Labrador sea water spreading and the Atlantic meridional overturning circulation

• Published in: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
• Main Author: Le Bras, Isabela Alexander-Astiz
• Format: Text
• Language: English
• Published: The Royal Society 2023
• Subjects: Articles; Labrador Sea; North Atlantic
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10590662/; http://www.ncbi.nlm.nih.gov/pubmed/37866386; https://doi.org/10.1098/rsta.2022.0189

In 1982, Talley and McCartney used the low potential vorticity signature of Labrador Sea Water (LSW) to make the first North Atlantic maps of its properties. Forty years later, our understanding of LSW variability, spreading time scales and importance has deepened. In this review and synthesis article, I showcase recent observational advances in our understanding of how LSW spreads from its formation regions into the Deep Western Boundary Current and southward into the subtropical North Atlantic. I reconcile the fact that decadal variability in LSW formation is reflected in the Deep Western Boundary Current with the fact that LSW formation does not control subpolar overturning strength and discuss hypothesized connections between LSW spreading and decadal Atlantic Meridional Overturning Circulation variability. Ultimately, LSW spreading is of fundamental interest because it is a significant pathway for dissolved gasses such as oxygen and carbon dioxide into the deep ocean. We should hence prioritize adding dissolved gas measurements to standard hydrographic and circulation observations, particularly at targeted western boundary locations. This article is part of a discussion meeting issue ‘Atlantic overturning: new observations and challenges’.