Inter-decadal changes in stratification and double diffusion in a transatlantic section along 7.5°N
We use three transatlantic cruises (1957, 1993 and 2010) along 7.5°N to analyse inter-decadal variations of the neutral buoyancy frequency (with neutral density replacing potential density) and Turner angle. We also use Argo data from the 2003-2011 period to show that, within central and intermediat...
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Online Access: | http://hdl.handle.net/10553/49042 https://doi.org/10.3989/scimar.03616.19G |
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ftunivlaspalmas:oai:accedacris.ulpgc.es:10553/49042 2023-05-15T13:58:41+02:00 Inter-decadal changes in stratification and double diffusion in a transatlantic section along 7.5°N Cambios interdecadales en estratificación y doble difusión en la sección transatlántica 7.5°N San Antolín Plaza, Miguel Ángel Pelegrí Llopart,José Luis Machín, Francisco José Benítez Barrios, Verónica Pelegri, Josep Machin, Francisco 55343332500 7003869003 6602804374 55342976200 2215652 358123 1451397 27091199 WOS:Plaza, MAS WOS:Pelegri, JL WOS:Machin, FJ WOS:Barrios, VB 2012 http://hdl.handle.net/10553/49042 https://doi.org/10.3989/scimar.03616.19G eng eng Scientia Marina 76 0214-8358 http://hdl.handle.net/10553/49042 doi:10.3989/scimar.03616.19G 84865324128 000308673500014 WOS:000308673500014 L-5815-2014 A-9287-2009 Scientia Marina [ISSN 0214-8358], v. 76 (S1), p. 189-207 251007 Oceanografía física Transatlantic section Stratification Neutral buoyancy frequency Turner angle Inter-decadal changes Vertical diffusion info:eu-repo/semantics/Article Article 2012 ftunivlaspalmas https://doi.org/10.3989/scimar.03616.19G 2020-06-02T23:08:19Z We use three transatlantic cruises (1957, 1993 and 2010) along 7.5°N to analyse inter-decadal variations of the neutral buoyancy frequency (with neutral density replacing potential density) and Turner angle. We also use Argo data from the 2003-2011 period to show that, within central and intermediate waters, the changes between the three sections are slightly greater than the seasonal and inter-annual variations, so they may be interpreted as actual inter-decadal variations. The results point to a generalized sinking of isoneutrals between 1957 and 2010, with maximum zonally-averaged values of about 100 m in the central and upper deep layers. They also reveal the occurrence of substantial changes in the intermediate and neighbouring water strata, with differential vertical sinking of isoneutrals and the transformation of their thermohaline characteristics. The neutral buoyancy frequency increased in the lower central and upper intermediate layers and decreased in the lower intermediate and upper deep layers. The distributions of Turner angle highlight a predominance of salt-fingering in the North Atlantic, except for a gravitationally doubly-stable layer located immediately below the intermediate water core; this stable layer thinned substantially between 1957 and 2010 because of the sinking of the lower intermediate isoneutrals acting together with actual water transformations from Antarctic Intermediate Waters into North Atlantic Deep Waters. We conclude that a significant portion of the water column underwent both increased vertical stratification and enhanced salt-fingering, two mechanisms with opposite effects on the effective vertical diffusion. 207 189 Article in Journal/Newspaper Antarc* Antarctic North Atlantic Universidad de Las Palmas de Gran Canaria: Acceda Antarctic Doble ENVELOPE(-62.550,-62.550,-64.667,-64.667) Scientia Marina 76 S1 189 207 |
institution |
Open Polar |
collection |
Universidad de Las Palmas de Gran Canaria: Acceda |
op_collection_id |
ftunivlaspalmas |
language |
English |
topic |
251007 Oceanografía física Transatlantic section Stratification Neutral buoyancy frequency Turner angle Inter-decadal changes Vertical diffusion |
spellingShingle |
251007 Oceanografía física Transatlantic section Stratification Neutral buoyancy frequency Turner angle Inter-decadal changes Vertical diffusion San Antolín Plaza, Miguel Ángel Pelegrí Llopart,José Luis Machín, Francisco José Benítez Barrios, Verónica Inter-decadal changes in stratification and double diffusion in a transatlantic section along 7.5°N |
topic_facet |
251007 Oceanografía física Transatlantic section Stratification Neutral buoyancy frequency Turner angle Inter-decadal changes Vertical diffusion |
description |
We use three transatlantic cruises (1957, 1993 and 2010) along 7.5°N to analyse inter-decadal variations of the neutral buoyancy frequency (with neutral density replacing potential density) and Turner angle. We also use Argo data from the 2003-2011 period to show that, within central and intermediate waters, the changes between the three sections are slightly greater than the seasonal and inter-annual variations, so they may be interpreted as actual inter-decadal variations. The results point to a generalized sinking of isoneutrals between 1957 and 2010, with maximum zonally-averaged values of about 100 m in the central and upper deep layers. They also reveal the occurrence of substantial changes in the intermediate and neighbouring water strata, with differential vertical sinking of isoneutrals and the transformation of their thermohaline characteristics. The neutral buoyancy frequency increased in the lower central and upper intermediate layers and decreased in the lower intermediate and upper deep layers. The distributions of Turner angle highlight a predominance of salt-fingering in the North Atlantic, except for a gravitationally doubly-stable layer located immediately below the intermediate water core; this stable layer thinned substantially between 1957 and 2010 because of the sinking of the lower intermediate isoneutrals acting together with actual water transformations from Antarctic Intermediate Waters into North Atlantic Deep Waters. We conclude that a significant portion of the water column underwent both increased vertical stratification and enhanced salt-fingering, two mechanisms with opposite effects on the effective vertical diffusion. 207 189 |
author2 |
Pelegri, Josep Machin, Francisco 55343332500 7003869003 6602804374 55342976200 2215652 358123 1451397 27091199 WOS:Plaza, MAS WOS:Pelegri, JL WOS:Machin, FJ WOS:Barrios, VB |
format |
Article in Journal/Newspaper |
author |
San Antolín Plaza, Miguel Ángel Pelegrí Llopart,José Luis Machín, Francisco José Benítez Barrios, Verónica |
author_facet |
San Antolín Plaza, Miguel Ángel Pelegrí Llopart,José Luis Machín, Francisco José Benítez Barrios, Verónica |
author_sort |
San Antolín Plaza, Miguel Ángel |
title |
Inter-decadal changes in stratification and double diffusion in a transatlantic section along 7.5°N |
title_short |
Inter-decadal changes in stratification and double diffusion in a transatlantic section along 7.5°N |
title_full |
Inter-decadal changes in stratification and double diffusion in a transatlantic section along 7.5°N |
title_fullStr |
Inter-decadal changes in stratification and double diffusion in a transatlantic section along 7.5°N |
title_full_unstemmed |
Inter-decadal changes in stratification and double diffusion in a transatlantic section along 7.5°N |
title_sort |
inter-decadal changes in stratification and double diffusion in a transatlantic section along 7.5°n |
publishDate |
2012 |
url |
http://hdl.handle.net/10553/49042 https://doi.org/10.3989/scimar.03616.19G |
long_lat |
ENVELOPE(-62.550,-62.550,-64.667,-64.667) |
geographic |
Antarctic Doble |
geographic_facet |
Antarctic Doble |
genre |
Antarc* Antarctic North Atlantic |
genre_facet |
Antarc* Antarctic North Atlantic |
op_source |
Scientia Marina [ISSN 0214-8358], v. 76 (S1), p. 189-207 |
op_relation |
Scientia Marina 76 0214-8358 http://hdl.handle.net/10553/49042 doi:10.3989/scimar.03616.19G 84865324128 000308673500014 WOS:000308673500014 L-5815-2014 A-9287-2009 |
op_doi |
https://doi.org/10.3989/scimar.03616.19G |
container_title |
Scientia Marina |
container_volume |
76 |
container_issue |
S1 |
container_start_page |
189 |
op_container_end_page |
207 |
_version_ |
1766267021431930880 |