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 precipita ble water vapor (IPWV) using a global positioning system (GPS) network in t he Mediterranean area during the whole year 1999. The assessment of IPWV re trieval has been carried out by means of an experimental campaign conducted in the proximity of the city of Cagliari, Italy, located on the Southern c oast 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 o bservations from radiosondes (RAOBs) released four times a day from the Cag liari-Elmas Airport, approximately 15 km away from the GPS and WVR site. Th e long-term comparison has shown a fairly good agreement among the two remo te sensors and the RAOBs, with a higher correlation between GPS and WVR.