EGU General Assembly 2020
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Reconciling the role of the Labrador Sea overturning circulation in OSNAP and climate models

Susan Lozier1, Matthew Menary2, and Laura Jackson3
Susan Lozier et al.
  • 1Division of Earth and Ocean Sciences, Duke University, Durham, NC, USA
  • 2LOCEAN, Sorbonne Université, Paris, France
  • 3Met Office Hadley Centre, Met Office, Exeter, UK

The AMOC (Atlantic Meridional Overturning Circulation) is a key driver of climate change and variability. Since continuous, direct measurements of the overturning strength in the North Atlantic subpolar gyre (SPG) have been unavailable until recently, the understanding, based largely on climate models, is that the Labrador Sea has an important role in shaping the evolution of the AMOC. However, a recent high profile observational campaign (Overturning in the Subpolar North Atlantic, OSNAP) has called into question the importance of the Labrador Sea, and hence of the credibility of the AMOC representation in climate models. Here, we reconcile these viewpoints by comparing the OSNAP data with a new, high-resolution coupled climate model: HadGEM3-GC3.1-MM. Unlike many previous models, we find our model compares well to the OSNAP overturning observations. Furthermore, overturning variability across the eastern OSNAP section (OSNAP-E), and not in the Labrador Sea region, appears linked to AMOC variability further south. Labrador Sea densities are shown to be an important indicator of downstream AMOC variability, but these densities are driven by upstream variability across OSNAP-E rather than local processes in the Labrador Sea.

How to cite: Lozier, S., Menary, M., and Jackson, L.: Reconciling the role of the Labrador Sea overturning circulation in OSNAP and climate models, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-2981,, 2020.