Reversed North Atlantic gyre dynamics in present and glacial climates
The dynamics of the North Atlantic subpolar gyre (SPG) are assessed under present and glacial boundary conditions by investigating the SPG sensitivity to surface wind-stress changes in a coupled climate model. To this end, the gyre transport is decomposed in Ekman, thermohaline, and bottom transport...
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ftubpotsdam:oai:kobv.de-opus4-uni-potsdam:36987 2024-04-21T08:03:54+00:00 Reversed North Atlantic gyre dynamics in present and glacial climates Montoya, Marisa Born, Andreas Levermann, Anders (Prof. Dr.) 2011 https://publishup.uni-potsdam.de/frontdoor/index/index/docId/36987 https://doi.org/10.1007/s00382-009-0729-y eng eng https://publishup.uni-potsdam.de/frontdoor/index/index/docId/36987 https://doi.org/10.1007/s00382-009-0729-y info:eu-repo/semantics/closedAccess Institut für Physik und Astronomie article doc-type:article 2011 ftubpotsdam https://doi.org/10.1007/s00382-009-0729-y 2024-03-27T15:02:48Z The dynamics of the North Atlantic subpolar gyre (SPG) are assessed under present and glacial boundary conditions by investigating the SPG sensitivity to surface wind-stress changes in a coupled climate model. To this end, the gyre transport is decomposed in Ekman, thermohaline, and bottom transports. Surface wind-stress variations are found to play an important indirect role in SPG dynamics through their effect on water-mass densities. Our results suggest the existence of two dynamically distinct regimes of the SPG, depending on the absence or presence of deep water formation (DWF) in the Nordic Seas and a vigorous Greenland-Scotland ridge (GSR) overflow. In the first regime, the GSR overflow is weak and the SPG strength increases with wind-stress as a result of enhanced outcropping of isopycnals in the centre of the SPG. As soon as a vigorous GSR overflow is established, its associated positive density anomalies on the southern GSR slope reduce the SPG strength. This has implications for past glacial abrupt climate changes, insofar as these can be explained through latitudinal shifts in North Atlantic DWF sites and strengthening of the North Atlantic current. Regardless of the ultimate trigger, an abrupt shift of DWF into the Nordic Seas could result both in a drastic reduction of the SPG strength and a sudden reversal in its sensitivity to wind-stress variations. Our results could provide insight into changes in the horizontal ocean circulation during abrupt glacial climate changes, which have been largely neglected up to now in model studies. Article in Journal/Newspaper Greenland Greenland-Scotland Ridge Nordic Seas north atlantic current North Atlantic University of Potsdam: publish.UP Climate Dynamics 36 5-6 1107 1118 |
institution |
Open Polar |
collection |
University of Potsdam: publish.UP |
op_collection_id |
ftubpotsdam |
language |
English |
topic |
Institut für Physik und Astronomie |
spellingShingle |
Institut für Physik und Astronomie Montoya, Marisa Born, Andreas Levermann, Anders (Prof. Dr.) Reversed North Atlantic gyre dynamics in present and glacial climates |
topic_facet |
Institut für Physik und Astronomie |
description |
The dynamics of the North Atlantic subpolar gyre (SPG) are assessed under present and glacial boundary conditions by investigating the SPG sensitivity to surface wind-stress changes in a coupled climate model. To this end, the gyre transport is decomposed in Ekman, thermohaline, and bottom transports. Surface wind-stress variations are found to play an important indirect role in SPG dynamics through their effect on water-mass densities. Our results suggest the existence of two dynamically distinct regimes of the SPG, depending on the absence or presence of deep water formation (DWF) in the Nordic Seas and a vigorous Greenland-Scotland ridge (GSR) overflow. In the first regime, the GSR overflow is weak and the SPG strength increases with wind-stress as a result of enhanced outcropping of isopycnals in the centre of the SPG. As soon as a vigorous GSR overflow is established, its associated positive density anomalies on the southern GSR slope reduce the SPG strength. This has implications for past glacial abrupt climate changes, insofar as these can be explained through latitudinal shifts in North Atlantic DWF sites and strengthening of the North Atlantic current. Regardless of the ultimate trigger, an abrupt shift of DWF into the Nordic Seas could result both in a drastic reduction of the SPG strength and a sudden reversal in its sensitivity to wind-stress variations. Our results could provide insight into changes in the horizontal ocean circulation during abrupt glacial climate changes, which have been largely neglected up to now in model studies. |
format |
Article in Journal/Newspaper |
author |
Montoya, Marisa Born, Andreas Levermann, Anders (Prof. Dr.) |
author_facet |
Montoya, Marisa Born, Andreas Levermann, Anders (Prof. Dr.) |
author_sort |
Montoya, Marisa |
title |
Reversed North Atlantic gyre dynamics in present and glacial climates |
title_short |
Reversed North Atlantic gyre dynamics in present and glacial climates |
title_full |
Reversed North Atlantic gyre dynamics in present and glacial climates |
title_fullStr |
Reversed North Atlantic gyre dynamics in present and glacial climates |
title_full_unstemmed |
Reversed North Atlantic gyre dynamics in present and glacial climates |
title_sort |
reversed north atlantic gyre dynamics in present and glacial climates |
publishDate |
2011 |
url |
https://publishup.uni-potsdam.de/frontdoor/index/index/docId/36987 https://doi.org/10.1007/s00382-009-0729-y |
genre |
Greenland Greenland-Scotland Ridge Nordic Seas north atlantic current North Atlantic |
genre_facet |
Greenland Greenland-Scotland Ridge Nordic Seas north atlantic current North Atlantic |
op_relation |
https://publishup.uni-potsdam.de/frontdoor/index/index/docId/36987 https://doi.org/10.1007/s00382-009-0729-y |
op_rights |
info:eu-repo/semantics/closedAccess |
op_doi |
https://doi.org/10.1007/s00382-009-0729-y |
container_title |
Climate Dynamics |
container_volume |
36 |
container_issue |
5-6 |
container_start_page |
1107 |
op_container_end_page |
1118 |
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1796943582792253440 |