GAW stations network and other measurements
A network of measurement stations is the backbone of the GAW programme. This network consists of GAW Global and Regional measurement stations with additional measurements from Contributing stations. Both Global and Regional stations are operated by their host countries, either by their National Meteorological Services or by other national scientific organizations. More than 80 countries actively host GAW stations.
GAW Global stations
In recent years satellite programmes have produced important measurements of atmospheric compounds and related parameters that complement the GAW network measurements. When highly accurate local measurements from GAW ground-based stations are coupled with the near global coverage of satellite measurements it results in a more complete picture of atmospheric composition and processes on global scales, and provides complimentary checks of instrument calibrations. The Committee on Earth Observation (CEOS) has developed a strategy for such co-operation within an integrated system for monitoring of the atmosphere (WMO/GAW Report No.140 ).