Effect of forest understory on synthetic aperture radar backscatter

This paper studies the effect of the understory on radar backscatter from forest stands. The purpose is to understand in what extent the understory presence modifies the backscatter composition. In order to account for the understory, a third layer of scattering media, just above the ground, is added to the Michigan Microwave Scattering model. The model is parametrized with experimental data gathered at a forest site, constituted by typical Portuguese forest stand of maritime pine plantations, and published data on North American trembling aspen forest. A sensitivity analysis is conducted in order to evaluate the effect of the understory at L, C and X bands and different polarizations. Simulation results show the importance of the forest understory on the backscattering process, and suggest the feasibility of inverting the proposed model for understory parameter inference.