Water mass transformation in the Iceland Sea
The water mass transformation that takes place in the Iceland Sea during winter is investigated using historical hydrographic data and atmospheric reanalysis fields. Surface densities exceeding σθ ¼ 27:8 kg=m3, and hence of sufficient density to contribute to the lower limb of the Atlantic Meridiona...
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Online Access: | https://hdl.handle.net/1956/16721 https://doi.org/10.1016/j.dsr.2015.04.001 |
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ftunivbergen:oai:bora.uib.no:1956/16721 2023-05-15T16:00:38+02:00 Water mass transformation in the Iceland Sea Våge, Kjetil Moore, George William Kent Jónsson, Steingrímur Valdimarsson, Héðinn 2017-08-25T11:16:59Z application/pdf https://hdl.handle.net/1956/16721 https://doi.org/10.1016/j.dsr.2015.04.001 eng eng Elsevier Norges forskningsråd: 231647 urn:issn:0967-0637 urn:issn:1879-0119 https://hdl.handle.net/1956/16721 https://doi.org/10.1016/j.dsr.2015.04.001 cristin:1246621 Attribution CC BY-NC-ND http://creativecommons.org/licenses/by-nc-nd/4.0/ Copyright 2015 Elsevier Ltd. Deep Sea Research Part I: Oceanographic Research Papers Iceland Sea Open-ocean convection North Icelandic Jet Denmark Strait Overflow Water Atlantic Meridional Overturning Circulation Cold air outbreak VDP::Matematikk og naturvitenskap: 400::Geofag: 450::Oseanografi: 452 VDP::Mathematics and natural scienses: 400::Geosciences: 450::Oceanography: 452 Peer reviewed Journal article 2017 ftunivbergen https://doi.org/10.1016/j.dsr.2015.04.001 2023-03-14T17:43:25Z The water mass transformation that takes place in the Iceland Sea during winter is investigated using historical hydrographic data and atmospheric reanalysis fields. Surface densities exceeding σθ ¼ 27:8 kg=m3, and hence of sufficient density to contribute to the lower limb of the Atlantic Meridional Overturning Circulation via the overflows across the Greenland-Scotland Ridge, exist throughout the interior Iceland Sea east of the Kolbeinsey Ridge at the end of winter. The deepest and densest mixed layers are found in the northwest Iceland Sea on the outskirts of the basin׳s cyclonic gyre, largely determined by stronger atmospheric forcing near the ice edge. Much of the accumulated wintertime heat loss in that region takes place during a few extreme cold air outbreak events. Only a small number of hydrographic profiles (2%) recorded mixed layers sufficiently dense to supply the deepest part of the North Icelandic Jet, a current along the slope off northern Iceland that advects overflow water into the Denmark Strait. However, low values of potential vorticity at depth indicate that waters of this density class may be ventilated more regularly than the direct observations of dense mixed layers in the sparse data set indicate. A sudden increase in the depth of this deep isopycnal around 1995 suggests that the supply of dense water to the North Icelandic Jet, and hence to the densest component of the Atlantic Meridional Overturning Circulation, may have diminished over the past 20 years. Concurrent reductions in the turbulent heat fluxes and wind stress curl over the Iceland Sea are consistent with a decrease in convective activity and a weakening of the cyclonic gyre, both of which could have caused the increase in depth of these dense waters. acceptedVersion Article in Journal/Newspaper Denmark Strait Greenland Greenland-Scotland Ridge Iceland Kolbeinsey University of Bergen: Bergen Open Research Archive (BORA-UiB) Curl ENVELOPE(-63.071,-63.071,-70.797,-70.797) Greenland Kolbeinsey ENVELOPE(-18.687,-18.687,67.149,67.149) Kolbeinsey Ridge ENVELOPE(-16.917,-16.917,68.833,68.833) Deep Sea Research Part I: Oceanographic Research Papers 101 98 109 |
institution |
Open Polar |
collection |
University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
topic |
Iceland Sea Open-ocean convection North Icelandic Jet Denmark Strait Overflow Water Atlantic Meridional Overturning Circulation Cold air outbreak VDP::Matematikk og naturvitenskap: 400::Geofag: 450::Oseanografi: 452 VDP::Mathematics and natural scienses: 400::Geosciences: 450::Oceanography: 452 |
spellingShingle |
Iceland Sea Open-ocean convection North Icelandic Jet Denmark Strait Overflow Water Atlantic Meridional Overturning Circulation Cold air outbreak VDP::Matematikk og naturvitenskap: 400::Geofag: 450::Oseanografi: 452 VDP::Mathematics and natural scienses: 400::Geosciences: 450::Oceanography: 452 Våge, Kjetil Moore, George William Kent Jónsson, Steingrímur Valdimarsson, Héðinn Water mass transformation in the Iceland Sea |
topic_facet |
Iceland Sea Open-ocean convection North Icelandic Jet Denmark Strait Overflow Water Atlantic Meridional Overturning Circulation Cold air outbreak VDP::Matematikk og naturvitenskap: 400::Geofag: 450::Oseanografi: 452 VDP::Mathematics and natural scienses: 400::Geosciences: 450::Oceanography: 452 |
description |
The water mass transformation that takes place in the Iceland Sea during winter is investigated using historical hydrographic data and atmospheric reanalysis fields. Surface densities exceeding σθ ¼ 27:8 kg=m3, and hence of sufficient density to contribute to the lower limb of the Atlantic Meridional Overturning Circulation via the overflows across the Greenland-Scotland Ridge, exist throughout the interior Iceland Sea east of the Kolbeinsey Ridge at the end of winter. The deepest and densest mixed layers are found in the northwest Iceland Sea on the outskirts of the basin׳s cyclonic gyre, largely determined by stronger atmospheric forcing near the ice edge. Much of the accumulated wintertime heat loss in that region takes place during a few extreme cold air outbreak events. Only a small number of hydrographic profiles (2%) recorded mixed layers sufficiently dense to supply the deepest part of the North Icelandic Jet, a current along the slope off northern Iceland that advects overflow water into the Denmark Strait. However, low values of potential vorticity at depth indicate that waters of this density class may be ventilated more regularly than the direct observations of dense mixed layers in the sparse data set indicate. A sudden increase in the depth of this deep isopycnal around 1995 suggests that the supply of dense water to the North Icelandic Jet, and hence to the densest component of the Atlantic Meridional Overturning Circulation, may have diminished over the past 20 years. Concurrent reductions in the turbulent heat fluxes and wind stress curl over the Iceland Sea are consistent with a decrease in convective activity and a weakening of the cyclonic gyre, both of which could have caused the increase in depth of these dense waters. acceptedVersion |
format |
Article in Journal/Newspaper |
author |
Våge, Kjetil Moore, George William Kent Jónsson, Steingrímur Valdimarsson, Héðinn |
author_facet |
Våge, Kjetil Moore, George William Kent Jónsson, Steingrímur Valdimarsson, Héðinn |
author_sort |
Våge, Kjetil |
title |
Water mass transformation in the Iceland Sea |
title_short |
Water mass transformation in the Iceland Sea |
title_full |
Water mass transformation in the Iceland Sea |
title_fullStr |
Water mass transformation in the Iceland Sea |
title_full_unstemmed |
Water mass transformation in the Iceland Sea |
title_sort |
water mass transformation in the iceland sea |
publisher |
Elsevier |
publishDate |
2017 |
url |
https://hdl.handle.net/1956/16721 https://doi.org/10.1016/j.dsr.2015.04.001 |
long_lat |
ENVELOPE(-63.071,-63.071,-70.797,-70.797) ENVELOPE(-18.687,-18.687,67.149,67.149) ENVELOPE(-16.917,-16.917,68.833,68.833) |
geographic |
Curl Greenland Kolbeinsey Kolbeinsey Ridge |
geographic_facet |
Curl Greenland Kolbeinsey Kolbeinsey Ridge |
genre |
Denmark Strait Greenland Greenland-Scotland Ridge Iceland Kolbeinsey |
genre_facet |
Denmark Strait Greenland Greenland-Scotland Ridge Iceland Kolbeinsey |
op_source |
Deep Sea Research Part I: Oceanographic Research Papers |
op_relation |
Norges forskningsråd: 231647 urn:issn:0967-0637 urn:issn:1879-0119 https://hdl.handle.net/1956/16721 https://doi.org/10.1016/j.dsr.2015.04.001 cristin:1246621 |
op_rights |
Attribution CC BY-NC-ND http://creativecommons.org/licenses/by-nc-nd/4.0/ Copyright 2015 Elsevier Ltd. |
op_doi |
https://doi.org/10.1016/j.dsr.2015.04.001 |
container_title |
Deep Sea Research Part I: Oceanographic Research Papers |
container_volume |
101 |
container_start_page |
98 |
op_container_end_page |
109 |
_version_ |
1766396646062555136 |