Articles | Volume 12, issue 2
https://doi.org/10.5194/os-12-507-2016
https://doi.org/10.5194/os-12-507-2016
Research article
 | 
06 Apr 2016
Research article |  | 06 Apr 2016

Turbulent heat transfer as a control of platelet ice growth in supercooled under-ice ocean boundary layers

Miles G. McPhee, Craig L. Stevens, Inga J. Smith, and Natalie J. Robinson

Abstract. Late winter measurements of turbulent quantities in tidally modulated flow under land-fast sea ice near the Erebus Glacier Tongue, McMurdo Sound, Antarctica, identified processes that influence growth at the interface of an ice surface in contact with supercooled seawater. The data show that turbulent heat exchange at the ocean–ice boundary is characterized by the product of friction velocity and (negative) water temperature departure from freezing, analogous to similar results for moderate melting rates in seawater above freezing. Platelet ice growth appears to increase the hydraulic roughness (drag) of fast ice compared with undeformed fast ice without platelets. Platelet growth in supercooled water under thick ice appears to be rate-limited by turbulent heat transfer and that this is a significant factor to be considered in mass transfer at the underside of ice shelves and sea ice in the vicinity of ice shelves.

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Short summary
Measurements of turbulent heat fluxes in tidally modulated flow of supercool seawater under Antarctic land-fast sea ice show that turbulent heat exchange at the ocean–ice boundary is characterized by the product of friction velocity and (negative) water temperature departure from freezing. Also, the conditions cause platelet ice growth to form on the underside of the sea ice which increases the hydraulic roughness (drag) of fast ice compared to ice without platelets.