On the role of mesoscale eddies in the ventilation of Antarctic Intermediate Water
International audience The spatial distribution of Antarctic Intermediate Water (AAIW) formation and ventilation remains a matter of debate. Some studies suggest that AAIW forms nearly homogeneously in a circumpolar pattern, whereas others favor more localized formation particularly in the southeast...
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ftmeteofrance:oai:HAL:hal-04113668v1 2023-06-18T03:36:32+02:00 On the role of mesoscale eddies in the ventilation of Antarctic Intermediate Water Lachkar, Z. Orr, J. -C. Dutay, J. -C. Delecluse, P. Météo-France à renseigner, Unknown Region 2023-06-01 https://hal.science/hal-04113668 en eng HAL CCSD hal-04113668 https://hal.science/hal-04113668 BIBCODE: 2009EGUGA.11.9601L EGU General Assembly 2009 https://hal.science/hal-04113668 EGU General Assembly 2009, 0000, à renseigner, Unknown Region. pp.9601 [SDU]Sciences of the Universe [physics] info:eu-repo/semantics/conferenceObject Conference papers 2023 ftmeteofrance 2023-06-06T22:39:36Z International audience The spatial distribution of Antarctic Intermediate Water (AAIW) formation and ventilation remains a matter of debate. Some studies suggest that AAIW forms nearly homogeneously in a circumpolar pattern, whereas others favor more localized formation particularly in the southeast Pacific Ocean. We show here that the patterns and magnitude of AAIW formation and ventilation are substantially affected by mesoscale eddies. To diagnose the role of eddies, we made global CFC-11 simulations in two versions of the ocean general circulation model OPA9, a "non-eddying", coarse-resolution version (2 °cosφÃ- 2 °, ORCA2) and an "eddying" or eddy-permitting version (1 2 °cosφÃ-1 2 °, ORCA05). In the noneddying simulation, AAIW subducts in a near homogeneous, circumpolar pattern; in the eddying simulation, the distribution of AAIW ventilation is patchier. Increasing resolution causes the AAIW layer to thin by 32% on average in the Indian sector, but only by 11% in the Pacific sector. This patchiness appears due to the zonal wind stress, which is weak over much of the Pacific and southwest Atlantic sectors but is strong over the Indian sector. Consequently, the effect of eddies is largest in the Indian Ocean, moderate in the Atlantic, and smallest in the Pacific basin. Although the Gent & McWilliams (GM) eddy parameterization improves the overall vertical structure of density in the Southern Ocean, applying it in our non-eddying model still results in the nearly uniform circumpolar distribution of AAIW ventilation, in contrast to the observations. Conference Object Antarc* Antarctic Southern Ocean Météo-France: HAL Antarctic Southern Ocean Pacific Indian |
institution |
Open Polar |
collection |
Météo-France: HAL |
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ftmeteofrance |
language |
English |
topic |
[SDU]Sciences of the Universe [physics] |
spellingShingle |
[SDU]Sciences of the Universe [physics] Lachkar, Z. Orr, J. -C. Dutay, J. -C. Delecluse, P. On the role of mesoscale eddies in the ventilation of Antarctic Intermediate Water |
topic_facet |
[SDU]Sciences of the Universe [physics] |
description |
International audience The spatial distribution of Antarctic Intermediate Water (AAIW) formation and ventilation remains a matter of debate. Some studies suggest that AAIW forms nearly homogeneously in a circumpolar pattern, whereas others favor more localized formation particularly in the southeast Pacific Ocean. We show here that the patterns and magnitude of AAIW formation and ventilation are substantially affected by mesoscale eddies. To diagnose the role of eddies, we made global CFC-11 simulations in two versions of the ocean general circulation model OPA9, a "non-eddying", coarse-resolution version (2 °cosφÃ- 2 °, ORCA2) and an "eddying" or eddy-permitting version (1 2 °cosφÃ-1 2 °, ORCA05). In the noneddying simulation, AAIW subducts in a near homogeneous, circumpolar pattern; in the eddying simulation, the distribution of AAIW ventilation is patchier. Increasing resolution causes the AAIW layer to thin by 32% on average in the Indian sector, but only by 11% in the Pacific sector. This patchiness appears due to the zonal wind stress, which is weak over much of the Pacific and southwest Atlantic sectors but is strong over the Indian sector. Consequently, the effect of eddies is largest in the Indian Ocean, moderate in the Atlantic, and smallest in the Pacific basin. Although the Gent & McWilliams (GM) eddy parameterization improves the overall vertical structure of density in the Southern Ocean, applying it in our non-eddying model still results in the nearly uniform circumpolar distribution of AAIW ventilation, in contrast to the observations. |
author2 |
Météo-France |
format |
Conference Object |
author |
Lachkar, Z. Orr, J. -C. Dutay, J. -C. Delecluse, P. |
author_facet |
Lachkar, Z. Orr, J. -C. Dutay, J. -C. Delecluse, P. |
author_sort |
Lachkar, Z. |
title |
On the role of mesoscale eddies in the ventilation of Antarctic Intermediate Water |
title_short |
On the role of mesoscale eddies in the ventilation of Antarctic Intermediate Water |
title_full |
On the role of mesoscale eddies in the ventilation of Antarctic Intermediate Water |
title_fullStr |
On the role of mesoscale eddies in the ventilation of Antarctic Intermediate Water |
title_full_unstemmed |
On the role of mesoscale eddies in the ventilation of Antarctic Intermediate Water |
title_sort |
on the role of mesoscale eddies in the ventilation of antarctic intermediate water |
publisher |
HAL CCSD |
publishDate |
2023 |
url |
https://hal.science/hal-04113668 |
op_coverage |
à renseigner, Unknown Region |
geographic |
Antarctic Southern Ocean Pacific Indian |
geographic_facet |
Antarctic Southern Ocean Pacific Indian |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_source |
EGU General Assembly 2009 https://hal.science/hal-04113668 EGU General Assembly 2009, 0000, à renseigner, Unknown Region. pp.9601 |
op_relation |
hal-04113668 https://hal.science/hal-04113668 BIBCODE: 2009EGUGA.11.9601L |
_version_ |
1769006787598483456 |