Characterising the chaotic nature of ocean ventilation
Ventilation of the upper ocean plays an important role in climate variability on interannual to decadal timescales by influencing the exchange of heat and carbon dioxide between the atmosphere and ocean. The turbulent nature of ocean circulation, manifest in a vigorous mesoscale eddy field, means th...
Published in: | Journal of Geophysical Research: Oceans |
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American Geophysical Union
2017
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Online Access: | https://doi.org/10.1002/2017JC012875 https://ora.ox.ac.uk/objects/uuid:6cffd0b5-2d93-448e-a93c-362701699e85 |
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ftuloxford:oai:ora.ox.ac.uk:uuid:6cffd0b5-2d93-448e-a93c-362701699e85 2023-05-15T17:32:46+02:00 Characterising the chaotic nature of ocean ventilation MacGilchrist, G Marshall, D Johnson, H Lique, C Thomas, M 2017-09-06 https://doi.org/10.1002/2017JC012875 https://ora.ox.ac.uk/objects/uuid:6cffd0b5-2d93-448e-a93c-362701699e85 unknown American Geophysical Union doi:10.1002/2017JC012875 https://ora.ox.ac.uk/objects/uuid:6cffd0b5-2d93-448e-a93c-362701699e85 https://doi.org/10.1002/2017JC012875 info:eu-repo/semantics/openAccess CC Attribution (CC BY) CC-BY Journal article 2017 ftuloxford https://doi.org/10.1002/2017JC012875 2022-06-28T20:14:51Z Ventilation of the upper ocean plays an important role in climate variability on interannual to decadal timescales by influencing the exchange of heat and carbon dioxide between the atmosphere and ocean. The turbulent nature of ocean circulation, manifest in a vigorous mesoscale eddy field, means that pathways of ventilation, once thought to be quasi-laminar, are in fact highly chaotic. We characterise the chaotic nature of ventilation pathways according to a nondimensional ‘filamentation number', which estimates the reduction in filament width of a ventilated fluid parcel due to mesoscale strain. In the subtropical North Atlantic of an eddy-permitting ocean model, the filamentation number is large everywhere across three upper ocean density surfaces — implying highly chaotic ventilation pathways — and increases with depth. By mapping surface ocean properties onto these density surfaces, we directly resolve the highly filamented structure and confirm that the filamentation number captures its spatial variability. These results have implications for the spreading of atmospherically-derived tracers into the ocean interior. Article in Journal/Newspaper North Atlantic ORA - Oxford University Research Archive Journal of Geophysical Research: Oceans 122 9 7577 7594 |
institution |
Open Polar |
collection |
ORA - Oxford University Research Archive |
op_collection_id |
ftuloxford |
language |
unknown |
description |
Ventilation of the upper ocean plays an important role in climate variability on interannual to decadal timescales by influencing the exchange of heat and carbon dioxide between the atmosphere and ocean. The turbulent nature of ocean circulation, manifest in a vigorous mesoscale eddy field, means that pathways of ventilation, once thought to be quasi-laminar, are in fact highly chaotic. We characterise the chaotic nature of ventilation pathways according to a nondimensional ‘filamentation number', which estimates the reduction in filament width of a ventilated fluid parcel due to mesoscale strain. In the subtropical North Atlantic of an eddy-permitting ocean model, the filamentation number is large everywhere across three upper ocean density surfaces — implying highly chaotic ventilation pathways — and increases with depth. By mapping surface ocean properties onto these density surfaces, we directly resolve the highly filamented structure and confirm that the filamentation number captures its spatial variability. These results have implications for the spreading of atmospherically-derived tracers into the ocean interior. |
format |
Article in Journal/Newspaper |
author |
MacGilchrist, G Marshall, D Johnson, H Lique, C Thomas, M |
spellingShingle |
MacGilchrist, G Marshall, D Johnson, H Lique, C Thomas, M Characterising the chaotic nature of ocean ventilation |
author_facet |
MacGilchrist, G Marshall, D Johnson, H Lique, C Thomas, M |
author_sort |
MacGilchrist, G |
title |
Characterising the chaotic nature of ocean ventilation |
title_short |
Characterising the chaotic nature of ocean ventilation |
title_full |
Characterising the chaotic nature of ocean ventilation |
title_fullStr |
Characterising the chaotic nature of ocean ventilation |
title_full_unstemmed |
Characterising the chaotic nature of ocean ventilation |
title_sort |
characterising the chaotic nature of ocean ventilation |
publisher |
American Geophysical Union |
publishDate |
2017 |
url |
https://doi.org/10.1002/2017JC012875 https://ora.ox.ac.uk/objects/uuid:6cffd0b5-2d93-448e-a93c-362701699e85 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
doi:10.1002/2017JC012875 https://ora.ox.ac.uk/objects/uuid:6cffd0b5-2d93-448e-a93c-362701699e85 https://doi.org/10.1002/2017JC012875 |
op_rights |
info:eu-repo/semantics/openAccess CC Attribution (CC BY) |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1002/2017JC012875 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
122 |
container_issue |
9 |
container_start_page |
7577 |
op_container_end_page |
7594 |
_version_ |
1766131027127828480 |