Climate Dynamics

, Volume 48, Issue 7–8, pp 2297–2314

Impact of the Madden Julian Oscillation on the summer West African monsoon in AMIP simulations

  • Coumba Niang
  • Elsa Mohino
  • Amadou T. Gaye
  • J. Bayo Omotosho
Article

DOI: 10.1007/s00382-016-3206-4

Cite this article as:
Niang, C., Mohino, E., Gaye, A.T. et al. Clim Dyn (2017) 48: 2297. doi:10.1007/s00382-016-3206-4

Abstract

At intraseasonal timescales, convection over West Africa is modulated by the Madden Julian Oscillation (MJO). In this work we investigate the simulation of such relationship by 11 state-of-the-art atmospheric general circulation models runs with prescribed observed sea surface temperatures. In general, the Atmospheric Model Intercomparison Project simulations show good skill in capturing the main characteristics of the summer MJO as well as its influence on convection and rainfall over West Africa. Most models simulate an eastward spatiotemporal propagation of enhanced and suppressed convection similar to the observed MJO, although their signal over West Africa is weaker in some models. In addition, the ensemble average of models’ composites gives a better performance in reproducing the main features and timing of the MJO and its impact over West Africa. The influence on rainfall is well captured in both Sahel and Guinea regions thereby adequately producing the transition between positive and negative rainfall anomalies through the different phases as in the observations. Furthermore, the results show that a strong active convection phase is clearly associated with a stronger African Easterly Jet (AEJ) but the weak convective phase is associated with a much weaker AEJ. Our analysis of the equatorial waves suggests that the main impact over West Africa is established by the propagation of low-frequency waves within the MJO and Rossby spectral peaks. Results from the simulations confirm that it may be possible to predict anomalous convection over West Africa with a time lead of 15–20 day.

Keywords

Madden Julian Oscillation Summer rainfall West Africa AMIP simulations 

Supplementary material

382_2016_3206_MOESM1_ESM.doc (6 mb)
Supplementary material 1 (DOC 6156 kb)

Funding information

Funder NameGrant NumberFunding Note
Agencia Estatal Consejo Superior de Investigaciones Cientificas (CSIC) of Spain
  • program: I-COOP+ reference COOPA20029
German Federal Ministry of Education and Research (BMBF) via WASCAL (West African Science Service Center on Climate Change and Adapted Land Use) project
    Universidad Complutense de Madrid (UCM) via the collaboration between TROPA-UCM-IGEO and LPAO-SF (Laboratoire de Physique de l'Atmosphere et de l'Ocean Simeon Fongang) group
    • project 63 from the IX UCM Call for Cooperation and Development Projects 2012
    TROPA (Tropical Atlantic Variability Group) from UCM
      European Union Seventh Framework Programme (FP7/2007-2013)
      • grant agreement no 603521 and the Spanish project CGL2012-38923-C02-01
      MINECO ICMAT Severo Ochoa
      • project SEV-2011-0087

      Copyright information

      © Springer-Verlag Berlin Heidelberg 2016

      Authors and Affiliations

      1. 1.Laboratoire de Physique de l’Atmosphère et de l’Océan Siméon Fongang (LPAO-SF), Ecole Supérieure Polytechnique (ESP)Université Cheikh Anta DiopDakar-FannSenegal
      2. 2.Instituto de Geociencias (IGEO)Agencia Estatal Consejo Superior de Investigaciones Cientificas CSICMadridSpain
      3. 3.Departamento de Fisica de la Tierra, Astronomia y Astrofisica I, Geofisica y MeteorologiaUniversidad Complutense de Madrid (UCM)MadridSpain
      4. 4.WASCAL, Department of MeteorologyFederal University of Technology AkureOndo StateNigeria
      5. 5.Instituto de Ciencias MatematicasCSIC-UAM-UC3M-UCMMadridSpain

      Personalised recommendations