Evaluation of recent hydro-climatic changes in four tributaries of the Niger River Basin (West Africa) |
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Authors: | Djigbo Félicien Badou Evison Kapangaziwiri Bernd Diekkrüger Jean Hounkpè Abel Afouda |
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Affiliation: | 1. Graduate Research Programme on Climate Change and Water Resources (GRP CCWR), West African Science Service Centre on Climate Change and Adapted Land Use (WASCAL), University of Abomey-Calavi, Cotonou, Benin;2. Hydrosciences Research Group, CSIR Natural Resources and the Environment, Pretoria, South Africa;3. Department of Geography, University of Bonn, Bonn, Germany |
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Abstract: | West Africa experienced severe drought during the 1970s and 1980s, posing a threat to water resources. A wetter climate more recently suggests recovery from the drought. The Mann-Kendall trend and Theil-Sen’s slope estimator were applied to detect probable trends in weather elements in four sub-basins of the Niger River Basin between 1970 and 2010. The cross-entropy method was used to detect breakpoints in rainfall and runoff, Spearman’s rank test for correlation between the two, and cross-correlation analysis for possible lags. Results showed an overall increase in rainfall and runoff and a decrease in sunshine duration. Spearman’s coefficients suggest significant (5%) moderate to strong rainfall–runoff correlation for three sub-basins. A significant lower runoff was observed around 1979, with a rainfall break around 1992, indicating possible cessation of the drought. Temperatures increased significantly, at 0.02–0.05°C year-1, with a negative wind speed trend for most stations. Half of the stations exhibited an increase in potential evapotranspiration.EDITOR M.C. AcremanASSOCIATE EDITOR Not assigned |
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Keywords: | Climate variability climate trends breakpoint analysis cross-entropy method Benin |
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