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| Titel |
Response of Southern Ocean natural carbon cycle to a positive phase of the Southern Annular Mode |
| VerfasserIn |
Carolina O. Dufour, Julien Le Sommer, Marion Gehlen, James C. Orr, Jennifer Simeon, Bernard Barnier |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250045539
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| Zusammenfassung |
| The response of the Southern Ocean carbon sink to the current climate trend in the
Southern Annular Mode (SAM) is thought to be dominated by the response of
upwelling intensity to changes in wind forcing. As part of the natural carbon cycle,
upwelling brings dissolved carbon-rich water masses to the surface south of the
Antarctic Circumpolar Current, inducing an outgassing of CO2 to the atmosphere.
Investigating the response of the natural carbon cycle to the SAM thus requires a realistic
representation (i) of the ocean dynamics and biogeochemistry and (ii) of the SAM
forcing. However, most modelling studies published to date lack a realistic modelling
framework. This study focuses on the sensitivity of the Southern Ocean natural carbon
cycle to the trend in the SAM in a coupled ocean-sea ice -biogeochemistry model
(OPA-LIM-PISCES) forced by atmospheric reanalyses. The model regional configuration
includes all ocean south of 30-S, and is run at eddy-permitting resolution (0.5-;
corresponding to a grid size of 25km at 60-S). In order to understand the response of
air-sea CO2 fluxes to the SAM, two realistic simulations of the Southern Ocean are
run over the period 1977-2004: a control experiment during which winds are left
unperturbed and a sensitivity experiment where an anomaly corresponding to a
positive phase of the SAM is added. The control simulation is assessed towards
observations and shows a good representation of both dynamical and biogeochemical
tracers. Anomalies of pCO2 and variability of air-sea CO2 fluxes in the sensitivity
experiment will be investigated, as well as anomalies of mixed layer depth and
upwelling intensities in order to understand which processes drive the model response. |
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