SURFRAD - A national surface radiation budget network for atmospheric research

A surface radiation budget observing network (SURFRAD) has been established for the United States to support satellite retrieval validation, modeling, and climate, hydrology, and weather research. The primary measurements are the downwelling and upwelling components of broadband solar and thermal in frared irradiance. A hallmark of the network is the measurement and computa tion of ancillary parameters important to the transmission of radiation. SU RFRAD commenced operation in 1995. Presently, it, is made up of six station s in diverse climates, including the moist subtropical environment of the U .S. southeast, the cool and dry northern plains, and the hot and arid deser t southwest. Network operation involves a rigorous regimen of frequent cali bration, quality assurance, and data quality control. An efficient supporti ng infrastructure has been created to gather, check, and disseminate the ba sic data expeditiously. Quality controlled daily processed data files from each station are usually available via the Internet within a day of real ti me. Data from SURFRAD have been used to validate measurements from NASA's E arth Observing System series of satellites, satellite-bused retrievals of s urface erythematogenic radiation, the national ultraviolet index, and real- time National Environmental Satellite, Data, and Information Service (NESDI S) products. It has also been used for carbon sequestration studies, to che ck radiative transfer codes in various physical models, for basic research and instruction at universities, climate research, and fur many other appli cations. Two stations now have atmospheric energy flux and soil heat flux i nstrumentation, making them full surface energy balance sites. It is hoped that eventually all SURFRAD stations will have this capability.