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TitleThe seasonal appearance of ice shelf water in coastal Antarctica and its effect on sea ice growth
Publication TypeJournal Article
Year of Publication2011
AuthorsMahoney, A.R., Gough A.J., Langhorne P.J., Robinson N.J., Stevens C.L., Williams M.M.J., and Haskell T.G.
JournalJournal of Geophysical Research: Oceans
Date Published2011
ISSN21699291 (ISSN)
KeywordsAntarctica, coastal zone, crystal structure, Crystallographic analysis, crystallography, East Antarctica, First-year, Freezing, Growth enhancement, Ice growth, ice shelf, Ice shelf waters, Land-fast, McMurdo Sound, mooring system, Ocean profiles, photography, polynya, salinity, Salt flux, Sea ice, Sea ice growth, seasonality, supercooling, Surface freezing, Water column, Water columns
AbstractIn this paper we report measurements from the first year-round mooring underneath sea ice in McMurdo Sound, Antarctica, which we combine with full-depth ocean profiles to identify the incremental appearance of potentially supercooled ice shelf water (ISW). We investigate the effects of ISW on sea ice using observations of sea ice growth and crystal structure together with under-ice photography. We show that the appearance of ISW at the surface leads to a disruption in the columnar texture of the sea ice, but that persistent growth enhancement occurs only once the entire water column has cooled to the surface freezing point. In doing so, we demonstrate the possibility of inferring the presence of ISW beneath sea ice through crystallographic analysis of cores. These findings will be useful for both modeling and observing the extent of ISW-enhanced ice growth. In addition, we found that the local growth of first-year landfast sea ice only accounted for half of the observed increase in salinity over the water column, which indicates that polynyas are responsible for approximately half of the salt flux into McMurdo Sound. Copyright 2011 by the American Geophysical Union.

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