The comparison of GPS SWV measurements against WVR in variational weather conditions

The comparison for the GPS SWV measurements against the WVR according to the variation of the weather condition during the period between 19 August and 16 September 2007 has been accomplished. The weather condition is classified into 6 groups, namely, all-weather, rainy, no-rain, cloudy, cloudy-fine and fine abbreviated as ALL, RP, NRP, CC, CF, FW respectively. The variational range of SWV measurements is a few mm to 400 mm. The GPS and WVR SWV measurements have good coherence with a 11.66 mm rms error and a 3.81 mm bias error. Generally, the GPS SWV measurements are wetter than the WVR except that it is in the rainy weather. The bias and rms errors become smaller with the going up of the elevation angle. The variation of the weather condition can lead to the change in the bias and rms errors, but it can not eliminate the systematic bias.