Spreading of Labrador Sea Water in the eastern North Atlantic.
International audience The spreading of Labrador Sea Water (LSW) in the eastern North Atlantic south of 55°N is described on the basis of recent, high-resolution hydrographic lines and using an inverse model of that basin general circulation. The isopycnic “salinity anomaly” relative to a standard θ...
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ftccsdartic:oai:HAL:hal-00274745v1 2023-05-15T17:06:08+02:00 Spreading of Labrador Sea Water in the eastern North Atlantic. Paillet, Jérôme Arhan, Michel Mccartney, Michael S. Service Hydrographique et Océanographique de la Marine (SHOM) Ministère de la Défense Laboratoire de physique des océans (LPO) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) Woods Hole Oceanographic Institution (WHOI) 1998 https://hal.archives-ouvertes.fr/hal-00274745 en eng HAL CCSD Wiley-Blackwell hal-00274745 https://hal.archives-ouvertes.fr/hal-00274745 ISSN: 2169-9275 EISSN: 2169-9291 Journal of Geophysical Research. Oceans https://hal.archives-ouvertes.fr/hal-00274745 Journal of Geophysical Research. Oceans, Wiley-Blackwell, 1998, 103 (C5), pp.10,223-10,239 [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/article Journal articles 1998 ftccsdartic 2021-11-28T01:40:49Z International audience The spreading of Labrador Sea Water (LSW) in the eastern North Atlantic south of 55°N is described on the basis of recent, high-resolution hydrographic lines and using an inverse model of that basin general circulation. The isopycnic “salinity anomaly” relative to a standard θ/S curve is used to detect the main branches and limits of dominant influence of the intermediate water masses. The LSW crosses the Mid-Atlantic Ridge at latitudes around 50°N with parts spreading farther eastward and southward. One southward pathway along the eastern side of the Mid-Atlantic-Ridge stands out as an eastern basin counterpart of the western Atlantic “Deep Western Boundary Current.” An entry into the Bay of Biscay in its northern part is also evidenced with striking similitudes between two data sets from 1974 and 1989–1990. At the southern limit of the LSW extension, in the vicinity of the Azores-Biscay Rise, a marked front exists basinwide around 1800 m with the more saline Deep Mediterranean Water (DMW). The inverse model velocity field is consistent with most features of the tracer distributions and allows estimation of LSW transports: 6.3 ± 1.2 Sv of LSW with salinities lower than 34.94 cross the 35°W meridian eastward between 44°N and 54°N, one fourth of which recirculates southwestward in the western basin, while another fourth turns northward across 54°N and the remaining half proceeds southward in the eastern basin. The model circulation suggests that DMW results from mixing between eastern basin LSW and the overlying Mediterranean Outflow Water, most probably through double diffusion. We finally describe several mesoscale structures of anomalously high LSW influence south of the LSW-DMW front, notably one sampled by a RAFOS float. The velocity and potential vorticity fields suggest that these “LSW-eddies” are formed through baroclinic instability at the LSW-DMW front. Article in Journal/Newspaper Labrador Sea North Atlantic Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Mid-Atlantic Ridge Western Basin |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
spellingShingle |
[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography Paillet, Jérôme Arhan, Michel Mccartney, Michael S. Spreading of Labrador Sea Water in the eastern North Atlantic. |
topic_facet |
[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
International audience The spreading of Labrador Sea Water (LSW) in the eastern North Atlantic south of 55°N is described on the basis of recent, high-resolution hydrographic lines and using an inverse model of that basin general circulation. The isopycnic “salinity anomaly” relative to a standard θ/S curve is used to detect the main branches and limits of dominant influence of the intermediate water masses. The LSW crosses the Mid-Atlantic Ridge at latitudes around 50°N with parts spreading farther eastward and southward. One southward pathway along the eastern side of the Mid-Atlantic-Ridge stands out as an eastern basin counterpart of the western Atlantic “Deep Western Boundary Current.” An entry into the Bay of Biscay in its northern part is also evidenced with striking similitudes between two data sets from 1974 and 1989–1990. At the southern limit of the LSW extension, in the vicinity of the Azores-Biscay Rise, a marked front exists basinwide around 1800 m with the more saline Deep Mediterranean Water (DMW). The inverse model velocity field is consistent with most features of the tracer distributions and allows estimation of LSW transports: 6.3 ± 1.2 Sv of LSW with salinities lower than 34.94 cross the 35°W meridian eastward between 44°N and 54°N, one fourth of which recirculates southwestward in the western basin, while another fourth turns northward across 54°N and the remaining half proceeds southward in the eastern basin. The model circulation suggests that DMW results from mixing between eastern basin LSW and the overlying Mediterranean Outflow Water, most probably through double diffusion. We finally describe several mesoscale structures of anomalously high LSW influence south of the LSW-DMW front, notably one sampled by a RAFOS float. The velocity and potential vorticity fields suggest that these “LSW-eddies” are formed through baroclinic instability at the LSW-DMW front. |
author2 |
Service Hydrographique et Océanographique de la Marine (SHOM) Ministère de la Défense Laboratoire de physique des océans (LPO) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) Woods Hole Oceanographic Institution (WHOI) |
format |
Article in Journal/Newspaper |
author |
Paillet, Jérôme Arhan, Michel Mccartney, Michael S. |
author_facet |
Paillet, Jérôme Arhan, Michel Mccartney, Michael S. |
author_sort |
Paillet, Jérôme |
title |
Spreading of Labrador Sea Water in the eastern North Atlantic. |
title_short |
Spreading of Labrador Sea Water in the eastern North Atlantic. |
title_full |
Spreading of Labrador Sea Water in the eastern North Atlantic. |
title_fullStr |
Spreading of Labrador Sea Water in the eastern North Atlantic. |
title_full_unstemmed |
Spreading of Labrador Sea Water in the eastern North Atlantic. |
title_sort |
spreading of labrador sea water in the eastern north atlantic. |
publisher |
HAL CCSD |
publishDate |
1998 |
url |
https://hal.archives-ouvertes.fr/hal-00274745 |
geographic |
Mid-Atlantic Ridge Western Basin |
geographic_facet |
Mid-Atlantic Ridge Western Basin |
genre |
Labrador Sea North Atlantic |
genre_facet |
Labrador Sea North Atlantic |
op_source |
ISSN: 2169-9275 EISSN: 2169-9291 Journal of Geophysical Research. Oceans https://hal.archives-ouvertes.fr/hal-00274745 Journal of Geophysical Research. Oceans, Wiley-Blackwell, 1998, 103 (C5), pp.10,223-10,239 |
op_relation |
hal-00274745 https://hal.archives-ouvertes.fr/hal-00274745 |
_version_ |
1766061130862559232 |