Prediction of doses biologically active ultraviolet solar radiation from measurements of global solar radiation

The main objective of this research, estimated of mean seasonal variations doses biologically active of UV-Bm solar radiation from global broadband solar irradiance over Egypt. The measurements of global solar radiation (G) and biologically effective erythematic radiation (EER) incident on a horizontal surface during the period time 1985 - 2015 at Cairo, Egypt are discussed. The monthly mean variation of slant ozone Z and UV-Bm transmission KtUV-B at the present work are found. The comparison between the two variables slant ozone Z and UV-Bm transmission KtUV-B are found. The seasonal statistical values of regression equations as the slopes (β), intercepts (α) and the standard errors (SE) for the fitted lines are done. The minimum slope occurs in winter, indicating that the percentage reduction in EER at higher slant ozone Z is larger than G. The variations of the slopes (β) during the year ranges from a minimum of 0.2867 in winter to a maximum of 0.3253 in summer, the intercepts also show their minimum and maximum values in cold humid and hot dry months. The temporal variability of the percentage ratio of the total hourly mean daily erythema to total hourly mean daily broadband solar global irradiation (EER/G) is presented. The estimated values of UV-Best solar radiation are a good agreement with the measured values of the UV-Bm solar radiation. The difference between the estimated and measured values of UV-B solar radiation varies from 3.1 to 4.25%.