EGU21-7981, updated on 04 Mar 2021
https://doi.org/10.5194/egusphere-egu21-7981
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Multi-year variability in hydrological extremes in Africa: what are the main drivers?

Job Ekolu1, Bastien Dieppois1,2, Moussa Sidibe3, Jonathan Eden1, Yves Tramblay4, Gabriele Villarini5, Gil Mahé4, Jean-Emmanuel Paturel4, and Marco Van de Wiel1
Job Ekolu et al.
  • 1Coventry University, Centre for Agroecology, Water and Resilience, United Kingdom of Great Britain – England, Scotland, Wales (ekoluj@uni.coventry.ac.uk)
  • 2Department of Oceanography, MARE Institute, University of Cape Town, Cape Town, RSA
  • 3West African Science Service Centre on Climate Change and Adapted Land Use (WASCAL), Ouagadougou, Burkina Faso
  • 4HydroSciences Montpellier (HSM), Université de Montpellier – Institut de Recherche et le Dévelopment (IRD), Montpellier, France
  • 5IIHR – Hydroscience & Engineering, University of Iowa, Iowa City, Iowa, USA

Africa is affected by a high-level of temporal and spatial variability in climate, with large impacts on water resources, human lives and economies. Due to data scarcity, the impact of multi-year climate variations on hydrological variability and extremes, i.e. flood and drought, as well as how catchment properties could modulate those impacts, are generally poorly understood across the African continent. In this study, we first use machine learning algorithms to develop a new complete reconstructed daily streamflow dataset using more than 1500 stream gauges between 1950 and 2018, and covering most of Africa. We then examine historical trends and variability in hydrological extremes over the entire African continent, focusing on different hydrological characteristics, such as the timing, frequency and duration of high- and low-flow events, based on the peaks-over-threshold method. Following an assessment of the relative sensitivities of hydrological extreme indices to interannual (2-8-years) and decadal (>10-years) variability in the different regions of Africa, we analyze the respective contribution of different rainfall, temperature and soil moisture indices (e.g. frequency, duration and intensity of wet/dry or warmer/colder days) at both timescales, using relative importance analysis. We finally discuss how catchment properties (e.g. area, topography, land use/ land cover, drainage path lengths) modulate the relationship between hydrological extremes and climate.

How to cite: Ekolu, J., Dieppois, B., Sidibe, M., Eden, J., Tramblay, Y., Villarini, G., Mahé, G., Paturel, J.-E., and Van de Wiel, M.: Multi-year variability in hydrological extremes in Africa: what are the main drivers?, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7981, https://doi.org/10.5194/egusphere-egu21-7981, 2021.

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