The cause of azimuthal variations in directional reflectance of vegetative canopies

The variation of the directional reflectance of a vegetative canopy with azimuthal view angle becomes prominent when the canopy is illuminated by the sun at large angles from zenith. An extension of a previous directional reflectance model of vegetative canopies is presented to quantify this effect. The results indicate that the cause of the azimuthal variation can be traced to solar flux illumination of the vertically oriented canopy components and that the extreme variations of reflectance with azimuth of view are moderated by the azimuthally isotropic sources of flux from skylight and canopy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34213/1/0000502.pd