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| Titel |
The contribution of the Weddell Gyre to the global overturning circulation |
| VerfasserIn |
Loic Jullion, Alberto Naveira Garabato, Sheldon Bacon, Michael Meredith, Pete Brown, Sinhue Torres-Valdes, Kevin Speer, Paul Holland, Dorothée Bakker, Mario Hoppema |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250103766
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| Publikation (Nr.) |
 EGU/EGU2015-3183.pdf |
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| Zusammenfassung |
| The horizontal and vertical circulation of the Weddell Gyre is diagnosed using a box inverse
model constructed with recent hydrographic sections and including mobile sea ice and eddy
transports. The gyre is found to convey 42 ± 8 Sv (1 Sv = 106 m3 s-1) across the central
Weddell Sea and to intensify to 54 ± 15 Sv further offshore. This circulation injects
36 ± 13 TW of heat from the Antarctic Circumpolar Current to the gyre, and exports
51 ± 23 mSv of freshwater, including 13 ± 1 mSv as sea ice to the mid-latitude
Southern Ocean. The gyre’s overturning circulation has an asymmetric double-cell
structure, in which 13 ± 4 Sv of Circumpolar Deep Water (CDW) and relatively
light Antarctic Bottom Water (AABW) are transformed into upper-ocean water
masses by mid-gyre upwelling (at a rate of 2 ± 2 Sv) and into denser AABW by
downwelling focussed at the western boundary (8 ± 2 Sv). The gyre circulation exhibits a
substantial throughflow component, by which CDW and AABW enter the gyre
from the Indian sector, undergo ventilation and densification within the gyre, and
are exported to the South Atlantic across the gyre’s northern rim. The relatively
modest net production of AABW in the Weddell Gyre (6 ± 2 Sv) suggests that the
gyre’s prominence in the closure of the lower limb of global oceanic overturning
stems largely from the recycling and equatorward export of Indian-sourced AABW. |
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