Salinity evolution and mechanical properties of snow-loaded multiyear sea ice near an ice shelf

• Published in: Antarctic science 2013-12, Vol.25 (6), p.821-831
• Main Authors: Gough, A.J., Mahoney, A.R., Langhorne, P.J., Haskell, T.G.
• Format: Article
• Language: English
• Subjects: Earth, ocean, space; Exact sciences and technology; External geophysics; Marine; Physical Sciences; Physics of the oceans; Sea ice
• ISSN: 0954-1020; 1365-2079
• DOI: 10.1017/S0954102013000217

Sea ice often forms attached to floating ice shelves. Accumulating snow can depress its freeboard, creating a flooded slush layer that may subsequently freeze to form snow ice, rejecting brine as it freezes. The resulting salinity profile determines the mechanical properties of the sea ice. We provide measurements of snow-loaded, multiyear sea ice from summer to winter. Brine from a slush layer is not completely expelled from the sea ice when the slush refreezes to form snow ice. Measurements of sea ice salinity and temperature indicate that the fate of this brine depends on the permeability of the sea ice below it. The sea ice in this study was also deformed by a nearby ice shelf over eleven years at a strain rate $$--> \dot{{\epsilon}} $$$ = (-8 ± 3) × 10-4 yr-1 (or 3 × 10-11 s-1). From transects of sea ice thickness and structure we estimate an effective Young's modulus at medium scales for sea ice mostly composed of snow ice of 0.1 GPa < E < 0.4 GPa, suggesting that this eleven year old sea ice cover has similar mechanical properties to warm first year sea ice. This is important for the parameterisations needed to simulate multiyear sea ice in the complex region near an ice shelf.