Extension of an Ice Shelf Water plume model beneath sea ice

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TitleExtension of an Ice Shelf Water plume model beneath sea ice with application in McMurdo Sound, AntarcticaAbstractA one-dimensional, frazil-laden plume model predicts the properties of Ice Shelf Water (ISW) as it evolves beneath sea ice beyond the ice shelf edge. An idealized background ocean circulation, which moves parallel to the plume, imitates forcings other than the plume's own buoyancy. The size distribution and concentration of the plume's suspended frazil ice crystals are affected by the background circulation velocity, the root-mean square tidal velocity, the drag coefficient, and the efficiency of secondary nucleation. Consequently, these variables are the key physical controls on the survival of supercooled water with distance from the ice shelf, which is predicted using several realistic parameter choices. Starting at 65 m thick, the in situ supercooled layer thins to 11Â±5 and 4+-3 m at distances of 50 and 100 km, respectively. We apply the extended model in McMurdo Sound, Antarctica, along the expected path of the coldest water. Three late-winter oceanographic stations along this path, in conjunction with historical data, provide initial conditions and evaluation of the simulations. Near the ice shelf in the western Sound, the water column consisted entirely of ISW, and the subice platelet layer thickness exceeded 5 m with platelet crystals dominating the sea ice structure suggesting that ISW persisted throughout winter. Presuming a constant ISW flux, the model predicts that the plume increases thermodynamic growth of sea ice by approximately 0.1 m yr-1 (~5 percent of the average growth rate) even as far as 100 km beyond the ice shelf edge. Copyright 2014. American Geophysical Union. All Rights Reserved.AcknowledgementsThis study was funded by a University of Otago Postgraduate Scholarship,the Kelly Tarlton's Antarctic Scholarship, and a University of Otago Research grant. We would like to thank Mike Williams from the National Institute of Water and Atmospheric Research (NIWA) for help in planning the oceanographic study and loan of the CTD profiler, Lars Smedsrud for providing us with the code for the SJ04 model, and Inga Smith and Natalie Robinson for their helpful discussion both as this study took shape and as this manuscript neared submission. Fieldwork logistics were provided by Antarctica New Zealand, and we are grateful to the other members of Event K063 who also took ice thickness measurements: AlexGough, Christian Haas, Dan Price,Justin Beckers, Kelvin Barnsdale, and Wolfgang Rack. The comments of two anonymous reviewers helped significantly improve this manuscript.The data archive associated with this paper can be found in the Global Change Master Directory under the keyword K063_20 11_2012_NZ_1.

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1st AuthorHughes, K.AuthorHughes, K.Langhorne, P.Leonard, G.Stevens, C.Year2014JournalJournal of Geophysical Research C: OceansVolume119Number12Pages8662-8687DOI10.1002/2013JC009411URLhttps://www.scopus.com/inward/recor.....18e527faa3511666153b31889Keywordsbuoyancydrag coefficientice crystalice movementice shelfmodel testnucleationoceanic circulationone-dimensional modelingplumesea icesize distributionthermodynamics, AntarcticaEast AntarcticaMcMurdo Sound, rank5Author Keywordsice shelf waterMcMurdo Soundplume modelsea ice growthProgrammeK131 - Sea Ice and Southern Ocean Processes

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TypeArticleCitationHughes, K., Langhorne, P., Leonard, G. and Stevens, C. (2014). Extension of an Ice Shelf Water plume model beneath sea ice with application in McMurdo Sound, Antarctica. Journal of Geophysical Research C: Oceans, 119(12): 8662-8687