Modeling microwave bistatic scattering from rice canopy based on radiative transfer equation and antenna array theory

摘要

Numerous works show the great potential of microwave remote sensing in assessing biophysical variables of rice plants. However, most studies are focusing on the backscattering character of rice canopy. Comparatively, much lesser attention has been devoted to modeling bistatic scattering behavior of rice canopy. Therefore, this study aims to improve the understanding of bistatic scattering response of rice canopy, and thus help design a bistatic radar system for better monitoring rice growth and yield estimation. Firstly, a bistatic scattering of a cluster of rice plant was modeled by solving the vector radiative transfer equations. Then, the concept of antenna array is applied to account for the inter-cluster wave interactions to obtain the total scattered field and bistatic scattering coefficient. The results show that the coherent scattering of clusters is found to be a function of vegetation growth stages. Scattering coefficient corrections need to be considered, especially at initial growth stages, and in the forward scattering direction.