Spatial Distribution and Temporal Variation of Solar UV Radiation over the Tibetan Plateau

Abstract

The Tibetan Plateau has very high levels of ultraviolet radiation. To study the UV radiation across the Tibetan Plateau, data from the TOMS (Total Ozone Mapping Spectrometer) satellite for the periods 1979 -1992 and 1997–¬ 2003 are used. The analysis shows a 21-year average of the spatial distribution of daily summer erythemal UV doses across the Tibetan Plateau and its vicinity with a spatial resolution of 1° Lat. - 1.25° Long., also obtains temporal variations during the period 1979 ¬- 2003 of UV radiation for the region by selecting seven locations across the Tibetan Plateau and its neighboring areas. The results show that during the summer months from May to August the average daily erythemal UV doses at the selected seven sites across the Tibetan Plateau range from 7.5 to 9.0 kJ/m2. These daily erythemal UV doses are considerably higher than those observed at geographically close, lower-altitude locations such as Chengdu in China and New Delhi in India, which had corresponding values of 4.1 kJ/m2 and 5.8 kJ/m2, respectively. During the period from 1979 to 1992 observe a clear trend of increasing erythemal UV doses over the Tibetan Plateau. Comparisons between satellite derived UV radiation and ground-based measurements of UV radiation for Lhasa are made.