Physical-geometric optics method for large size faceted particles

Abstract

A new physical-geometric optics method is developed to compute the single-scattering properties of faceted particles. It incorporates a general absorption vector to accurately account for inhomogeneous wave effects, and subsequently yields the relevant analytical formulas effective and computationally efficient for absorptive scattering particles. A bundle of rays incident on a certain facet can be traced as a single beam. For a beam incident on multiple facets, a systematic beam-splitting technique based on computer graphics is used to split the original beam into several sub-beams so that each sub-beam is incident only on an individual facet. The new beam-splitting technique significantly reduces the computational burden. The present physical-geometric optics method can be generalized to arbitrary faceted particles with either convex or concave shapes and with a homogeneous or an inhomogeneous (e.g., a particle with a core) composition. The single-scattering properties of irregular convex homogeneous and inhomogeneous hexahedra are simulated and compared to their counterparts from two other methods including a numerically rigorous method.

Light scattering by pure water and seawater: the depolarization ratio and its variation with salinity

“…In Fig. 2, we compare δ p simulated at 532 nm for particles of two very different shapes, sphere versus asymmetrical hexahedron [52,53], of sizes from 1 to ∼300 nm and of two refractive indices, 1.02 and 1.20 relative to the refractive index of water. In addition, we also examined the effect of the FOV of a detector on δ p .…”

A Brief Review of Mueller Matrix Calculations Associated with Oceanic Particles

“…Equations (7) and (8) are fundamental to the PGOM, which substantially extend the applicability of the principles of geometric optics in conjunction with physical optics to from large to moderate particles. For faceted particles, the ray-tracing process can be analytically accomplished since the phase change on a facet is linear [61][62][63]. The PGOM can be effectively used to compute the light scattering properties of oceanic particles.…”

A Review of Ice Cloud Optical Property Models for Passive Satellite Remote Sensing

“…The plates are randomly oriented in terms of their rotations around the asymmetry axes that are aligned vertically and columns are horizontally oriented with two parallel faces perpendicular to the vertical direction (known as Parry oriented columns). The physical-geometric optical computational program developed by Sun et al [89] is used for this simulation.…”

“…An interested reader is referred to Mishchenko et al [59,86] for non-spherical particles in general and Liou and Yang [4] for ice particles more specifically. In particular, we note that light scattering in the entire size parameter region may be effectively simulated by a synergetic combination of efficient implementations of the invariant imbedding T-matrix method [87] and the physical-optical method [83,84] in conjunction with recent improvements on its computational efficiency [88,89].…”