Estimation of dry matter content in leaves using normalized indexes and PROSPECT model inversion
2012
Romero, Agnes | Aguado, Inmaculada | Yebra, Marta
This work applies remote sensing techniques to estimate dry matter (DM) content in tree leaves. Two methods were used to estimate DM content: a normalized index obtained from the radiative transfer model (RTM) leaf optical properties spectra (PROSPECT) in direct mode and the inversion of the PROSPECT model. The data were obtained from the Leaf Optical Properties Experiment 93 (LOPEX93) database, and only 11 species were used in this study. The species selection was based mainly on the availability of data on fresh and dry samples. The estimation of DM content was obtained from an exponential function that correlated the values of the index proposed, (R ₂₃₀₅ − R ₁₄₉₅)/(R ₂₃₀₅ + R ₁₄₉₅), against the DM content of fresh and dry leaf samples. The determination coefficient obtained (r ² = 0.672) was higher than the coefficient obtained from the inversion of the PROSPECT model (r ² = 0.507). The data set used to validate the normalized index was provided by the Accelerated Canopy Chemistry Program (ACCP). The determination coefficient between the values obtained from ACCP data and the values estimated for the normalized index was r ² = 0.767.
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