A hybrid experimental/theoretical scattering model for dense random media

Abstract

Abstract-The subject of scattering of electromagnetic waves by dense media has been one of intense interest in recent years. The present paper describes polarimetric backscatter measurements made at Ku-band on layers of a dense medium under very carefully controlled circumstances. The experiments have a dual purpose: 1) to evaluate the degree to which the experimental observations are predicted by theoretical, particle-based, random media models and 2) to test a proposed hybrid model by which the scattering and extinction properties of a dense medium are characterized experimentally, allowing future modeling of the polarimetric response for any arbitrary configuration of the medium. The hybrid model assumes that first-order vector radiative transfer (RT) is a suitable theoretical structure, providing that the extinction and phase matrix components are appropriately specified; the specification is accomplished through an inversion algorithm involving polarimetric backscatter measurements. The major conclusions of the study are the following: 1) hybrid model is an adequate description of the dense medium scattering behavior; 2) conventional RT appears to give a reasonable estimate of the observed radar response, but dense medium RT gives a very low estimate; 3) phase function of the effective volume scattering element of the medium, obtained via the hybrid model, suggests a larger effective scatterer than the physical ones.Index Terms-Random media, scattering and propagation, scattering model.

Evaluating Snow Depth Retrievals from Sentinel-1 Volume Scattering over NASA SnowEx Sites

“…Other studies have suggested that dry snowpacks are not fully transparent at C-band. A study using artificial snow in a laboratory setting showed a cross-polarized (orthogonal transmitting and receiving antennas) backscatter increase of 5 dB with a 1 m snow depth increase (Kendra, 1995). Two recent tower-based studies showed 2-5 dB increases in co-polarized backscatter for C-band radiation (Naderpour et al, 2022) and significant volume scattering from C-band cross-polarized backscatter at snowpack layering interfaces (Brangers et al, 2023), likely due to surface roughness effects.…”