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Changes in the geometry and strength of the Atlantic Meridional Overturning Circulation during the last glacial (20–50 ka)

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Burckel Pierre, Waelbroeck Claire, Luo Yiming, Roche Didier, Pichat Sylvain, Jaccard Samuel, Gherardi Jeanne, Govin Aline, Lippold Jörg, Thil François,
Project SeaO2 - Past changes in Southern Ocean overturning circulation - implications for the partitioning of carbon and oxygen between the ocean and the atmosphere
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Original article (peer-reviewed)

Journal Climate of the Past
Volume (Issue) 12
Page(s) 2061 - 2075
Title of proceedings Climate of the Past
DOI 10.5194/cp-2016-26

Open Access

URL http://www.clim-past-discuss.net/cp-2016-26/
Type of Open Access Publisher (Gold Open Access)

Abstract

We reconstruct the geometry and strength of the Atlantic Meridional Overturning Circulation during Heinrich Stadial 2 and three Greenland interstadials of the 20–50 ka period based on the comparison of new and published sedimentary 231Pa/230Th data with simulated sedimentary 231Pa/230Th. We show that the deep Atlantic circulation during these interstadials was very different from that of the Holocene. Northern-sourced waters likely circulated above 2500 m depth, with a flow rate lower than that of the present day North Atlantic Deep Water (NADW). Southern-sourced deep waters most probably flowed northwards below 4000 m depth into the North Atlantic basin, and then southwards as a return flow between 2500 and 4000 m depth. The flow rate of this southern-sourced deep water was likely larger than that of the modern Antarctic Bottom Water (AABW). At the onset of Heinrich Stadial 2, the structure of the AMOC significantly changed. The deep Atlantic was probably directly affected by a southern sourced water mass below 2500 m depth, while a slow southward flowing water mass originating from the North Atlantic likely influenced depths between 1500 and 2500 m down to the equator.
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