The approximate bulk-scattering phase function of a polydisperse system of dust particles is derived in an analytical form. In the theoretical solution, the particle size distribution is modeled by a modified gamma function that can satisfy various media differing in modal radii. Unlike the frequently applied power law, the modified gamma distribution shows no singularity when the particle radius approaches zero. The approximate scattering phase function is related to the parameters of the size distribution function. This is an important advantage compared to the empirical Henyey–Greenstein (HG) approximation, which is a simple function of the average cosine. However, any optimized value of average cosine of the HG function cannot provide the information on particle microphysical characteristics, such as the size distribution function. In this paper, the mapping between average cosine and the parameters of size distribution function is given by a semianalytical expression that is applicable in rapid numerical simulations on various dust populations. In particular, the modal radius and half-width can be quickly estimated using the presented formulas.
© 2011 Optical Society of America
Atmospheric and Oceanic Optics
Original Manuscript: January 25, 2011
Manuscript Accepted: March 22, 2011
Published: June 1, 2011
Vol. 6, Iss. 7 Virtual Journal for Biomedical Optics
Miroslav Kocifaj, "Approximate analytical scattering phase function dependent on microphysical characteristics of dust particles," Appl. Opt. 50, 2493-2499 (2011)