Ensemble-based CMIP5 simulations of West African summer monsoon rainfall: current climate and future changes

  • A. A. Akinsanola
  • Wen ZhouEmail author
Original Paper


The West African summer monsoon (WASM) rainfall is of significant socioeconomic importance. Therefore, its response to climate change is of great concern to climate scientists. Based on observations, reanalysis, and multi-model ensemble mean (EnsMean) simulations of Coupled Model Intercomparison Project phase 5 (CMIP5) models, the responses of WASM rainfall, as well as some relevant atmospheric features, to global warming are investigated. Results from the historical period (1980–2005) indicate that EnsMean reasonably reproduced the characteristics of WASM rainfall, and the strength and position of the upper-level Tropical Easterly Jet (TEJ) and mid-level African Easterly Jet (AEJ). Under global warming, EnsMean exhibits localized future changes in spatial rainfall pattern; specifically, a statistically significant increase (decrease) is evident over the central-eastern (western) Sahel subregion. Similarly, the annual cycle exhibits a decrease (increase) in pre-monsoon (post-monsoon) rainfall over the region, evident over the Sahel subregion. Increased surface evaporation and enhanced atmospheric moisture convergence are notable over the region of increasing WASM rainfall, while a weakened and possible alteration of large-scale atmospheric circulation features is evident over the study area.



The authors appreciate the World Climate Research Program’s Working Group on Coupled Modeling, which is responsible for CMIP5, and we also thank the climate modeling groups listed in Table 1 for producing and making available their model output. We are also grateful to the services that have operated the GPCP, CRU, and NCEP/NCAR datasets.

Funding information

This work is supported by the National Nature Science Foundation of China Grant (41675062) and the Research Grants Council of the Hong Kong Special Administrative Region, China (CityU 11305715 and 11335316). The first author is a recipient of a research studentship provided by the City University of Hong Kong (CityU).


  1. Abiodun BJ, Lawal KA, Salami AT, Abatan AA (2013) Potential influences of global warming on future climate and extreme events in Nigeria. Reg Environ Chang 13:477–491. CrossRefGoogle Scholar
  2. Adler, et al (2016) An update (Version 2.3) of the GPCP monthly analysis. (in preparation)Google Scholar
  3. Akinsanola AA, Zhou W (2018) Projections of West African summer monsoon rainfall extremes from two CORDEX models. Clim Dyn.
  4. Akinsanola AA, Ogunjobi KO, Gbode IE, Ajayi VO (2015) Assessing the capabilities of three regional climate models over CORDEX Africa in simulating West African summer monsoon precipitation. Adv Meteorol 2015:1–13. CrossRefGoogle Scholar
  5. Akinsanola AA, Ogunjobi KO, Ajayi VO, Adefisan EA, Omotosho JA, Sanogo S (2016) Comparison of five gridded precipitation products at climatological scales over West Africa. Meteorog Atmos Phys 129:669–689. CrossRefGoogle Scholar
  6. Akinsanola AA, Ajayi VO et al (2017) Evaluation of rainfall simulations over West Africa in dynamically downscaled CMIP5 global circulation models. Theor Appl Climatol 132:437–450. CrossRefGoogle Scholar
  7. Biasutti M (2013) Forced Sahel rainfall trends in the CMIP5 archive. J Geophys Res Atmos 118:1613–1623. CrossRefGoogle Scholar
  8. Christensen JH, et al (2007) Regional climate projections. In: Solomon, S., et al. (Eds.), Climate change 2007: the physical science basis. Cambridge University Press, pp. 847–940.Google Scholar
  9. Clark DB, Xue Y, Harding RJ, Valdes PJ (2001) Modeling the impact of land surface degradation on the climate of tropical North Africa. J Clim 14:1809–1822CrossRefGoogle Scholar
  10. Cook KH (1999) Generation of the African easterly jet and its role in determining West African precipitation. J Clim 12:1165–1184.,1165:GOTAEJ.2.0.CO;2. CrossRefGoogle Scholar
  11. Diallo I, Giorgi F, Tall M, Mariotti L, Gaye AT (2016) Projected changes of summer monsoon extreme and hydroclimatic regimes over West Africa for the twenty-first century. Clim Dyn 47:3931–3954. CrossRefGoogle Scholar
  12. Fasullo J, Webster PJ (2003) A hydrological definition of the Indian summer monsoon onset and withdrawal. J Clim 16:3200–3211CrossRefGoogle Scholar
  13. Giorgi F (2014) Introduction to the special issue: the phase I CORDEX RegCM4 hyper-matrix (CREMA) experiment. Clim Chang 125:1–5. CrossRefGoogle Scholar
  14. Harris I, Jones PD, Osborn TJ, Lister DH (2014) Updated high-resolution grids of monthly climatic observations—the CRU TS3.10 dataset. Int J Climatol 34:623–642. CrossRefGoogle Scholar
  15. Hartmann DL, Klein Tank AMG, Rusticucci M, Alexander LV, Brönnimann S, Charabi Y, Dentener FJ, Dlugokencky EJ, Easterling DR, Kaplan A, Soden BJ, Thorne PW, Wild M, Zhai PM (2013) Observations: atmosphere and surface. In: Stocker TF, Qin D, Plattner G-K, Tignor MMB, Allen SK, Boschung J, Nauels A, Xia Y, Bex V, Midgley PM (eds) Climate change (2013) the physical science basis. Contribution of working group I to the fifth assessment report of the intergovernmental panel on climate change. Cambridge, United Kingdom. Cambridge University Press, New YorkGoogle Scholar
  16. Hourdin F, Musat I, Guichard F, Ruti PM, Favot F, Filiberti MA, Pham M, Grandpeix JY, Polcher J, Marquet P, Boone A, Lafore JP, Redelsperger JL, Dellaquila A, Losada DT, Khadre TA, Gallee H (2010) AMMA—model intercomparison project. Bull Am Meteorol Soc 91:95–104. CrossRefGoogle Scholar
  17. IPCC (2013) Climate change 2013: The physical science basis, in Working Group I Contribution to the Fifth Assessment Report of the IPCC, edited by T. F. Stocker, Cambridge Univ. Press, Cambridge.Google Scholar
  18. James R, Washington R, Jones R (2015) Process-based assessment of an ensemble of climate projections for West Africa. J Geophys Res Atmos 120:1221–1238. CrossRefGoogle Scholar
  19. Kalnay E et al (1996) The NCEP/NCAR 40-year reanalysis project. Bull Am Meteorol Soc 77:437–471CrossRefGoogle Scholar
  20. Karl T et al (2015) Possible artifacts of data biases in the recent global surface warming hiatus. Science 348:1469–1472CrossRefGoogle Scholar
  21. Kitoh A, Endo H, Krishna Kumar K, Cavalcanti IFA, Goswami P, Zhou T (2013) Monsoons in a changing world: a regional perspective in a global context. J Geophys Res Atmos 118:3053–3065. CrossRefGoogle Scholar
  22. Li RQ, Lv SH, Han B (2013) Simulations of Asian-Australian monsoon circulation and variability by 10 CMIP5 models. J Trop Meteorol 29(5):749–758Google Scholar
  23. Li R, Lü S, Han B et al (2015) Connections between the South Asian summer monsoon and the tropical sea surface temperature in CMIP5. J Meteorol Res 29:106.
  24. Lintner BR, Biasutti M, Diffenbaugh NS, Lee JE, Niznik MJ, Findell KL (2012) Amplification of wet and dry month occurrence over tropical land regions in response to global warming. J Geophys Res 117:D11106. CrossRefGoogle Scholar
  25. Mertz O, Mbow C, Reenberg A, Genesio L, Lambin EF, D’haen S et al (2011) Adaptation strategies and climate vulnerability in the Sudano-Sahelian region of West Africa. Atmos Sci Lett 12(1):104–108CrossRefGoogle Scholar
  26. Monerie PA, Fontaine B, Roucou P (2012) Expected future changes in the African monsoon between 2030 and 2070 using some CMIP3 and CMIP5 models under a medium-low RCP scenario. J Geophys Res Atmos 117:D16111. CrossRefGoogle Scholar
  27. Moss RH et al (2010) The next generation of scenarios for climate change research and assessment. Nature 463:747–756. CrossRefGoogle Scholar
  28. Nikulin G, Jones C, Giorgi F, Asrar G, Buchner M, Cerezo-Mota R, Christensen OB, Deque M, Fernandez J, Hansler A, van Meijgaard E, Samuelsson P, Sylla MB, Sushama L (2012) Precipitation climatology in an ensemble of CORDEX-Africa regional climate simulations. J Clim 25:6057–6078. CrossRefGoogle Scholar
  29. Odoulami RC, Akinsanola AA (2017) Recent assessment of West African summer monsoon daily rainfall trends. Weather.
  30. Seth A, Rauscher SA, Biasutti M, Giannini A, Camargo SJ, Rojas M (2013) CMIP5 projected changes in the annual cycle of precipitation in monsoon regions. J Clim 26:7328–7351. CrossRefGoogle Scholar
  31. Sillmann J, Kharin VV, Zwiers FW, Zhang X, Bronaugh D (2013) Climate extremes indices in the CMIP5 multimodel ensemble: part 2. Future climate projections. J Geophys Res Atmos 118:2473–2493. CrossRefGoogle Scholar
  32. Sylla MB, Gaye AT, Jenkins GS (2012) On the fine-scale topography regulating changes in atmospheric hydrological cycle and extreme rainfall over West Africa in regional climate model projections. Int J Geophys 2012:981649.
  33. Sylla MB, Diallo I, Pal JS (2013) West African monsoon in state-of-the-science regional climate models. Climate variability: regional and thematic patterns, A. Tarhule, Ed., InTech, 3–36,
  34. Sylla MB, Elguindi N, Giorgi F, Wisser D (2016) Projected robust shift of climate zones over West Africa in response to anthropogenic climate change for the late 21st century. Clim Chang 134(1):241–253. CrossRefGoogle Scholar
  35. Taylor KE, Stouffer RJ, Meehl GA (2012) An overview of CMIP5 and the experiment design. Bull Am Meteorol Soc 93:485–498. CrossRefGoogle Scholar
  36. Thorncroft CD, Blackburn M (1999) Maintenance of the African Easterly Jet. Q J Roy Meteorol Soc 125:763–786Google Scholar
  37. van Vuuren DP, Edmonds J, Kainuma M, Riahi K, Thomson A, Hibbard K, Hurtt GC, Kram T, Krey V, Lamarque JF, Masui T, Meinshausen M, Nakicenovic N, Smith SJ, Rose SK (2011) The representative concentration pathways: an overview. Clim Chang 109(1–2):5–31. CrossRefGoogle Scholar
  38. Wang YJ et al (2008) Millennial- and orbital-scale changes in the east Asian monsoon over the past 224,000 years. Nature 451:1090–1093CrossRefGoogle Scholar
  39. Xin XG et al (2013) How well does BCC_CSM1.1 reproduce the 20th century climate change over China? Atmos Oceanic Sci Lett 6:21–26Google Scholar

Copyright information

© Springer-Verlag GmbH Austria, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Guy Carpenter Asia-Pacific Climate Impact Centre, School of Energy and EnvironmentCity University of Hong KongHong KongChina

Personalised recommendations