Development and Evaluation of a Solar Ultraviolet-B Radiometer

Abstract

A new band-spectral solar ultraviolet-B (UV-B: 290-320 nm) radiometer is developed for easy and accurate outdoor measurement. The spectral response of the radiometer is a maximum at 305 nm and has a 20-nm bandwidth. In this radiometer, incident global solar UVB irradiance is converted to visible light by a phosphor layer and is detected by a Si-photodiode. The spectral, cosine, azimuth, and temperature responses of the radiometer are evaluated. Contamination by the UV-A irradiance longer than 320 nm is less than 6% of the measured UV-B irradiance. No changes in the instrumental constant or in the spectral responses of the radiometer were found by periodical checks over a two-year period. Results indicate that this radiometer is useful for continuous, high time-resolution measurement of global solar UV-B irradiance.