ИСТИНА

The UV-index (UVI) is a measure of the erythemally effective solar radiation reaching the Earth surface. It was introduced to alert people about the need of sun protection and to help for elaborating recommendations about safety exposure to solar UV radiation. Therefore, the UVI has to be determined with adequate accuracy and its forecast appears to be an essential task. To minimize the risk of too high sunburn levels, the UVI previsions are usually made for clear sky conditions (cloud and aerosol free atmosphere). In such conditions, the solar UV irradiance over a given geographical location depends mainly on the total ozone column (TOC) and thus, the UVI forecast implicates the knowledge of the TOC. Schemes of one-day UVI forecast for Stara Zagora and Bulgaria are presented and discussed in the present report. А detailed analysis has been supported by results of the first tests performed from 19th Sep. to 19th Oct. 2019.