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| Titel |
Sea ice and the ocean mixed layer over the Antarctic shelf seas |
| VerfasserIn |
A. A. Petty, P. R. Holland, D. L. Feltham |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 8, no. 2 ; Nr. 8, no. 2 (2014-04-29), S.761-783 |
| Datensatznummer |
250116099
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| Publikation (Nr.) |
 copernicus.org/tc-8-761-2014.pdf |
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| Zusammenfassung |
| An ocean mixed-layer model has been incorporated into the Los Alamos sea ice
model CICE to investigate regional variations in the surface-driven formation
of Antarctic shelf waters. This model captures well the expected sea ice
thickness distribution, and produces deep (> 500 m) mixed layers in the
Weddell and Ross shelf seas each winter. This results in the complete
destratification of the water column in deep southern coastal regions leading
to high-salinity shelf water (HSSW) formation, and also in some shallower
regions (no HSSW formation) of these seas. Shallower mixed layers are
produced in the Amundsen and Bellingshausen seas. By deconstructing the
surface processes driving the mixed-layer depth evolution, we show that the
net salt flux from sea ice growth/melt dominates the evolution of the mixed
layer in all regions, with a smaller contribution from the surface heat flux
and a negligible input from wind stress. The Weddell and Ross shelf seas
receive an annual surplus of mixing energy at the surface; the Amundsen shelf
sea energy input in autumn/winter is balanced by energy extraction in
spring/summer; and the Bellingshausen shelf sea experiences an annual surface
energy deficit, through both a low energy input in autumn/winter and the
highest energy loss in spring/summer. An analysis of the sea ice mass balance
demonstrates the contrasting mean ice growth, melt and export in each region.
The Weddell and Ross shelf seas have the highest annual ice growth, with a
large fraction exported northwards each year, whereas the Bellingshausen
shelf sea experiences the highest annual ice melt, driven by the advection of
ice from the northeast. A linear regression analysis is performed to
determine the link between the autumn/winter mixed-layer deepening and
several atmospheric variables. The Weddell and Ross shelf seas show stronger
spatial correlations (temporal mean – intra-regional variability) between the
autumn/winter mixed-layer deepening and several atmospheric variables
compared to the Amundsen and Bellingshausen. In contrast, the Amundsen and
Bellingshausen shelf seas show stronger temporal correlations (shelf sea mean
– interannual variability) between the autumn/winter mixed-layer deepening
and several atmospheric variables. |
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