Détermination du volume des troncs des forêts à partir de données VHF RSO : observation et modélisation
| Autor: | Melon, P., Martinez, J.M., Le Toan, Thuy, Ulander, L.M., Beaudoin, Amélie |
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| Přispěvatelé: | Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), FOI LINKOPING SWE, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Laboratoire commun de télédétection (UR LCMO), Centre national du machinisme agricole, du génie rural, des eaux et forêts (CEMAGREF), Ecole Nationale du Génie Rural, des Eaux et des Forêts (ENGREF) |
| Jazyk: | angličtina |
| Rok vydání: | 2001 |
| Předmět: | |
| Zdroj: | IEEE Transactions on Geoscience and Remote Sensing IEEE Transactions on Geoscience and Remote Sensing, Institute of Electrical and Electronics Engineers, 2001, 39 (11), pp.2364-2372 |
| ISSN: | 0196-2892 |
| Popis: | International audience; The objective of this paper is to investigate the relationships between VHF data and forest biomass using data acquired by the Airborne Imaging Radar CARABAS over two different pine plantation forests in southern France. Data are analyzed using detailed ground truth measurements available on both sites. The backscattering coefficient is strongly correlated to characteristics of the tree trunk. Signal saturation is not observed up to goo m(3)/ha. However, the sensitivity to the volume is high in the range of 0-500 m(3)/ha (e.g., 1 to 1.5 dB for 50 m(3)/ha), whereas it is reduced beyond 500 m(3)/ba (< 0.5 dB for 50 m(3)/ha). The experimental analysis is supported by theoretical modeling using a coherent backscatter model based on the distorted Born approximation coupled with a tree growth model giving a fine and precise description of the trees at both sites. The modeling results show that the trunk is the main scatterer, but that, when the branch dimensions are not insignificant compared to trunk dimension, branch scattering needs to be accounted for. However, since the two species under study are both coniferous, branch dimensions are relatively small compared to trunk dimension. This explains no significant differences observed in the backscatter behavior between both sites, except for mature stands with low stem density. Finally, the effect of topography is investigated both experimentally, using a digital elevation model (DEM), and theoretically with the coherent model. The loss of sensitivity to stem volume due to slope is clearly demonstrated and explained by the decrease of the dihedral trunk-ground interaction as the slope increases. |
| Databáze: | OpenAIRE |
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