Locations and mechanisms of ocean ventilation in the high-latitude North Atlantic in an eddy-permitting ocean model
International audience A substantial fraction of the deep ocean is ventilated in the high-latitude North Atlantic. Consequently, the region plays a crucial role in transient climate change through the uptake of carbon dioxide and heat. However, owing to the Lagrangian nature of the process, many asp...
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Online Access: | https://hal.science/hal-04202637 https://hal.science/hal-04202637/document https://hal.science/hal-04202637/file/clim-jcliD200191.pdf https://doi.org/10.1175/JCLI-D-20-0191.1 |
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ftunivbrest:oai:HAL:hal-04202637v1 2024-04-21T08:03:59+00:00 Locations and mechanisms of ocean ventilation in the high-latitude North Atlantic in an eddy-permitting ocean model Macgilchrist, Graeme A. Johnson, Helen L. Marshall, David P. Lique, Camille Thomas, Matthew Jackson, Laura C. Wood, Richard A. Laboratoire d'Océanographie Physique et Spatiale (LOPS) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) 2020-12 https://hal.science/hal-04202637 https://hal.science/hal-04202637/document https://hal.science/hal-04202637/file/clim-jcliD200191.pdf https://doi.org/10.1175/JCLI-D-20-0191.1 en eng HAL CCSD American Meteorological Society info:eu-repo/semantics/altIdentifier/doi/10.1175/JCLI-D-20-0191.1 hal-04202637 https://hal.science/hal-04202637 https://hal.science/hal-04202637/document https://hal.science/hal-04202637/file/clim-jcliD200191.pdf doi:10.1175/JCLI-D-20-0191.1 info:eu-repo/semantics/OpenAccess ISSN: 0894-8755 EISSN: 1520-0442 Journal of Climate https://hal.science/hal-04202637 Journal of Climate, 2020, 33 (23), pp.10113-10131. ⟨10.1175/JCLI-D-20-0191.1⟩ [SDU]Sciences of the Universe [physics] info:eu-repo/semantics/article Journal articles 2020 ftunivbrest https://doi.org/10.1175/JCLI-D-20-0191.1 2024-04-10T23:46:14Z International audience A substantial fraction of the deep ocean is ventilated in the high-latitude North Atlantic. Consequently, the region plays a crucial role in transient climate change through the uptake of carbon dioxide and heat. However, owing to the Lagrangian nature of the process, many aspects of deep Atlantic Ocean ventilation and its representation in climate simulations remain obscure. We investigate the nature of ventilation in the high latitude North Atlantic in an eddy-permitting numerical ocean circulation model using a comprehensive set of Lagrangian trajectory experiments. Backwards-in-time trajectories from a model-defined ‘North Atlantic DeepWater’ (NADW) reveal the locations of subduction from the surface mixed layer at high spatial resolution. The major fraction of NADW ventilation results from subduction in the Labrador Sea, predominantly within the boundary current (̴ 60% of ventilated NADW volume) and a smaller fraction arising from open ocean deep convection (̴ 25%). Subsurface transformations — due in part to the model’s parameterization of bottom-intensified mixing—facilitate NADWventilation, such that water subducted in the boundary current ventilates all of NADW, not just the lighter density classes. There is a notable absence of ventilation arising from subduction in the Greenland-Iceland-Norwegian Seas, due to the re-entrainment of those waters as they move southward. Taken together, our results emphasize an important distinction between ventilation and dense water formation in terms of the location where each takes place, and their concurrent sensitivities. These features of NADW ventilation are explored to understand how the representation of high-latitude processes impacts properties of the deep ocean in a state-of-the-science numerical simulation. Article in Journal/Newspaper Greenland Iceland Labrador Sea NADW North Atlantic Université de Bretagne Occidentale: HAL Journal of Climate 33 23 10113 10131 |
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Open Polar |
collection |
Université de Bretagne Occidentale: HAL |
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ftunivbrest |
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English |
topic |
[SDU]Sciences of the Universe [physics] |
spellingShingle |
[SDU]Sciences of the Universe [physics] Macgilchrist, Graeme A. Johnson, Helen L. Marshall, David P. Lique, Camille Thomas, Matthew Jackson, Laura C. Wood, Richard A. Locations and mechanisms of ocean ventilation in the high-latitude North Atlantic in an eddy-permitting ocean model |
topic_facet |
[SDU]Sciences of the Universe [physics] |
description |
International audience A substantial fraction of the deep ocean is ventilated in the high-latitude North Atlantic. Consequently, the region plays a crucial role in transient climate change through the uptake of carbon dioxide and heat. However, owing to the Lagrangian nature of the process, many aspects of deep Atlantic Ocean ventilation and its representation in climate simulations remain obscure. We investigate the nature of ventilation in the high latitude North Atlantic in an eddy-permitting numerical ocean circulation model using a comprehensive set of Lagrangian trajectory experiments. Backwards-in-time trajectories from a model-defined ‘North Atlantic DeepWater’ (NADW) reveal the locations of subduction from the surface mixed layer at high spatial resolution. The major fraction of NADW ventilation results from subduction in the Labrador Sea, predominantly within the boundary current (̴ 60% of ventilated NADW volume) and a smaller fraction arising from open ocean deep convection (̴ 25%). Subsurface transformations — due in part to the model’s parameterization of bottom-intensified mixing—facilitate NADWventilation, such that water subducted in the boundary current ventilates all of NADW, not just the lighter density classes. There is a notable absence of ventilation arising from subduction in the Greenland-Iceland-Norwegian Seas, due to the re-entrainment of those waters as they move southward. Taken together, our results emphasize an important distinction between ventilation and dense water formation in terms of the location where each takes place, and their concurrent sensitivities. These features of NADW ventilation are explored to understand how the representation of high-latitude processes impacts properties of the deep ocean in a state-of-the-science numerical simulation. |
author2 |
Laboratoire d'Océanographie Physique et Spatiale (LOPS) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Macgilchrist, Graeme A. Johnson, Helen L. Marshall, David P. Lique, Camille Thomas, Matthew Jackson, Laura C. Wood, Richard A. |
author_facet |
Macgilchrist, Graeme A. Johnson, Helen L. Marshall, David P. Lique, Camille Thomas, Matthew Jackson, Laura C. Wood, Richard A. |
author_sort |
Macgilchrist, Graeme A. |
title |
Locations and mechanisms of ocean ventilation in the high-latitude North Atlantic in an eddy-permitting ocean model |
title_short |
Locations and mechanisms of ocean ventilation in the high-latitude North Atlantic in an eddy-permitting ocean model |
title_full |
Locations and mechanisms of ocean ventilation in the high-latitude North Atlantic in an eddy-permitting ocean model |
title_fullStr |
Locations and mechanisms of ocean ventilation in the high-latitude North Atlantic in an eddy-permitting ocean model |
title_full_unstemmed |
Locations and mechanisms of ocean ventilation in the high-latitude North Atlantic in an eddy-permitting ocean model |
title_sort |
locations and mechanisms of ocean ventilation in the high-latitude north atlantic in an eddy-permitting ocean model |
publisher |
HAL CCSD |
publishDate |
2020 |
url |
https://hal.science/hal-04202637 https://hal.science/hal-04202637/document https://hal.science/hal-04202637/file/clim-jcliD200191.pdf https://doi.org/10.1175/JCLI-D-20-0191.1 |
genre |
Greenland Iceland Labrador Sea NADW North Atlantic |
genre_facet |
Greenland Iceland Labrador Sea NADW North Atlantic |
op_source |
ISSN: 0894-8755 EISSN: 1520-0442 Journal of Climate https://hal.science/hal-04202637 Journal of Climate, 2020, 33 (23), pp.10113-10131. ⟨10.1175/JCLI-D-20-0191.1⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1175/JCLI-D-20-0191.1 hal-04202637 https://hal.science/hal-04202637 https://hal.science/hal-04202637/document https://hal.science/hal-04202637/file/clim-jcliD200191.pdf doi:10.1175/JCLI-D-20-0191.1 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1175/JCLI-D-20-0191.1 |
container_title |
Journal of Climate |
container_volume |
33 |
container_issue |
23 |
container_start_page |
10113 |
op_container_end_page |
10131 |
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1796943628806914048 |