Radar backscatter modeling of 3D vegetation structure

The authors´ current 3D radar backscatter model treats vegetation layers or tree crowns as homogeneous volumes consisting of various scatterers. The volume scattering and attenuation properties of the vegetation layers used in radiative transfer models were calculated by averaging the Stokes matrix (incoherent summation) or the scattering matrix (coherent summation) from these scatterers. This averaging process, by integration over the size and orientation distributions of the scatterers, eliminates the discrete nature of the vegetation structure and creates a continuous medium description of vegetation structure. Certain scattering properties based on the discrete nature and relative position of scatterers, for example, the corner reflectors formed by branches, have been lost in the model. Trees simulated from a tree growth model were used to investigate the effect of crown discrete structure on radar backscattering. This paper presents preliminary results from modifying models for this purposes