Surface vertical PV fluxes and subtropical mode water formation in an eddy-resolving numerical simulation
International audience Subtropical mode waters are characterized by low potential vorticity (PV) and so the mechanisms by which PV is extracted from the ocean by air-sea interaction are of great relevance to our understanding of how mode waters are formed. This study analyzes those mechanisms by com...
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ftsorbonneuniv:oai:HAL:hal-00836525v1 2024-09-15T18:23:03+00:00 Surface vertical PV fluxes and subtropical mode water formation in an eddy-resolving numerical simulation Maze, Guillaume Deshayes, Julie Marshall, John Tréguier, Anne-Marie Chronis, Alexandre Vollmer, Lukas 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) Department of Earth, Atmospheric and Planetary Sciences MIT, Cambridge (EAPS) Massachusetts Institute of Technology (MIT) 2013 https://hal.science/hal-00836525 https://doi.org/10.1016/j.dsr.2.2013.02.026 en eng HAL CCSD Elsevier info:eu-repo/semantics/altIdentifier/doi/10.1016/j.dsr.2.2013.02.026 hal-00836525 https://hal.science/hal-00836525 doi:10.1016/j.dsr.2.2013.02.026 ISSN: 0967-0645 Deep Sea Research Part II: Topical Studies in Oceanography https://hal.science/hal-00836525 Deep Sea Research Part II: Topical Studies in Oceanography, 2013, 91, pp.128-138. ⟨10.1016/j.dsr.2.2013.02.026⟩ Subtropical mode water Potential vorticity flux Mesoscale turbulence [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/article Journal articles 2013 ftsorbonneuniv https://doi.org/10.1016/j.dsr.2.2013.02.026 2024-07-25T23:47:31Z International audience Subtropical mode waters are characterized by low potential vorticity (PV) and so the mechanisms by which PV is extracted from the ocean by air-sea interaction are of great relevance to our understanding of how mode waters are formed. This study analyzes those mechanisms by comparing the magnitude and spatial patterns of surface PV fluxes of diabatic and frictional origin in a high resolution numerical simulation of the North Atlantic. The model resolves mesoscale eddies and exhibits realism in the volume and regional distribution of subtropical mode water, both in the annual-mean and seasonal cycle. It is found that the diabatic and mechanic fluxes of PV through the sea surface are of similar amplitude locally, but their spatial structures are very different. The diabatic PV flux has a large scale pattern that reflects that of air-sea heat fluxes directed from the ocean to the atmosphere along and to the south of the separated Gulf Stream. In contrast the mechanical PV flux, because of its dependence on horizontal surface density gradients, exhibits much smaller scales but embedded within a coherent large scale pattern. When mapped over the North Atlantic subtropical mode water (EDW) outcropping region, the diabatic PV flux pattern is found to be directed out of the ocean everywhere, whereas the mechanical PV fluxes exhibits small-scale patterns of both sign. The amplitude of the diabatic PV fluxes is found to be at least one order of magnitude larger than the mechanical PV fluxes demonstrating the overwhelming importance of diabatic processes in creating mode waters. Finally, we note that the large scale climatological patterns and magnitudes of both diabatic and mechanical PV flux mapped over the EDW outcropping region, are very similar to patterns obtained from coarse-grained ocean state estimates that do not resolve the eddy field. Article in Journal/Newspaper North Atlantic HAL Sorbonne Université |
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Open Polar |
collection |
HAL Sorbonne Université |
op_collection_id |
ftsorbonneuniv |
language |
English |
topic |
Subtropical mode water Potential vorticity flux Mesoscale turbulence [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
spellingShingle |
Subtropical mode water Potential vorticity flux Mesoscale turbulence [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography Maze, Guillaume Deshayes, Julie Marshall, John Tréguier, Anne-Marie Chronis, Alexandre Vollmer, Lukas Surface vertical PV fluxes and subtropical mode water formation in an eddy-resolving numerical simulation |
topic_facet |
Subtropical mode water Potential vorticity flux Mesoscale turbulence [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
International audience Subtropical mode waters are characterized by low potential vorticity (PV) and so the mechanisms by which PV is extracted from the ocean by air-sea interaction are of great relevance to our understanding of how mode waters are formed. This study analyzes those mechanisms by comparing the magnitude and spatial patterns of surface PV fluxes of diabatic and frictional origin in a high resolution numerical simulation of the North Atlantic. The model resolves mesoscale eddies and exhibits realism in the volume and regional distribution of subtropical mode water, both in the annual-mean and seasonal cycle. It is found that the diabatic and mechanic fluxes of PV through the sea surface are of similar amplitude locally, but their spatial structures are very different. The diabatic PV flux has a large scale pattern that reflects that of air-sea heat fluxes directed from the ocean to the atmosphere along and to the south of the separated Gulf Stream. In contrast the mechanical PV flux, because of its dependence on horizontal surface density gradients, exhibits much smaller scales but embedded within a coherent large scale pattern. When mapped over the North Atlantic subtropical mode water (EDW) outcropping region, the diabatic PV flux pattern is found to be directed out of the ocean everywhere, whereas the mechanical PV fluxes exhibits small-scale patterns of both sign. The amplitude of the diabatic PV fluxes is found to be at least one order of magnitude larger than the mechanical PV fluxes demonstrating the overwhelming importance of diabatic processes in creating mode waters. Finally, we note that the large scale climatological patterns and magnitudes of both diabatic and mechanical PV flux mapped over the EDW outcropping region, are very similar to patterns obtained from coarse-grained ocean state estimates that do not resolve the eddy field. |
author2 |
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) Department of Earth, Atmospheric and Planetary Sciences MIT, Cambridge (EAPS) Massachusetts Institute of Technology (MIT) |
format |
Article in Journal/Newspaper |
author |
Maze, Guillaume Deshayes, Julie Marshall, John Tréguier, Anne-Marie Chronis, Alexandre Vollmer, Lukas |
author_facet |
Maze, Guillaume Deshayes, Julie Marshall, John Tréguier, Anne-Marie Chronis, Alexandre Vollmer, Lukas |
author_sort |
Maze, Guillaume |
title |
Surface vertical PV fluxes and subtropical mode water formation in an eddy-resolving numerical simulation |
title_short |
Surface vertical PV fluxes and subtropical mode water formation in an eddy-resolving numerical simulation |
title_full |
Surface vertical PV fluxes and subtropical mode water formation in an eddy-resolving numerical simulation |
title_fullStr |
Surface vertical PV fluxes and subtropical mode water formation in an eddy-resolving numerical simulation |
title_full_unstemmed |
Surface vertical PV fluxes and subtropical mode water formation in an eddy-resolving numerical simulation |
title_sort |
surface vertical pv fluxes and subtropical mode water formation in an eddy-resolving numerical simulation |
publisher |
HAL CCSD |
publishDate |
2013 |
url |
https://hal.science/hal-00836525 https://doi.org/10.1016/j.dsr.2.2013.02.026 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
ISSN: 0967-0645 Deep Sea Research Part II: Topical Studies in Oceanography https://hal.science/hal-00836525 Deep Sea Research Part II: Topical Studies in Oceanography, 2013, 91, pp.128-138. ⟨10.1016/j.dsr.2.2013.02.026⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.dsr.2.2013.02.026 hal-00836525 https://hal.science/hal-00836525 doi:10.1016/j.dsr.2.2013.02.026 |
op_doi |
https://doi.org/10.1016/j.dsr.2.2013.02.026 |
_version_ |
1810463175537065984 |