Surface downwelling solar radiation measurements at the four original GMD baseline observatories began when each of the observatories was founded. Subsequently, additional measurement of thermal longwave, upwelling irradiances, and aerosol optical depth were added at these sites. The Trinidad Head site was established later. The intent of these measurements was to maintain long-term records of surface radiation budget components at globally remote sites and to support the other GMD research programs being conducted at these sites. Two of these sites (Barrow and South Pole) also contribute to the BSRN program as described below and all are part of the GAW project as described below also.

The G-Rad group maintains three additional sites that are contributers to the World Climate Research Programs (WCRP) Baseline Surface Radiation Network (BSRN). The BSRN sites, including Barrow and South Pole were selected for the site's spatial representativeness and suitability for the applications in climate research involving global climate models and/or satellite-derived related data sets. Alert, Eureka and Tiksi are part of the SEARCH program. Bermuda and Kwajalein are funded by NASA HQ Radiation Sciences.

Baseline Surface Radiation Network

The G-Rad group maintains seven radiation budget stations in the continental U.S. comprising the Surface Radiation (SURFRAD) Network. SURFRAD is a component of the World Climate Research Programs (WCRP) Baseline Surface Radiation Network (BSRN). The SURFRAD sites were selected for their spatial representativeness and suitability for the applications in climate research involving global climate models and/or satellite-derived related data sets.

Surface Radiation Network (SURFRAD)

The Global Atmospheric Watch (GAW) program of the World Meteorological Organization (WMO) has chosen all of the GMD baseline sites as participants. In addition, the G-Rad group assisted in the establishment of downwelling solar irradiance measurement programs at five of the GAW Global Baseline Observatory sites sponsored by Global Environment Fund of the World Bank. The G-Rad program continues to provide assistance to these sites, with the data being processed by the sites and submitted to the World Radiation Data Center (WRDC).

Global Atmosphere Watch

The NOAA/EPA Brewer Spectrophotometer Network consists of six stations located in the western, central and eastern United States. Brewer instruments provide daily Ultra-Violet (UV) Radiation and Total-Column Ozone measurements. Many Brewers are co-located at NOAA SURFRAD stations equipped with Total Surface Radiation Budget instrumentation, and Total Sky Imagers.

NOAA-EPA Brewer Spectrophotometer UV and Ozone Network

The Antarctic UV network provides data to researchers studying the effects of ozone depletion on terrestrial and marine biological systems, ozone hole monitoring, validation of satellite observations, and verification of atmospheric radiation transfer models.

NOAA Antarctic UV Monitoring Network

NOAA Integrated Surface Irradiance Study (ISIS) monitoring surface radiation in the continental United States, in collaboration with NOAA's SURFRAD Network. The ISIS stations Oak Ridge (ORT) and Tallahassee (TLH) closed on June 8, 2007 and Oct 30, 2002, respectively.

Integrated Surface Irradiance Study network