Variability of Warm Deep Water Inflow in a Submarine Trough on the Amundsen Sea Shelf

The ice shelves in the Amundsen Sea are thinning rapidly, and the main reason for their decline appearsto be warm ocean currents circulating below the ice shelves and melting these from below. Ocean currentstransportwarm densewater ontothe shelf,channeledby bathymetric troughs leadingto the deep inn...

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Bibliographic Details
Published in:Journal of Physical Oceanography
Main Authors: Wåhlin, Anna, Kalén, Ola, Arneborg, Lars, Björk, Göran, Carvajal, Gisela, Ha, Ho Kyung, Kim, TaeWan, Lee, Sang Hoon, Lee, JaeHak, Stranne, Christian
Language:unknown
Published: 2013
Subjects:
Oceanography
Hydrology
Water Resources
ocean
Amundsen Sea
deep water velocity
surface wind
Austral
Bya
Ice Shelves
Online Access:https://doi.org/10.1175/JPO-D-12-0157.1
https://research.chalmers.se/en/publication/199062
Description
Summary:The ice shelves in the Amundsen Sea are thinning rapidly, and the main reason for their decline appearsto be warm ocean currents circulating below the ice shelves and melting these from below. Ocean currentstransportwarm densewater ontothe shelf,channeledby bathymetric troughs leadingto the deep inner basins.A hydrographic mooring equipped with an upward-looking ADCP has been placed in one of these troughs onthe central Amundsen shelf. The two years (2010/11) of mooring data are here used to characterize the inflowof warm deep water to the deep shelf basins. During both years, the warm layer thickness and temperaturepeaked in austral fall. The along-trough velocity is dominated by strong fluctuations that do not vary in thevertical. These fluctuations are correlated with the local wind, with eastward wind over the shelf and shelfbreak giving flow toward the ice shelves. In addition, there is a persistent flow of dense lower CircumpolarDeep Water (CDW) toward the ice shelves in the bottom layer. This bottom-intensified flow appears to bedriven by buoyancy forces rather than the shelfbreak wind. The years of 2010 and 2011 were characterized bya comparatively stationary Amundsen Sea low, and hence there were no strong eastward winds during winterthat could drive an upwelling of warm water along the shelf break. Regardless of this, there was a persistentflow of lower CDW in the bottom layer during the two years. The average heat transport toward the iceshelves in the trough was estimated from the mooring data to be 0.95 TW.

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