Ndiaye P. M. auteur aut IRD Ogilvie Andrew auteur aut IRD Bodian A. auteur aut IRD Descroix Luc auteur aut IRD Legay T. auteur aut IRD Guillet R. auteur aut IRD text journalArticle eng text/pdf born digital access 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. specialized gap-filling satellite datasets hydrological modelling hydrological variability West Africa large rivers GR4J AFRIQUE DE L'OUEST GAMBIE GUINEE GUINEE BISSAU SENEGAL MAURITANIE MALI GAMBIE COURS D'EAU KAYANGA GEBA COURS D'EAU KOLIBA CORUBAL COURS D'EAU SENEGAL COURS D'EAU BASSIN VERSANT 062 072 020 Early access [19 p.] 2025 0262-6667 https://www.documentation.ird.fr/hor/fdi:010094962 10.1080/02626667.2025.2542477 0262-6667 [F B010094962] https://www.documentation.ird.fr/hor/fdi:010094962 https://www.documentation.ird.fr/intranet/publi/2025-10/010094962.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2025-10-29 2025-11-04 fdi:010094962 fre