Water Vapor Radiometer Data in Very Long Baseline Interferometry Data Analysis

Abstract

We investigate the possibilities to use data from water vapor radiometers (WVR) to calibrate the wet tropospheric delays in geodetic Very Long Baseline Interferometry (VLBI) observations. We test three methods: (1) direct calibration using WVR measurements aquired in the directions of the VLBI observations, (2) estimating zenith wet delays and gradients from the WVR data and use these to correct the VLBI data, and (3) including the WVR measurements as additional observations in the VLBI data analysis. Furthermore, in all cases we model the WVR calibration errors in the data analysis. We test the three methods using data from the continuous VLBI campaigns CONT02–CONT14. We find clear improvements when applying methods 1 and 3 for CONT05 campaign, however, the results are degraded for the other campaigns.