地表反射太阳辐射的参数化计算方法
Parameterized model of solar radiation reflection by the ground
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摘要: 从能量守恒定律出发，建立了朗伯地表对下行辐射的反射作用引起天空亮度变化的解析计算模型。利用射线追踪原理，提出了地表与大气之间多次反射作用的理论模型。引入了一个多次散射的影响因子，并对附加的天空亮度进行了修正。利用混合修正的d-Eddington近似和互易性原理计算了大气的透射率、反照率以及半球平均反照率。最后计算了地表反照率分别为0.15，0.25和0.35情形下的天空亮度增量，实验测量数据证实了这些结果。结果表明：当地表的反照率不为0时，存在“临边增亮”效应，并且随着地表反照率的增大，这种效应更加明显。Abstract: It is important to evaluate sky radiance for a ground-to-air measurement system. Based on energy conservation law and the assumption that the underlying surface is a Lambert’s surface, a model was developed to calculate the additional sky radiance due to the ground reflectance. According to the ray trace principle, multiple reflectance between the earth’s albedo surface and the atmosphere was also taken into account. The hybrid modified delta-Eddington approximation was used to calculate the transmission, reflection and average reflection of the atmosphere from the ground to the top of the atmosphere. The additional sky radiance was calculated under surface albedos of 0.15, 0.25 and 0.35, and compared with the measured data. The results show that there is a limb-brightening effect for sk
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Key words:
- earth’s surface /
- solar radiation /
- reflectance /
- sky radiance /
- principle of reciprocity /
- lambert’s law
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