Hydrological variability of large rivers in West Africa: gap-filling with Earth observations and daily rainfall-runoff modelling

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Název: Hydrological variability of large rivers in West Africa: gap-filling with Earth observations and daily rainfall-runoff modelling
Autoři: Ndiaye, Papa Malick, Ogilvie, Andrew, Bodian, Ansoumana, Descroix, Luc, Legay, Thomas, Guillet, Rémi
Přispěvatelé: NAULT, Isabelle
Zdroj: Hydrological Sciences Journal. 70:2219-2237
Informace o vydavateli: Informa UK Limited, 2025.
Rok vydání: 2025
Témata: [SDE] Environmental Sciences, West Africa, GR4J, hydrological variability, large rivers, hydrological modelling, satellite datasets, gap-filling
Popis: In West Africa, hydrological variability remains poorly understood in many watersheds where observation networks are sparse. After gap-filling gauge data with remote sensing datasets and daily rainfall-runoff modelling, the hydroclimatic variability in upper catchments of the Gambia, KolibaCorubal, KayangaGeba, and Senegal rivers is investigated. CHIRPS rainfall and GLEAM evapotranspiration are used to simulate discharge in 38 sub-basins over 1981-2023 with the GR4J model. Robust performance observed in 34 basins (KGE > 0.5) confirms the effectiveness of the approach even at a daily time step in poorly gauged basins. A dry period (1981-1993), followed by two distinct wet periods (1994-2007, 2008-2023) are identified using standardized precipitation index (SPI), standardized streamflow index (SSI) and the non-parametric Mann-Kendall test. Increased variability in extreme flows and a later peak flood are observed in some basins. Understanding non-stationarity in West African basins is essential to support stakeholders in defining adequate river basin development strategies.
Druh dokumentu: Article
Jazyk: English
ISSN: 2150-3435
0262-6667
DOI: 10.1080/02626667.2025.2542477
Přístupová URL adresa: https://hal.inrae.fr/hal-05281295v1
https://doi.org/10.1080/02626667.2025.2542477
Přístupové číslo: edsair.doi.dedup.....faa808bdd7fd50349542053d32a05624
Databáze: OpenAIRE
Popis
Abstrakt:In West Africa, hydrological variability remains poorly understood in many watersheds where observation networks are sparse. After gap-filling gauge data with remote sensing datasets and daily rainfall-runoff modelling, the hydroclimatic variability in upper catchments of the Gambia, KolibaCorubal, KayangaGeba, and Senegal rivers is investigated. CHIRPS rainfall and GLEAM evapotranspiration are used to simulate discharge in 38 sub-basins over 1981-2023 with the GR4J model. Robust performance observed in 34 basins (KGE > 0.5) confirms the effectiveness of the approach even at a daily time step in poorly gauged basins. A dry period (1981-1993), followed by two distinct wet periods (1994-2007, 2008-2023) are identified using standardized precipitation index (SPI), standardized streamflow index (SSI) and the non-parametric Mann-Kendall test. Increased variability in extreme flows and a later peak flood are observed in some basins. Understanding non-stationarity in West African basins is essential to support stakeholders in defining adequate river basin development strategies.
ISSN:21503435
02626667
DOI:10.1080/02626667.2025.2542477