Evaluation of soil moisture downscaling using a simple thermal-based proxy – the REMEDHUS network (Spain) example
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...
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doaj-627b08ac20ec44f3a7604b91f7afc2cd2020-11-24T23:45:21ZengCopernicus PublicationsHydrology and Earth System Sciences1027-56061607-79382015-12-0119124765478210.5194/hess-19-4765-2015Evaluation of soil moisture downscaling using a simple thermal-based proxy – the REMEDHUS network (Spain) exampleJ. Peng0J. Niesel1A. Loew2Max Planck Institute for Meteorology, 20146 Hamburg, GermanyMax Planck Institute for Meteorology, 20146 Hamburg, GermanyMax Planck Institute for Meteorology, 20146 Hamburg, GermanySoil 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.http://www.hydrol-earth-syst-sci.net/19/4765/2015/hess-19-4765-2015.pdf |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
J. Peng J. Niesel A. Loew |
spellingShingle |
J. Peng J. Niesel A. Loew Evaluation of soil moisture downscaling using a simple thermal-based proxy – the REMEDHUS network (Spain) example Hydrology and Earth System Sciences |
author_facet |
J. Peng J. Niesel A. Loew |
author_sort |
J. Peng |
title |
Evaluation of soil moisture downscaling using a simple thermal-based proxy – the REMEDHUS network (Spain) example |
title_short |
Evaluation of soil moisture downscaling using a simple thermal-based proxy – the REMEDHUS network (Spain) example |
title_full |
Evaluation of soil moisture downscaling using a simple thermal-based proxy – the REMEDHUS network (Spain) example |
title_fullStr |
Evaluation of soil moisture downscaling using a simple thermal-based proxy – the REMEDHUS network (Spain) example |
title_full_unstemmed |
Evaluation of soil moisture downscaling using a simple thermal-based proxy – the REMEDHUS network (Spain) example |
title_sort |
evaluation of soil moisture downscaling using a simple thermal-based proxy – the remedhus network (spain) example |
publisher |
Copernicus Publications |
series |
Hydrology and Earth System Sciences |
issn |
1027-5606 1607-7938 |
publishDate |
2015-12-01 |
description |
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. |
url |
http://www.hydrol-earth-syst-sci.net/19/4765/2015/hess-19-4765-2015.pdf |
work_keys_str_mv |
AT jpeng evaluationofsoilmoisturedownscalingusingasimplethermalbasedproxytheremedhusnetworkspainexample AT jniesel evaluationofsoilmoisturedownscalingusingasimplethermalbasedproxytheremedhusnetworkspainexample AT aloew evaluationofsoilmoisturedownscalingusingasimplethermalbasedproxytheremedhusnetworkspainexample |
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1725496087010082816 |