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An Empirical Model for Backscattering Coefficients of Vegetation Fields at 5.4 GHz
오이석,Chang Jisung Geba,Shoshany Maxim 한국전자파학회 2022 Journal of Electromagnetic Engineering and Science Vol.22 No.2
A new, simple empirical model for microwave backscattering from vegetation fields at 5.4 GHz is proposed in this paper. First, a modified radiative transfer model (RTM) is used to generate a database of multi-polarized backscattering coefficients of various vegetation fields at 5.4 GHz with wide ranges of vegetation biomasses and soil moistures. Second, we propose a functional form of an empirical model that is a simplified water cloud model (WCM) after closely examining the behaviors of the well-known WCM based on an extensive database that includes the modified RTM outputs, scatterometer measurements, SAR datasets, and in situ measured ground-truth data for various vegetation fields. Finally, the unknown constant parameters of the empirical model are determined for each soil moisture condition based on the extensive database. The new empirical model is verified with the database itself, and also with independent Sentinel-1 synthetic aperture radar (SAR) data and in situ measured ground-truth data.
Yisok Oh,Jisung Geba Chang,Maxim Shoshany 한국전자파학회JEES 2021 Journal of Electromagnetic Engineering and Science Vol.21 No.2
The first-order vector radiative transfer model (FVRTM) is modified mainly by examining the effects of leaf curvature of vegetation canopies, the higher-order multiple scattering among vegetation scattering particles, and the underlying-surface roughness for forward reflection on radar backscattering from farming fields at C- and X-bands. At first, we collected the backscattering coefficients measured by scatterometers and space-borne synthetic aperture radar (SAR), field-measured ground-truth data sets, and theoretical scattering models for radar backscattering from vegetation fields at microwaves. Then, these effects on the RTM were examined using the database at the C- and X-bands. Finally, an improved RTM was obtained by adjusting its parameters, mainly related with the leaf curvature, the higher-order multiple scattering, and the underlying-surface small-roughness characteristics, and its accuracy was verified by comparisons between the improved RTM and measurement data sets.