The dependence of the radiative characteristics of optically thick media on the shape of particles

The aim of this paper is to study the dependence of reflection, absorption, and transmission of light by optically thick, weakly absorbing disperse me dia on the shape of constituent particles. Single scattering by nonspherica l particles is calculated in the framework of the Rayleigh and geometrical optics approximations. The ratio of the average Volume to the average surfa ce of particles and their volumetric concentration are kept constant. Thus, the extinction coefficient and the optical thickness of different media un der consideration are the same. Calculations are performed for ice particle s at wavelengths of 0.645, 1.24, 1.64, and 2.13 mu m. The respective refrac tive indices range from 1.3082-i1.325 x 10(-8)(weak absorption) to 1.2674-i 5.65 x 10(-4) (moderate absorption). The radiative characteristics are calc ulated in the framework of approximate analytical formulae valid for optica lly thick, weakly absorbing media. (C) 1999 Elsevier Science Ltd. All right s reserved.