CHLOROPHYLL a+b CONTENT ESTIMATION THROUGH TURBID-MEDIUM AND MONTE-CARLO RT MODEL INVERSION FOR FOREST CANOPIES USING HYPERSPECTRAL DATA

Predictions of chlorophyll content (chla+b) or any other canopy biophysical parameter from airborne or satellite canopy reflectance are generally carried out through four different methodologies: i) directly studying the statistical relationships between ground-measured biochemical data and canopy-measured reflectance (Johnson et al., 1994; Matson et al., 1994); ii) applying the leaf-level relationships derived between optical indices and the pigment content directly to canopy-measured reflectance (Peterson et al., 1988; Yoder and Pettigrew-Crosby, 1995; Zagolski et al., 1996); iii) scaling-up the leaf-level relationships based on optical indices related to pigment content through models of canopy reflectance or infinite reflectance (Zarco-Tejada et al., 1999a; 1999b; 2000); and iv) inverting the observed canopy reflectance through a canopy reflectance or infinite reflectance model coupled with a leaf model to estimate the optimum pigment content (Jacquemoud et al., 1995; Kuusk, 1998; Demarez and GastelluEtchegorry, 2000; Weiss et al., 2000; Jacquemoud et al., 2000).