Atlantic Circulation and Ice Sheet Influences on Upper South Atlantic Temperatures During the Last Deglaciation
Atlantic Meridional Overturning Circulation (AMOC) disruption during the last deglaciation is hypothesized to have caused large subsurface ocean temperature anomalies, but records from key regions are not available to test this hypothesis, and other possible drivers of warming have not been fully co...
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ftanucanberra:oai:openresearch-repository.anu.edu.au:1885/202023 2024-01-14T10:07:44+01:00 Atlantic Circulation and Ice Sheet Influences on Upper South Atlantic Temperatures During the Last Deglaciation Umling, N. E. Oppo, D. W. Chen, Pujiao Yu, Jimin Liu, Z. Yan, M. Gebbie, G Lund, D. C. Pietro, K. R. Jin, Z. D. Huang, K.-F. Costa, K. B. Toledo, F. A. L. application/pdf http://hdl.handle.net/1885/202023 https://doi.org/10.1029/2019PA003558 https://openresearch-repository.anu.edu.au/bitstream/1885/202023/5/01_Umling_Atlantic_Circulation_and_Ice_2019.pdf.jpg en_AU eng Wiley 1944-9186 http://hdl.handle.net/1885/202023 doi:10.1029/2019PA003558 https://openresearch-repository.anu.edu.au/bitstream/1885/202023/5/01_Umling_Atlantic_Circulation_and_Ice_2019.pdf.jpg © 2019. The Authors. https://creativecommons.org/licenses/by-nc-nd/4.0/ Creative Commons Attribution‐NonCommercial‐NoDerivs License Paleoceanography and Paleoclimatology Journal article ftanucanberra https://doi.org/10.1029/2019PA003558 2023-12-15T09:35:32Z Atlantic Meridional Overturning Circulation (AMOC) disruption during the last deglaciation is hypothesized to have caused large subsurface ocean temperature anomalies, but records from key regions are not available to test this hypothesis, and other possible drivers of warming have not been fully considered. Here, we present the first reliable evidence for subsurface warming in the South Atlantic during Heinrich Stadial 1, confirming the link between large‐scale heat redistribution and AMOC. Warming extends across the Bølling‐Allerød despite predicted cooling at this time, thus spanning intervals of both weak and strong AMOC indicating another forcing mechanism that may have been previously overlooked. Transient model simulations and quasi‐conservative water mass tracers suggest that reduced northward upper ocean heat transport was responsible for the early deglacial (Heinrich Stadial 1) accumulation of heat at our shallower (~1,100 m) site. In contrast, the results suggest that warming at our deeper site (~1,900 m) site was dominated by southward advection of North Atlantic middepth heat anomalies. During the Bølling‐Allerød, the demise of ice sheets resulted in oceanographic changes in the North Atlantic that reduced convective heat loss to the atmosphere, causing subsurface warming that overwhelmed the cooling expected from an AMOC reinvigoration. The data and simulations suggest that rising atmospheric CO2 did not contribute significantly to deglacial subsurface warming at our sites. Article in Journal/Newspaper Ice Sheet North Atlantic Australian National University: ANU Digital Collections Paleoceanography and Paleoclimatology 34 6 990 1005 |
institution |
Open Polar |
collection |
Australian National University: ANU Digital Collections |
op_collection_id |
ftanucanberra |
language |
English |
description |
Atlantic Meridional Overturning Circulation (AMOC) disruption during the last deglaciation is hypothesized to have caused large subsurface ocean temperature anomalies, but records from key regions are not available to test this hypothesis, and other possible drivers of warming have not been fully considered. Here, we present the first reliable evidence for subsurface warming in the South Atlantic during Heinrich Stadial 1, confirming the link between large‐scale heat redistribution and AMOC. Warming extends across the Bølling‐Allerød despite predicted cooling at this time, thus spanning intervals of both weak and strong AMOC indicating another forcing mechanism that may have been previously overlooked. Transient model simulations and quasi‐conservative water mass tracers suggest that reduced northward upper ocean heat transport was responsible for the early deglacial (Heinrich Stadial 1) accumulation of heat at our shallower (~1,100 m) site. In contrast, the results suggest that warming at our deeper site (~1,900 m) site was dominated by southward advection of North Atlantic middepth heat anomalies. During the Bølling‐Allerød, the demise of ice sheets resulted in oceanographic changes in the North Atlantic that reduced convective heat loss to the atmosphere, causing subsurface warming that overwhelmed the cooling expected from an AMOC reinvigoration. The data and simulations suggest that rising atmospheric CO2 did not contribute significantly to deglacial subsurface warming at our sites. |
format |
Article in Journal/Newspaper |
author |
Umling, N. E. Oppo, D. W. Chen, Pujiao Yu, Jimin Liu, Z. Yan, M. Gebbie, G Lund, D. C. Pietro, K. R. Jin, Z. D. Huang, K.-F. Costa, K. B. Toledo, F. A. L. |
spellingShingle |
Umling, N. E. Oppo, D. W. Chen, Pujiao Yu, Jimin Liu, Z. Yan, M. Gebbie, G Lund, D. C. Pietro, K. R. Jin, Z. D. Huang, K.-F. Costa, K. B. Toledo, F. A. L. Atlantic Circulation and Ice Sheet Influences on Upper South Atlantic Temperatures During the Last Deglaciation |
author_facet |
Umling, N. E. Oppo, D. W. Chen, Pujiao Yu, Jimin Liu, Z. Yan, M. Gebbie, G Lund, D. C. Pietro, K. R. Jin, Z. D. Huang, K.-F. Costa, K. B. Toledo, F. A. L. |
author_sort |
Umling, N. E. |
title |
Atlantic Circulation and Ice Sheet Influences on Upper South Atlantic Temperatures During the Last Deglaciation |
title_short |
Atlantic Circulation and Ice Sheet Influences on Upper South Atlantic Temperatures During the Last Deglaciation |
title_full |
Atlantic Circulation and Ice Sheet Influences on Upper South Atlantic Temperatures During the Last Deglaciation |
title_fullStr |
Atlantic Circulation and Ice Sheet Influences on Upper South Atlantic Temperatures During the Last Deglaciation |
title_full_unstemmed |
Atlantic Circulation and Ice Sheet Influences on Upper South Atlantic Temperatures During the Last Deglaciation |
title_sort |
atlantic circulation and ice sheet influences on upper south atlantic temperatures during the last deglaciation |
publisher |
Wiley |
url |
http://hdl.handle.net/1885/202023 https://doi.org/10.1029/2019PA003558 https://openresearch-repository.anu.edu.au/bitstream/1885/202023/5/01_Umling_Atlantic_Circulation_and_Ice_2019.pdf.jpg |
genre |
Ice Sheet North Atlantic |
genre_facet |
Ice Sheet North Atlantic |
op_source |
Paleoceanography and Paleoclimatology |
op_relation |
1944-9186 http://hdl.handle.net/1885/202023 doi:10.1029/2019PA003558 https://openresearch-repository.anu.edu.au/bitstream/1885/202023/5/01_Umling_Atlantic_Circulation_and_Ice_2019.pdf.jpg |
op_rights |
© 2019. The Authors. https://creativecommons.org/licenses/by-nc-nd/4.0/ Creative Commons Attribution‐NonCommercial‐NoDerivs License |
op_doi |
https://doi.org/10.1029/2019PA003558 |
container_title |
Paleoceanography and Paleoclimatology |
container_volume |
34 |
container_issue |
6 |
container_start_page |
990 |
op_container_end_page |
1005 |
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1788062130342199296 |