ABSTRACT

Limited efforts have been made to investigate the utility of radiative transfer models for grassland canopies, and fewer still for heterogeneous ones. This study explored the potential of the Soil-Leaf-Canopy (SLC) model, a recent development of the widely used PROSAIL model for estimating leaf chlorophyll content in a heterogeneous northern mixed grassland. By means of a lookup table (LUT), the SLC model was inverted for estimating leaf chlorophyll content. A sensitivity analysis was performed prior to parameterizing the LUT for model inversion. Four scenes, including a green canopy, a mixed canopy with green and brown material, and two mixed canopies with fractional gaps including green and brown material and soil, were tested. Leaf chlorophyll content for the green canopy was predicted with high accuracy [root-mean-square error (RMSE) = 0.01], but was overestimated for the mixed green and brown canopy (RMSE = 0.02) and mixed green and brown canopies with exposed soil (RMSE = 0.02–0.03). Results indicated that the SLC model could not correctly simulate brown pigment and background soil, but confirmed the potential for estimating leaf chlorophyll content for grass species. We conclude by providing insight regarding the recalibration of the SLC model for future investigation of heterogeneous grass canopies.