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Persistent Identifier
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perma:LIST.XVV1YK |
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Publication Date
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2026-07-06 |
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Title
| Spatially remotely sensed evapotranspiration estimates in Sahel region using an ensemble contextual model with automated heterogeneity assessment [* Cross-Reference *] |
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Other Identifier
| https://doi.org/10.1016/j.srs.2025.100229
SCOPUS_ID:105004914926 |
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Author
| Farhani, Nesrine (Laboratoire HydroSciences Montpellier) - ORCID: 0000-0003-1568-7143
Etchanchu, Jordi (Laboratoire HydroSciences Montpellier) - ORCID: 0000-0001-7330-0686
Boulet, Gilles (Université de Toulouse, Indo French Cell for Water Sciences) - ORCID: 0000-0002-3905-7560
Gamet, Philippe (Université de Toulouse)
Olioso, Albert (Ecologie des Forêts Méditerranéennes (URFM)) - ORCID: 0000-0001-8342-9272
Dezetter, Alain (Laboratoire HydroSciences Montpellier)
Bodian, Ansoumana (Université Gaston Berger de Saint-Louis)
Chahinian, Nanée (Laboratoire HydroSciences Montpellier) - ORCID: 0000-0002-0037-5377
Mallick, Kanishka (Luxembourg Institute of Science and Technology, Department of Environmental Science, Policy, and Management)
Ollivier, Chloé (Laboratoire HydroSciences Montpellier)
Roupsard, Olivier (Université de Montpellier, CIRAD, Institut de Recherche pour le Développement Dakar) - ORCID: 0000-0002-1319-142X
Allies, Aubin (Laboratoire HydroSciences Montpellier, GreenTriangle SAS) - ORCID: 0000-0002-1589-5797
Demarty, Jérôme (Laboratoire HydroSciences Montpellier) - ORCID: 0000-0001-5173-9030 |
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Point of Contact
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Use email button above to contact.
LIST RDS (LIST) |
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Description
| Water scarcity and the inter-annual variability of water resources in semi-arid areas are limiting factors for agricultural production. The characterization of plant water use, together with water stress, can help us to monitor the impact of drought on agrosystems and ecosystems, especially in the Sahel region. Indeed, this region is identified as a ”hot spot” for climate change. In-situ measurements often are insufficient for accounting for spatial variability at large scales (>100 km) due to the scarcity of gauge networks. To tackle this issue, remotely sensed evaporation is often used. In this study, estimates using thermal infrared and visible data from MODIS/TERRA and AQUA are used. Spatially distributed estimates of the daily actual evapotranspiration (ETd) are simulated using the EVASPA S-SEBI Sahel (E3S) ensemble contextual method over a mesoscale area (145x145 km) in central Senegal. E3S uses a set of different methods in order to identify the dry and wet edges of the surface temperature/albedo scatterplot and therefore estimate the evaporative fraction (EF). However, contextual approaches assume the simultaneous presence of sufficient fully wet and fully dry pixels within the same satellite image. This assumption of heterogeneity does not always hold, especially in the Sahel, which is characterized by the alternation of dry and wet seasons due to the monsoon-influenced climate. To tackle this issue, E3S uses different sets of methods depending on the season, based on local knowledge. The present study thus aims at generalizing the approach by proposing a new version of E3S called ”E3S-V2”. This latter allows an automatic detection of different heterogeneity conditions. Therefore, a sensitivity analysis examining the effect of using different EF estimation methods over different spatial coverages was performed. It made it possible to identify relevant normalized indicators to determine the heterogeneity level, as well as to discriminate among the most adapted EF determination methods for each situation. From this analysis, an automated procedure of method selection according to the heterogeneity conditions is proposed. A local-scale evaluation was performed using eddy-covariance measurements in the Senegal Groundnut Basin. A spatialized evaluation was also performed using GLEAM and ERA5-Land, which are proven reference ETd products over the area. ”E3S-V2” simulations yield comparable performances with in-situ and reference products in our study area. (2025-06-01)
***This entry has been automatically imported via Infodoc(ASO) CSV by LIST harvest scripts. Please refer to https://doi.org/10.1016/j.srs.2025.100229 for the original and latest version of the dataset and data downloads*** (2026-06-09) |
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Subject
| Earth and Environmental Sciences |
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Keyword
| Contextual
evapotranspiration
EVASPA
S-SEBI
Sahel
Semi-arid |
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Funding Information
| Centre National d’Etudes Spatiales |
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Deposit Date
| 2025-06-01 |
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Data Type
| Article |
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Data Source
| Science of Remote Sensing; eISSN: 26660172, vol. 11, 2025 |