Climate Dynamics

, Volume 37, Issue 9–10, pp 1707–1725

Changes in the interannual SST-forced signals on West African rainfall. AGCM intercomparison

  • Elsa Mohino
  • Belén Rodríguez-Fonseca
  • Teresa Losada
  • Sébastien Gervois
  • Serge Janicot
  • Juergen Bader
  • Paolo Ruti
  • Fabrice Chauvin
Article

DOI: 10.1007/s00382-011-1093-2

Cite this article as:
Mohino, E., Rodríguez-Fonseca, B., Losada, T. et al. Clim Dyn (2011) 37: 1707. doi:10.1007/s00382-011-1093-2

Abstract

Rainfall over West Africa shows strong interannual variability related to changes in Sea Surface Temperature (SST). Nevertheless, this relationship seem to be non-stationary. A particular turning point is the decade of the 1970s, which witnessed a number of changes in the climatic system, including the climate shift of the late 1970s. The first aim of this study is to explore the change in the interannual variability of West African rainfall after this shift. The analysis indicates that the dipolar features of the rainfall variability over this region, related to changes in the Atlantic SST, disappear after this period. Also, the Pacific SST variability has a higher correlation with Guinean rainfall in the recent period. The results suggest that the current relationship between the Atlantic and Pacific El Niño phenomena is the principal responsible for these changes. A fundamental goal of climate research is the development of models simulating a realistic current climate. For this reason, the second aim of this work is to test the performance of Atmospheric General Circulation models in simulating rainfall variability over West Africa. The models have been run with observed SSTs for the common period 1957–1998 as part of an intercomparison exercise. The results show that the models are able to reproduce Guinean interannual variability, which is strongly related to SST variability in the Equatorial Atlantic. Nevertheless, problems in the simulation of the Sahelian interannual variability appear: not all models are able to reproduce the observed negative link between rainfall over the Sahel and El Niño-like anomalies in the Pacific, neither the positive correlation between Mediterranean SSTs and Sahelian rainfall.

Keywords

Interannual climate variability West African Monsoon Atmospheric general circulation models 

Supplementary material

382_2011_1093_MOESM1_ESM.pdf (206 kb)
Supplementary material 1 (PDF 206 kb)

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Elsa Mohino
    • 1
    • 2
  • Belén Rodríguez-Fonseca
    • 3
    • 4
  • Teresa Losada
    • 3
  • Sébastien Gervois
    • 1
  • Serge Janicot
    • 5
  • Juergen Bader
    • 6
  • Paolo Ruti
    • 7
  • Fabrice Chauvin
    • 8
  1. 1.LOCEAN/IPSL, Université Pierre et Marie CurieParis Cedex 05France
  2. 2.Universidad de SevillaSevillaSpain
  3. 3.Dpto. Geofísica y MeteorologíaUniversidad Complutense de MadridMadridSpain
  4. 4.Instituto de Geociencias (CSIC-UCM)MadridSpain
  5. 5.LOCEAN/IPSL, IRD, Université Pierre et Marie CurieParisFrance
  6. 6.Bjerknes Centre for Climate ResearchBergenNorway
  7. 7.Progetto Speciale Clima Globale, Ente Nazionale per le Nuove Tecnologie, l’Energia e l’AmbienteRomeItaly
  8. 8.GAME/CNRM, Météo-France/CNRSToulouseFrance

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