A stable Faroe Bank Channel overflow 1995–2015
The Faroe Bank Channel (FBC) is the deepest passage across the Greenland–Scotland Ridge (GSR) and there is a continuous deep flow of cold and dense water passing through it from the Arctic Mediterranean into the North Atlantic and further to the rest of the world ocean. This FBC overflow is part of...
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ftcopernicus:oai:publications.copernicus.org:os53782 2023-05-15T15:03:46+02:00 A stable Faroe Bank Channel overflow 1995–2015 Hansen, Bogi Húsgarð Larsen, Karin Margretha Hátún, Hjálmar Østerhus, Svein 2018-09-15 info:eu-repo/semantics/application/pdf https://doi.org/10.5194/os-12-1205-2016 https://os.copernicus.org/articles/12/1205/2016/ eng eng info:eu-repo/grantAgreement/EC/FP7/308299 doi:10.5194/os-12-1205-2016 https://os.copernicus.org/articles/12/1205/2016/ info:eu-repo/semantics/openAccess eISSN: 1812-0792 info:eu-repo/semantics/Text 2018 ftcopernicus https://doi.org/10.5194/os-12-1205-2016 2020-07-20T16:23:55Z The Faroe Bank Channel (FBC) is the deepest passage across the Greenland–Scotland Ridge (GSR) and there is a continuous deep flow of cold and dense water passing through it from the Arctic Mediterranean into the North Atlantic and further to the rest of the world ocean. This FBC overflow is part of the Atlantic Meridional Overturning Circulation (AMOC), which has recently been suggested to have weakened. From November 1995 to May 2015, the FBC overflow has been monitored by a continuous ADCP (acoustic Doppler current profiler) mooring, which has been deployed in the middle of this narrow channel. Combined with regular hydrography cruises and several short-term mooring experiments, this allowed us to construct time series of volume transport and to follow changes in the hydrographic properties and density of the FBC overflow. The mean kinematic overflow, derived solely from the velocity field, was found to be (2.2 ± 0.2) Sv (1 Sv = 10 6 m 3 s −1 ) with a slight, but not statistically significant, positive trend. The coldest part, and probably the bulk, of the FBC overflow warmed by a bit more than 0.1 °C, especially after 2002, increasing the transport of heat into the deep ocean. This warming was, however, accompanied by increasing salinities, which seem to have compensated for the temperature-induced density decrease. Thus, the FBC overflow has remained stable in volume transport as well as density during the 2 decades from 1995 to 2015. After crossing the GSR, the overflow is modified by mixing and entrainment, but the associated change in volume (and heat) transport is still not well known. Whatever effect this has on the AMOC and the global energy balance, our observed stability of the FBC overflow is consistent with reported observations from the other main overflow branch, the Denmark Strait overflow, and the three Atlantic inflow branches to the Arctic Mediterranean that feed the overflows. If the AMOC has weakened during the last 2 decades, it is not likely to have been due to its northernmost extension – the exchanges across the Greenland–Scotland Ridge. Other/Unknown Material Arctic Denmark Strait Greenland Greenland-Scotland Ridge North Atlantic Copernicus Publications: E-Journals Arctic Faroe Bank ENVELOPE(-8.667,-8.667,60.917,60.917) Greenland Ocean Science 12 6 1205 1220 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
The Faroe Bank Channel (FBC) is the deepest passage across the Greenland–Scotland Ridge (GSR) and there is a continuous deep flow of cold and dense water passing through it from the Arctic Mediterranean into the North Atlantic and further to the rest of the world ocean. This FBC overflow is part of the Atlantic Meridional Overturning Circulation (AMOC), which has recently been suggested to have weakened. From November 1995 to May 2015, the FBC overflow has been monitored by a continuous ADCP (acoustic Doppler current profiler) mooring, which has been deployed in the middle of this narrow channel. Combined with regular hydrography cruises and several short-term mooring experiments, this allowed us to construct time series of volume transport and to follow changes in the hydrographic properties and density of the FBC overflow. The mean kinematic overflow, derived solely from the velocity field, was found to be (2.2 ± 0.2) Sv (1 Sv = 10 6 m 3 s −1 ) with a slight, but not statistically significant, positive trend. The coldest part, and probably the bulk, of the FBC overflow warmed by a bit more than 0.1 °C, especially after 2002, increasing the transport of heat into the deep ocean. This warming was, however, accompanied by increasing salinities, which seem to have compensated for the temperature-induced density decrease. Thus, the FBC overflow has remained stable in volume transport as well as density during the 2 decades from 1995 to 2015. After crossing the GSR, the overflow is modified by mixing and entrainment, but the associated change in volume (and heat) transport is still not well known. Whatever effect this has on the AMOC and the global energy balance, our observed stability of the FBC overflow is consistent with reported observations from the other main overflow branch, the Denmark Strait overflow, and the three Atlantic inflow branches to the Arctic Mediterranean that feed the overflows. If the AMOC has weakened during the last 2 decades, it is not likely to have been due to its northernmost extension – the exchanges across the Greenland–Scotland Ridge. |
format |
Other/Unknown Material |
author |
Hansen, Bogi Húsgarð Larsen, Karin Margretha Hátún, Hjálmar Østerhus, Svein |
spellingShingle |
Hansen, Bogi Húsgarð Larsen, Karin Margretha Hátún, Hjálmar Østerhus, Svein A stable Faroe Bank Channel overflow 1995–2015 |
author_facet |
Hansen, Bogi Húsgarð Larsen, Karin Margretha Hátún, Hjálmar Østerhus, Svein |
author_sort |
Hansen, Bogi |
title |
A stable Faroe Bank Channel overflow 1995–2015 |
title_short |
A stable Faroe Bank Channel overflow 1995–2015 |
title_full |
A stable Faroe Bank Channel overflow 1995–2015 |
title_fullStr |
A stable Faroe Bank Channel overflow 1995–2015 |
title_full_unstemmed |
A stable Faroe Bank Channel overflow 1995–2015 |
title_sort |
stable faroe bank channel overflow 1995–2015 |
publishDate |
2018 |
url |
https://doi.org/10.5194/os-12-1205-2016 https://os.copernicus.org/articles/12/1205/2016/ |
long_lat |
ENVELOPE(-8.667,-8.667,60.917,60.917) |
geographic |
Arctic Faroe Bank Greenland |
geographic_facet |
Arctic Faroe Bank Greenland |
genre |
Arctic Denmark Strait Greenland Greenland-Scotland Ridge North Atlantic |
genre_facet |
Arctic Denmark Strait Greenland Greenland-Scotland Ridge North Atlantic |
op_source |
eISSN: 1812-0792 |
op_relation |
info:eu-repo/grantAgreement/EC/FP7/308299 doi:10.5194/os-12-1205-2016 https://os.copernicus.org/articles/12/1205/2016/ |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/os-12-1205-2016 |
container_title |
Ocean Science |
container_volume |
12 |
container_issue |
6 |
container_start_page |
1205 |
op_container_end_page |
1220 |
_version_ |
1766335623861370880 |