Retrieval of Forest Canopy Parameters by Inversion of the PROFLAIR Leaf-Canopy Reflectance Model Using the LUT Approach

The potential of simulating broad leaf forest canopy spectral reflectance using a canopy-leaf PROFLAIR (PROSPECT + FLAIR) model was investigated in this study. The model was inverted with hyperspectral Hyperion data using a look up table (LUT) approach to retrieve canopy leaf area index (LAI), leaf chlorophyll content (C_a+b) and canopy integrated chlorophyll content (LAI × C_a+b). The LUT was populated by simulating the model in forward mode using a space of realization generated based on the specific distribution of the input parameters and based on a priori information from the field. The estimated variables were then compared to ground measurements collected in the field. The results showed the ability of the PROFLAIR model to realistically simulate canopy spectral reflectance. When compared to ground measurements, the model showed a reasonable performance to retrieve canopy LAI with an RMSE of 0.47 and leaf chlorophyll content with an RMSE of 4.46 μg/cm².