Inversion of the PROSPECT + SAIL Canopy Reflectance Model from AVIRIS Equivalent Spectra: Theoretical Study
نویسنده
چکیده
T h e potentials and limits of estimating canopy parameters are investigated using only a reflectance spectrum in the optical domain, and the PROSPECT + SAIL model. Simulations are performed on A VIRIS (Airborne Visible~Infrared Imaging Spectrometer) equivalent spectra, corrected for the atmospheric effects. It is established that this model is numerically invertible. The sensitivity analysis of reflectance spectral features to changes in the values of canopy parameters (leaf mesophyll structure N, chlorophyll a + b concentration Cab, water depth Cw, leaf area index, LAL and average leaf inclination angle 01) suggests that the accuracy of the inversion procedure needs some constraints. The C~a, and Cw parameters, which describe the leaf physiological status, can be generally retrieved with a reasonable accuracy; it is somewhat di3ficult to estimate the canopy geometrical parameters (LAI and 01) separately. Determining the fraction of absorbed photosynthetic active radiation (APAR) with parameters derived from the inversion procedure is discussed.
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