Estimated strength of the Atlantic overturning circulation during the last deglaciation

Ritz, Stefan; Stocker, Thomas; Grimalt, J. O.; Menviel, Laurie; Timmermann, A. (2013). Estimated strength of the Atlantic overturning circulation during the last deglaciation. Nature geoscience, 6(3), pp. 208-212. Nature Publishing Group 10.1038/ngeo1723

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The Atlantic meridional overturning circulation affects the latitudinal distribution of heat, and is a key component of the climate system. Proxy reconstructions, based on sedimentary Pa-231/Th-230 ratios and the difference between surface-and deep-water radiocarbon ages, indicate that during the last glacial period, the overturning circulation was reduced during millennial-scale periods of cooling(1-5). However, much debate exists over the robustness of these proxies(6-8). Here e combine proxy reconstructions of sea surface and air temperatures and a global climate model to quantitatively estimate changes in the strength of the Atlantic meridional overturning circulation during the last glacial period. We find that, relative to the Last Glacial Maximum, the overturning circulation was reduced by approximately 14 Sv during the cold Heinrich event 1. During the Younger Dryas cold event, the overturning circulation was reduced by approximately 12 Sv, relative to the preceding warm interval. These changes are consistent with qualitative estimates of the overturning circulation from sedimentary Pa-231/Th-230 ratios. In addition, we find that the strength of the overturning circulation during the Last Glacial Maximum and the Holocene epoch are indistinguishable within the uncertainty of the reconstruction.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Climate and Environmental Physics
10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)

UniBE Contributor:

Ritz, Stefan; Stocker, Thomas and Menviel, Laurie

Subjects:

500 Science > 530 Physics

ISSN:

1752-0894

Publisher:

Nature Publishing Group

Language:

English

Submitter:

Doris Rätz

Date Deposited:

29 Sep 2014 14:19

Last Modified:

22 Jan 2015 10:16

Publisher DOI:

10.1038/ngeo1723

Web of Science ID:

000316945800022

BORIS DOI:

10.7892/boris.47706

URI:

https://boris.unibe.ch/id/eprint/47706

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