A Scatter Model for Leafy Vegetation

A model for vegetation scatter is developed using the first-order renormalization method. The vegetated medium is taken to be an inhomogeneous medium characterized by a random permittivity function with a cylindrically symmetric fast-decaying correlation function. The permittivity of the vegetation (taken to be a combination of water and some solid material) is estimated by a mixing formula after de Loor [13], and the permittivity of the vegetated medium (taken to be a combination of vegetation and air) is estimated using a formula by Pierce [16]. The backscattering coefficient from such a model is computed as a function of the incidence angle, the frequency, and the moisture content of the vegetation. Comparisons are made with measured data from soybeans, alfalfa, and corn. The agreements obtained in both the absolute levels and the angular trends of the backscattering coefficient appear to justify both the permittivity and the scatter model for vegetation.