7 Visible Light and UV Radiation
7 Visible Light and UV Radiation
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7 可见光和紫外线辐射
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发表时间：
2004
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通讯作者：
J. Moan
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作者：
J. Moan
太阳是最重要的可见光和紫外线辐射源。即使太阳到地球的距离很大-约150×10 km -太阳辐射在地球上的注量率，太阳常数，约为1 360 W/m 2。大约40%的辐射被反射回太空。剩下的60%是地球上所有生命的驱动力。许多色素已经被生命开发出来以收获太阳能：叶绿素a（350-700 nm）、藻红蛋白（45-580 nm）、藻蓝蛋白（460-650 nm）、细菌叶绿素a（750-850 nm）和细菌叶绿素B b（950-1 050 nm）是一些最重要的色素。此外，动物已经开发了视觉色素，视紫红质，看到光。通过对DNA的作用，来自太阳的紫外线辐射诱导了突变，加速了新物种的产生和发展。紫外线辐射对人体免疫系统有积极和消极的作用，例如诱发癌症和参与维生素D的产生。本章回顾了一些关于可见光和紫外线太阳辐射的基本事实：光谱及其随太阳周期阶段的变化、臭氧水平、时间、纬度、高度、反射和天空覆盖。此外，讨论了光辐射在大气中和人体皮肤中的散射和吸收。最后，对红斑、不同类型的皮肤癌、对人体免疫系统的影响和光复活（光诱导的DNA损伤修复）的作用谱进行了综述。这些现象的生物学将在第31章“紫外线辐射和可见光的影响”中讨论。
The sun is the most important source of visible and ultraviolet (UV) radiation. Even though the distance from the sun to the Earth is large – about 150×10 km – the fluence rate of solar radiation on Earth, the solar constant, is about 1 360 W/m 2 . Approximately 40% of this radiation is reflected back into space. The remaining 60% is the driving force of all life on Earth. A number of pigments have been developed by life to harvest solar energy: chlorophyll a (350-700 nm), phycoerythrin (45-580 nm), phycocyanin (460-650 nm), bacteriochlorophyll a (750-850 nm) and bacterio-chlorophyll b (950-1 050 nm) are some of the most important ones. Furthermore, animals have developed visual pigments, the rhodopsins, to see light. By its action on DNA, UV radiation from the sun has induced mutations to speed up generation and development of new species. UV radiation acts positively and negatively on the human immune system, e.g. induces cancer and takes part in the production of vitamin D. This chapter reviews some of the basic facts about visible and UV solar radiation: spectra and their variations with the phases of the solar cycle, ozone level, time, latitude, altitude, albedo (reflection), and sky cover. Furthermore, scattering and absorption of optical radiation in the atmosphere and in human skin are discussed. Finally, there is a review of the action spectra for erythema, skin cancer of different types, effects on the human immune system and photoreactivation (light-induced repair of DNA damage). The biology of these phenomena will be dealt with in Chapter 31 'Effects of UV Radiation and Visible Light'.