Surface downwelling solar radiation measurements at the four original GML 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 GML research programs being conducted at these sites. Two of these sites (Barrow and South Pole) also contribute to the BSRN program as described below.
The GRAD group maintains 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. Bermuda and Kwajalein are funded by NASA HQ Radiation Sciences.
The GRAD 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.
The NOAA SOLRAD network monitors surface radiation in the continental United States, in collaboration with NOAA's SURFRAD Network. The SOLRAD stations Oak Ridge (ORT) and Tallahassee (TLH) closed on June 8, 2007 and Oct 30, 2002, respectively.
Spectral UV measurements are made at two networks in the United States and Antarctica. The NOAA/EPA Brewer Spectrophotometer Network in the United States provides daily Ultra-Violet (UV) Radiation and Total-Column Ozone measurements. Many Brewer instruments are co-located at NOAA SURFRAD stations equipped with SURFRAD instrumentation and Total Sky Imagers. 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.
Aerosol measurements began at the GML baseline observatories in the mid-1970's. Baseline measurements provide information about long-term changes in background aerosol properties. These sites are remote from aerosol sources and typically represent clean background air; although, occasionally, they may be impacted by long-range transport.
The NOAA Federated Aerosol Network (FAN) is a long-term cooperative program with shared data access, making atmospheric aerosol measurements that are directly comparable with all the other FAN stations. FAN collaborators contribute scientific interest, instruments, on-site technicians, long-term station costs, and operations support, while NOAA contributes software for data acquisition and processing, as well as technical expertise The cooperative nature of the FAN allows for collection of consistent datasets for evaluating regionally representative aerosol climatologies, trends, and radiative forcing at 30 sites around the world.