GPS Zenith Total Delay Estimation in the Mediterranean Area for Climatological and Meteorological Applications

Abstract A ground network of global positioning system (GPS) receivers is a powerful source of continuous integrated precipitable water vapor (IPWV) data that can be suitable for weather prediction and climate studies. The technical features of two different GPS data analysis strategies, one for climatological and the other for meteorological applications, are thoroughly described together with the achieved accuracy of the related atmospheric products. The Centro di Geodesia Spaziale (CGS) of the Italian Space Agency in Matera, Italy, has been processing, since January 1999, GPS data from a network covering the central Mediterranean area, providing GPS postprocessed zenith total delay (ZTD) with a latency of 15 days, suitable for climate applications only. In June 2001 a near-real-time (NRT) datastream was set up to deliver, on an hourly basis and with 1 h, 45 min latency, GPS ZTD useful for assimilation into numerical weather prediction models. The GPS internal validation of the postprocessed ZTD perform...