The Smithsonian Institution is a participant in the US Interagency Ultraviolet Radiation Monitoring Network, whose overall goals are to define short- and long-term variation in spectral UV-B; study the variation of UV-B over latitudinal gradients; and study the effects of clouds and other factors, such as aerosols, on UV-B. The program also supports the Smithsonian Environmental Research Center's (SERC's) program of UV-B effects research, which is performed by its Photobiology & Solar Research Laboratory.

The SERC program uses a narrow-band, multifilter instrument, the SR-18 which continuously monitors incident solar UV-B and short-wavelength UV-A (290-324 nm). We have recently developed an extended range instrument the SR-19 which monitors out to 330 nm. The instruments are designed, constructed and calibrated at SERC to maintain quality control as needed to ensure consistent long-term data.

The SR-18 and SR-19 are the most recent products of a long-running program of solar instrument development at the Smithsonian. A previous UV-B instrument was the SR-8. Instruments of this design were in operation in Maryland (first at Rockville then Edgewater) since 1975 (Correll et al. 1992), and at Mauna Loa, Hawaii since 1984 (Neale et al., 1994a; Hofmann et al., 1995). SERC maintains a data base of 12-minute averages through the day for Maryland for the period since 1975. This is currently being distributed upon request on computer media (e.g. CD) with a nominal charge for duplication. An electronic distribution system is currently under development in collaboration with the National Institutes of Standards and Technology (NIST).