Eddy-induced variability of the meridional overturning circulation in a model of the North Atlantic

Observations of the Atlantic Meridional Overturning Circulation (AMOC) show that it varies on all timescales. Here we isolate the contribution of eddies to AMOC variability using an eddy-permitting model of the North Atlantic driven by climatological and steady forcing. The eddy-induced AMOC variability is found to be ubiquitous and significant at all latitudes, with a magnitude comparable to the seasonal cycle in the subtropics. Furthermore, the eddy-induced AMOC variability is manifested not only at high frequencies but also at interannual and longer timescales. These results imply that a significant fraction of the AMOC variability is inherently unpredictable at seasonal to interannual timescales.