Estimation of soil moisture from multi-polarized SAR data over wheat coverage areas

Abstract

Radar data has important implications in agricultural fields monitoring, particularly in the retrieval of the crop height, leaf area index (LAI) and soil moisture information. The objective of this study was to estimate soil moisture contents based on multi-polarized synthetic aperture radar (SAR) data acquired over wheat fields. The soil moisture inversion algorithm was based on semi-empirical backscattering models and the prior estimation of wheat heights (h) and wheat water contents (WC) from SAR data(RADARSAT-2). The co-polarized correlation coefficient (ρ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">vvhh</sub> ) and the ratio of the absolute value of the cross polarization to the crop height (Λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">vh</sub> ) were analyzed with respect to variations in wheat height and wheat water content. The results showed average relative errors of 14%, 32% and 24% for the retrieval of wheat height, wheat water content and soil moisture, respectively.