Impact of warm ENSO events on atmospheric circulation and convection over the tropical Atlantic and West Africa

Empirical studies have shown that warm El Nino/Southern Oscillation (ENSO) episodes are associated during northern summer with, first, a southward location of the intertropical convergence zone (ITCZ) over the tropical Atlantic, and, second, a weakened convection over West Africa where the ITCZ...

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Bibliographic Details
Main Author: S. Janicot
Format: Article
Language:English
Published: Copernicus Publications 1997-04-01
Series:Annales Geophysicae
Online Access:https://www.ann-geophys.net/15/471/1997/angeo-15-471-1997.pdf
Description
Summary:Empirical studies have shown that warm El Nino/Southern Oscillation (ENSO) episodes are associated during northern summer with, first, a southward location of the intertropical convergence zone (ITCZ) over the tropical Atlantic, and, second, a weakened convection over West Africa where the ITCZ is near its mean latitude. A modelling experiment presented here is used to help explain this apparent contradiction. In simulated ENSO conditions, the ITCZ is located southwards over the tropical Atlantic. Over West Africa the intertropical front is also displaced southwards, but more slightly; the ITCZ is located at its climatological latitude and the vertical development of convective clouds over West and Central Africa is reduced due to dynamical subsidence in the upper levels.
ISSN:0992-7689
1432-0576