Climate Dynamics

, Volume 38, Issue 11–12, pp 2319–2334 | Cite as

Impact of the Indian part of the summer MJO on West Africa using nudged climate simulations

  • Elsa Mohino
  • Serge Janicot
  • Hervé Douville
  • Laurent Z. X. Li
Original Article

Abstract

Observational evidence suggests a link between the summer Madden Julian Oscillation (MJO) and anomalous convection over West Africa. This link is further studied with the help of the LMDZ atmospheric general circulation model. The approach is based on nudging the model towards the reanalysis in the Asian monsoon region. The simulation successfully captures the convection associated with the summer MJO in the nudging region. Outside this region the model is free to evolve. Over West Africa it simulates convection anomalies that are similar in magnitude, structure, and timing to the observed ones. In accordance with the observations, the simulation shows that 15–20 days after the maximum increase (decrease) of convection in the Indian Ocean there is a significant reduction (increase) in West African convection. The simulation strongly suggests that in addition to the eastward-moving MJO signal, the westward propagation of a convectively coupled equatorial Rossby wave is needed to explain the overall impact of the MJO on convection over West Africa. These results highlight the use of MJO events to potentially predict regional-scale anomalous convection and rainfall spells over West Africa with a time lag of approximately 15–20 days.

Keywords

Madden Julian Oscillation West Africa Atmospheric general circulation models Nudging 

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Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Elsa Mohino
    • 1
    • 3
  • Serge Janicot
    • 2
  • Hervé Douville
    • 4
  • Laurent Z. X. Li
    • 5
  1. 1.LOCEAN/IPSLUniversité Pierre et Marie CurieParis Cedex 05France
  2. 2.LOCEAN/IPSL, IRDUniversité Pierre et Marie CurieParis Cedex 05France
  3. 3.Universidad de SevillaSevillaSpain
  4. 4.Météo-France/CNRM-GAMEToulouseFrance
  5. 5.LMD/IPSL, CNRSUniversité Pierre et Marie CurieParisFrance

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