Model-based estimation of forest canopy parameters using polarimetric and interferometric SAR

Synthetic aperture radar (SAR), interferometric SAR (INSAR),and polarimetric INSAR (POLINSAR) have been shown to be sensitive to various biophysical forest canopy parameters. The two general classes of models employed in parameter extraction are random-media and structure-based. Since the quality of canopy parameter retrieval depends on the attributes of the forward-scattering models that are inverted, we review the general characteristics of each type of model. The random-media models invoke simplifying assumptions, such as independent scattering statistics, to yield analytical expressions. Some of the central assumptions, however, do-not hold as resolution increases. Structure-based models can be used in these high-resolution scenarios. We are developing a new structure-based wideband SAR/INSAR/POLINSAR model to explore the effects of increasing resolution on POLINSAR observables. A simple example of a structure-based SAR simulator is presented.