Author(s): Bard Blaesterdalen; David Wrangborg; Aleksey Marchenko; Knut V. Hoyland
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Abstract: Growth and permeability of coastal ice are discussed using results from a fieldwork conducted in Van Mijenfjorden, Svalbard during the winter season of 2014. A number of measurements, including ice thickness and temperature recordings, were performed in the partly grounded coastal ice and the free-floating ice. The coastal ice was found to be warmer and grow quicker than the free-floating ice, a consequence of frequent flooding and creation of superimposed ice. The largest recorded ice thicknesses were 84 cm and 171 cm in the free-floating ice and the hinge zone, respectively. In February/March tidal movement caused a column of water/brine to oscillate within the highly permeable coastal ice. Later the ice got colder and the motion wasstopped, presumably by a disconnection of the brine network in the less saline top part of the ice. Calculated average permeability was then 1.1·10 m, one order of magnitude larger than thepercolation threshold given by the so-called “law of fives”. Rapid brine flow and varying air content in the upper part of the ice are expected to have caused certain errors in the calculations of permeability.
Year: 2016