Minimal change in Antarctic Circumpolar Current flow speed between the last glacial and Holocene
The Antarctic Circumpolar Current is key to the mixing and ventilation of the world’s oceans. This current flows from west to east between about 45° and 70°S connecting the Atlantic, Pacific and Indian oceans, and is driven by westerly winds and buoyancy forcing. High levels of productivity in the c...
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ftnerc:oai:nora.nerc.ac.uk:504465 2023-05-15T13:48:08+02:00 Minimal change in Antarctic Circumpolar Current flow speed between the last glacial and Holocene McCave, I. N. Crowhurst, S. J. Kuhn, G. Hillenbrand, C-D. Meredith, M. P. 2014-02-01 text http://nora.nerc.ac.uk/id/eprint/504465/ https://nora.nerc.ac.uk/id/eprint/504465/1/McCave%20et%20MS%20NGeo%20accepted.pdf https://doi.org/10.1038/ngeo2037 en eng https://nora.nerc.ac.uk/id/eprint/504465/1/McCave%20et%20MS%20NGeo%20accepted.pdf McCave, I. N.; Crowhurst, S. J.; Kuhn, G.; Hillenbrand, C-D. orcid:0000-0003-0240-7317 Meredith, M. P. orcid:0000-0002-7342-7756 . 2014 Minimal change in Antarctic Circumpolar Current flow speed between the last glacial and Holocene. Nature Geoscience, 7 (2). 113-116. https://doi.org/10.1038/ngeo2037 <https://doi.org/10.1038/ngeo2037> Publication - Article PeerReviewed 2014 ftnerc https://doi.org/10.1038/ngeo2037 2023-02-04T19:38:27Z The Antarctic Circumpolar Current is key to the mixing and ventilation of the world’s oceans. This current flows from west to east between about 45° and 70°S connecting the Atlantic, Pacific and Indian oceans, and is driven by westerly winds and buoyancy forcing. High levels of productivity in the current regulate atmospheric CO2 concentrations. Reconstructions of the current during the last glacial period suggest that flow speeds were faster or similar to present, and it is uncertain whether the strength and position of the westerly winds changed. Here we reconstruct Antarctic Circumpolar Current bottom speeds through the constricting Drake Passage and Scotia Sea during the Last Glacial Maximum and Holocene based on the mean grain size of sortable silt from a suite of sediment cores. We find essentially no change in bottom flow speeds through the region, and, given that the momentum imparted by winds, and modulated by sea-ice cover, is balanced by the interaction of these flows with the seabed, this argues against substantial changes in wind stress. However, glacial flow speeds in the sea-ice zone south of 56°S were significantly slower than present, whereas flow in the north was faster, but not significantly so. We suggest that slower flow over the rough topography south of 56°S may have reduced diapycnal mixing in this region during the last glacial period, possibly reducing the diapycnal contribution to the Southern Ocean overturning circulation. Article in Journal/Newspaper Antarc* Antarctic Drake Passage Scotia Sea Sea ice Southern Ocean Natural Environment Research Council: NERC Open Research Archive Antarctic Southern Ocean The Antarctic Drake Passage Scotia Sea Pacific Indian Nature Geoscience 7 2 113 116 |
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Open Polar |
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Natural Environment Research Council: NERC Open Research Archive |
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ftnerc |
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English |
description |
The Antarctic Circumpolar Current is key to the mixing and ventilation of the world’s oceans. This current flows from west to east between about 45° and 70°S connecting the Atlantic, Pacific and Indian oceans, and is driven by westerly winds and buoyancy forcing. High levels of productivity in the current regulate atmospheric CO2 concentrations. Reconstructions of the current during the last glacial period suggest that flow speeds were faster or similar to present, and it is uncertain whether the strength and position of the westerly winds changed. Here we reconstruct Antarctic Circumpolar Current bottom speeds through the constricting Drake Passage and Scotia Sea during the Last Glacial Maximum and Holocene based on the mean grain size of sortable silt from a suite of sediment cores. We find essentially no change in bottom flow speeds through the region, and, given that the momentum imparted by winds, and modulated by sea-ice cover, is balanced by the interaction of these flows with the seabed, this argues against substantial changes in wind stress. However, glacial flow speeds in the sea-ice zone south of 56°S were significantly slower than present, whereas flow in the north was faster, but not significantly so. We suggest that slower flow over the rough topography south of 56°S may have reduced diapycnal mixing in this region during the last glacial period, possibly reducing the diapycnal contribution to the Southern Ocean overturning circulation. |
format |
Article in Journal/Newspaper |
author |
McCave, I. N. Crowhurst, S. J. Kuhn, G. Hillenbrand, C-D. Meredith, M. P. |
spellingShingle |
McCave, I. N. Crowhurst, S. J. Kuhn, G. Hillenbrand, C-D. Meredith, M. P. Minimal change in Antarctic Circumpolar Current flow speed between the last glacial and Holocene |
author_facet |
McCave, I. N. Crowhurst, S. J. Kuhn, G. Hillenbrand, C-D. Meredith, M. P. |
author_sort |
McCave, I. N. |
title |
Minimal change in Antarctic Circumpolar Current flow speed between the last glacial and Holocene |
title_short |
Minimal change in Antarctic Circumpolar Current flow speed between the last glacial and Holocene |
title_full |
Minimal change in Antarctic Circumpolar Current flow speed between the last glacial and Holocene |
title_fullStr |
Minimal change in Antarctic Circumpolar Current flow speed between the last glacial and Holocene |
title_full_unstemmed |
Minimal change in Antarctic Circumpolar Current flow speed between the last glacial and Holocene |
title_sort |
minimal change in antarctic circumpolar current flow speed between the last glacial and holocene |
publishDate |
2014 |
url |
http://nora.nerc.ac.uk/id/eprint/504465/ https://nora.nerc.ac.uk/id/eprint/504465/1/McCave%20et%20MS%20NGeo%20accepted.pdf https://doi.org/10.1038/ngeo2037 |
geographic |
Antarctic Southern Ocean The Antarctic Drake Passage Scotia Sea Pacific Indian |
geographic_facet |
Antarctic Southern Ocean The Antarctic Drake Passage Scotia Sea Pacific Indian |
genre |
Antarc* Antarctic Drake Passage Scotia Sea Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Drake Passage Scotia Sea Sea ice Southern Ocean |
op_relation |
https://nora.nerc.ac.uk/id/eprint/504465/1/McCave%20et%20MS%20NGeo%20accepted.pdf McCave, I. N.; Crowhurst, S. J.; Kuhn, G.; Hillenbrand, C-D. orcid:0000-0003-0240-7317 Meredith, M. P. orcid:0000-0002-7342-7756 . 2014 Minimal change in Antarctic Circumpolar Current flow speed between the last glacial and Holocene. Nature Geoscience, 7 (2). 113-116. https://doi.org/10.1038/ngeo2037 <https://doi.org/10.1038/ngeo2037> |
op_doi |
https://doi.org/10.1038/ngeo2037 |
container_title |
Nature Geoscience |
container_volume |
7 |
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2 |
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113 |
op_container_end_page |
116 |
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1766248733985472512 |