An empirical correlation between erythemal UVB and global irradiation developed for a single site and tested at two sites in Israel

An empirical correlation to predict the terrestrial erythemal UVB irradiation under all sky conditions as a function of a single measured parameter, global irradiation, which is available at most meteorological stations is proposed. A database consisting of measurements performed in Beer Sheva between 1996 and 2018 was divided into two sets. A primary data set consisting of measurements between 1996 and 2011 (5553 days) was utilized to develop the empirical correlation. Two secondary data sets consisting of measurements performed at Beer Sheva (1272 days) and Neve Zohar (1047 days) between January 2012 and September 2018 were used to validate the correlation. The results of the statistical analysis of the primary data reported in terms of %MBE, %RMSE, and the correlation coefficient R were − 0.01, 14.85, and 0.947, respectively. The statistical analysis for the validation procedures gives the following results: %MBE, %RMSE, and R for Beer Sheva were − 0.57, 19.80, and 0.914, respectively, and 0.95, 18.49, and 0.950 for Neve Zohar, respectively. An inter-comparison between the results of the statistical analysis of the present empirical correlation with those for previously proposed correlations, requiring more measured/calculated parameters, exhibited essentially the same degree of agreement between calculated and measured values.