朗伯下垫面的漫反射作用对天空亮度的影响  

Mathematical Model of Sky Radiation Reflection by Lambert Underlying Surface

作　　者：杨春平[1] 吴健[1] 冷杰[2] 

机构地区：[1]电子科技大学光电信息学院,成都610054 [2]中国工程物理研究院应用电子学研究所,四川绵阳621900

出　　处：《电子科技大学学报》2007年第4期775-777,共3页Journal of University of Electronic Science and Technology of China

基　　金：国家自然科学基金资助项目(10376007)

摘　　要：随机粗糙下垫面对入射到地表的太阳辐射的漫反射必然引起天空亮度的增加。本文基于下垫面为朗伯粗糙表面的假设基础上,对下垫面对向下太阳辐射的漫反射作用引起天空亮度变化的计算方法进行了研究,分析了利用互易性原理计算大气反射率、半球平均反射率和透过率的方法。对不同下垫面反照率对天空亮度的影响随观察天顶角的变化进行了计算和比较,结果表明随着观察天顶角的增加,下垫面的漫反射作用对天空亮度的影响也随之增强,特别当天顶角接近90°时,这种影响迅速增强。The solar radiance diffused by a randomly-rough underlying surface might lead to increase sky radiance. The computation of sky radiance resulted from the earth’s diffuse reflection is studied based on a hypothesis that a underlying surface is randomly rough. The paper gives an analysis of the method to calculate the reflectivity, average hemisphere reflectivity, and transmission in virtue of the reciprocity law from the earth’s surface to the top of the atmosphere. The calculation of the effect of different albedo of underlying surface on sky radiance is made at different viewing zenith angles and compared with the experimental result. The results show that sky radiance rises rapidly as the albedo of the earth’s surface becomes big while viewing zenith angle is close to 90°.

关 键 词：Eddington近似 朗伯表面 互易性原理 天空亮度 下垫面 

分 类 号：O438[机械工程—光学工程]