Assessing forest parameters by radiative transfer modelling

Two-layer homogeneous canopy reflectance model ACRM is applied for the estimation of leaf area index of forested landscape using Proba/CHRIS spectral signatures and model inversion. A regularity parameter in the model accounts for the grouping of foliage into tree crowns. Results of LAI estimation at the Järvselja forested test site, Estonia, are compared to LAI estimates in MODIS and MERIS land products for the test site. The estimated LAI values from ACRM inversion using CHRIS data have wide range because of smaller pixel size. In general, LAI values from CHRIS data are between MODIS and MERIS LAI values, however, systematically less than allometric LAI of forest stands.