Sie befinden Sich nicht im Netzwerk der Universität Paderborn. Der Zugriff auf elektronische Ressourcen ist gegebenenfalls nur via VPN oder Shibboleth (DFN-AAI) möglich. mehr Informationen...
Anisotropic reflectance effects on spectral indices for estimating ecophysiological parameters using a portable goniometer system
Ist Teil von
Canadian journal of remote sensing, 2010-01, Vol.36 (sup2), p.S355-S364
Ort / Verlag
Taylor & Francis
Erscheinungsjahr
2010
Quelle
Taylor & Francis
Beschreibungen/Notizen
Remote sensing studies are affected by the inherently anisotropic nature of reflectance from natural surfaces. The objective of this study was to investigate the effect of anisotropic reflectance on the 970 nm water band index (WBI) for Pleurozium schreberi moss from the Fluxnet Canada Western Peatland site in northern Alberta. A series of hyperspectral bidirectional reflectance measurements from the University of Lethbridge Goniometer System (ULGS-I) were assessed for their effect on a variety of WBI and NDVI spectral indices. These indices are often used to estimate ecophysiological parameters such as plant water content, pigment content, and leaf area and subsequently have the potential to contribute to estimates of ecosystem CO
2
flux across large regions. Estimates of the bidirectional reflectance distribution function (BRDF) from laboratory ULGS-I measurements of P. schreberi moss were made under controlled illumination conditions from which WBI and NDVI were computed to evaluate the variation in index magnitude by view direction. As view angle increased from nadir, WBI declined dramatically from 1.40 to 1.24, and NDVI values changed from 0.87 to 0.96. This finding increases our understanding of the effect of anisotropic reflectance on vegetation indices and enhances our ability to derive improved information from remote sensing data when these angular effects are prevalent for different surface targets.