Publications des scientifiques de l'IRD

Magagi R.D., Kerr Y.H. (1996). Vegetation cover study over arid semi-arid areas : use of ERS1 wind scatterometer. In : Hoepffner Michel (ed.), Lebel Thierry (ed.), Monteny Bruno (ed.). Interactions surface continentale/atmosphère : l'expérience HAPEX-Sahel. Paris : ORSTOM, p. 619-634. (Colloques et Séminaires). Journées Hydrologiques, 10., Montpellier (FRA), 1994/09/13-14. ISBN 2-7099-1307-0. ISSN 0767-2896.

Titre du document
Vegetation cover study over arid semi-arid areas : use of ERS1 wind scatterometer
Année de publication
1996
Type de document
Partie d'ouvrage
Auteurs
Magagi R.D., Kerr Y.H.
In
Hoepffner Michel (ed.), Lebel Thierry (ed.), Monteny Bruno (ed.) Interactions surface continentale/atmosphère : l'expérience HAPEX-Sahel
Source
Paris : ORSTOM, 1996, p. 619-634 (Colloques et Séminaires). ISBN 2-7099-1307-0 ISSN 0767-2896
Colloque
Journées Hydrologiques, 10., Montpellier (FRA), 1994/09/13-14
The ERS-1 wind scatterometer (5.3 Ghz) operates in VV polarization with a resolution of 50 km. For a particular target, it measures three backscattering coefficients from its 3 antennas. The aim of this study is to use the information delivered by the wind scatterometer over land surfaces in arid and semi-arid environments to infer soil moisture. The rationale of the approach presented is that, if we assume that the soil/vegetation interaction term can be ignored, the signal is the sum of soil and vegetation contributions. The soil contribution is driven by the soil's dielectric properties and surface roughness. In the presence of vegetation, this contribution is attenuated by a factor which depends on canopy characteristics (water content, shape, height, density) and radiometer viewing characteristics. To assess and monitor soil moisture, a knowledge of the vegetation characteristics is thus required. In order to quantify the influence of vegetation on the signal, we will use a semi-empirical model (first order radiative transfer model), extract canopy optical thickness (tau) and simple scattering albedo using the angle dependence. The different contributions of the signal will be compared within different angular ranges. The semi-empirical model will be applied at low incidence angles to retrieve soil moisture. (Résumé d'auteur)
Plan de classement
Dynamique de l'eau à l'interface sol-plante-atmosphère [062MECEAU02] ; Hydrologie [126TELAPP04]
Descripteurs
COUVERT VEGETAL ; HUMIDITE DU SOL ; RADIOMETRIE ; TELEDETECTION SPATIALE ; SATELLITE ERS1 ; SIMULATION ; VARIATION TEMPORELLE
Description Géographique
ZONE ARIDE ; ZONE SEMIARIDE ; NIGER
Localisation
Fonds IRD [F A010008340] ; Montpellier (Centre IRD) ; Montpellier (Maison des Sciences de l'Eau)
Identifiant IRD
fdi:010008381
Contact