Relating tropical forest biomass to P-band SAR tomography

The retrieval of above-ground biomass in dense tropical forests using Synthetic Aperture Radar (SAR) images is widely recognized as a challenging task, because of the backscatter saturation effect at high biomass values and the ground topography effect. The study presented in this paper is an attempt to overcome these issues based on direct three-dimensional imaging of the forest volume, which is possible through multi-baseline SAR tomography. In this way, forest biomass can be investigated by considering not only the backscattered power at each slant range, azimuth location, but also its vertical distribution. It was found that the power from the a layer at 30m ± 10m above the ground yields the best correlation and best sensitivity with forest biomass in all polarizations, for biomass ranging from 250 to 450 tons/ha.