Atmospheric water vapor retrieval by means of both a GPS network and a microwave radiometer during an experimental campaign in Cagliari, Italy, in 1999

This paper considers the remote sensing of atmospheric integrated precipitable water vapor (IPWV) using a global positioning system (GPS) network in the Mediterranean area during the whole year 1999. The assessment of IPWV retrieval has been carried out by means of an experimental campaign conducted in the proximity of the city of Cagliari, Italy, located on the Southern coast of the Sardinian Island in the Mediterranean Sea. We have compared GPS estimates with co-located measurements from a microwave dual-channel water vapor radiometer (WVR) collected in nonprecipitating conditions and with observations from radiosondes (RAOBs) released four times a day from the Cagliari-Elmas Airport, approximately 15 km away from the GPS and WVR site. The long-term comparison has shown a fairly good agreement among the two remote sensors and the RAOBs, with a higher correlation between GPS and WVR.