[1] [1] Diffey B L. Solar ultraviolet radiation effects on biological systems[J].Phys. Med. Biol., 1991, 3(3): 299-328.

[2] [2] Narayanan D L, Saladi R N, Fox J L. Ultraviolet radiation and skin cancer[J].Int. J. Dermatol., 2010, 49(9): 978-986.

[3] [3] Lucas R M, Ponsonby A L. Ultraviolet radiation and health: friend and foe[J].Med. J. Australia, 2002, 177(11): 594-598.

[4] [4] Paul N D, Moore J P, McPherson M,et al. Ecological responses to UV radiation: interactions between the biological effects of UV on plants and on associated organisms[J]. Physiol. Plantarum, 2012, 145(4): 565-581.

[5] [5] Ren P B C, Sigernes F, Gjessing Y. Ground-based measurements of solar ultraviolet radiation in Tibet: Preliminary results[J].Geophys. Res. Lett., 1997, 24(11): 1359-1362.

[6] [6] Norsang G, Kocbach L, Stamnes J,et al. Spatial distribution and temporal variation of solar UV radiation over the Tibetan Plateau[J]. Appl. Phys. Res., 2011, 3(1): 37-46.

[7] [7] Dahlback A, Norsang G, Stamnes J,et al. UV measurements in the 3000-5000 m altitude region in Tibet[J]. J. Geophys. Res. Atmos., 2007, 112: D09308.

[8] [8] Hφiskar B A, Haugen R, Danielsen T, et al. Multichannel moderate-bandwidth filter instrument for measurement of the ozone-column amount, cloud transmittance, and ultraviolet dose rates[J]. Appl. Opt., 2003, 42(18): 3472-3479.

[9] [9] Dahlback A. Measurements of biologically effective UV doses, total ozone abundances, and cloud effects with multichannel, moderate bandwidth filter instruments[J].Appl. Opt., 1996, 35(33): 6514-6521.

[10] [10] McKinlay A F, Diffey B L. A reference action spectrum for ultraviolet induced erythema in human skin[J].Comput. Ind. Eng. 1987, 6: 17-22.

[11] [11] World Meteorological Organization. Report of the WMO meeting of experts on UV-B measurements, data, quality and standardization of UV indices[R]. Geneva, WMO, 1994.

[12] [12] World Health Organization. Global solar UV index: A practical guide[R]. Geneva, WHO, 2002.

[13] [13] Stamnes K, Jin Z, Slusser J,et al. Several-fold enhancement of biologically effective ultraviolet radiation levels at McMurdo Station Antarctica during the 1990 ozone “hole”[J]. Geophys. Res. Lett., 1992, 19(10): 1013-1016.

[14] [14] Kylling A, Dahlback A, Mayer B. The effect of clouds and surface albedo on UV irradiances at a high latitude site[J].Geophys. Res. Lett., 2000, 27(9): 1411-1414.

[15] [15] Calbó J, Pagès D, González J A. Empirical studies of cloud effects on UV radiation: A review[J].Rev. Geophys., 2005, 43(2): RG2002.

[16] [16] Dahlback A, Stamnes K. A new spherical model for computing the radiation field available for photolysis and heating at twilight[J].Planet. Space Sci., 1991, 39(5): 671-683.

[17] [17] Stamnes K, Tsay S C, Wiscombe W,et al. Numerically stable algorithm for discrete-ordinate-method radiative transfer in multiple scattering and emitting layered media[J]. Appl. Opt., 1988, 27(12): 2502-2509.

[18] [18] Stamnes K, Slusser J, Bowen M. Derivation of total ozone abundance and cloud effects from spectral irradiance measurements[J].Appl. Opt., 1991, 30(30): 4418-4426.

[19] [19] Lu Longhua, Zhou Guoxian, Zhang Zhengqiu. Direct and global solar radiations in the region of Mt. Qomolangma during the summer 1992[J].Acta Energiae Solaris Sinica, 1995, 1(3): 229-233(in Chinese).

[20] [20] Wang Leidi, Lü Daren, Zhang Wenxing. Study on characteristic of solar radiation at Nam Co and Yangbajain in Qinghai-Xizang Plateau[J].Plateau Meteorology, 32(2): 315-32(in Chinese).

[21] [21] Chen Shu, Zheng Xiangdong, Lin Weili,et al. Observation study on the ground-based UVI at Dangxiong of Tibet[J]. Journal of Applied Meteorological Science, 2015, 2(4): 482-491(in Chinese).

[22] [22] Piacentini R D, Salum G M, Fraidenraich N,et al. Extreme total solar irradiance due to cloud enhancement at sea level of the NE Atlantic coast of Brazil[J]. Renew. Energ., 2011, 3(1): 409-412.