Stabilization of dense Antarctic water supply to the Atlantic Ocean overturning circulation

Abrahamsen, E. Povl ORCID: https://orcid.org/0000-0001-5924-5350; Meijers, Andrew J.S. ORCID: https://orcid.org/0000-0003-3876-7736; Polzin, Kurt L.; Naveira Garabato, Alberto C.; King, Brian A. ORCID: https://orcid.org/0000-0003-1338-3234; Firing, Yvonne L. ORCID: https://orcid.org/0000-0002-3640-3974; Sallee, Jean-Baptiste; Sheen, Katy L.; Gordon, Arnold L.; Huber, Bruce A.; Meredith, Michael P. ORCID: https://orcid.org/0000-0002-7342-7756. 2019 Stabilization of dense Antarctic water supply to the Atlantic Ocean overturning circulation. Nature Climate Change, 9 (10). 742-746. https://doi.org/10.1038/s41558-019-0561-2

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Preview	Text (c) the Author(s). This is a postprint version of an article published in Nature Climate Change doi: 10.1038/s41558-019-0561-2 Terms of use: https://www.nature.com/nature-research/editorial-policies/self-archiving-and-license-to-publish#terms-for-use Main text and methods with figures.pdf - Accepted Version Download (2MB) | Preview
Preview	Text (c) the Author(s). This is a postprint version of an article published in Nature Climate Change doi: 10.1038/s41558-019-0561-2 Terms of use: https://www.nature.com/nature-research/editorial-policies/self-archiving-and-license-to-publish#terms-for-use Supplementary information.pdf - Supplemental Material Download (342kB) | Preview

Abstract/Summary

The lower limb of the Atlantic overturning circulation is resupplied by the sinking of dense Antarctic Bottom Water (AABW) that forms via intense air–sea–ice interactions next to Antarctica, especially in the Weddell Sea. In the last three decades, AABW has warmed, freshened and declined in volume across the Atlantic Ocean and elsewhere, suggesting an ongoing major reorganization of oceanic overturning. However, the future contributions of AABW to the Atlantic overturning circulation are unclear. Here, using observations of AABW in the Scotia Sea, the most direct pathway from the Weddell Sea to the Atlantic Ocean, we show a recent cessation in the decline of the AABW supply to the Atlantic overturning circulation. The strongest decline was observed in the volume of the densest layers in the AABW throughflow from the early 1990s to 2014; since then, it has stabilized and partially recovered. We link these changes to variability in the densest classes of abyssal waters upstream. Our findings indicate that the previously observed decline in the supply of dense water to the Atlantic Ocean abyss may be stabilizing or reversing and thus call for a reassessment of Antarctic influences on overturning circulation, sea level, planetary-scale heat distribution and global climate.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1038/s41558-019-0561-2
ISSN:	1758678X
Date made live:	02 Sep 2019 16:10 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/517264

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