Mohino E. auteur aut IRD Janicot Serge auteur aut IRD Douville H. auteur aut IRD Li L. Z. X. auteur aut IRD text journalArticle eng text/pdf born digital access 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. specialized Madden Julian Oscillation West Africa Atmospheric general circulation models Nudging 021 020 38 11-12 2319-2334 2012 0930-7575 https://www.documentation.ird.fr/hor/fdi:010055941 10.1007/s00382-011-1206-y 0930-7575 [F B010055941] https://www.documentation.ird.fr/hor/fdi:010055941 https://www.documentation.ird.fr/intranet/publi/2012/07/010055941.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2012-07-24 2017-08-23 fdi:010055941 fre