Long-term variations in Iceland–Scotland overflow strength during the Holocene
The overflow of deep water from the Nordic seas into the North Atlantic plays a critical role in global ocean circulation and climate. Approximately half of this overflow occurs via the Iceland–Scotland (I–S) overflow, yet the history of its strength throughout the Holocene (~ 0–11 700 yr ago, ka) i...
Published in: | Climate of the Past |
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Format: | Article in Journal/Newspaper |
Language: | English |
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Copernicus GmbH (Copernicus Publications)
2013
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Online Access: | http://eprints.esc.cam.ac.uk/2906/ http://eprints.esc.cam.ac.uk/2906/1/clim%20past.pdf http://eprints.esc.cam.ac.uk/2906/2/cp-9-2073-2013-supplement.pdf http://www.clim-past.net/9/2073/2013/ https://doi.org/10.5194/cp-9-2073-2013 |
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ftucambridgeesc:oai:eprints.esc.cam.ac.uk:2906 2023-05-15T15:00:47+02:00 Long-term variations in Iceland–Scotland overflow strength during the Holocene Thornalley, D. J. R. Blaschek, M. Davies, F. J. Praetorius, S. Oppo, D. W. McManus, I. R. Kleiven, H. F. Renssen, H. McCave, I. N. 2013-09 text http://eprints.esc.cam.ac.uk/2906/ http://eprints.esc.cam.ac.uk/2906/1/clim%20past.pdf http://eprints.esc.cam.ac.uk/2906/2/cp-9-2073-2013-supplement.pdf http://www.clim-past.net/9/2073/2013/ https://doi.org/10.5194/cp-9-2073-2013 en eng Copernicus GmbH (Copernicus Publications) http://eprints.esc.cam.ac.uk/2906/1/clim%20past.pdf http://eprints.esc.cam.ac.uk/2906/2/cp-9-2073-2013-supplement.pdf Thornalley, D. J. R. and Blaschek, M. and Davies, F. J. and Praetorius, S. and Oppo, D. W. and McManus, I. R. and Kleiven, H. F. and Renssen, H. and McCave, I. N. (2013) Long-term variations in Iceland–Scotland overflow strength during the Holocene. Climate of the past, 9 (5). pp. 2073-2084. ISSN 1814-9340 DOI https://doi.org/10.5194/cp-9-2073-2013 <https://doi.org/10.5194/cp-9-2073-2013> cc_by CC-BY 01 - Climate Change and Earth-Ocean Atmosphere Systems Article PeerReviewed 2013 ftucambridgeesc https://doi.org/10.5194/cp-9-2073-2013 2020-08-27T18:09:27Z The overflow of deep water from the Nordic seas into the North Atlantic plays a critical role in global ocean circulation and climate. Approximately half of this overflow occurs via the Iceland–Scotland (I–S) overflow, yet the history of its strength throughout the Holocene (~ 0–11 700 yr ago, ka) is poorly constrained, with previous studies presenting apparently contradictory evidence regarding its long-term variability. Here, we provide a comprehensive reconstruction of I–S overflow strength throughout the Holocene using sediment grain size data from a depth transect of 13 cores from the Iceland Basin. Our data are consistent with the hypothesis that the main axis of the I–S overflow on the Iceland slope was shallower during the early Holocene, deepening to its present depth by ~ 7 ka. Our results also reveal weaker I–S overflow during the early and late Holocene, with maximum overflow strength occurring at ~ 7 ka, the time of a regional climate thermal maximum. Climate model simulations suggest a shoaling of deep convection in the Nordic seas during the early and late Holocene, consistent with our evidence for weaker I–S overflow during these intervals. Whereas the reduction in I–S overflow strength during the early Holocene likely resulted from melting remnant glacial ice sheets, the decline throughout the last 7000 yr was caused by an orbitally induced increase in the amount of Arctic sea ice entering the Nordic seas. Although the flux of Arctic sea ice to the Nordic seas is expected to decrease throughout the next century, model simulations predict that under high emissions scenarios, competing effects, such as warmer sea surface temperatures in the Nordic seas, will result in reduced deep convection, likely driving a weaker I–S overflow. Article in Journal/Newspaper Arctic Climate change Iceland Nordic Seas North Atlantic Sea ice University of Cambridge, Department of Earth Sciences: ESC Publications Arctic Climate of the Past 9 5 2073 2084 |
institution |
Open Polar |
collection |
University of Cambridge, Department of Earth Sciences: ESC Publications |
op_collection_id |
ftucambridgeesc |
language |
English |
topic |
01 - Climate Change and Earth-Ocean Atmosphere Systems |
spellingShingle |
01 - Climate Change and Earth-Ocean Atmosphere Systems Thornalley, D. J. R. Blaschek, M. Davies, F. J. Praetorius, S. Oppo, D. W. McManus, I. R. Kleiven, H. F. Renssen, H. McCave, I. N. Long-term variations in Iceland–Scotland overflow strength during the Holocene |
topic_facet |
01 - Climate Change and Earth-Ocean Atmosphere Systems |
description |
The overflow of deep water from the Nordic seas into the North Atlantic plays a critical role in global ocean circulation and climate. Approximately half of this overflow occurs via the Iceland–Scotland (I–S) overflow, yet the history of its strength throughout the Holocene (~ 0–11 700 yr ago, ka) is poorly constrained, with previous studies presenting apparently contradictory evidence regarding its long-term variability. Here, we provide a comprehensive reconstruction of I–S overflow strength throughout the Holocene using sediment grain size data from a depth transect of 13 cores from the Iceland Basin. Our data are consistent with the hypothesis that the main axis of the I–S overflow on the Iceland slope was shallower during the early Holocene, deepening to its present depth by ~ 7 ka. Our results also reveal weaker I–S overflow during the early and late Holocene, with maximum overflow strength occurring at ~ 7 ka, the time of a regional climate thermal maximum. Climate model simulations suggest a shoaling of deep convection in the Nordic seas during the early and late Holocene, consistent with our evidence for weaker I–S overflow during these intervals. Whereas the reduction in I–S overflow strength during the early Holocene likely resulted from melting remnant glacial ice sheets, the decline throughout the last 7000 yr was caused by an orbitally induced increase in the amount of Arctic sea ice entering the Nordic seas. Although the flux of Arctic sea ice to the Nordic seas is expected to decrease throughout the next century, model simulations predict that under high emissions scenarios, competing effects, such as warmer sea surface temperatures in the Nordic seas, will result in reduced deep convection, likely driving a weaker I–S overflow. |
format |
Article in Journal/Newspaper |
author |
Thornalley, D. J. R. Blaschek, M. Davies, F. J. Praetorius, S. Oppo, D. W. McManus, I. R. Kleiven, H. F. Renssen, H. McCave, I. N. |
author_facet |
Thornalley, D. J. R. Blaschek, M. Davies, F. J. Praetorius, S. Oppo, D. W. McManus, I. R. Kleiven, H. F. Renssen, H. McCave, I. N. |
author_sort |
Thornalley, D. J. R. |
title |
Long-term variations in Iceland–Scotland overflow strength during the Holocene |
title_short |
Long-term variations in Iceland–Scotland overflow strength during the Holocene |
title_full |
Long-term variations in Iceland–Scotland overflow strength during the Holocene |
title_fullStr |
Long-term variations in Iceland–Scotland overflow strength during the Holocene |
title_full_unstemmed |
Long-term variations in Iceland–Scotland overflow strength during the Holocene |
title_sort |
long-term variations in iceland–scotland overflow strength during the holocene |
publisher |
Copernicus GmbH (Copernicus Publications) |
publishDate |
2013 |
url |
http://eprints.esc.cam.ac.uk/2906/ http://eprints.esc.cam.ac.uk/2906/1/clim%20past.pdf http://eprints.esc.cam.ac.uk/2906/2/cp-9-2073-2013-supplement.pdf http://www.clim-past.net/9/2073/2013/ https://doi.org/10.5194/cp-9-2073-2013 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Climate change Iceland Nordic Seas North Atlantic Sea ice |
genre_facet |
Arctic Climate change Iceland Nordic Seas North Atlantic Sea ice |
op_relation |
http://eprints.esc.cam.ac.uk/2906/1/clim%20past.pdf http://eprints.esc.cam.ac.uk/2906/2/cp-9-2073-2013-supplement.pdf Thornalley, D. J. R. and Blaschek, M. and Davies, F. J. and Praetorius, S. and Oppo, D. W. and McManus, I. R. and Kleiven, H. F. and Renssen, H. and McCave, I. N. (2013) Long-term variations in Iceland–Scotland overflow strength during the Holocene. Climate of the past, 9 (5). pp. 2073-2084. ISSN 1814-9340 DOI https://doi.org/10.5194/cp-9-2073-2013 <https://doi.org/10.5194/cp-9-2073-2013> |
op_rights |
cc_by |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/cp-9-2073-2013 |
container_title |
Climate of the Past |
container_volume |
9 |
container_issue |
5 |
container_start_page |
2073 |
op_container_end_page |
2084 |
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1766332854502948864 |