Construction and Evaluation of Empirical Model for Estimating UV Erythemal Irradiance using Global Horizontal Irradiance in South Korea

Abstract

Ultraviolet (UV; 100~400 nm) radiation, which is a short-wavelength part of the solar spectrum, has harmful effects on the human body, such as skin aging, sunburn, and skin cancer. Because overexposure to UV causes erythema in human skin, the UV erythemal irradiance (UVER) is provided to people as an index of the risks of UV irradiation. In this study, statistical empirical models for estimating surface UVER were developed and evaluated at Gangneung, Pohang, Mokpo, and Gosan sites in South Korea, where UVER and global horizontal irradiance (GHI) observation data have been collected for a long period. For the establishment of an empirical model, the clearness index of the GHI (  ), total column ozone, and solar zenith angle were used as independent variables. The underestimations of the empirical models were improved by grouping the dataset with   . The improved models exhibited an average R 2 of 90% at the four sites during the validation period. The atmospheric transmittance of the UVER was reconstructed using the empirical model at the GHI observation network during past 5 year data in South Korea, and the monthly variation showed seasonality with high values in May-August and low values in December-January.