Impact of atmospheric forcing on Antarctic continental shelf water masses

Petty, A. A., Feltham, D. L. ORCID: https://orcid.org/0000-0003-2289-014X and Holland, P. R. (2013) Impact of atmospheric forcing on Antarctic continental shelf water masses. Journal of Physical Oceanography, 43 (5). pp. 920-940. ISSN 0022-3670 doi: 10.1175/JPO-D-12-0172.1

Abstract/Summary

The Antarctic continental shelf seas feature a bimodal distribution of water mass temperature, with the Amundsen and Bellingshausen Seas flooded by Circumpolar Deep Water that is several degrees Celsius warmer than the cold shelf waters prevalent in the Weddell and Ross Seas. This bimodal distribution could be caused by differences in atmospheric forcing, ocean dynamics, ocean and ice feedbacks, or some combination of these factors. In this study, a highly simplified coupled sea ice–mixed layer model is developed to investigate the physical processes controlling this situation. Under regional atmospheric forcings and parameter choices the 10-yr simulations demonstrate a complete destratification of the Weddell Sea water column in winter, forming cold, relatively saline shelf waters, while the Amundsen Sea winter mixed layer remains shallower, allowing a layer of deep warm water to persist. Applying the Weddell atmospheric forcing to the Amundsen Sea model destratifies the water column after two years, and applying the Amundsen forcing to the Weddell Sea model results in a shallower steady-state winter mixed layer that no longer destratifies the water column. This suggests that the regional difference in atmospheric forcings alone is sufficient to account for the bimodal distribution in Antarctic shelf-sea temperatures. The model prediction of mixed layer depth is most sensitive to the air temperature forcing, but a switch in all forcings is required to prevent destratification of the Weddell Sea water column.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/34577
Identification Number/DOI	10.1175/JPO-D-12-0172.1
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	American Meteorological Society
Publisher Statement	© Copyright 2009 of the American Meteorological Society. The AMS Copyright Policy is available on the AMS web site at http://www.ametsoc.org.
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