A note on suitable viewing configuration for retrieval of forest understory reflectance from multi-angle remote sensing data

The contribution of understory vegetation especially to the reflectance of boreal forest landscapes cannot be ignored. In this letter, we identify the most suitable angular configuration for accurate retrieval of the understory signal. We use a new high angular resolution bidirectional reflectance factor data set with accompanying in situ measurements of understory reflectance in two RAdiation transfer Model Intercomparison (RAMI) mature stands in Jarvselja, Estonia. Our results are pertinent towards the ultimate goal of achieving more reliable estimates of biophysical properties of the tree layer through separating the effect of understory on forest reflectance. (C) 2014 Elsevier Inc. All rights reserved.