Modeling of Radiation Fields of Uniform Anisotropically Scattering Slab of Aarbitrary Optical Thickness

Abstract

Modeling of radiation fields of an arbitrary optical thickness uniform slab in the case of a weak absorption and strongly elongated phase functions has been carried. The simple modification of classical Ambarzumian’s — Chandrasekhar’s invariance principle indispensable for the receiving of new non-linear integral equations connected with azimuthal Fourier harmonics of generalized unified photometric function and photometric invariants has been used. These values join upgoing and downgoing radiation fields intensities making use of simple linear manner at arbitrary optical levels in mirror vision directions including fixed azimuthal angles and solar zenith distance. Parametrizations of obtained non-linear integral equations have demonstrated in the absence of reflecting underlying surfaces, placed at the lowest level of considered uniform slab, the possibility to express angular-spatial properties of unified photometrical function and appropriate photometrical invariants taking into account the phase functions strongly elongation near small scattering angles and small slab’s absorption with the help of primary scattered radiation field intensities and adaptive fitting multipliers. These functional adaptive corrections have been stipulated by uniform slab’s multiple light scattering and possess the clear physical interpretation. The use of mirror reflection (symmetry) principle, elaborated by the author, and conception of unified photometric function allows one to estimate the above-mentioned peculiarities of real environment’s phase functions in the framework of photometric invariants numerical modeling. An analysis of appropriate radiative modeling results has shown a dominating influence of primary light scattering in the formation of anisotropically scattered radiation fields of an arbitrary optical thickness uniform slab in the case of weak radiation absorption and strongly elongated phase functions.