Interactions of microwaves with forests: simulations at L-band

The potential of L-band in forest monitoring has been demonstrated in several studies: a good dynamics exists between backscattering from bare soil and the one from forests; forest radiometry has also recently received increasing attention, in view of future satellite missions aimed at monitoring underlying soil moisture; finally, the bistatic radar technique has been proposed in order to overcome the saturation effect, which could prevent operational use of microwave remote sensing for higher biomass values. On the other hand, it is recognized that modeling the interactions between forests and L-band microwaves is important for several objectives, since models may single out the contributions of single components and can be helpful to predict the performance of future systems. The electromagnetic model developed at Tor Vergata University is able to simulate the backscattering coefficient, the emissivity and the bistatic scattering coefficient using a unified approach, based on the radiative transfer theory. Comparisons between model simulations and measurements of emissivity and backscattering coefficient, at L-band, showed a fairly good agreement. The model was also used to predict the performances of an L-band radiometer in monitoring soil moisture under forests and to predict the trends of the specular scattering coefficient as a function of biomass