Pending recovery in the strength of the meridional overturning circulation at 26° N
The strength of the Atlantic meridional overturning circulation (AMOC) at 26∘ N has now been continuously measured by the RAPID array over the period April 2004–September 2018. This record provides unique insight into the variability of the large-scale ocean circulation, previously only measured by...
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2020
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Online Access: | http://nora.nerc.ac.uk/id/eprint/528215/ https://nora.nerc.ac.uk/id/eprint/528215/1/os-16-863-2020.pdf https://doi.org/10.5194/os-16-863-2020 |
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ftnerc:oai:nora.nerc.ac.uk:528215 2023-05-15T17:35:15+02:00 Pending recovery in the strength of the meridional overturning circulation at 26° N Moat, Ben I. Smeed, David A. Frajka-Williams, Eleanor Desbruyères, Damien G. Beaulieu, Claudie Johns, William E. Rayner, Darren Sanchez-Franks, Alejandra Baringer, Molly O. Volkov, Denis Jackson, Laura C. Bryden, Harry L. 2020-07-23 text http://nora.nerc.ac.uk/id/eprint/528215/ https://nora.nerc.ac.uk/id/eprint/528215/1/os-16-863-2020.pdf https://doi.org/10.5194/os-16-863-2020 en eng https://nora.nerc.ac.uk/id/eprint/528215/1/os-16-863-2020.pdf Moat, Ben I. orcid:0000-0001-8676-7779 Smeed, David A. orcid:0000-0003-1740-1778 Frajka-Williams, Eleanor orcid:0000-0001-8773-7838 Desbruyères, Damien G.; Beaulieu, Claudie; Johns, William E.; Rayner, Darren orcid:0000-0002-2283-4140 Sanchez-Franks, Alejandra orcid:0000-0002-4831-5461 Baringer, Molly O.; Volkov, Denis; Jackson, Laura C.; Bryden, Harry L. 2020 Pending recovery in the strength of the meridional overturning circulation at 26° N. Ocean Science, 16 (4). 863-874. https://doi.org/10.5194/os-16-863-2020 <https://doi.org/10.5194/os-16-863-2020> cc_by_4 CC-BY Publication - Article PeerReviewed 2020 ftnerc https://doi.org/10.5194/os-16-863-2020 2023-02-04T19:50:55Z The strength of the Atlantic meridional overturning circulation (AMOC) at 26∘ N has now been continuously measured by the RAPID array over the period April 2004–September 2018. This record provides unique insight into the variability of the large-scale ocean circulation, previously only measured by sporadic snapshots of basin-wide transport from hydrographic sections. The continuous measurements have unveiled striking variability on timescales of days to a decade, driven largely by wind forcing, contrasting with previous expectations about a slowly varying buoyancy-forced large-scale ocean circulation. However, these measurements were primarily observed during a warm state of the Atlantic multidecadal variability (AMV) which has been steadily declining since a peak in 2008–2010. In 2013–2015, a period of strong buoyancy forcing by the atmosphere drove intense water-mass transformation in the subpolar North Atlantic and provides a unique opportunity to investigate the response of the large-scale ocean circulation to buoyancy forcing. Modelling studies suggest that the AMOC in the subtropics responds to such events with an increase in overturning transport, after a lag of 3–9 years. At 45∘ N, observations suggest that the AMOC may already be increasing. Examining 26∘ N, we find that the AMOC is no longer weakening, though the recent transport is not above the long-term mean. Extending the record backwards in time at 26∘ N with ocean reanalysis from GloSea5, the transport fluctuations at 26∘ N are consistent with a 0- to 2-year lag from those at 45∘ N, albeit with lower magnitude. Given the short span of time and anticipated delays in the signal from the subpolar to subtropical gyres, it is not yet possible to determine whether the subtropical AMOC strength is recovering nor how the AMOC at 26∘ N responds to intense buoyancy forcing. Article in Journal/Newspaper North Atlantic Natural Environment Research Council: NERC Open Research Archive Ocean Science 16 4 863 874 |
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Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
The strength of the Atlantic meridional overturning circulation (AMOC) at 26∘ N has now been continuously measured by the RAPID array over the period April 2004–September 2018. This record provides unique insight into the variability of the large-scale ocean circulation, previously only measured by sporadic snapshots of basin-wide transport from hydrographic sections. The continuous measurements have unveiled striking variability on timescales of days to a decade, driven largely by wind forcing, contrasting with previous expectations about a slowly varying buoyancy-forced large-scale ocean circulation. However, these measurements were primarily observed during a warm state of the Atlantic multidecadal variability (AMV) which has been steadily declining since a peak in 2008–2010. In 2013–2015, a period of strong buoyancy forcing by the atmosphere drove intense water-mass transformation in the subpolar North Atlantic and provides a unique opportunity to investigate the response of the large-scale ocean circulation to buoyancy forcing. Modelling studies suggest that the AMOC in the subtropics responds to such events with an increase in overturning transport, after a lag of 3–9 years. At 45∘ N, observations suggest that the AMOC may already be increasing. Examining 26∘ N, we find that the AMOC is no longer weakening, though the recent transport is not above the long-term mean. Extending the record backwards in time at 26∘ N with ocean reanalysis from GloSea5, the transport fluctuations at 26∘ N are consistent with a 0- to 2-year lag from those at 45∘ N, albeit with lower magnitude. Given the short span of time and anticipated delays in the signal from the subpolar to subtropical gyres, it is not yet possible to determine whether the subtropical AMOC strength is recovering nor how the AMOC at 26∘ N responds to intense buoyancy forcing. |
format |
Article in Journal/Newspaper |
author |
Moat, Ben I. Smeed, David A. Frajka-Williams, Eleanor Desbruyères, Damien G. Beaulieu, Claudie Johns, William E. Rayner, Darren Sanchez-Franks, Alejandra Baringer, Molly O. Volkov, Denis Jackson, Laura C. Bryden, Harry L. |
spellingShingle |
Moat, Ben I. Smeed, David A. Frajka-Williams, Eleanor Desbruyères, Damien G. Beaulieu, Claudie Johns, William E. Rayner, Darren Sanchez-Franks, Alejandra Baringer, Molly O. Volkov, Denis Jackson, Laura C. Bryden, Harry L. Pending recovery in the strength of the meridional overturning circulation at 26° N |
author_facet |
Moat, Ben I. Smeed, David A. Frajka-Williams, Eleanor Desbruyères, Damien G. Beaulieu, Claudie Johns, William E. Rayner, Darren Sanchez-Franks, Alejandra Baringer, Molly O. Volkov, Denis Jackson, Laura C. Bryden, Harry L. |
author_sort |
Moat, Ben I. |
title |
Pending recovery in the strength of the meridional overturning circulation at 26° N |
title_short |
Pending recovery in the strength of the meridional overturning circulation at 26° N |
title_full |
Pending recovery in the strength of the meridional overturning circulation at 26° N |
title_fullStr |
Pending recovery in the strength of the meridional overturning circulation at 26° N |
title_full_unstemmed |
Pending recovery in the strength of the meridional overturning circulation at 26° N |
title_sort |
pending recovery in the strength of the meridional overturning circulation at 26° n |
publishDate |
2020 |
url |
http://nora.nerc.ac.uk/id/eprint/528215/ https://nora.nerc.ac.uk/id/eprint/528215/1/os-16-863-2020.pdf https://doi.org/10.5194/os-16-863-2020 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
https://nora.nerc.ac.uk/id/eprint/528215/1/os-16-863-2020.pdf Moat, Ben I. orcid:0000-0001-8676-7779 Smeed, David A. orcid:0000-0003-1740-1778 Frajka-Williams, Eleanor orcid:0000-0001-8773-7838 Desbruyères, Damien G.; Beaulieu, Claudie; Johns, William E.; Rayner, Darren orcid:0000-0002-2283-4140 Sanchez-Franks, Alejandra orcid:0000-0002-4831-5461 Baringer, Molly O.; Volkov, Denis; Jackson, Laura C.; Bryden, Harry L. 2020 Pending recovery in the strength of the meridional overturning circulation at 26° N. Ocean Science, 16 (4). 863-874. https://doi.org/10.5194/os-16-863-2020 <https://doi.org/10.5194/os-16-863-2020> |
op_rights |
cc_by_4 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/os-16-863-2020 |
container_title |
Ocean Science |
container_volume |
16 |
container_issue |
4 |
container_start_page |
863 |
op_container_end_page |
874 |
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1766134346881695744 |