A Model of Spectral Albedo of Particulate Surfaces: Implications for Optical Properties of the Moon

• Published in: Icarus (New York, N.Y. 1962) N.Y. 1962), 1999-02, Vol.137 (2), p.235-246
• Main Authors: Shkuratov, Yurij, Starukhina, Larissa, Hoffmann, Harald, Arnold, Gabriele
• Format: Article
• Language: English
• ISSN: 0019-1035; 1090-2643
• DOI: 10.1006/icar.1998.6035

A simple one-dimensional geometrical-optics model for spectral albedo of powdered surfaces, in particular of lunar regolith, is presented. As distinct from, e.g., the Kubelka–Munk formula, which deals with two effective parameters of a medium, the suggested model uses spectra of optical constants of the medium materials. Besides, our model is invertible, i.e., allows estimations of spectral absorption using albedo spectrum, ifa prioridata on the real part of refractive index and surface porosity are known. The model has been applied to interpret optical properties of the Moon. In particular, it has been shown that: (1) both color indices and depth of absorption bands for regolith-like surfaces depend on particle size, which should be taken into account when correlations between these optical characteristics and abundance of Fe and Ti in the lunar regolith are studied; (2) fine-grained reduced iron occurring in regolith particles affects band minima positions in reflectance spectra of lunar pyroxenes and, consequently, affects the result of determination of pyroxene types and Fe abundance by Adams' method.