Water mass transformation in the Greenland Sea during the period 1986-2016
Hydrographic measurements from ships, autonomous profiling floats, and instrumented seals over the period 1986–2016 are used to examine the temporal variability in open-ocean convection in the Greenland Sea during winter. This process replenishes the deep ocean with oxygen and is central to maintain...
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ftunivbergen:oai:bora.uib.no:1956/21589 2023-05-15T15:11:38+02:00 Water mass transformation in the Greenland Sea during the period 1986-2016 Brakstad, Ailin Våge, Kjetil Håvik, Lisbeth Moore, G.W.K. 2019-12-19T14:37:10Z application/pdf https://hdl.handle.net/1956/21589 https://doi.org/10.1175/jpo-d-17-0273.1 eng eng American Meteorological Society Norges forskningsråd: 231647 Bergens forskningsstiftelse: BFS2016REK01 urn:issn:0022-3670 urn:issn:1520-0485 https://hdl.handle.net/1956/21589 https://doi.org/10.1175/jpo-d-17-0273.1 cristin:1648999 Attribution CC BY http://creativecommons.org/licenses/by/4.0/ Copyright 2018 American Meteorological Society Journal of Physical Oceanography Ocean Arctic North Atlantic Ocean Convection In situ oceanic observations Interannual variability VDP::Matematikk og naturvitenskap: 400::Geofag: 450::Oseanografi: 452 VDP::Mathematics and natural scienses: 400::Geosciences: 450::Oceanography: 452 Peer reviewed Journal article 2019 ftunivbergen https://doi.org/10.1175/jpo-d-17-0273.1 2023-03-14T17:39:55Z Hydrographic measurements from ships, autonomous profiling floats, and instrumented seals over the period 1986–2016 are used to examine the temporal variability in open-ocean convection in the Greenland Sea during winter. This process replenishes the deep ocean with oxygen and is central to maintaining its thermohaline properties. The deepest and densest mixed layers in the Greenland Sea were located within its cyclonic gyre and exhibited large interannual variability. Beginning in winter 1994, a transition to deeper (>500 m) mixed layers took place. This resulted in the formation of a new, less dense class of intermediate water that has since become the main product of convection in the Greenland Sea. In the preceding winters, convection was limited to <300-m depth, despite strong atmospheric forcing. Sensitivity studies, performed with a one-dimensional mixed layer model, suggest that the deeper convection was primarily the result of reduced water-column stability. While anomalously fresh conditions that increased the stability of the upper part of the water column had previously inhibited convection, the transition to deeper mixed layers was associated with increased near-surface salinities. Our analysis further suggests that the volume of the new class of intermediate water has expanded in line with generally increased depths of convection over the past 10–15 years. The mean export of this water mass from the Greenland Sea gyre from 1994 to present was estimated to be 0.9 ± 0.7 Sv (1 Sv ≡ 10^6 m^3 s^−1), although rates in excess of 1.5 Sv occurred in summers following winters with deep convection. publishedVersion Article in Journal/Newspaper Arctic Greenland Greenland Sea North Atlantic University of Bergen: Bergen Open Research Archive (BORA-UiB) Arctic Greenland Journal of Physical Oceanography 49 1 121 140 |
institution |
Open Polar |
collection |
University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
topic |
Ocean Arctic North Atlantic Ocean Convection In situ oceanic observations Interannual variability VDP::Matematikk og naturvitenskap: 400::Geofag: 450::Oseanografi: 452 VDP::Mathematics and natural scienses: 400::Geosciences: 450::Oceanography: 452 |
spellingShingle |
Ocean Arctic North Atlantic Ocean Convection In situ oceanic observations Interannual variability VDP::Matematikk og naturvitenskap: 400::Geofag: 450::Oseanografi: 452 VDP::Mathematics and natural scienses: 400::Geosciences: 450::Oceanography: 452 Brakstad, Ailin Våge, Kjetil Håvik, Lisbeth Moore, G.W.K. Water mass transformation in the Greenland Sea during the period 1986-2016 |
topic_facet |
Ocean Arctic North Atlantic Ocean Convection In situ oceanic observations Interannual variability VDP::Matematikk og naturvitenskap: 400::Geofag: 450::Oseanografi: 452 VDP::Mathematics and natural scienses: 400::Geosciences: 450::Oceanography: 452 |
description |
Hydrographic measurements from ships, autonomous profiling floats, and instrumented seals over the period 1986–2016 are used to examine the temporal variability in open-ocean convection in the Greenland Sea during winter. This process replenishes the deep ocean with oxygen and is central to maintaining its thermohaline properties. The deepest and densest mixed layers in the Greenland Sea were located within its cyclonic gyre and exhibited large interannual variability. Beginning in winter 1994, a transition to deeper (>500 m) mixed layers took place. This resulted in the formation of a new, less dense class of intermediate water that has since become the main product of convection in the Greenland Sea. In the preceding winters, convection was limited to <300-m depth, despite strong atmospheric forcing. Sensitivity studies, performed with a one-dimensional mixed layer model, suggest that the deeper convection was primarily the result of reduced water-column stability. While anomalously fresh conditions that increased the stability of the upper part of the water column had previously inhibited convection, the transition to deeper mixed layers was associated with increased near-surface salinities. Our analysis further suggests that the volume of the new class of intermediate water has expanded in line with generally increased depths of convection over the past 10–15 years. The mean export of this water mass from the Greenland Sea gyre from 1994 to present was estimated to be 0.9 ± 0.7 Sv (1 Sv ≡ 10^6 m^3 s^−1), although rates in excess of 1.5 Sv occurred in summers following winters with deep convection. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Brakstad, Ailin Våge, Kjetil Håvik, Lisbeth Moore, G.W.K. |
author_facet |
Brakstad, Ailin Våge, Kjetil Håvik, Lisbeth Moore, G.W.K. |
author_sort |
Brakstad, Ailin |
title |
Water mass transformation in the Greenland Sea during the period 1986-2016 |
title_short |
Water mass transformation in the Greenland Sea during the period 1986-2016 |
title_full |
Water mass transformation in the Greenland Sea during the period 1986-2016 |
title_fullStr |
Water mass transformation in the Greenland Sea during the period 1986-2016 |
title_full_unstemmed |
Water mass transformation in the Greenland Sea during the period 1986-2016 |
title_sort |
water mass transformation in the greenland sea during the period 1986-2016 |
publisher |
American Meteorological Society |
publishDate |
2019 |
url |
https://hdl.handle.net/1956/21589 https://doi.org/10.1175/jpo-d-17-0273.1 |
geographic |
Arctic Greenland |
geographic_facet |
Arctic Greenland |
genre |
Arctic Greenland Greenland Sea North Atlantic |
genre_facet |
Arctic Greenland Greenland Sea North Atlantic |
op_source |
Journal of Physical Oceanography |
op_relation |
Norges forskningsråd: 231647 Bergens forskningsstiftelse: BFS2016REK01 urn:issn:0022-3670 urn:issn:1520-0485 https://hdl.handle.net/1956/21589 https://doi.org/10.1175/jpo-d-17-0273.1 cristin:1648999 |
op_rights |
Attribution CC BY http://creativecommons.org/licenses/by/4.0/ Copyright 2018 American Meteorological Society |
op_doi |
https://doi.org/10.1175/jpo-d-17-0273.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
49 |
container_issue |
1 |
container_start_page |
121 |
op_container_end_page |
140 |
_version_ |
1766342460866297856 |