The observation-based application of a regional thermohaline inverse method to diagnose the formation and transformation of water masses north of the osnap array from 2013 to 2015
The strength of the meridional overturning circulation (MOC) in the North Atlantic is dependent upon the formation of dense waters that occurs at high northern latitudes. Wintertime deep convection in the Labrador and Irminger Seas forms the intermediate water mass known as Labrador Sea Water (LSW)....
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American Meteorological Society
2020
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Online Access: | http://hdl.handle.net/1959.4/unsworks_73556 https://doi.org/10.1175/JPO-D-19-0188.1 |
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ftunswworks:oai:unsworks.library.unsw.edu.au:1959.4/unsworks_73556 2024-05-12T08:00:28+00:00 The observation-based application of a regional thermohaline inverse method to diagnose the formation and transformation of water masses north of the osnap array from 2013 to 2015 Mackay, N Wilson, C Holliday, NP Zika, JD 2020-01-01 http://hdl.handle.net/1959.4/unsworks_73556 https://doi.org/10.1175/JPO-D-19-0188.1 unknown American Meteorological Society http://purl.org/au-research/grants/arc/DP160103130 http://hdl.handle.net/1959.4/unsworks_73556 https://doi.org/10.1175/JPO-D-19-0188.1 metadata only access http://purl.org/coar/access_right/c_14cb CC-BY-NC-ND https://creativecommons.org/licenses/by-nc-nd/4.0/ urn:ISSN:0022-3670 urn:ISSN:1520-0485 Journal of Physical Oceanography, 50, 6, 1533-1555 anzsrc-for: 0405 Oceanography anzsrc-for: 0911 Maritime Engineering journal article http://purl.org/coar/resource_type/c_6501 2020 ftunswworks https://doi.org/10.1175/JPO-D-19-0188.1 2024-04-17T15:18:05Z The strength of the meridional overturning circulation (MOC) in the North Atlantic is dependent upon the formation of dense waters that occurs at high northern latitudes. Wintertime deep convection in the Labrador and Irminger Seas forms the intermediate water mass known as Labrador Sea Water (LSW). Changes in the rate of formation and subsequent export of LSW are thought to play a role in MOC variability, but formation rates are uncertain and the link between formation and export is complex. We present the first observation-based application of a recently developed regional thermohaline inverse method (RTHIM) to a region encompassing the Arctic and part of the North Atlantic subpolar gyre for the years 2013, 2014, and 2015. RTHIM is a novel method that can diagnose the formation and export rates of water masses such as the LSW identified by their temperature and salinity, apportioning the formation rates into contributions from surface fluxes and interior mixing. We find LSW formation rates of up to 12 Sv (1 Sv ≡ 106 m3 s21) during 2014–15, a period of strong wintertime convection, and around half that value during 2013 when convection was weak. We also show that the newly convected water is not exported directly, but instead is mixed isopycnally with warm, salty waters that have been advected into the region, before the products are then exported. RTHIM solutions for 2015 volume, heat, and freshwater transports are compared with observations from a mooring array deployed for the Overturning in the Subpolar North Atlantic Program (OSNAP) and show good agreement, lending validity to our results. Article in Journal/Newspaper Arctic Labrador Sea North Atlantic UNSW Sydney (The University of New South Wales): UNSWorks Arctic Journal of Physical Oceanography 50 6 1533 1555 |
institution |
Open Polar |
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UNSW Sydney (The University of New South Wales): UNSWorks |
op_collection_id |
ftunswworks |
language |
unknown |
topic |
anzsrc-for: 0405 Oceanography anzsrc-for: 0911 Maritime Engineering |
spellingShingle |
anzsrc-for: 0405 Oceanography anzsrc-for: 0911 Maritime Engineering Mackay, N Wilson, C Holliday, NP Zika, JD The observation-based application of a regional thermohaline inverse method to diagnose the formation and transformation of water masses north of the osnap array from 2013 to 2015 |
topic_facet |
anzsrc-for: 0405 Oceanography anzsrc-for: 0911 Maritime Engineering |
description |
The strength of the meridional overturning circulation (MOC) in the North Atlantic is dependent upon the formation of dense waters that occurs at high northern latitudes. Wintertime deep convection in the Labrador and Irminger Seas forms the intermediate water mass known as Labrador Sea Water (LSW). Changes in the rate of formation and subsequent export of LSW are thought to play a role in MOC variability, but formation rates are uncertain and the link between formation and export is complex. We present the first observation-based application of a recently developed regional thermohaline inverse method (RTHIM) to a region encompassing the Arctic and part of the North Atlantic subpolar gyre for the years 2013, 2014, and 2015. RTHIM is a novel method that can diagnose the formation and export rates of water masses such as the LSW identified by their temperature and salinity, apportioning the formation rates into contributions from surface fluxes and interior mixing. We find LSW formation rates of up to 12 Sv (1 Sv ≡ 106 m3 s21) during 2014–15, a period of strong wintertime convection, and around half that value during 2013 when convection was weak. We also show that the newly convected water is not exported directly, but instead is mixed isopycnally with warm, salty waters that have been advected into the region, before the products are then exported. RTHIM solutions for 2015 volume, heat, and freshwater transports are compared with observations from a mooring array deployed for the Overturning in the Subpolar North Atlantic Program (OSNAP) and show good agreement, lending validity to our results. |
format |
Article in Journal/Newspaper |
author |
Mackay, N Wilson, C Holliday, NP Zika, JD |
author_facet |
Mackay, N Wilson, C Holliday, NP Zika, JD |
author_sort |
Mackay, N |
title |
The observation-based application of a regional thermohaline inverse method to diagnose the formation and transformation of water masses north of the osnap array from 2013 to 2015 |
title_short |
The observation-based application of a regional thermohaline inverse method to diagnose the formation and transformation of water masses north of the osnap array from 2013 to 2015 |
title_full |
The observation-based application of a regional thermohaline inverse method to diagnose the formation and transformation of water masses north of the osnap array from 2013 to 2015 |
title_fullStr |
The observation-based application of a regional thermohaline inverse method to diagnose the formation and transformation of water masses north of the osnap array from 2013 to 2015 |
title_full_unstemmed |
The observation-based application of a regional thermohaline inverse method to diagnose the formation and transformation of water masses north of the osnap array from 2013 to 2015 |
title_sort |
observation-based application of a regional thermohaline inverse method to diagnose the formation and transformation of water masses north of the osnap array from 2013 to 2015 |
publisher |
American Meteorological Society |
publishDate |
2020 |
url |
http://hdl.handle.net/1959.4/unsworks_73556 https://doi.org/10.1175/JPO-D-19-0188.1 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Labrador Sea North Atlantic |
genre_facet |
Arctic Labrador Sea North Atlantic |
op_source |
urn:ISSN:0022-3670 urn:ISSN:1520-0485 Journal of Physical Oceanography, 50, 6, 1533-1555 |
op_relation |
http://purl.org/au-research/grants/arc/DP160103130 http://hdl.handle.net/1959.4/unsworks_73556 https://doi.org/10.1175/JPO-D-19-0188.1 |
op_rights |
metadata only access http://purl.org/coar/access_right/c_14cb CC-BY-NC-ND https://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_doi |
https://doi.org/10.1175/JPO-D-19-0188.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
50 |
container_issue |
6 |
container_start_page |
1533 |
op_container_end_page |
1555 |
_version_ |
1798842359967907840 |