Changes in the strength of the Nordic Seas Overflows over the past 3000 years
The Nordic Seas Overflows constitute the densest component of the deep limb of the Atlantic Meridional Overturning Circulation (AMOC). Changes in the vigour of the overflows may have had important climatic effects in the past and may also have in the future. Yet, evidence for multidecadal to millenn...
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ftucl:oai:eprints.ucl.ac.uk.OAI2:1499144 2023-12-24T10:16:11+01:00 Changes in the strength of the Nordic Seas Overflows over the past 3000 years Moffa-Sanchez, P Hall, IR Thornalley, DJR Barker, S Stewart, C 2015-09-01 text https://discovery.ucl.ac.uk/id/eprint/1499144/1/Thornalley_Overflows_29May15_MS.pdf https://discovery.ucl.ac.uk/id/eprint/1499144/ eng eng PERGAMON-ELSEVIER SCIENCE LTD https://discovery.ucl.ac.uk/id/eprint/1499144/1/Thornalley_Overflows_29May15_MS.pdf https://discovery.ucl.ac.uk/id/eprint/1499144/ open Quaternary Science Reviews , 123 pp. 134-143. (2015) Physical geosciences multidisciplinary physical geography geology late Holocene North Atlantic Nordic Overflows paleoceanography Denmark strait overflow Faroe-Bank Channel Greenland-Scotland ridge surface temperature variability North-Atlantic oscillation revised circulation scheme Western Boundary current deep-water oceanographic variability Icelandic shelf Article 2015 ftucl 2023-11-27T13:07:28Z The Nordic Seas Overflows constitute the densest component of the deep limb of the Atlantic Meridional Overturning Circulation (AMOC). Changes in the vigour of the overflows may have had important climatic effects in the past and may also have in the future. Yet, evidence for multidecadal to millennial changes in the deep limb of the AMOC and their potential relationship to North Atlantic climate variability during the Holocene remains weakly constrained. Here we present grain size data, as a proxy for near-bottom current speed, from sub-decadal to decadally resolved sediment cores located in the direct pathway of the two Nordic Overflows east and west of Iceland, the Iceland-Scotland Overflow Water (ISOW) and the Denmark Strait Overflow Water (DSOW), respectively. The results show no clear relationship between reconstructed changes in the vigour of the Nordic Overflows and the well-known periods of centennial-scale climate variability recorded in the North Atlantic region. However, well-defined millennial-scale trends are found in both of the overflow strength records over the last 3000 years, which were possibly related to hydrographic reorganizations in the Nordic Seas, driven by the decrease in Northern Hemisphere summer insolation over the Neoglacial period. A comparison between the near-bottom flow speed reconstructions from ISOW and DSOW suggests an anti-phased relationship between the Nordic Seas Overflows east and west of Iceland over the last 3000 years. This feature has been observed in climate models potentially as a result of shifts in the deep water formation sites as a response to changes in atmospheric patterns over the Nordic Seas. Article in Journal/Newspaper Denmark Strait Greenland Greenland-Scotland Ridge Iceland Nordic Seas North Atlantic North Atlantic oscillation University College London: UCL Discovery Faroe Bank ENVELOPE(-8.667,-8.667,60.917,60.917) Greenland |
institution |
Open Polar |
collection |
University College London: UCL Discovery |
op_collection_id |
ftucl |
language |
English |
topic |
Physical geosciences multidisciplinary physical geography geology late Holocene North Atlantic Nordic Overflows paleoceanography Denmark strait overflow Faroe-Bank Channel Greenland-Scotland ridge surface temperature variability North-Atlantic oscillation revised circulation scheme Western Boundary current deep-water oceanographic variability Icelandic shelf |
spellingShingle |
Physical geosciences multidisciplinary physical geography geology late Holocene North Atlantic Nordic Overflows paleoceanography Denmark strait overflow Faroe-Bank Channel Greenland-Scotland ridge surface temperature variability North-Atlantic oscillation revised circulation scheme Western Boundary current deep-water oceanographic variability Icelandic shelf Moffa-Sanchez, P Hall, IR Thornalley, DJR Barker, S Stewart, C Changes in the strength of the Nordic Seas Overflows over the past 3000 years |
topic_facet |
Physical geosciences multidisciplinary physical geography geology late Holocene North Atlantic Nordic Overflows paleoceanography Denmark strait overflow Faroe-Bank Channel Greenland-Scotland ridge surface temperature variability North-Atlantic oscillation revised circulation scheme Western Boundary current deep-water oceanographic variability Icelandic shelf |
description |
The Nordic Seas Overflows constitute the densest component of the deep limb of the Atlantic Meridional Overturning Circulation (AMOC). Changes in the vigour of the overflows may have had important climatic effects in the past and may also have in the future. Yet, evidence for multidecadal to millennial changes in the deep limb of the AMOC and their potential relationship to North Atlantic climate variability during the Holocene remains weakly constrained. Here we present grain size data, as a proxy for near-bottom current speed, from sub-decadal to decadally resolved sediment cores located in the direct pathway of the two Nordic Overflows east and west of Iceland, the Iceland-Scotland Overflow Water (ISOW) and the Denmark Strait Overflow Water (DSOW), respectively. The results show no clear relationship between reconstructed changes in the vigour of the Nordic Overflows and the well-known periods of centennial-scale climate variability recorded in the North Atlantic region. However, well-defined millennial-scale trends are found in both of the overflow strength records over the last 3000 years, which were possibly related to hydrographic reorganizations in the Nordic Seas, driven by the decrease in Northern Hemisphere summer insolation over the Neoglacial period. A comparison between the near-bottom flow speed reconstructions from ISOW and DSOW suggests an anti-phased relationship between the Nordic Seas Overflows east and west of Iceland over the last 3000 years. This feature has been observed in climate models potentially as a result of shifts in the deep water formation sites as a response to changes in atmospheric patterns over the Nordic Seas. |
format |
Article in Journal/Newspaper |
author |
Moffa-Sanchez, P Hall, IR Thornalley, DJR Barker, S Stewart, C |
author_facet |
Moffa-Sanchez, P Hall, IR Thornalley, DJR Barker, S Stewart, C |
author_sort |
Moffa-Sanchez, P |
title |
Changes in the strength of the Nordic Seas Overflows over the past 3000 years |
title_short |
Changes in the strength of the Nordic Seas Overflows over the past 3000 years |
title_full |
Changes in the strength of the Nordic Seas Overflows over the past 3000 years |
title_fullStr |
Changes in the strength of the Nordic Seas Overflows over the past 3000 years |
title_full_unstemmed |
Changes in the strength of the Nordic Seas Overflows over the past 3000 years |
title_sort |
changes in the strength of the nordic seas overflows over the past 3000 years |
publisher |
PERGAMON-ELSEVIER SCIENCE LTD |
publishDate |
2015 |
url |
https://discovery.ucl.ac.uk/id/eprint/1499144/1/Thornalley_Overflows_29May15_MS.pdf https://discovery.ucl.ac.uk/id/eprint/1499144/ |
long_lat |
ENVELOPE(-8.667,-8.667,60.917,60.917) |
geographic |
Faroe Bank Greenland |
geographic_facet |
Faroe Bank Greenland |
genre |
Denmark Strait Greenland Greenland-Scotland Ridge Iceland Nordic Seas North Atlantic North Atlantic oscillation |
genre_facet |
Denmark Strait Greenland Greenland-Scotland Ridge Iceland Nordic Seas North Atlantic North Atlantic oscillation |
op_source |
Quaternary Science Reviews , 123 pp. 134-143. (2015) |
op_relation |
https://discovery.ucl.ac.uk/id/eprint/1499144/1/Thornalley_Overflows_29May15_MS.pdf https://discovery.ucl.ac.uk/id/eprint/1499144/ |
op_rights |
open |
_version_ |
1786203539596378112 |