Physical Properties and Structural-Stratographic Variations of Frazil, Platlet and Congelation Sea Ice, Ross Sea, Antarctica

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This project is an examination of the mechanical and structural properties of the antarctic ice pack in the Ross Sea, with the goal of defining the geographical variability of various ice types, the deformation processes that are active in the antarctic ice pack, and the large-scale thermodynamics and heat exchange processes of the ice-covered Southern Ocean. Four specific objectives have been defined for this project: (1) A determination of the fraction of frazil, platelet, and congelation ice of the Ross Sea pack ice; (2) an examination of differences in the salinities of these ice types, and a study of whether salinity variations are related to ice structure and stratigraphy; (3) a documentation of grain size and morphology variations in frazil and platelet ice and their relation to salinity differences; and (4) an investigation of the brine exclusion process, and how salt is lost from the sea ice. Differences in ice types are the result of differences in the environment in which the ice forms; frazil ice is formed in supercooled sea water, normally through wind or wave-induced turbulence, while platelet and congelation ice is formed under quiescent conditions. The fraction of frazil ice (which has been observed to be generally in excess of 50% in Weddell Sea ice floes) is an important variable in the energy budget of the upper ocean, and contributes to our understanding of the redistribution of salt, sediment, and micro-organisms in the ocean, and will improve our understanding of microwave and synthetic aperture radar images of sea ice to be obtained form a new generation of polar orbiting satellites.