Effects of mesoscale eddies on global ocean distributions of CFC-11, CO2, and Δ14C
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...
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fttriple:oai:gotriple.eu:oai:doaj.org/article:e079f7eff28a49098211ec93e39b28e7 2023-05-15T13:38:12+02:00 Effects of mesoscale eddies on global ocean distributions of CFC-11, CO2, and Δ14C P. Delecluse J.-C. Dutay J. C. Orr Z. Lachkar 2007-10-01 http://www.ocean-sci.net/3/461/2007/os-3-461-2007.pdf https://doaj.org/article/e079f7eff28a49098211ec93e39b28e7 en eng Copernicus Publications 1812-0784 1812-0792 http://www.ocean-sci.net/3/461/2007/os-3-461-2007.pdf https://doaj.org/article/e079f7eff28a49098211ec93e39b28e7 undefined Ocean Science, Vol 3, Iss 4, Pp 461-482 (2007) envir geo Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2007 fttriple 2023-01-22T19:12:51Z 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°cosφ×2°, ORCA2) and eddy-permitting (½°cosφ×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 Δ14C uptake and storage. Yet for anthropogenic CO2 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 CO2 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 Δ14C'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 Unknown Antarctic The Antarctic |
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envir geo P. Delecluse J.-C. Dutay J. C. Orr Z. Lachkar Effects of mesoscale eddies on global ocean distributions of CFC-11, CO2, and Δ14C |
topic_facet |
envir geo |
description |
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°cosφ×2°, ORCA2) and eddy-permitting (½°cosφ×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 Δ14C uptake and storage. Yet for anthropogenic CO2 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 CO2 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 Δ14C'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. |
format |
Article in Journal/Newspaper |
author |
P. Delecluse J.-C. Dutay J. C. Orr Z. Lachkar |
author_facet |
P. Delecluse J.-C. Dutay J. C. Orr Z. Lachkar |
author_sort |
P. Delecluse |
title |
Effects of mesoscale eddies on global ocean distributions of CFC-11, CO2, and Δ14C |
title_short |
Effects of mesoscale eddies on global ocean distributions of CFC-11, CO2, and Δ14C |
title_full |
Effects of mesoscale eddies on global ocean distributions of CFC-11, CO2, and Δ14C |
title_fullStr |
Effects of mesoscale eddies on global ocean distributions of CFC-11, CO2, and Δ14C |
title_full_unstemmed |
Effects of mesoscale eddies on global ocean distributions of CFC-11, CO2, and Δ14C |
title_sort |
effects of mesoscale eddies on global ocean distributions of cfc-11, co2, and δ14c |
publisher |
Copernicus Publications |
publishDate |
2007 |
url |
http://www.ocean-sci.net/3/461/2007/os-3-461-2007.pdf https://doaj.org/article/e079f7eff28a49098211ec93e39b28e7 |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Ocean Science, Vol 3, Iss 4, Pp 461-482 (2007) |
op_relation |
1812-0784 1812-0792 http://www.ocean-sci.net/3/461/2007/os-3-461-2007.pdf https://doaj.org/article/e079f7eff28a49098211ec93e39b28e7 |
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