Effect of Forest Structure on Scattering Center Height from Model and SAR Data

Modeling vegetation using coherent approaches has attained prominence over the past two decades [1-4]. The distorted Born approximation has been known as one of the basic approaches used for coherent modeling of vegetation, in which each scatterer is illuminated by a mean field and the backscattered fields are added coherently. In some papers, Lindenmayer Systems (L-systems) were employed to generate accurate 3D tree structures. Although this method is found to be useful, it needs too many input parameters. Thus it is not suitable to retrieve forest parameters by model inversion. In this study the three-dimensional radar backscatter model of forest canopy constructed by Sun and Ranson in 1995 was modified to be a coherent model for simulation of InSAR signals. It provides a balance between the accuracy and feasibility of parameters' retrieval. The effects of incident wave length and forest stand structure on phase center heights were analyzed. The phase center heights were also compared with the phase center heights from PALSAR LHH InSAR data. It shows that the simpler coherent model described in this study gives acceptable results.