ANGEO Annales Geophysicae ANGEO Ann. Geophys. 1432-0576 Copernicus Publications Göttingen, Germany 10.5194/angeo-26-4075-2008 Is the decadal variability in the tropical Atlantic a precursor to the NAO? Wainer I. 1 Servain J. 2 4 Clauzet G. 3 Universidade de São Paulo, São Paulo, Brazil Institut de Recherche pour le Développement (IRD), UR182, Paris, France ASA South America, Rua Purpurina 155, Cj 96, 05435-030, São Paulo, Brazil currently at: FUNCEME, Fortaleza, CE, Brazil 12 12 2008 26 12 4075 4080 Copyright: © 2008 I. Wainer et al. 2008 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://angeo.copernicus.org/articles/26/4075/2008/angeo-26-4075-2008.html The full text article is available as a PDF file from https://angeo.copernicus.org/articles/26/4075/2008/angeo-26-4075-2008.pdf

In the past two decades climate research in the tropical Atlantic with respect to the inter-hemispheric gradient of sea surface temperature (SST) emphasized the predominance of decadal-scale variability. Our results show that this mode of variability is prevalent only for part of the last 130-years record (the 1880s, the 1920s and, especially, the 1970s). There is a lag of a few months between the decadal variations of the inter-hemispheric gradient of SST and the decadal variability of the North Atlantic Oscillation (NAO). This seems to indicate that the 10-year variability first develops in the tropics and then propagates polewards. The inter-hemispheric gradient of SST mode should be thought as episodic and not as a periodic oscillation.

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