A MODEL FOR SOIL SURFACE-ROUGHNESS INFLUENCE ON THE SPECTRAL RESPONSE OF BARE SOILS IN THE VISIBLE AND NEAR-INFRARED RANGE

A mathematical model dealing with the influence of soil surface roughness on soil reflectance in the visible and near-infrared range is discussed. The model is based on the assumption that the reflectance from anisotropic rough soil surfaces is strongly correlated with the area of shadowed soil fragments, and therefore depends on the degree of soil roughness as well as on the illumination and the viewing geometry. It has been found that relation between measured and predicted reflectance coefficient is similar for all the tested soils.