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| Titel |
Evaluation of soil moisture downscaling using a simple thermal-based proxy – the REMEDHUS network (Spain) example |
| VerfasserIn |
J. Peng, J. Niesel, A. Loew |
| 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 ; 19, no. 12 ; Nr. 19, no. 12 (2015-12-03), S.4765-4782 |
| Datensatznummer |
250120863
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| Publikation (Nr.) |
 copernicus.org/hess-19-4765-2015.pdf |
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| Zusammenfassung |
| Soil moisture retrieved from satellite microwave remote sensing normally has
spatial resolution on the order of tens of kilometers, which are too coarse
for many regional hydrological applications such as agriculture monitoring
and drought prediction. Therefore, various downscaling methods have been
proposed to enhance the spatial resolution of satellite soil moisture
products. The aim of this study is to investigate the validity and
robustness of the simple vegetation temperature condition index (VTCI)
downscaling scheme over a dense soil moisture observational network
(REMEDHUS) in Spain. First, the optimized VTCI was determined through
sensitivity analyses of VTCI to surface temperature, vegetation index,
cloud, topography, and land cover heterogeneity, using data from
Moderate Resolution Imaging Spectroradiometer~(MODIS) and
MSG SEVIRI (METEOSAT Second Generation – Spinning Enhanced
Visible and Infrared Imager). Then the downscaling scheme was applied to improve the spatial
resolution of the European Space Agency's Water Cycle Multi-mission
Observation Strategy and Climate Change Initiative (ESA CCI) soil moisture,
which is a merged product based on both active and passive microwave
observations. The results from direct validation against soil moisture
observations, spatial pattern comparison, as well as seasonal and land use
analyses show that the downscaling method can significantly improve the
spatial details of CCI soil moisture while maintaining the accuracy of CCI soil
moisture. The accuracy level is comparable to other downscaling methods that
were also validated against the REMEDHUS network. Furthermore, slightly better
performance of MSG SEVIRI over MODIS was observed, which suggests the high
potential of applying a geostationary satellite for downscaling soil moisture
in the future. Overall, considering the simplicity, limited data
requirements and comparable accuracy level to other complex methods, the
VTCI downscaling method can facilitate relevant hydrological applications
that require high spatial and temporal resolution soil moisture. |
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