Deep through-flow in the Bight Fracture Zone and its imprint in the Irminger Sea
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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Copernicus Publications
2022
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00060745 2023-05-15T16:47:30+02:00 Deep through-flow in the Bight Fracture Zone and its imprint in the Irminger Sea Petit, Tillys Thierry, Virginie Mercier, Herlé 2022-04 electronic https://doi.org/10.5194/egusphere-2022-248 https://noa.gwlb.de/receive/cop_mods_00060745 https://egusphere.copernicus.org/preprints/egusphere-2022-248/egusphere-2022-248.pdf eng eng Copernicus Publications https://doi.org/10.5194/egusphere-2022-248 https://noa.gwlb.de/receive/cop_mods_00060745 https://egusphere.copernicus.org/preprints/egusphere-2022-248/egusphere-2022-248.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/restrictedAccess CC-BY article Verlagsveröffentlichung article Text doc-type:article 2022 ftnonlinearchiv https://doi.org/10.5194/egusphere-2022-248 2022-05-01T23:09:44Z 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 Niedersächsisches Online-Archiv NOA 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) |
institution |
Open Polar |
collection |
Niedersächsisches Online-Archiv NOA |
op_collection_id |
ftnonlinearchiv |
language |
English |
topic |
article Verlagsveröffentlichung |
spellingShingle |
article Verlagsveröffentlichung Petit, Tillys Thierry, Virginie Mercier, Herlé Deep through-flow in the Bight Fracture Zone and its imprint in the Irminger Sea |
topic_facet |
article Verlagsveröffentlichung |
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, Herlé |
author_facet |
Petit, Tillys Thierry, Virginie Mercier, Herlé |
author_sort |
Petit, Tillys |
title |
Deep through-flow in the Bight Fracture Zone and its imprint in the Irminger Sea |
title_short |
Deep through-flow in the Bight Fracture Zone and its imprint in the Irminger Sea |
title_full |
Deep through-flow in the Bight Fracture Zone and its imprint in the Irminger Sea |
title_fullStr |
Deep through-flow in the Bight Fracture Zone and its imprint in the Irminger Sea |
title_full_unstemmed |
Deep through-flow in the Bight Fracture Zone and its imprint in the Irminger Sea |
title_sort |
deep through-flow in the bight fracture zone and its imprint in the irminger sea |
publisher |
Copernicus Publications |
publishDate |
2022 |
url |
https://doi.org/10.5194/egusphere-2022-248 https://noa.gwlb.de/receive/cop_mods_00060745 https://egusphere.copernicus.org/preprints/egusphere-2022-248/egusphere-2022-248.pdf |
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_relation |
https://doi.org/10.5194/egusphere-2022-248 https://noa.gwlb.de/receive/cop_mods_00060745 https://egusphere.copernicus.org/preprints/egusphere-2022-248/egusphere-2022-248.pdf |
op_rights |
https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/restrictedAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/egusphere-2022-248 |
_version_ |
1766037592219844608 |