Document Type

Article

Publication Date

1-2013

DOI

10.1175/JPO-D-11-0237.1

Publication Title

Journal of Physical Oceanography

Volume

43

Issue

1

Pages

51-64

Abstract

Oceanic exchanges across the continental shelves of Antarctica play an important role in biological systems and the mass balance of ice sheets. The focus of this study is on the mechanisms responsible for the circulation of warm Circumpolar Deep Water (CDW) within troughs running perpendicular to the continental shelf. This is examined using process-oriented numerical experiments with an eddy-resolving (1 km) 3D ocean model that includes a static and thermodynamically active ice shelf. Three mechanisms that create a significant onshore flow within the trough are identified: 1) a deep onshore flow driven by the melt of the ice shelf, 2) interaction between the longshore mean flow and the trough, and 3) interaction between a Rossby wave along the shelf break and the trough. In each case the onshore flow is sufficient to maintain the warm temperatures underneath the ice shelf and basal melt rates of O(1 m yr−1). The third mechanism in particular reproduces several features revealed by moorings from Marguerite Trough (Bellingshausen Sea): the temperature maximum at middepth, a stronger intrusion on the downstream edge of the trough, and the appearance of warm anticyclonic anomalies every week. Sensitivity experiments highlight the need to properly resolve the small baroclinic radii of these regions (5 km on the shelf)-simulations at 3-km resolution cannot reproduce mechanism 3 and the associated heat transport.

Original Publication Citation

St-Laurent, P., Klinck, J.M., & Dinniman, M.S. (2013). On the role of coastal troughs in the circulation of warm circumpolar deep water on Antarctic shelves. Journal of Physical Oceanography, 43(1), 51-64. doi: 10.1175/JPO-D-11-0237.1

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