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Airborne measurement of hot spot reflectance signatures / F. Camacho-De Coca in Remote sensing of environment, vol 90 n° 1 (15/03/2004)  

Public [article]  inRemote sensing of environment > vol 90 n° 1 (15/03/2004) . - pp 63 - 75 Titre : Airborne measurement of hot spot reflectance signatures Type de document : Article/Communication Auteurs : F. Camacho-De Coca, Auteur ; François-Marie Bréon, Auteur ; M. Leroy, Auteur ; F.J. Garcia-Haro, Auteur Année de publication : 2004 Article en page(s) : pp 63 - 75 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] ARAT [Termes IGN] composition colorée [Termes IGN] couvert végétal [Termes IGN] cultures [Termes IGN] distribution du coefficient de réflexion bidirectionnelle BRDF [Termes IGN] Espagne [Termes IGN] image DAIS [Termes IGN] image en couleur composée [Termes IGN] image HYMAP [Termes IGN] image POLDER [Termes IGN] Leaf Area Index [Termes IGN] réflectance végétale [Termes IGN] tâche claire [Termes IGN] transfert radiatif Résumé : (Auteur) The so-called hot spot is a fine directional signature of the surface reflectance observed for phase angles close to zero. In this paper, we analyze and discuss several such signatures acquired from the airborne POLDER and HyMap instruments during the DAISEX'99 campaign over agricultural crops. The observed signatures are very similar to those acquired from space at a resolution of several tens of kilometers [J. Geophys. Res. 107 (2002)], which provides further evidence that the hot spot is a scale-free feature. The hot spots can be fitted by a twoparameter function (amplitude and width) of the phase angle derived from canopy radiative transfer modeling. The model predicts that the amplitude is directly related to the leaf reflectance, while the width is a function of the canopy structure. The retrieved leaf reflectance values over a wide spectral range are in very good agreement with noncoincident laboratory measurement. The retrieved half widths are on the order of 1° with no significant variability between the analyzed targets. There is an apparent spectral variability in the half width, a feature in contradiction with the modeling, although the variations are not larger than the uncertainties. Numéro de notice : A2004-128 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2003.11.019 En ligne : https://doi.org/10.1016/j.rse.2003.11.019 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26655 [article]