Seasonal cycle of hydrography on the eastern shelf of the Filchner Trough, Weddell Sea, Antarctica


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svenja.ryan [ at ] awi.de

Abstract

New two-year long records from three moorings, located at 76°S along the eastern flank and shelf of the Filchner Trough, give insight in the seasonal cycle of hydrography to a region where Modified Warm Deep Water (MWDW) enters the southern Weddell Sea continental shelf, possibly reaching the Filchner Ronne Ice Shelf, the biggest ice shelf (by volume) in Antarctica. A persistent northward flow of Ice Shelf Water (ISW) is found along the slope of the trough at 600 m depth, while the data on the shelf indicate a seasonal cycle, characterized by four phases. A distinct warm inflow period (separated in two phases), with maximum temperatures of −1°C, appears to be related to the seasonal heaving of the Antarctic Slope Front thermocline along the continental shelf break further north and a seasonal extension of the ISW layer onto the Eastern Shelf. The density gradients between the ISW in the trough and the MWDW on the adjacent shelf drive the southward flow during these phases. A flow reversal is found in winter, ceasing the southward flow along the eastern flank of the trough. Weaker density gradients between the trough and the shelf during winter allow a westward flow, partly driven by a N-S density gradient, existing across the Eastern Shelf during this time. From spring through to summer the ISW layer in the trough extends onto the eastern shelf where it occupies the bottom layer at our moorings and it is associated with northward flow.



Item Type
Article
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Primary Division
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Peer revision
Peer-reviewed
Publication Status
Published
Eprint ID
45293
DOI 10.1002/2017JC012916

Cite as
Ryan, S. , Hattermann, T. , Darelius, E. and Schröder, M. (2017): Seasonal cycle of hydrography on the eastern shelf of the Filchner Trough, Weddell Sea, Antarctica , Journal of Geophysical Research-Oceans, 122 (8), pp. 6437-6453 . doi: 10.1002/2017JC012916


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