Lake Maggiore - Italy, 3-6 April 2000 Development of a spectral index optimized for the VEGETATION InstrumentNadine
Gobron, Bernard Pinty, Michel M. Verstraete, Jean-Luc Widlowski Vegetation indices have traditionally been used to interpret satellite remote sensing data, for example in terms of land cover types or to estimate simple vegetation characteristics. To the extent that the radiances measured by the sensors at the top of the atmosphere are affected not only by the plant cover but also by the atmosphere and the underlying soil, these indices may be significantly affected by these undesirable perturbations. One approach would be to correct the data to take these effects into account, but this requires access to considerable additional data sets (e.g., the analysis of large amounts of weather data). An alternative approach consists in developing new indices designed to remain sensitive to the presence of vegetation, but also to be less sensitive to these perturbing factors. This research proposal permitted the developement of a spectral index optimized to monitor vegetation on the basis of the radiometric data which are produced by the VEGETATION instrument. This index is designed to represent the Fraction of Absorbed Photosynthetically Active Radiation. The performance of this index has been evaluated and compared to existing indices. This evaluation has been based on a large set of simulations including various atmospheric type and composition as well as surface conditions. A preliminary application of this optimized index against actual VEGETATION data will be shown. |
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