NCAR Global, 2-hourly Ground-Based GPS Precipitable Water

NCAR global, 2-hourly GPS precipitable water data are derived from ground-based GPS measurements of zenith path delay (ZPD) using three different resources, including the International GNSS (Global Navigation Satellite Systems) Service (IGS) tropospheric products (since year 1995), U.S. SuomiNet (UCAR/COSMIC) products (since year 2002) and Japanese GEONET (GPS Earth Observation Network) data (~1100 stations, 1997-2005).The data are divided into two groups: one is from GEONET network, and the data are available from 1997 to 2005; the other one combines IGS and SuomiNet network, and the data are available since year 1995 and planned to be updated yearly.