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Modelling soil moisture at SMOS scale by use of a SVAT model over the Valencia Anchor Station
1Centre d'Études Spatiales de la BIOsphére, UMR 5126 (CNRS, CNES, IRD, UPS), Toulouse, France
2Ecologie fonctionnelle et PHYSique de l'Environnement (INRA/EPHYSE), Bordeaux, France
3Universitat de Valencia, Departament de Termodinamica i Fisica de la Terra, Valencia, Spain
4Center for Desertification Research (CIDE), Dept. of Territorial Planning, Valencia, Spain
5European Space Research and Technology Centre (ESA/ESTEC), Noordwijk, The Netherlands
Abstract. The main goal of the SMOS (Soil Moisture and Ocean Salinity) mission is to deliver global fields of surface soil moisture and sea surface salinity using L-band (1.4 GHz) radiometry. Within the context of the preparation for this mission over land, the Valencia Anchor Station experimental site, in Spain, was chosen to be one of the main test sites in Europe for the SMOS Calibration/Validation (Cal/Val) activities. Ground and meteorological measurements over the area are used as the input of a Soil-Vegetation-Atmosphere-Transfer (SVAT) model, SURFEX (Externalized Surface)-module ISBA (Interactions between Soil-Biosphere-Atmosphere) so as to simulate the surface soil moisture. The calibration as well as the validation of the ISBA model was made using in situ soil moisture measurements. It is shown that a good consistency was reached when point comparisons between simulated and in situ soil moisture measurements were made. In order to obtain an accurate soil moisture mapping over the Valencia Anchor Station (50×50 km2 area), a spatialization method has been applied. To validate the approach, a comparison with remote sensing data from the Advanced Microwave Scanning Radiometer on Earth observing System (AMSR-E) and from the European Remote Sensing Satellites (ERS-Scat) was performed. Despite the fact that AMSR-E surface soil moisture product is not reproducing accurately the absolute values, it provides trustworthy information on surface soil moisture temporal variability. However, during the vegetation growing season the signal is perturbed. By using the polarization ratio a better agreement is obtained. ERS-Scat soil moisture products were also used to be compared with the simulated spatialized soil moisture. The seasonal variations were well reproduced. However, the lack of soil moisture data over the area (45 observations for one year) was a limit into completely understanding the soil moisture variability.
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Citation: Juglea, S., Kerr, Y., Mialon, A., Wigneron, J.-P., Lopez-Baeza, E., Cano, A., Albitar, A., Millan-Scheiding, C., Carmen Antolin, M., and Delwart, S.: Modelling soil moisture at SMOS scale by use of a SVAT model over the Valencia Anchor Station, Hydrol. Earth Syst. Sci. Discuss., 7, 649-686, 2010. Bibtex EndNote Reference Manager
