Remote sensing and characterizations of temporal and spatial variations in the wet refractivity and the wet delay

The authors have investigated the agreement between the zenith wet delay values derived from radiometer data and GPS data and found an root-mean-square (RMS) difference of 9 mm between them. During most of the periods when the radiometer observed distinct wet delay gradients no gradients were found in the Global Positioning System (GPS) data. There were, however, periods where also horizontal gradients were in good agreement