Water mass transports and pathways in the North Brazil ‐ Equatorial Undercurrent retroflection
The equatorial retroflection of the North Brazil Current (NBC) into the Equatorial Undercurrent (EUC) and its posterior tropical recirculation is a major regulator for the returning limb of the Atlantic Meridional Overturning Circulation. Indeed, most surface and thermocline NBC waters retroflect at...
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ftunivutrecht:oai:dspace.library.uu.nl:1874/421161 2023-07-23T04:20:36+02:00 Water mass transports and pathways in the North Brazil ‐ Equatorial Undercurrent retroflection Vallès‐Casanova, Ignasi Fraile‐Nuez, Eugenio Martín‐Rey, Marta Sebille, Erik Cabré, Anna Olivé‐Abelló, Anna Pelegrí, Josep L. Sub Physical Oceanography Sub Science Education Marine and Atmospheric Research 2022-05 application/pdf https://dspace.library.uu.nl/handle/1874/421161 en eng 2169-9275 https://dspace.library.uu.nl/handle/1874/421161 info:eu-repo/semantics/OpenAccess Lagrangian transports Tropical Atlantic western boundary current Geochemistry and Petrology Geophysics Earth and Planetary Sciences (miscellaneous) Space and Planetary Science Oceanography Article 2022 ftunivutrecht 2023-07-02T03:42:12Z The equatorial retroflection of the North Brazil Current (NBC) into the Equatorial Undercurrent (EUC) and its posterior tropical recirculation is a major regulator for the returning limb of the Atlantic Meridional Overturning Circulation. Indeed, most surface and thermocline NBC waters retroflect at the equator all the way into the central and eastern Atlantic Ocean, before they recirculate back through the tropics to the western boundary. Here, we use cruise data in the western equatorial Atlantic during April 2010 and reanalysis time series for the equatorial and tropical waters in both hemispheres in order to explore the recirculation pathways and transport variability. During the 1998–2016 period, the annual-mean EUC transports 15.1 ± 1.3 Sv at 32°W, with 2.8 ± 0.4 Sv from the North Atlantic and 11.4 ± 1.3 Sv from the South Atlantic. At 32°W most of the total EUC transport comes from the western boundary retroflection south of 3°N (7.2 ± 0.9 Sv), a substantial fraction retroflects north of 3°N (5.6 ± 0.4 Sv), and the remaining flow (2.3 Sv) joins through the interior basin. The South Atlantic subtropical waters feed the EUC at all thermocline depths while the North Atlantic and South Atlantic tropical waters do so at the surface and upper-thermocline levels. The EUC transport at 32°W has a pronounced seasonality, with spring and fall maxima and a range of 8.8 Sv. The 18 yr of reanalysis data shows a weak yet significant correlation with an Atlantic Niño index, and also suggests an enhanced contribution from the South Atlantic tropical waters during 2008–2016 as compared with 1997–2007. Article in Journal/Newspaper North Atlantic Utrecht University Repository |
institution |
Open Polar |
collection |
Utrecht University Repository |
op_collection_id |
ftunivutrecht |
language |
English |
topic |
Lagrangian transports Tropical Atlantic western boundary current Geochemistry and Petrology Geophysics Earth and Planetary Sciences (miscellaneous) Space and Planetary Science Oceanography |
spellingShingle |
Lagrangian transports Tropical Atlantic western boundary current Geochemistry and Petrology Geophysics Earth and Planetary Sciences (miscellaneous) Space and Planetary Science Oceanography Vallès‐Casanova, Ignasi Fraile‐Nuez, Eugenio Martín‐Rey, Marta Sebille, Erik Cabré, Anna Olivé‐Abelló, Anna Pelegrí, Josep L. Water mass transports and pathways in the North Brazil ‐ Equatorial Undercurrent retroflection |
topic_facet |
Lagrangian transports Tropical Atlantic western boundary current Geochemistry and Petrology Geophysics Earth and Planetary Sciences (miscellaneous) Space and Planetary Science Oceanography |
description |
The equatorial retroflection of the North Brazil Current (NBC) into the Equatorial Undercurrent (EUC) and its posterior tropical recirculation is a major regulator for the returning limb of the Atlantic Meridional Overturning Circulation. Indeed, most surface and thermocline NBC waters retroflect at the equator all the way into the central and eastern Atlantic Ocean, before they recirculate back through the tropics to the western boundary. Here, we use cruise data in the western equatorial Atlantic during April 2010 and reanalysis time series for the equatorial and tropical waters in both hemispheres in order to explore the recirculation pathways and transport variability. During the 1998–2016 period, the annual-mean EUC transports 15.1 ± 1.3 Sv at 32°W, with 2.8 ± 0.4 Sv from the North Atlantic and 11.4 ± 1.3 Sv from the South Atlantic. At 32°W most of the total EUC transport comes from the western boundary retroflection south of 3°N (7.2 ± 0.9 Sv), a substantial fraction retroflects north of 3°N (5.6 ± 0.4 Sv), and the remaining flow (2.3 Sv) joins through the interior basin. The South Atlantic subtropical waters feed the EUC at all thermocline depths while the North Atlantic and South Atlantic tropical waters do so at the surface and upper-thermocline levels. The EUC transport at 32°W has a pronounced seasonality, with spring and fall maxima and a range of 8.8 Sv. The 18 yr of reanalysis data shows a weak yet significant correlation with an Atlantic Niño index, and also suggests an enhanced contribution from the South Atlantic tropical waters during 2008–2016 as compared with 1997–2007. |
author2 |
Sub Physical Oceanography Sub Science Education Marine and Atmospheric Research |
format |
Article in Journal/Newspaper |
author |
Vallès‐Casanova, Ignasi Fraile‐Nuez, Eugenio Martín‐Rey, Marta Sebille, Erik Cabré, Anna Olivé‐Abelló, Anna Pelegrí, Josep L. |
author_facet |
Vallès‐Casanova, Ignasi Fraile‐Nuez, Eugenio Martín‐Rey, Marta Sebille, Erik Cabré, Anna Olivé‐Abelló, Anna Pelegrí, Josep L. |
author_sort |
Vallès‐Casanova, Ignasi |
title |
Water mass transports and pathways in the North Brazil ‐ Equatorial Undercurrent retroflection |
title_short |
Water mass transports and pathways in the North Brazil ‐ Equatorial Undercurrent retroflection |
title_full |
Water mass transports and pathways in the North Brazil ‐ Equatorial Undercurrent retroflection |
title_fullStr |
Water mass transports and pathways in the North Brazil ‐ Equatorial Undercurrent retroflection |
title_full_unstemmed |
Water mass transports and pathways in the North Brazil ‐ Equatorial Undercurrent retroflection |
title_sort |
water mass transports and pathways in the north brazil ‐ equatorial undercurrent retroflection |
publishDate |
2022 |
url |
https://dspace.library.uu.nl/handle/1874/421161 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
2169-9275 https://dspace.library.uu.nl/handle/1874/421161 |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1772185110419865600 |