The analysis of ultraviolet radiation in the Dead Sea basin, Israel

The Dead Sea basin offers a unique siteito study the attenuation of the ultraviolet (UV) radiation, as it is situated at the lowest Point on Earth, about 400m below sea level, and the air above the Dead Sea is characterized by a relatively high aerosol content due to the very high salt content of the Dead Sea. In view of its being an internationally recognized centre for clmatotherapy, it is of interest to study both its UV intensity and attnuation as a function of wavelength relative to other sites. In order to provide a basis for intercomparision of the radiation intensity parameters measured t the Dead Sea, a second set of identical parameters were being measured simultaneously at a second site, located at a distance of ca. 65 km and to the west aad situated above sea-level (Beer Sheva at + 315 m a. s. l). The ultraviolet radiation, both UV-B and UV-A, were monitored continuously at both sites using Solar Light Co. Inc. broad-band meters. In addition, sporadic measurements utilizing a narrow-band spectroradiometer were performed to ascertain the extent of site-specific spectrral selectivity in the ultraviolet spectrum. The monthly average daily attenuation ratest were found to vary from - 10.2 to -17-3 per cent 1000m^-1and -3.3 to -8 7 per cent 1000m^-1 for UV-B and UV-A, respectively The average monthly valumes for UV-B and UV-A are -14-6 percent 1000m^-1 and -5-4 per cent 1000 m^-1, respectively These values are in the range of values reported previously for performed at high attitudes, e.g in the Alps and the Andes. The relative attenuation in the ultraviolet of wavelength. i.e. Site-specific spectral selectivity, decreases with increasing wavelength Consequently, the most effective with regard to erythema undergoes the highest degree of attenuation. These findings are in accordance with radiation scatter theory