Methods of sensitivity analysis in remote sensing: implications for canopy reflectance model inversion

Local and global sensitivity analysis (SA) methods were compared to demonstrate how the choice of SA method leads to differences in the quantification of the relative importance of model parameters in driving canopy reflectance variability. The global SA method used was the Extended Fourier Amplitude Sensitivity Test (EFAST), while a series of basecase simulations were defined for the local SA, and model parameters were perturbed sequentially. Canopy reflectance was simulated using the ProGOSAIL model. Some pronounced differences were found between the two methods in terms of the magnitude of the importance, the rank importance, and the wavelengths at which model parameters are most important in explaining reflectance variability.