Effect of the vegetation clumping on the BRDF of a semi-arid grassland: comparison of the SAIL model and ray tracing method applied to a 3D computerized vegetation canopy

Luquet D., Bégué Agnès, Dauzat Jean, Nouvellon Yann, Rey Hervé. 1998. Effect of the vegetation clumping on the BRDF of a semi-arid grassland: comparison of the SAIL model and ray tracing method applied to a 3D computerized vegetation canopy. In : IGARSS'98 IEEE International Geoscience and Remote Sensing symposium proceedings "sensing and managing the environment". IEEE. Piscataway : IEEE, 791-793. International Geoscience and Remote Sensing Symposium, Seattle, États-Unis, 6 Juillet 1998/10 Juillet 1998.

Autre titre : Effet de l'agrégation de la végétation sur la BRDF d'une prairie semi-aride : comparaison du modèle SAIL et de la méthode du "lancer de rayons" sur maquette 3D du couvert végétal

Résumé : A 3D model of vegetation, the AMAP Software (Atelier de Modélisation de l'Architecture des Plantes, CIRAD), is used with a ray-tracing method to compute radiative transfer of sparse canopies. In a first step, the ray-tracing model is validated against two well-known radiative transfer models: a turbid medium model, SAIL, in the case of an homogeneous canopy, and a geometrical model of cylinders for clumped vegetation. Then, botanical measurements of semi-arid grassland acquired during SALSA project in 1997 (Sonora, Mexico) are used to create 3D realistic scenes of vegetation. The BRDF (bidirectional reflectance distribution function) of these 3D scenes is compared to the BRDF of a turbid medium equivalent in terms of vegetation parameters (leaf area index, leaf angle inclination ...). It is then possible to evaluate the error committed when sparse clumped canopies are treated as turbid mediums.

Mots-clés Agrovoc : herbage, couvert, modèle de simulation, bilan radiatif, climat semi-aride, modélisation

Mots-clés géographiques Agrovoc : Sonora

Classification Agris : U30 - Méthodes de recherche
U10 - Informatique, mathématiques et statistiques
F50 - Anatomie et morphologie des plantes

Auteurs et affiliations

• Luquet D.
• Bégué Agnès, CIRAD-AMIS-AGRONOMIE (FRA)
• Dauzat Jean, CIRAD-AMIS-AGRONOMIE (FRA)
• Nouvellon Yann ORCID: 0000-0003-1920-3847
• Rey Hervé, CIRAD-AMIS-AMAP (FRA)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/390378/)

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