Influences of the Clearness Index on UV Solar Radiation for Two Locations in the Tibetan Plateau -Lhasa and Haibei

• Published in: Advances in atmospheric sciences Vol. 25; no. 5; pp. 885 - 896
• Main Author: 胡波 王跃思 刘广仁
• Format: Journal Article
• Language: English
• Published: Heidelberg SP Science Press 01.09.2008; Springer Nature B.V; State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry(LAPC),Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijng 100029
• Subjects: Altitude; Atmospheric Sciences; Climate; Climate science; Earth and Environmental Science; Earth Sciences; Ecological effects; Ecological monitoring; Geophysics/Geodesy; Health; Human; Meteorology; Solar radiation; Thinning; Ultraviolet radiation; 紫外线辐射; 西藏高原; ultraviolet radiation; clearness index; Tibetan plateau
• ISSN: 0256-1530; 1861-9533
• DOI: 10.1007/s00376-008-0885-8

Ultraviolet （UV） solar radiation has a significant influence on human health, the environment and climate. A series of measurements, including UV radiation （290 400 nm） and global solar radiation （Rs）, were continuously recorded from August 2004 at the Lhasa and Haibei sites on the Tibetan Plateau. Both observation sites＇ altitudes are above 3000 m and have similar meteorological conditions. The data from 2005 2006 was used to identify the varying characteristics of UV radiation. It＇s relation to the clearness index Ks, the relative optical mass mr, and Rs were established. The annual mean values of total daily UV radiation are 0.92 and 0.67 MJ m^-2 at Lhasa and Haibei, respectively. The UV radiation in Lhasa represented 4.6% of the global solar radiation while in Haibei this percentage was 4.2%. In the case of clear days （Ks 〉 0.8）, these percentages ranged between 4.0% and 4.5% in Lhasa and between 5.1% and 5.5% in Haibei. In the case of cloudy days （Ks 〈 0.4）, these percentages ranged from 4.4% to 6.8% in Lhasa and from 5.1% to 5.5% in Haibei. The maximum values of UV radiation for each relative optical mass diminished exponentially with mr. Thus, for Lhasa and Haibei, UV=46.25mr-129, and UV=51.76mr-142, respectively. The results of this study can be used to obtain more UV radiation data for the study of UV climate characteristics, the effects of UV on ecological processes and the feedback of the thinning of the stratospheric ozone, from more routine measurements Rs data.