Nature of SPG–AMOC interaction and relative importance of convection regions

Determine the exact nature of the dynamical interaction between the North Atlantic subpolar gyre and the Atlantic Meridional Overturning Circulation (AMOC), and ascertain the comparative relevance of the Labrador Sea versus the Irminger Sea and Nordic Seas in contributing convection to the overturning circulation.

Background

The paper investigates whether a proposed mechanism for bistability of the North Atlantic subpolar gyre is represented in CMIP6 models using causal inference. While several internal feedbacks within the gyre are identified, the broader interaction between the subpolar gyre and the Atlantic Meridional Overturning Circulation (AMOC) is not analyzed directly and remains uncertain.

The authors highlight contrasting evidence: observational data indicates that much of the AMOC-related transport occurs in the eastern subpolar Atlantic, whereas the deepest convection is observed in the Labrador Sea. This motivates the need to clarify both the mechanistic link between the subpolar gyre and AMOC and the relative importance of different convection regions (Labrador, Irminger, Nordic seas) for the overturning circulation.