Comparisons of UV synthetic spectra retrieved from the USDA UV multi-filter rotating shadow-band radiometer with collocated USDA reference UV spectroradiometer and NIWA UV spectroradiometer

The United States Department of Agriculture (USDA) UV-B Radiation Monitoring and Research Program began installing the UV Multi-Filter Rotating Shadow-band Radiometer for long-term measurements of UV radiation in 1995 and the program now has 28 sites across the U.S., as well as 2 sites in Canada. The UV-MFRSR uses 7 independent interference filter photodiode detector combinations to make total horizontal solar irradiance measurements at 300, 305.5, 311.4, 317.6, 325.4, 332.4 and 368 nm (nominal 2 nm FWHM bandwidth) through a single Lambertian detector. UV effects researchers want to apply their particular action spectrum to the measured spectra to estimate damage due to UV. The UV synthetic spectra retrieval model is used to estimate the continuous spectral distribution based on the seven UV radiometer channel measurements. In this study, we made comparisons of these synthetic spectra with the spectra measured from co-located USDA Reference UV and NIWA UV spectroradiometers at Table Mountain near Boulder, Colorado, U.S. A preliminary comparison of modeled erythemal-weighted dose with measurements performed by the two spectroradiometers is presented.