Prediction and measurement of soil bidirectional reflectance

• Published in: IEEE transactions on geoscience and remote sensing 1992-03, Vol.30 (2), p.249-260
• Main Authors: Irons, J.R., Campbell, G.S., Norman, J.M., Graham, D.W., Kovalick, W.M.
• Format: Article
• Language: English
• Subjects: Anisotropic magnetoresistance; Bidirectional control; Earth Resources And Remote Sensing; Equations; Land surface; Particle scattering; Reflectivity; Soil measurements; Soil properties; Solar radiation; Surface treatment
• ISSN: 0196-2892; 1558-0644
• DOI: 10.1109/36.134075

A model for soil bidirectional reflectance distribution functions in visible and reflective infrared wavelengths is introduced and compared to data acquired in the field. The model is based on the representation of soil surfaces by a collection of opaque spheres sitting on a Lambertian horizontal surface. The model is not sensitive to increases in the sphere area index beyond a value of 0.4. For comparison, soil reflectance factor data were acquired on a tilled field from many view directions and for a range of solar directions. The observed reflectance factor distributions were consistent with those predicted by the function; maximum reflectance occurred in the antisolar direction and reflectance decreased with increasing phase angle. Increasing the surface roughness by different tillage methods did not substantially alter the directional anisotropy of the soil reflectance factors. The model was fit to the data by a nonlinear least-squares procedure.< >