Proc. Int. Coll. Photosynthesis and Remote Sensing, 28-30 Aug. 1995, Montpellier (France), EARSel, Paris & INRA, Avignon, 1995, 149-157.
The procedure of estimating forest ecosystem parameters by inversion of a forest reflectance model developed by Nilson is described. The examples of inversion for a Quercus ilex L. stand near Montpellier, France are given. Different data were used for inversion: nadir reflectance factors measured by a four-channel radiometer from a tower above the canopy, Landsat TM, band 3 and 4 reflectances as well as total and diffuse canopy transmission coefficients measured with the radiometer. Leaf area indices of the Q. ilex stand determined by inversion of the reflectance model and other methods are compared to each other and the main causes of differences analyzed. A reliable estimation of ecosystem structural and optical parameters by inversion needs considerable a priori information about the values of other key parameters of the ecosystem and the existing relations between the ecosystem parameters.
KEY WORDS: Forest remote sensing, Reflectance models, Inverse problems, Leaf area index