642 
4. CONCLUSIONS 
The geometrical model of soil bidirectional reflectance presented in this paper demonstrates a clear 
backscattering character of the reflectance distribution along the solar principal plane. 
The model-generated bidirectional reflectance seem to find corroboration in the results of the 
correlation analysis carried out. Howewer, an examination of the accuracy of the model against more typical 
soils and a larger sample of measured reflectance data would be very interesting, especially in experiments in 
which the soil roughness state could be controlled adequately. 
5. AKNOWLEDGMENTS 
The authors wish to thank Jean Francois Hanocq (Bioclimatologie, Montfavet) for his help in measurements 
This work was partly supported by a grant from the French Ministry of Research and Technology. 
6. REFERENCES 
Barnsley, M. J., 1984. Effects of off-nadir view angles on the detected spectral response of vegetation canopies 
Int. J. Remote Sens., 15: 715-728. 
Ciemiewski, J., 1987. A model for soil surface roughness influence on the spectral response of bare soils in the 
visible and near-infrared range. Remote Sens. Environ., 123: 97-115. 
Ciemiewski, J., 1989. The influence of the viewing geometry of bare rough soil surfaces on their spectral 
response in the visible and near-infrared range. Remote Sens. Environ., 127: 135-142. 
Cooper, K. D. and Smith J. A., 1985. A Monte Carlo reflectance model for soil surfaces with three-dimensional 
structure. IEEE Trans. Geosci Remote Sens., 1GE-23: 668-673. 
Deering, D. W., Eack, T. F., and Otterman, J., 1990. Bidirectional reflectances of selected desert surfaces and 
their three-parameter soil characterization. Agricultural and Forest Meteorology 1, 52: 71-93. 
Foody, G. M., 1988. The effects of viewing geometry on image classification. Int. J. Remote Sens., 19: 1909- 
1915. 
Graetz, R. D. and Gentle, M. R., 1982. A study of the relationship between reflectance characteristics in the 
Landsat wavebands and the composition and structure of an Australian semi-arid rangeland. Photogramm 
Eng. Remote Sens., 148: 1721-1736. 
Huete, A. R., 1987. Soil and Sun angle interactions on partial canopy spectra. Int. J. Remote Sens., 18: 1307- 
1317. 
Irons, J. R., Campbell, G. S., Norman, J. M., Graham, D., W., and Kovalick, W. M., 1992. Prediction and 
measurement of soil bidirectional reflectance. IEEE Trans. Geosci Remote Sens., 30, 2: 249-260. 
Jacquemoud, S., Baret, F., and Hanocq, J. F., 1992. Modeling spectral and bidirectional soil reflectance 
Remote Sens. Environ., 41:123-132. 
Kimes, D. S., Seller, P. J., 1985. Inferring hemispherical reflectance of the Earth's surface for global energy 
budget from remotely sensed nadir or directional radiance values. Remote Sens. Environ., 118: 205-223. 
Kowalik, S., Marsh, S. E., and Lyon, R. J. (1982), A relation between Landsat digital numbers, surface 
reflectance, and the cosine of the solar zenith angle. Remote Sens. Environ., 112: 39-55. 
Milton, E., J. and Webb, J., P., 1987. Ground radiometry and airborne, multispectral survey of bare soils. Int. 
J. Remote Sens., 18: 3-14. 
Norman, J. M., Welles, J. M. and Walter, E. A., 1985. Contrast among bidirectional reflectance of leaves, 
canopies, and soils. IEEE Trans. Geosci. Remote Sens., 1GE-23: 659-667. 
Otterman, J., Weiss, G. H., 1984. Reflectance from a field of randomly located vertical protrusions. Appl. Opt., 
123: 1931-1936. 
Pech, R. P., Graetz, R. R., Davis, A. W., 1986. Reflectance modelling and the derivation of vegetation 
indices for an Australian semi-arid shrubland. Int. J. Remote Sens., 17: 389-403. 
Pinty, B., Verstraete, M. M., and Dickinson, R. E., 1989. A physical model for predicting bidirectional 
reflectances over bare soils. Remote Sens. Environ., 127: 273-288. 
Ranson, K. J., Biehl, L. L., and Bauer, M. E., 1985. Variation in spectral response of soybeans with respect to 
illumination, view and canopy geometry. Int. J. Remote Sens., 16: 1827-1842. 
Royer, A., Pierre, V., and Bonn, F., 1985. Evaluation and correction of viewing angle effects on satellite 
measurements of bidirectional reflectance. Photogramm. Eng. Remote Sens., 151: 1899-1914. 
Verbrugghe, M. and Ciemiewski, J., 1993. Effects of sun and view geometries on cotton bidirectional 
reflectance. Test of a geometrical model. Submitted to Remote Sens. Environ. Special Issue.