Evidence for northward expansion of Antarctic Bottom Water mass in the Southern Ocean during the last glacial inception

Type Article
Date 2009-01
Language English
Author(s) Govin Aline1, 2, Michel Elisabeth1, Labeyrie Laurent1, Waelbroeck Claire1, Dewilde Fabien1, Jansen Eystein2
Affiliation(s) 1 : UVSQ, CEA, CNRS, LSCE,IPSL, F-91190 Gif Sur Yvette, France.
2 : Univ Bergen, Bjerknes Ctr Climate Res, N-5007 Bergen, Norway.
Source Paleoceanography (0883-8305) (Amer Geophysical Union), 2009-01 , Vol. 24 , N. PA1202 , P. 1-14
DOI 10.1029/2008PA001603
WOS© Times Cited 73
Keyword(s) isotope substage 5E, ice core, interglacial period, climate variability, deep ocean, Atlantic, sea, circulation, temperature, hemisphere
Abstract We investigated deep water changes in the Southern Ocean during the last glacial inception, in relationship to surface hydrology and global climatology, to better understand the mechanisms of the establishment of a glacial ocean circulation. Changes in benthic foraminiferal delta(13)C from three high-resolution cores are compared and indicate decoupled intermediate and deep water changes in the Southern Ocean. From the comparison with records from the North Atlantic, South Atlantic, and the Southern Ocean, we show that the early southern deep water delta(13)C drop observed at the MIS 5.5-5.4 transition occurred before any significant reduction of North Atlantic Deep Water ventilation. We propose that this drop is linked to the northward expansion of poorly ventilated Antarctic Bottom Water (AABW) mass in the Southern Ocean. Associated with an early cooling in the high southern latitudes, the westerly winds and surface oceanic fronts would migrate equatorward, thus weakening the upwelling of Circumpolar Deep Waters. Reduced heat brought to Antarctic surface waters would enhance sea ice formation during winters and the deep convection of cold and poorly ventilated AABW.
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Govin Aline, Michel Elisabeth, Labeyrie Laurent, Waelbroeck Claire, Dewilde Fabien, Jansen Eystein (2009). Evidence for northward expansion of Antarctic Bottom Water mass in the Southern Ocean during the last glacial inception. Paleoceanography, 24(PA1202), 1-14. Publisher's official version : https://doi.org/10.1029/2008PA001603 , Open Access version : https://archimer.ifremer.fr/doc/00208/31952/