Variance in bidirectional reflectance over discontinuous plant canopies,” Remote Sensing of Environment 69

An exploratory study of the variance of the bidirec- (Deschamps et al., 1994) instruments. Also, directional measurements have been made in a variety of laboratorytional reflectance over discontinuous plant canopies indi-cates that the patterns in variance can be related to the or field settings. However, soon there will be consider-able directional imagery available, particularly from theproperties of the plant canopies. The spatial variance of the bidirectional reflectance calculated from ASAS im- MISR (Diner et al., 1989) and MODIS (Ardanuy et al., 1991) instruments. Thus, the opportunity for recovery ofages shows peak values at the hotspot and near nadir. This behavior can be explained by the geometric effect of surface parameters from directional measurements will increase dramatically.discontinuous tree crowns and the regularization effect. Validation of Jupp and Woodcock’s two-component geo- With the notion of recovery of surface parameters based on directional reflectance comes the idea thatmetric optical (GO) model (1992) shows that it captures the basic features of the spatial variance of the bidirec- BRDFs are the first-order directional properties of a landscape. Often critical to inversion processes and theirtional reflectance over discontinuous plant canopies. Their two-component GO model is modified to account for the success are the second-order directional properties. Lo-cal spatial variance and large, anisotropic change in re-spatial interactions of four scene components. Validation shows that the modified GO model improves predictions. corded radiance with changing Sun position and senso