Estimation of global solar UV index from UV-B irradiance measured with a narrow-band UV-B radiometer

摘要

The global solar UV index is an indicator for notifying the level of harmful solar ultraviolet radiation reaching the surface of the earth and the general public. It was proposed by the WHO/WMO/UNEP/ICNIRP and was standardized by the CIE in 2003. This index is derived from the product of the spectral solar UV irradiance from 250 to 400 nm and the CIE standard of reference erythema spectrum. For calculation of the UV index, the measurement of spectral solar UV irradiance is needed. Spectral radiometry is the best method of measurement of solar UV irradiance, however spectral radiometers are cost prohibitive. On the other hand, a narrow-band solar UV-B radiometer is widely used for measurement of solar UV-B irradiance in the world. The Tokai Solar Radiation Monitoring Network, and the UV Monitoring Network-Japan performed by the National Institute for Environmental Studies are two examples of monitoring networks using narrow-band solar UV-B radiometer in Japan. In this paper an estimation method of the UV index from the measured UV-B irradiance with the narrow-band UV-B radiometer.