Albedo is a measurement, expressed as a fraction, of the amount of radiation scattered from a surface or an object. In this chapter we describe those albedos most commonly used and describe methods to...Albedo is a measurement, expressed as a fraction, of the amount of radiation scattered from a surface or an object. In this chapter we describe those albedos most commonly used and describe methods to calculate them in cases where analytical solutions are difficult, if not impossible, to obtain. In order to do this we introduce two more photometric quantities, namely exitance M and intensity I.
A lambertian radiating surface is one whose intensity varies with angle according to Lambert's Law. The radiance of a lambertian radiating surface is independent of the angle from which it is viewed....A lambertian radiating surface is one whose intensity varies with angle according to Lambert's Law. The radiance of a lambertian radiating surface is independent of the angle from which it is viewed. Lambertian surfaces radiate isotropically. The radiance of a black body is lambertian. Since the Sun exhibits limb-darkening; the Sun is not a black body, nor is it lambertian.
