Ross, J. K., and A. L. Marshak, 1988: Calculation of canopy bidirectional reflectance using Monte Carlo method. Remote Sens. Environ., 24, 213-225.
Abstract
For a calculation of the plant canopy bidirectional reflectance distribution function (BRDF) the Monte Carlo method
is used. The plant architecture is given by a rather universal mathematical model which allows to consider such structural parameters as canopy density and height, the number of leaves per plant, distance between leaves, dimensions and orientations of leaves and stems, etc., and their influence on the shape of the BRDF as a function of solar and view directions. To quantify these effects, a series of numerical experiments has been carried out. The information content of the BRDF about canopy architecture is the largest, if it is determined in the principal plane. The change of the BRDF in the region of "' hot spot" characterizes leaf dimensions by increasing the leaf area or by
decreasing the distance between leaves, the region of the "hot spot" increases. The change of the BRDF near nadir
view direction is influenced by soil brightness and by arrangement of the leaves on the stem. The presence of vertical stems or nonhorizontal mat leaves increases the asymmetry of BRDF relative to nadir; in the opposite side of the sun the canopy reflectance is several times smaller than on the sun side. Adding the effect of multiple scattering to the BRDF changes the shape of BRDF only a little. The BRDF as a function of view directions contains information about canopy architecture and can be used for future progress of the remote sensing technique.
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