Effects of mesoscale eddies on global ocean distributions of CFC-11, CO 2 , and ? 14 C
International audience Global-scale tracer simulations are typically made at coarse resolution without explicitly modelling eddies. Here we ask what role do eddies play in ocean uptake, storage, and meridional transport of transient tracers. We made global anthropogenic transient-tracer simulations...
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ftinsu:oai:HAL:hal-00331146v1 2024-04-28T08:00:03+00:00 Effects of mesoscale eddies on global ocean distributions of CFC-11, CO 2 , and ? 14 C Lachkar, Z. Orr, J. C. Dutay, J.-C. Delecluse, P. Institut Pierre-Simon-Laplace (IPSL) École normale supérieure - Paris (ENS-PSL) Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS) Marine Environment Laboratories 2007-10-12 https://hal.science/hal-00331146 https://hal.science/hal-00331146/document https://hal.science/hal-00331146/file/os-3-461-2007.pdf en eng HAL CCSD European Geosciences Union hal-00331146 https://hal.science/hal-00331146 https://hal.science/hal-00331146/document https://hal.science/hal-00331146/file/os-3-461-2007.pdf info:eu-repo/semantics/OpenAccess ISSN: 1812-0784 EISSN: 1812-0792 Ocean Science https://hal.science/hal-00331146 Ocean Science, 2007, 3 (4), pp.461-482 [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere info:eu-repo/semantics/article Journal articles 2007 ftinsu 2024-04-05T00:36:33Z International audience Global-scale tracer simulations are typically made at coarse resolution without explicitly modelling eddies. Here we ask what role do eddies play in ocean uptake, storage, and meridional transport of transient tracers. We made global anthropogenic transient-tracer simulations in coarse-resolution (2°cosf×2°, ORCA2) and eddy-permitting (½°cosf×½°, ORCA05) versions of the ocean general circulation model OPA9. Our focus is on surface-to-intermediate waters of the southern extratropics where air-sea tracer fluxes, tracer storage, and meridional tracer transport are largest. Eddies have little effect on global and regional bomb ? 14 C uptake and storage. Yet for anthropogenic CO 2 and CFC-11, refining the horizontal resolution reduced southern extratropical uptake by 25% and 28%, respectively. There is a similar decrease in corresponding inventories, which yields better agreement with observations. With higher resolution, eddies strengthen upper ocean vertical stratification and reduce excessive ventilation of intermediate waters by 20% between 60° S and 40° S. By weakening the residual circulation, i.e., the sum of Eulerian mean flow and the opposed eddy-induced flow, eddies reduce the supply of tracer-impoverished deep waters to the surface near the Antarctic divergence, thus reducing the air-sea tracer flux. Thus in the eddy permitting model, surface waters in that region have more time to equilibrate with the atmosphere before they are transported northward and subducted. As a result, the eddy permitting model's inventories of CFC-11 and anthropogenic CO 2 are lower in that region because mixed-layer concentrations of both tracers equilibrate with the atmosphere on relatively short time scales (15 days and 6 months, respectively); conversely, bomb ? 14 C's air-sea equilibration time of 6 years is so slow that, even in the eddy permitting model, there is little time for surface concentrations to equilibrate with the atmosphere, i.e., before surface waters are subducted. Article in Journal/Newspaper Antarc* Antarctic Institut national des sciences de l'Univers: HAL-INSU |
institution |
Open Polar |
collection |
Institut national des sciences de l'Univers: HAL-INSU |
op_collection_id |
ftinsu |
language |
English |
topic |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
spellingShingle |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere Lachkar, Z. Orr, J. C. Dutay, J.-C. Delecluse, P. Effects of mesoscale eddies on global ocean distributions of CFC-11, CO 2 , and ? 14 C |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
description |
International audience Global-scale tracer simulations are typically made at coarse resolution without explicitly modelling eddies. Here we ask what role do eddies play in ocean uptake, storage, and meridional transport of transient tracers. We made global anthropogenic transient-tracer simulations in coarse-resolution (2°cosf×2°, ORCA2) and eddy-permitting (½°cosf×½°, ORCA05) versions of the ocean general circulation model OPA9. Our focus is on surface-to-intermediate waters of the southern extratropics where air-sea tracer fluxes, tracer storage, and meridional tracer transport are largest. Eddies have little effect on global and regional bomb ? 14 C uptake and storage. Yet for anthropogenic CO 2 and CFC-11, refining the horizontal resolution reduced southern extratropical uptake by 25% and 28%, respectively. There is a similar decrease in corresponding inventories, which yields better agreement with observations. With higher resolution, eddies strengthen upper ocean vertical stratification and reduce excessive ventilation of intermediate waters by 20% between 60° S and 40° S. By weakening the residual circulation, i.e., the sum of Eulerian mean flow and the opposed eddy-induced flow, eddies reduce the supply of tracer-impoverished deep waters to the surface near the Antarctic divergence, thus reducing the air-sea tracer flux. Thus in the eddy permitting model, surface waters in that region have more time to equilibrate with the atmosphere before they are transported northward and subducted. As a result, the eddy permitting model's inventories of CFC-11 and anthropogenic CO 2 are lower in that region because mixed-layer concentrations of both tracers equilibrate with the atmosphere on relatively short time scales (15 days and 6 months, respectively); conversely, bomb ? 14 C's air-sea equilibration time of 6 years is so slow that, even in the eddy permitting model, there is little time for surface concentrations to equilibrate with the atmosphere, i.e., before surface waters are subducted. |
author2 |
Institut Pierre-Simon-Laplace (IPSL) École normale supérieure - Paris (ENS-PSL) Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS) Marine Environment Laboratories |
format |
Article in Journal/Newspaper |
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 |
Effects of mesoscale eddies on global ocean distributions of CFC-11, CO 2 , and ? 14 C |
title_short |
Effects of mesoscale eddies on global ocean distributions of CFC-11, CO 2 , and ? 14 C |
title_full |
Effects of mesoscale eddies on global ocean distributions of CFC-11, CO 2 , and ? 14 C |
title_fullStr |
Effects of mesoscale eddies on global ocean distributions of CFC-11, CO 2 , and ? 14 C |
title_full_unstemmed |
Effects of mesoscale eddies on global ocean distributions of CFC-11, CO 2 , and ? 14 C |
title_sort |
effects of mesoscale eddies on global ocean distributions of cfc-11, co 2 , and ? 14 c |
publisher |
HAL CCSD |
publishDate |
2007 |
url |
https://hal.science/hal-00331146 https://hal.science/hal-00331146/document https://hal.science/hal-00331146/file/os-3-461-2007.pdf |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
ISSN: 1812-0784 EISSN: 1812-0792 Ocean Science https://hal.science/hal-00331146 Ocean Science, 2007, 3 (4), pp.461-482 |
op_relation |
hal-00331146 https://hal.science/hal-00331146 https://hal.science/hal-00331146/document https://hal.science/hal-00331146/file/os-3-461-2007.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1797572444305752064 |