UMR CNRS 5805 EPOC
Environnements et Paléoenvironnements
Océaniques et Continentaux

        

Consignes de Sécurité et Numéros d'Urgence
(à l'usage des personnels du laboratoire)

le 07-11-2019 à 11:00

Lieu Salle Univers, Bâtiment B18N, OASU, Université de Bordeaux Intervenant(s) Matthew Menary, Postdoctorant Marie Curie au LOCEAN, Paris

One paradigm of climate science is the important role of the northern North Atlantic subpolar gyre (SPG), and in particular the Labrador Sea, in shaping the evolution of the AMOC (Atlantic Meridional Overturning Circulation). This understanding is based largely on climate models as continuous, direct measurements of the overturning strength in the SPG have remained, until recently, unavailable. Climate models have long been able to simulate multi-decadal to centennial timescale variability, mediated by the SPG. Nonetheless, they are also known to have significant mean state temperature and salinity biases in this region, which may have consequences for the large-scale dynamics. These differences may partly explain the somewhat different climatic signatures associated with projected 21st century AMOC weakening. Indeed, such biases have already been shown to be influential in the skill of decadal predictions. Even more significantly, recent high profile observations (OSNAP: Overturning in the Subpolar North Atlantic) have called in to question whether the Labrador Sea really plays an important role in modulating real-world AMOC variability. In this talk, I will discuss some of these issues and try and reconcile these viewpoints by comparing the OSNAP data with a new, high-resolution coupled climate model. Finally, if it is true that our latest models are a more faithful representation of reality, do they say anything different about past and future AMOC change?