The North Atlantic Glacial Eastern Boundary Current as a key driver for ice‐sheet – AMOC interactions and climate instability

Type Article
Date 2021-03
Language English
Author(s) Toucanne SamuelORCID1, Soulet GuillaumeORCID1, Vazquez Riveiros NataliaORCID1, Boswell Steven M.2, Dennielou BernardORCID1, Waelbroeck ClaireORCID3, Bayon Germain1, Mojtahid MeryemORCID4, Bosq MathieuORCID5, Sabine Marjolaine6, Zaragosi Sébastien6, Bourillet Jean-FrancoisORCID1, Mercier HerleORCID7
Affiliation(s) 1 : IFREMER Unité de Recherche Géosciences Marines Laboratoire Géophysique et enregistrement Sédimentaire CS10070F‐29280 Plouzané ,France
2 : Lamont‐Doherty Earth Observatory Columbia University Palisades New York10964 ,United States
3 : Laboratoire d’Océanographie et du Climat : Expérimentation et Approches Numériques LOCEAN/IPSL Sorbonne Université‐CNRS‐IRD‐MNHN UMR7159, Paris, France
4 : LPG‐BIAF UMR‐CNRS 6112 Université d’Angers UFR Sciences 2 bd Lavoisier49045 Angers Cedex 01 ,France
5 : PACEA UMR 5199 CNRS ‐ Université Bordeaux Bâtiment B8allée Geoffroy Saint Hilaire33615 Pessac ,France
6 : UMR‐CNRS 5805 EPOC ‐ OASU Université de Bordeaux CS5002333615 Pessac, France
7 : CNRS IFREMER Université de Brest IRD Laboratoire d’Océanographie Physique et Spatiale (LOPS) Centre IFREMER de Bretagne CS10070F‐29280 Plouzané,France
Source Paleoceanography And Paleoclimatology (2572-4517) (American Geophysical Union (AGU)), 2021-03 , Vol. 36 , N. 3 , P. e2020PA004068 (23p.)
DOI 10.1029/2020PA004068
WOS© Times Cited 3
Keyword(s) AMOC, climate changes, Dansgaard&#8208, Oeschger events, Glacial Eastern Boundary Current, last glacial period
Abstract

The upper branch of the Atlantic Meridional Overturning Circulation (AMOC) plays a critical role in ocean circulation and climate change, yet its variability during the last glacial period is poorly documented. Here, we investigate the northward‐flowing Glacial Eastern Boundary Current (GEBC) in the North Atlantic, known today as the European Slope Current, and representing the easternmost portion of the upper branch of the AMOC. Based on flow speed and isotopic records, we show that Dansgaard‐Oeschger (D/O) interstadials (stadials) correspond to a faster (weaker) GEBC during the ∼50‐15 ka period. This, by analogy to present‐day conditions, suggests enhanced (reduced) strength of the subpolar gyre and, by extension, of northern‐sourced water production and AMOC during D‐O interstadials (stadials). Concomitant fluctuations of both the GEBC and the European Ice Sheet between ∼30 and 17 ka suggest an active role of the upper branch of AMOC in the poleward transport of heat and freshwater to the northern North Atlantic, with direct impacts on deep water formation and AMOC strength. We explore these ice‐sheet ‐ AMOC interactions and the associated abrupt climate changes over the last glacial period and the last deglaciation.

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Toucanne Samuel, Soulet Guillaume, Vazquez Riveiros Natalia, Boswell Steven M., Dennielou Bernard, Waelbroeck Claire, Bayon Germain, Mojtahid Meryem, Bosq Mathieu, Sabine Marjolaine, Zaragosi Sébastien, Bourillet Jean-Francois, Mercier Herle (2021). The North Atlantic Glacial Eastern Boundary Current as a key driver for ice‐sheet – AMOC interactions and climate instability. Paleoceanography And Paleoclimatology, 36(3), e2020PA004068 (23p.). Publisher's official version : https://doi.org/10.1029/2020PA004068 , Open Access version : https://archimer.ifremer.fr/doc/00683/79488/