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TitleImpact des conditions internes et externes aux couverts forestiers sur les indices spectraux dérivés de AVHRR
AuthorBannari, A; Teillet, P M; Richardson, G; Leckie, G; Fedosejevs, G
SourceProceedings of the 20th Canadian Symposium on Remote Sensing, Calgary, Canada; 1998 p. 169-174
Alt SeriesEarth Sciences Sector, Contribution Series 20042642
AbstractThis study addresses the analysis of the impact of variation of conditions intrinsic and extrinsic to forest canopies on spectral indices derived from simulated AVHRR data. Only the indices designed to minimize disturbing effects and to increase the signal emitted by vegetation were considered. To this end, spectroradiometric measurements of bare soils with various optical properties and a forest canopy at various degrees of defoliation were used. As a whole, the indices considered show conflicting strengths and weaknesses and none of them meet the requirements of an optimal index for a forest environment : if one index is resistant to one effect, it becomes sensitive to the other effects and vice versa. However, if data are adequately corrected for atmospheric effects, MSAVI may be the optimal index for the description of biophysical parameters in a forest environment. While being non-linear, it shows a good potential for minimizing the effects of the spectral properties of bare soils and it does not saturate in the presence of a very dense canopy, which allows differentiation between the various stand density levels and the various phenological changes that can occur.

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