Deep through-flow in the Bight Fracture Zone
Iceland-Scotland Overflow Water (ISOW) is exported from the Nordic Seas into the Iceland Basin to feed the lower limb of the Meridional Overturning Circulation. The Bight Fracture Zone (BFZ) is known to be a major route for ISOW toward the Irminger Sea, but the role of this gateway in the evolution...
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European Geosciences Union (EGU)
2022
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Online Access: | https://archimer.ifremer.fr/doc/00767/87921/93522.pdf https://archimer.ifremer.fr/doc/00767/87921/95216.pdf https://doi.org/10.5194/os-18-1055-2022 https://archimer.ifremer.fr/doc/00767/87921/ |
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ftarchimer:oai:archimer.ifremer.fr:87921 2023-05-15T16:47:30+02:00 Deep through-flow in the Bight Fracture Zone Petit, Tillys Thierry, Virginie Mercier, Herle 2022-07 application/pdf https://archimer.ifremer.fr/doc/00767/87921/93522.pdf https://archimer.ifremer.fr/doc/00767/87921/95216.pdf https://doi.org/10.5194/os-18-1055-2022 https://archimer.ifremer.fr/doc/00767/87921/ eng eng European Geosciences Union (EGU) https://archimer.ifremer.fr/doc/00767/87921/93522.pdf https://archimer.ifremer.fr/doc/00767/87921/95216.pdf doi:10.5194/os-18-1055-2022 https://archimer.ifremer.fr/doc/00767/87921/ info:eu-repo/semantics/openAccess restricted use Ocean Science (1812-0784) (European Geosciences Union (EGU)), 2022-07 , Vol. 18 , N. 4 , P. 1055-1071 text Publication info:eu-repo/semantics/article 2022 ftarchimer https://doi.org/10.5194/os-18-1055-2022 2022-08-16T22:50:27Z Iceland-Scotland Overflow Water (ISOW) is exported from the Nordic Seas into the Iceland Basin to feed the lower limb of the Meridional Overturning Circulation. The Bight Fracture Zone (BFZ) is known to be a major route for ISOW toward the Irminger Sea, but the role of this gateway in the evolution of ISOW properties over the subpolar gyre is unclear. A combination of ship-based and Deep-Argo data gathered between 2015 and 2018 allows us to investigate the pathways and hydrological evolution of ISOW as it flows through the BFZ, as well as its influence on the ISOW properties in the Irminger Sea. The ISOW flow through the BFZ amounts to 0.76 ± 0.2 Sv and is mainly fed by the lighter part of the ISOW layer flowing west of 29–30° W as part of the East Reykjanes Ridge Current in the Iceland Basin. In the rift valley of the BFZ, between an eastern and a western sill, the bathymetry of the BFZ shapes a cyclonic circulation along which the ISOW layer is homogenised. The largest changes in ISOW properties are however observed downstream of the western sill, at the exit of the BFZ. There, ISOW is mixed isopycnally with comparatively fresher ISOW from the Irminger Sea and lies over denser ISOW that entered the Irminger Sea south of the BFZ. These fresher ISOW result from the erosion of the ISOW core by mixing with inflows from the interior of the Irminger Sea as ISOW flows northward from the Charlie-Gibbs Fracture Zone. Hence, our analysis reveals the key role of the BFZ through-flow in compensating these inputs of fresh inflows along the northward Irminger Current. Article in Journal/Newspaper Iceland Nordic Seas Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) Bight Fracture Zone ENVELOPE(-33.000,-33.000,56.833,56.833) Irminger Sea ENVELOPE(-34.041,-34.041,63.054,63.054) Reykjanes ENVELOPE(-22.250,-22.250,65.467,65.467) Ocean Science 18 4 1055 1071 |
institution |
Open Polar |
collection |
Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) |
op_collection_id |
ftarchimer |
language |
English |
description |
Iceland-Scotland Overflow Water (ISOW) is exported from the Nordic Seas into the Iceland Basin to feed the lower limb of the Meridional Overturning Circulation. The Bight Fracture Zone (BFZ) is known to be a major route for ISOW toward the Irminger Sea, but the role of this gateway in the evolution of ISOW properties over the subpolar gyre is unclear. A combination of ship-based and Deep-Argo data gathered between 2015 and 2018 allows us to investigate the pathways and hydrological evolution of ISOW as it flows through the BFZ, as well as its influence on the ISOW properties in the Irminger Sea. The ISOW flow through the BFZ amounts to 0.76 ± 0.2 Sv and is mainly fed by the lighter part of the ISOW layer flowing west of 29–30° W as part of the East Reykjanes Ridge Current in the Iceland Basin. In the rift valley of the BFZ, between an eastern and a western sill, the bathymetry of the BFZ shapes a cyclonic circulation along which the ISOW layer is homogenised. The largest changes in ISOW properties are however observed downstream of the western sill, at the exit of the BFZ. There, ISOW is mixed isopycnally with comparatively fresher ISOW from the Irminger Sea and lies over denser ISOW that entered the Irminger Sea south of the BFZ. These fresher ISOW result from the erosion of the ISOW core by mixing with inflows from the interior of the Irminger Sea as ISOW flows northward from the Charlie-Gibbs Fracture Zone. Hence, our analysis reveals the key role of the BFZ through-flow in compensating these inputs of fresh inflows along the northward Irminger Current. |
format |
Article in Journal/Newspaper |
author |
Petit, Tillys Thierry, Virginie Mercier, Herle |
spellingShingle |
Petit, Tillys Thierry, Virginie Mercier, Herle Deep through-flow in the Bight Fracture Zone |
author_facet |
Petit, Tillys Thierry, Virginie Mercier, Herle |
author_sort |
Petit, Tillys |
title |
Deep through-flow in the Bight Fracture Zone |
title_short |
Deep through-flow in the Bight Fracture Zone |
title_full |
Deep through-flow in the Bight Fracture Zone |
title_fullStr |
Deep through-flow in the Bight Fracture Zone |
title_full_unstemmed |
Deep through-flow in the Bight Fracture Zone |
title_sort |
deep through-flow in the bight fracture zone |
publisher |
European Geosciences Union (EGU) |
publishDate |
2022 |
url |
https://archimer.ifremer.fr/doc/00767/87921/93522.pdf https://archimer.ifremer.fr/doc/00767/87921/95216.pdf https://doi.org/10.5194/os-18-1055-2022 https://archimer.ifremer.fr/doc/00767/87921/ |
long_lat |
ENVELOPE(-33.000,-33.000,56.833,56.833) ENVELOPE(-34.041,-34.041,63.054,63.054) ENVELOPE(-22.250,-22.250,65.467,65.467) |
geographic |
Bight Fracture Zone Irminger Sea Reykjanes |
geographic_facet |
Bight Fracture Zone Irminger Sea Reykjanes |
genre |
Iceland Nordic Seas |
genre_facet |
Iceland Nordic Seas |
op_source |
Ocean Science (1812-0784) (European Geosciences Union (EGU)), 2022-07 , Vol. 18 , N. 4 , P. 1055-1071 |
op_relation |
https://archimer.ifremer.fr/doc/00767/87921/93522.pdf https://archimer.ifremer.fr/doc/00767/87921/95216.pdf doi:10.5194/os-18-1055-2022 https://archimer.ifremer.fr/doc/00767/87921/ |
op_rights |
info:eu-repo/semantics/openAccess restricted use |
op_doi |
https://doi.org/10.5194/os-18-1055-2022 |
container_title |
Ocean Science |
container_volume |
18 |
container_issue |
4 |
container_start_page |
1055 |
op_container_end_page |
1071 |
_version_ |
1766037589699067904 |