Variability in flood frequency in sub-Saharan Africa: The role of large-scale climate modes of variability and their future impacts

• DOI: 10.1016/j.jhydrol.2024.131679
• Publication Date: 2024-07-14T18:56:33Z
• Authors: Job Ekolu; Bastien Dieppois; Yves Tramblay; Gabriele Villarini; Louise J. Slater; Gil Mahé; Jean-Emmanuel Pat...; Jonathan M. Eden; Simon Moulds; Moussa Sidibe; Pierre Camberlin; Benjamin Pohl; Marco van de Wiel
• Keywords: Flood Frequency; [SDU.STU.CL] Sciences of the Universe [physics]/Earth Sciences/Climatology; Sub-Saharan Africa; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; Observed and Future Impacts; [SDU.STU.HY] Sciences of the Universe [physics]/Earth Sciences/Hydrology; Ensembles (SMILEs); [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology; Internal Climate variability; CMIP5/6 Single Model Initial Condition Large

Sub-Saharan Africa (SSA) is strongly affected by flood hazards, endangering human lives and economic stability. However, the role of internal climate modes variability in driving fluctuations SSA occurrence remains poorly documented understood. To address this gap, we quantify relative combined contribution large-scale drivers to seasonal regional using a new 65-year daily streamflow dataset, sea-surface temperatures derived from observations, 12 Single Model Initial-condition Large Ensembles (SMILEs) Coupled Intercomparison Project Phases 5 6. We find significant relationships between floods across SSA, with climatic accounting for 30–90 % floods. Notably, western, central, summer-rain region southern display stronger teleconnections comparison East winter-rain South Africa, where circulation patterns activities may play more important role. In eastern are mainly influenced Pacific Indian Oceans, while western central Atlantic Ocean Mediterranean Sea larger also that number projected fluctuate ± 10–50 during 21st century response different sequences key variability. note contributions future risks generally consistent all SMILEs. Our findings thus provide valuable information long-term disaster risk reduction management.