Scattering of light in multilayer atmospheres. I. Diffuse reflection

A plane atmosphere consisting of an arbitrary number of homogeneous layers and illuminated by parallel rays is considered. A method is proposed for calculating the radiation intensity in the multilayer medium at arbitrary optical depth. The method is based on the use of invariance relations. In particular, the cases when one of the layers is semiinfinite and also when the multilayer atmosphere adjoins a light-reflecting surface are considered. The method is illustrated by the results of a calculation of the radiation field in a two-layer medium consisting of layers having different optical thicknesses, phase functions, and particle albedos. (Author)