Passive Microwave Remote Sensing of Forests

A model, based on the radiative transfer theory and the matrix doubling algorithm, is described and used to compute the emissivity e of forests. According to model simulations, the L-band emissivity trend versus forest biomass is more gradual than that of the backscatter coefficient. This gradual behavior is observed, in absence of leaves, also at C and X bands, while leaves anticipate saturation and make e higher in coniferous forests and lower in deciduous forests. Model results are successfully vali- dated by some available experimental data. Operational aspects, concerning the potential of airborne and spaceborne radiometers in identifying forest type and estimating biomass, are discussed.

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