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| Titel |
Modelling soil moisture at SMOS scale by use of a SVAT model over the Valencia Anchor Station |
| VerfasserIn |
S. Juglea, Y. Kerr, A. Mialon, J.-P. Wigneron, E. Lopez-Baeza, A. Cano, A. Albitar, C. Millan-Scheiding, M. Carmen Antolin, S. Delwart |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 14, no. 5 ; Nr. 14, no. 5 (2010-05-28), S.831-846 |
| Datensatznummer |
250012304
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| Publikation (Nr.) |
 copernicus.org/hess-14-831-2010.pdf |
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| Zusammenfassung |
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 Science preparation for SMOS, the
Valencia Anchor Station (VAS) experimental site, in Spain,
was chosen to be one of the main test sites in Europe for
Calibration/Validation (Cal/Val) activities.
In this framework, the paper presents an approach consisting in accurately simulating a whole SMOS
pixel by representing the spatial and temporal heterogeneity of the soil moisture fields over the wide VAS surface
(50×50 km2). 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) to simulate the spatial and temporal
distribution of surface soil moisture. The calibration as well as the
validation of the ISBA model are performed using in situ soil moisture
measurements. It is shown that a good consistency is reached when point
comparisons between simulated and in situ soil moisture measurements are
made.
Actually, an important challenge in remote sensing approaches concerns
product validation. In order to obtain an representative soil moisture mapping over the Valencia
Anchor Station (50×50 km2 area), a spatialization method is applied.
For verification, a comparison between the simulated spatialized soil
moisture and remote sensing data from the Advanced Microwave Scanning Radiometer on Earth observing System
(AMSR-E) and from the European Remote Sensing Satellites (ERS-SCAT) is
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 are also used to be compared with the simulated spatialized soil
moisture. However, the lack of
soil moisture data from the ERS-SCAT sensor over the area (45 observations for one year)
prevented capturing the soil moisture variability. |
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