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Titel |
An evaluation of ASCAT surface soil moisture products with in-situ observations in Southwestern France |
VerfasserIn |
C. Albergel, C. Rüdiger, D. Carrer, J.-C. Calvet, N. Fritz, V. Naeimi, Z. Bartalis, S. Hasenauer |
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 ; 13, no. 2 ; Nr. 13, no. 2 (2009-02-04), S.115-124 |
Datensatznummer |
250011754
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Publikation (Nr.) |
copernicus.org/hess-13-115-2009.pdf |
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Zusammenfassung |
A long term data acquisition effort of profile soil moisture is currently
underway at 13 automatic weather stations located in Southwestern France. In
this study, the soil moisture measured in-situ at 5 cm is used to evaluate
the normalised surface soil moisture (SSM) estimates derived from
coarse-resolution (25 km) active microwave data of the ASCAT scatterometer
instrument (onboard METOP), issued by EUMETSAT for a period of 6 months
(April–September) in 2007. The seasonal trend is removed from the satellite
and in-situ time series by considering scaled anomalies. One station
(Mouthoumet) of the ground network, located in a mountainous area, is
removed from the analysis as very few ASCAT SSM estimates are available. No
correlation is found for the station of Narbonne, which is close to the
Mediterranean sea. On the other hand, nine stations present significant
correlation levels. For two stations, a significant correlation is obtained
when considering only part of the ASCAT data. The soil moisture measured
in-situ at those stations, at 30 cm, is used to estimate the characteristic
time length (T) of an exponential filter applied to the ASCAT product. The
best correlation between a soil water index derived from ASCAT and the
in-situ soil moisture observations at 30 cm is obtained with a T-value of 14
days. |
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