Density-compensated overturning in the Labrador Sea

Journal Article (Journal Article)

The Atlantic Meridional Overturning Circulation, a key constituent of the climate system, is projected to slow down in the twenty-first century due to a weakening of the Labrador Sea convection, itself a response to greenhouse gas warming and/or enhanced freshwater flux from the Arctic. However, the first observations from the Overturning in the Subpolar North Atlantic Program reveal a minimal response of the Meridional Overturning Circulation to the strong Labrador Sea convection during the winters of 2015–2016. From an analysis of the observational and reanalysis data, we show here that this weak response can be explained by a strong density compensation in the Labrador Sea. Although convection induces important changes of temperature and salinity in the basin interior, the export of the thermal and haline anomalies to the boundary current largely takes place along density surfaces. As a result, the transformation across density surfaces, that is, the imprint on the overturning circulation, is relatively small. This finding highlights the critical relationship between temperature and salinity in determining the overturning strength in the Labrador Sea and underlines the necessity of accurate freshwater flux estimates for improved Meridional Overturning Circulation predictions.

Full Text

Duke Authors

Cited Authors

  • Zou, S; Lozier, MS; Li, F; Abernathey, R; Jackson, L

Published Date

  • February 1, 2020

Published In

Volume / Issue

  • 13 / 2

Start / End Page

  • 121 - 126

Electronic International Standard Serial Number (EISSN)

  • 1752-0908

International Standard Serial Number (ISSN)

  • 1752-0894

Digital Object Identifier (DOI)

  • 10.1038/s41561-019-0517-1

Citation Source

  • Scopus