Assessment of empirical models to estimate UV-A, UV-B and UV-E solar irradiance from GHI

Abstract

Exposure to the UV solar irradiance reaching the ground has an important impact on human health, vegetable growth and the degradation processes of several materials. As a first step of a larger project aiming to characterize typical UV exposure potential over the territory of Uruguay, three families of simple UV irradiation models based on GHI and atmospheric Ozone information are trained and evaluated using data from three sites (one of them in King George’s Island, Antarctica). The air mass, clearness index and satellite-derived (OMI/TOMS) daily Ozone column are used as predictors to estimate 15-minute irradiation inthe UV-A, UV-B, and UV-Erithemic bands. All models are locally adjusted and perform similarly. The best model predict UV irradiation with typical uncertainties between 6 and 7% and small but consistent negative biases. The use of a constant UV fraction is considered inadequate in the region for most applications.