Abstract
Interannual statistical connections are investigated in July-August between West African rainfall, atmospheric tropical circulation and equatorial Atlantic and Pacific SST. Analyses performed with rainfall data (1958-1989) and GCM outputs (1970-1988) point out the role of Hadley cells and tropical East-West divergent circulations in reference to two different types of Sahelian drought. A SST warming in the Gulf of Guinea implies a southward and enhanced Hadley circulation along with reduced rainfall in the Central Sahel and increased rainfall in the Guinean region. A SST warming in the eastern equatoricd Pacific leads to a stronger East-West divergent circulation over the tropical Atlantic and lower rainfall over all of West Africa. During some years, these two SST forcings interact to modulate West African rainfall variability. In particular the impact of the ENSO event of 1987 on West African monsoon dynamics is different from the statistical signal produced by other ENSO events because of warmer than usual SST in the tropical Atlantic.
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Janicot, S. (1994). The Recent West African Rainfall Variability Through Empirical and Modelling Investigations. In: Desbois, M., Désalmand, F. (eds) Global Precipitations and Climate Change. NATO ASI Series, vol 26. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-79268-7_7
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DOI: https://doi.org/10.1007/978-3-642-79268-7_7
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