A General Model–based Polarimetric Decomposition Scheme for Vegetated Areas

A simple vegetation model for polarimetric covariance and coherency matrix elements is presented. The model aims to represent vegetation characteristics which are observable by radar polarimetry, including the average particle anisotropy, the main orientation of the volume, the degree of orientation randomness in the volume, and the terrain slopes. The decomposition consists, in analogy to the Freeman–Durden model, of volume, surface, and double–bounce scattering components considering all vegetation characteristics. The goal of this approach is to quantify these parameters and to enable their estimation in a remote sensing parameter inversion framework. In particular, this paper addresses the modeling and the interpretation of the volume component. The retrieval of parameters related to effective particle shapes and the orientation distribution characteristics is presented.