Role of air–sea fluxes and ocean surface density in the production of deep waters in the eastern subpolar gyre of the North Atlantic
Wintertime convection in the North Atlantic Ocean is a key component of the global climate as it produces dense waters at high latitudes that flow equatorward as part of the Atlantic Meridional Overturning Circulation (AMOC). Recent work has highlighted the dominant role of the Irminger and Iceland...
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2021
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Online Access: | https://pure.uhi.ac.uk/en/publications/6881d148-1803-4b5d-867e-9a780450bf12 https://doi.org/10.5194/os-17-1353-2021 https://pureadmin.uhi.ac.uk/ws/files/16785824/os_17_1353_2021.pdf https://os.copernicus.org/articles/17/1353/2021/ |
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ftuhipublicatio:oai:pure.atira.dk:publications/6881d148-1803-4b5d-867e-9a780450bf12 2024-05-19T07:42:36+00:00 Role of air–sea fluxes and ocean surface density in the production of deep waters in the eastern subpolar gyre of the North Atlantic Petit, Tillys Lozier, M. Susan Josey, Simon A. Cunningham, Stuart A. 2021-10-05 application/pdf https://pure.uhi.ac.uk/en/publications/6881d148-1803-4b5d-867e-9a780450bf12 https://doi.org/10.5194/os-17-1353-2021 https://pureadmin.uhi.ac.uk/ws/files/16785824/os_17_1353_2021.pdf https://os.copernicus.org/articles/17/1353/2021/ eng eng https://pure.uhi.ac.uk/en/publications/6881d148-1803-4b5d-867e-9a780450bf12 info:eu-repo/semantics/openAccess Petit , T , Lozier , M S , Josey , S A & Cunningham , S A 2021 , ' Role of air–sea fluxes and ocean surface density in the production of deep waters in the eastern subpolar gyre of the North Atlantic ' , Ocean Science , vol. 17 , no. 5 , pp. 1353-1365 . https://doi.org/10.5194/os-17-1353-2021 article 2021 ftuhipublicatio https://doi.org/10.5194/os-17-1353-2021 2024-05-02T00:07:13Z Wintertime convection in the North Atlantic Ocean is a key component of the global climate as it produces dense waters at high latitudes that flow equatorward as part of the Atlantic Meridional Overturning Circulation (AMOC). Recent work has highlighted the dominant role of the Irminger and Iceland basins in the production of North Atlantic Deep Water. Dense water formation in these basins is mainly explained by buoyancy forcing that transforms surface waters to the deep waters of the AMOC lower limb. Air–sea fluxes and the ocean surface density field are both key determinants of the buoyancy-driven transformation. We analyze these contributions to the transformation in order to better understand the connection between atmospheric forcing and the densification of surface water. More precisely, we study the impact of air–sea fluxes and the ocean surface density field on the transformation of subpolar mode water (SPMW) in the Iceland Basin, a water mass that “pre-conditions” dense water formation downstream. Analyses using 40 years of observations (1980–2019) reveal that the variance in SPMW transformation is mainly influenced by the variance in density at the ocean surface. This surface density is set by a combination of advection, wind-driven upwelling and surface fluxes. Our study shows that the latter explains ∼ 30 % of the variance in outcrop area as expressed by the surface area between the outcropped SPMW isopycnals. The key role of the surface density in SPMW transformation partly explains the unusually large SPMW transformation in winter 2014–2015 over the Iceland Basin. Article in Journal/Newspaper Iceland North Atlantic Deep Water North Atlantic University of the Highlands and Islands: Research Database of UHI Ocean Science 17 5 1353 1365 |
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Open Polar |
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University of the Highlands and Islands: Research Database of UHI |
op_collection_id |
ftuhipublicatio |
language |
English |
description |
Wintertime convection in the North Atlantic Ocean is a key component of the global climate as it produces dense waters at high latitudes that flow equatorward as part of the Atlantic Meridional Overturning Circulation (AMOC). Recent work has highlighted the dominant role of the Irminger and Iceland basins in the production of North Atlantic Deep Water. Dense water formation in these basins is mainly explained by buoyancy forcing that transforms surface waters to the deep waters of the AMOC lower limb. Air–sea fluxes and the ocean surface density field are both key determinants of the buoyancy-driven transformation. We analyze these contributions to the transformation in order to better understand the connection between atmospheric forcing and the densification of surface water. More precisely, we study the impact of air–sea fluxes and the ocean surface density field on the transformation of subpolar mode water (SPMW) in the Iceland Basin, a water mass that “pre-conditions” dense water formation downstream. Analyses using 40 years of observations (1980–2019) reveal that the variance in SPMW transformation is mainly influenced by the variance in density at the ocean surface. This surface density is set by a combination of advection, wind-driven upwelling and surface fluxes. Our study shows that the latter explains ∼ 30 % of the variance in outcrop area as expressed by the surface area between the outcropped SPMW isopycnals. The key role of the surface density in SPMW transformation partly explains the unusually large SPMW transformation in winter 2014–2015 over the Iceland Basin. |
format |
Article in Journal/Newspaper |
author |
Petit, Tillys Lozier, M. Susan Josey, Simon A. Cunningham, Stuart A. |
spellingShingle |
Petit, Tillys Lozier, M. Susan Josey, Simon A. Cunningham, Stuart A. Role of air–sea fluxes and ocean surface density in the production of deep waters in the eastern subpolar gyre of the North Atlantic |
author_facet |
Petit, Tillys Lozier, M. Susan Josey, Simon A. Cunningham, Stuart A. |
author_sort |
Petit, Tillys |
title |
Role of air–sea fluxes and ocean surface density in the production of deep waters in the eastern subpolar gyre of the North Atlantic |
title_short |
Role of air–sea fluxes and ocean surface density in the production of deep waters in the eastern subpolar gyre of the North Atlantic |
title_full |
Role of air–sea fluxes and ocean surface density in the production of deep waters in the eastern subpolar gyre of the North Atlantic |
title_fullStr |
Role of air–sea fluxes and ocean surface density in the production of deep waters in the eastern subpolar gyre of the North Atlantic |
title_full_unstemmed |
Role of air–sea fluxes and ocean surface density in the production of deep waters in the eastern subpolar gyre of the North Atlantic |
title_sort |
role of air–sea fluxes and ocean surface density in the production of deep waters in the eastern subpolar gyre of the north atlantic |
publishDate |
2021 |
url |
https://pure.uhi.ac.uk/en/publications/6881d148-1803-4b5d-867e-9a780450bf12 https://doi.org/10.5194/os-17-1353-2021 https://pureadmin.uhi.ac.uk/ws/files/16785824/os_17_1353_2021.pdf https://os.copernicus.org/articles/17/1353/2021/ |
genre |
Iceland North Atlantic Deep Water North Atlantic |
genre_facet |
Iceland North Atlantic Deep Water North Atlantic |
op_source |
Petit , T , Lozier , M S , Josey , S A & Cunningham , S A 2021 , ' Role of air–sea fluxes and ocean surface density in the production of deep waters in the eastern subpolar gyre of the North Atlantic ' , Ocean Science , vol. 17 , no. 5 , pp. 1353-1365 . https://doi.org/10.5194/os-17-1353-2021 |
op_relation |
https://pure.uhi.ac.uk/en/publications/6881d148-1803-4b5d-867e-9a780450bf12 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/os-17-1353-2021 |
container_title |
Ocean Science |
container_volume |
17 |
container_issue |
5 |
container_start_page |
1353 |
op_container_end_page |
1365 |
_version_ |
1799482293293678592 |