AVHRR-derived vegetation mapping over Western Europe for use in numerical weather prediction models
Cartographie de la végétation sur l'Europe de l'Ouest dérivée d'AVHRR pour utilisation dans les modèles de prévision numérique du temps
Champeaux, J.-L. ; Arcos, D. ; Bazile, E. ; Giard, D. ; Goutorbe, J.-P. ; Habets, F. ; Noilhan, J. ; Rougean, J.-L.
Année de publication
2000
During the past decade, significant progress has been made towards the <br>development of surface schemes for Numerical Weather Prediction (NWP) <br>models. In order to simulate surface processes in such models <br>adequately, a realistic description of surface properties is necessary. <br>This is achieved using time series of NOAA (National Oceanic and <br>Atmospheric Administration) AVHRR (Advanced Very High Resolution <br>Radiometer) satellite data, and the method relies on an automatic <br>clustering of multi-temporal NDVI (Normalized Difference Vegetation <br>Index) maximum values. This leads to eleven vegetation classes where the<br> forests are readily identified from a thorough analysis of visible <br>reflectances in early summer. This intermediate step and look-up tables <br>allow for a final mapping of the roughness length, leaf area index, <br>fractional vegetation cover and minimum stomatal resistance. These are <br>primary parameters of the land surface parameterization scheme ISBA used<br> at Meteo-France and are updated from the seasonality of NDVI. In a last<br> step, parameters are spatially averaged at the grid box scale according<br> to aggregation rules. The reliability of the mapping is demonstrated <br>through the improvements of the French NWP model in short-range <br>forecasts.</div>
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