A two-layer model of the bidirectional reflectance of homogeneous vegetation canopies

A two-layer model of the bidirectional reflectance of homogeneous vegetation canopies is derived in this paper. The anisotropic scattering of both the vegetation canopy and the background, i.e., bare soil or leaf litter, is taken into consideration in this model. The effect of the anisotropic scattering from the background to the apparent canopy reflectance in different leaf area indices of three leaf-orientation canopies is presented. The model is validated against simulated and field-measurement data. The inversion process is used to retrieve the optical properties of leaf and background. The model is used to predict the bidirectional reflectances from the parameters retrieved by the inversion process. The predicted bidirectional reflectances agree well with those assumed by the simulated data. The leaf optical properties retrieved by the model inversion are discussed and validated against values known from the measurements.