THE 4SAIL MODEL ESTIMATING BIDIRECTIONAL REFLECTANCE FROM EUCALYPTUS CANOPIES

Scattering by Arbitrarily Inclined Leaves (SAIL) use was proposed in this work to simulate the spectral characterization from Eucalyptus sp. plantations comparing the resulting data to the bidirectional reflectance factors from orbital images. According visual comparison the differences between the WorldView 3 reflectance values and those calculated by the 4SAIL model suggest that the 4SAIL model does not take into account aspects that really participate of the canopy reflectance. In the statistical approach significant F values were calculated for the infrared region (NIR1 and NIR2) independent on the canopy level and the results to visible spectral region was performed poorly. In spite of being relatively easy to parametrize the 4SAIL model in order to calculate the canopy reflectance of some Eucalyptus plantations, at least using the WorldView 3 images converted to surface reflectance, in absolute terms the calculated canopy reflectance values calculated by the 4SAIL model were relatively different from those extracted from the WorldView 3 images.