Born A. auteur aut IRD Mignot Juliette auteur aut IRD Stocker T. F. auteur aut IRD text journalArticle eng text/pdf born digital access Decadal climate variability in the North Atlantic has received increased attention in recent years, because modeling results suggest predictability of heat content and circulation indices several years ahead. However, determining the applicability of these results in the real world is challenging because of an incomplete understanding of the underlying mechanisms. Here, the authors show that recent attempts to reconstruct the decadal variations in one of the dominant circulation systems of the region, the subpolar gyre (SPG), are not always consistent. A coherent picture is partly recovered by a simple conceptual model solely forced by reanalyzed surface air temperatures. This confirms that surface heat flux indeed plays a leading role for this type of variability, as has been suggested in previous studies. The results further suggest that large variations in the SPG correspond to the crossing of a bifurcation point that is predicted from idealized experiments and an analytical solution of the model used herein. Performance of this conceptual model is tested against a statistical stochastic model. Hysteresis and the existence of two stable modes of the SPG circulation shape its response to forcing by atmospheric temperatures. The identification of the essential dynamics and the reduction to a minimal model of SPG variability provide a quantifiable basis and a framework for future studies on decadal climate variability and predictability. specialized Geographic location entity North Atlantic Ocean Circulation Dynamics Ocean dynamics Atm Ocean Structure Phenomena Gyres Forecasting Climate prediction ATLANTIQUE NORD 032 28 22 8907-8922 2015 0894-8755 https://www.documentation.ird.fr/hor/fdi:010065458 10.1175/jcli-d-14-00813.1 0894-8755 [F B010065458] https://www.documentation.ird.fr/hor/fdi:010065458 https://www.documentation.ird.fr/intranet/publi/2015/12/010065458.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2016-01-14 2017-08-23 fdi:010065458 fre