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Interhemispheric Atlantic seesaw response during the last deglaciation.

https://arctichealth.org/en/permalink/ahliterature95433
Source
Nature. 2009 Feb 26;457(7233):1097-102
Publication Type
Article
Date
Feb-26-2009
Author
Barker Stephen
Diz Paula
Vautravers Maryline J
Pike Jennifer
Knorr Gregor
Hall Ian R
Broecker Wallace S
Author Affiliation
School of Earth and Ocean Sciences, Cardiff University, Cardiff CF10 3YE, UK. barkers3@cf.ac.uk
Source
Nature. 2009 Feb 26;457(7233):1097-102
Date
Feb-26-2009
Language
English
Publication Type
Article
Keywords
Antarctic Regions
Atlantic Ocean
Atmosphere - chemistry
Carbon Dioxide - analysis
Greenhouse Effect
Greenland
History, Ancient
Ice Cover
Plankton - metabolism
Seawater - analysis
Temperature
Water Movements
Abstract
The asynchronous relationship between millennial-scale temperature changes over Greenland and Antarctica during the last glacial period has led to the notion of a bipolar seesaw which acts to redistribute heat depending on the state of meridional overturning circulation within the Atlantic Ocean. Here we present new records from the South Atlantic that show rapid changes during the last deglaciation that were instantaneous (within dating uncertainty) and of opposite sign to those observed in the North Atlantic. Our results demonstrate a direct link between the abrupt changes associated with variations in the Atlantic meridional overturning circulation and the more gradual adjustments characteristic of the Southern Ocean. These results emphasize the importance of the Southern Ocean for the development and transmission of millennial-scale climate variability and highlight its role in deglacial climate change and the associated rise in atmospheric carbon dioxide.
Notes
Comment In: Nature. 2009 Feb 26;457(7233):1093-419242465
PubMed ID
19242468 View in PubMed
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Southern Ocean origin for the resumption of Atlantic thermohaline circulation during deglaciation.

https://arctichealth.org/en/permalink/ahliterature95897
Source
Nature. 2003 Jul 31;424(6948):532-6
Publication Type
Article
Date
Jul-31-2003
Author
Knorr Gregor
Lohmann Gerrit
Author Affiliation
Institut für Meteorologie, Universität Hamburg, Bundesstrasse 55, 20146 Hamburg, Germany. gregor.knorr@dkrz.de
Source
Nature. 2003 Jul 31;424(6948):532-6
Date
Jul-31-2003
Language
English
Publication Type
Article
Abstract
During the two most recent deglaciations, the Southern Hemisphere warmed before Greenland. At the same time, the northern Atlantic Ocean was exposed to meltwater discharge, which is generally assumed to reduce the formation of North Atlantic Deep Water. Yet during deglaciation, the Atlantic thermohaline circulation became more vigorous, in the transition from a weak glacial to a strong interglacial mode. Here we use a three-dimensional ocean circulation model to investigate the impact of Southern Ocean warming and the associated sea-ice retreat on the Atlantic thermohaline circulation. We find that a gradual warming in the Southern Ocean during deglaciation induces an abrupt resumption of the interglacial mode of the thermohaline circulation, triggered by increased mass transport into the Atlantic Ocean via the warm (Indian Ocean) and cold (Pacific Ocean) water route. This effect prevails over the influence of meltwater discharge, which would oppose a strengthening of the thermohaline circulation. A Southern Ocean trigger for the transition into an interglacial mode of circulation provides a consistent picture of Southern and Northern hemispheric climate change at times of deglaciation, in agreement with the available proxy records.
Notes
Comment In: Nature. 2003 Jul 31;424(6948):496-912891336
PubMed ID
12891352 View in PubMed
Less detail