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| Titel |
Modelling the seasonal variability of the Antarctic Slope Current |
| VerfasserIn |
P. Mathiot, H. Goosse, T. Fichefet, B. Barnier, H. Gallée |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1812-0784
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| Digitales Dokument |
URL |
| Erschienen |
In: Ocean Science ; 7, no. 4 ; Nr. 7, no. 4 (2011-07-06), S.455-470 |
| Datensatznummer |
250004718
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| Publikation (Nr.) |
 copernicus.org/os-7-455-2011.pdf |
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| Zusammenfassung |
One of the main features of the oceanic circulation along Antarctica is the
Antarctic Slope Current (ASC). This circumpolar current flows westwards and
contributes to communication between the three major oceanic basins around
Antarctica. The ASC is not very well known due to remote location and the
presence of sea ice during several months, allowing in situ studies only
during summertime. Moreover, only few modelling studies of this current have
been carried out. Here, we investigate the sensitivity of this simulated
current to four different resolutions in a coupled ocean-sea ice model and
to two different atmospheric forcing sets. Two series of simulations are
conducted. For the first series, global model configurations are run at
coarse (2°) to eddy-permitting (0.25°) resolutions with the same
atmospheric forcing. For the second series, simulations with two different
atmospheric forcings are performed using a regional circumpolar
configuration (south of 30° S) at 0.5° resolution. The first
atmospheric forcing is based on a global atmospheric reanalysis and
satellite data, while the second is based on a downscaling of the global
atmospheric reanalysis by a regional atmospheric model calibrated to
Antarctic meteorological conditions.
Sensitivity experiments to resolution indicate that a minimum model
resolution of 0.5° is needed to capture the dynamics of the ASC in terms
of water mass transport and recirculation. Sensitivity experiments to
atmospheric forcing fields shows that the wind speed along the Antarctic
coast strongly controls the water mass transport and the seasonal cycle of
the ASC. An increase in annual mean of easterlies by about 30 % leads to
an increase in the mean ASC transport by about 40 %. Similar effects are
obtained on the seasonal cycle: using a wind forcing field with a larger
seasonal cycle (+30 %) increases by more than 30 % the amplitude of
the seasonal cycle of the ASC. To confirm the importance of wind seasonal
cycle, a simulation without wind speed seasonal cycle is carried out. This
simulation shows a decrease by more than 50 % of the amplitude of the ASC
transport seasonal cycle without changing the mean value of ASC transport. |
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