Relationship between Net Radiation and Broadband Solar Radiation in the Tibetan Plateau

• Published in: Advances in atmospheric sciences Vol. 29; no. 1; pp. 135 - 143
• Main Author: 胡波 王跃思 刘广仁
• Format: Journal Article
• Language: English
• Published: Heidelberg SP Science Press 2012; Springer Nature B.V; State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029
• Subjects: Albedo; Atmospheric Sciences; Broadband; Deviation; Earth and Environmental Science; Earth Sciences; Estimates; Extraterrestrial environments; Geophysics/Geodesy; Meteorology; Net radiation; Radiation; Solar activity; Solar physics; Solar radiation; Winter; 估计值; 地表反照率; 太阳辐射; 宽带网; 模型应用; 西藏高原; 辐射数据; 青藏高原; Tibetan Plateau; net radiation; Tibetan Plateau; broadband solar radiation
• ISSN: 0256-1530; 1861-9533
• DOI: 10.1007/s00376-011-0221-6

The characteristics of net radiation （Rn） （0.3-10 μm） in Lhasa and Haibei in the Tibetan Plateau were analyzed based on long-term in-situ measurements of surface radiation data. The monthly average of daily Rn reached a minimum during the winter period followed by an increase until May and then a decline until January. This variation is consistent with solar activity. The annual mean daily total Rn values were 0.92 MJ m^-2 d^-1 and 0.66 MJ m-2 d-1 in Lhasa and Haibei, respectively. A relationship between Rn and broadband solar radiation （Rs） was demonstrated by a good linear correlation at the two sites. Rn can be an accurate estimate from Rs. The estimated Rn values were similar to the observed values, and the relative deviations between the estimates and measurements of Rn were 2.8% and 3.8% in Lhasa and Haibei, respectively. The application of the Rn estimating model to other locations showed that it could provide acceptable estimated Rn values from the Rs data. Furthermore, we analyzed the influence of clouds on Rn by different clear index （Ks）, defined as the ratio of Rs to the extraterrestrial solar irradiance on a horizontal surface. The results indicate that more accurate results are associated with increased cloudy conditions. The influence of the albedo was also considered, but its inclusion in the model resulted in only a slight improvement. Because surface albedo is not usually measured, an expression based solely ou global solar radiation could be of more extensive use.