology studies. This research uses hourly surface temperature and pressure (T & P) observations from Australia for GPS Precipitable Water Vapor (PWV) estimation. The paper outlines the basic meteorological data requirements, and presents experimental results to show the comparison between interpolated and observed T and P values, and agreement between GPS-PWV estimates, using surface meteorological data and radiosonde PWV results. Data analysis of 36 data points in the Victoria region has demonstrated that the Ordinary Kriging method is preferable to pressure interpolation, resulting in an overall standard deviation of 0.40 mbar in pressure or 0.15mm in PWV estimation. We use the interpolated T and P measurements for four Australian IGS GPS sites to estimate GPS-PWV and compare against the radiosonde PWV results for the closely located radiosonde observations. 195 comparisons from all the sites have shown that GPS-PWV estimates agree with the RadPWV solutions at an average mean difference of –0.604 mm and RMS of 1.74mm for the tested stations. This agreement level is considered very reasonable. The experimental study shows a possible way to develop GPS meteorology and applications with the existing meteorological data network. This could save significant costs in installation of GPS-Met sensors.