Variability of Warm Deep Water Inflow in a Submarine Trough on the Amundsen Sea Shelf
Journal article, 2013

The ice shelves in the Amundsen Sea are thinning rapidly, and the main reason for their decline appears to be warm ocean currents circulating below the ice shelves and melting these from below. Ocean currents transportwarm 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 on the central Amundsen shelf. The two years (2010/11) of mooring data are here used to characterize the inflow of warm deep water to the deep shelf basins. During both years, the warm layer thickness and temperature peaked in austral fall. The along-trough velocity is dominated by strong fluctuations that do not vary in the vertical. These fluctuations are correlated with the local wind, with eastward wind over the shelf and shelf break giving flow toward the ice shelves. In addition, there is a persistent flow of dense lower Circumpolar Deep Water (CDW) toward the ice shelves in the bottom layer. This bottom-intensified flow appears to be driven by buoyancy forces rather than the shelfbreak wind. The years of 2010 and 2011 were characterized by a comparatively stationary Amundsen Sea low, and hence there were no strong eastward winds during winter that could drive an upwelling of warm water along the shelf break. Regardless of this, there was a persistent flow of lower CDW in the bottom layer during the two years. The average heat transport toward the ice shelves in the trough was estimated from the mooring data to be 0.95 TW.

ocean

Amundsen Sea

deep water velocity

surface wind

Author

Anna Wåhlin

University of Gothenburg

Ola Kalén

University of Gothenburg

Lars Arneborg

University of Gothenburg

Göran Björk

University of Gothenburg

Gisela Carvajal

Chalmers, Earth and Space Sciences, Radar Remote Sensing

Ho Kyung Ha

Korea Polar Research Institute

TaeWan Kim

Korea Polar Research Institute

Sang Hoon Lee

Korea Polar Research Institute

JaeHak Lee

Korea Institute of Ocean Science and Technology

Christian Stranne

University of Gothenburg

Journal of Physical Oceanography

0022-3670 (ISSN) 1520-0485 (eISSN)

Vol. 43 10 2054 - 2070

Subject Categories

Oceanography, Hydrology, Water Resources

DOI

10.1175/JPO-D-12-0157.1

More information

Created

10/6/2017