Author(s): Fuko Sugimoto; Kazutaka Tateyama; Hiroyuki Enomoto; Kunio Shirasawa
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Keywords: Snow depth; Sea-ice thickness; Drilling; EM (ElectroMagnetic-inductive) measurement; Southern Ocean
Abstract: Ice-based electromagnetic-inductive (IEM) ice thickness measurements in conjunction with drilling, snow pit and ice coring programs were conducted during the Antarctic Remote Ice Sensing Experiment (ARISE) and the Sea Ice Physics and Ecosystems eXperiment (SIPEX) in the Antarctic seasonal ice-covered waters during the RSV Aurora Australis’cruises in September-October in 2003 and 2007, respectively. Drilling data indicate that on averaging drill-hole data over a transect of an ice floe, hydrostatic equilibrium nearly exists, although weight and buoyancy largely unbalance for an individual drill-hole with variable and uncertain snow and ice densities. Snow loading depresses buoyancy so that most likely flooding causes any slush formation and changes in snow and ice densities. The PDFs for snow depth appear distinct modes at 0.05 and 0.1 m for level ice in 2003 and 2007, respectively, but those for deformed ice show no distinct primary modes in both 2003 and 2007. Primary peaks are 0.75and 1.0 m in 2003 and 2007, respectively, for level ice thickness, and no distinct peaks appear in both 2003 and 2007 for deformed ice thickness. The relation between IEM and drill-hole total thickness shows a good agreement for level ice and in the range up to 2 m for deformed ice. By utilizing regression lines between snow depth and total thickness obtained from drilling, and IEM total thickness and drill-hole total thickness, IEM total thickness can be separated into snow depth and ice thickness.
Year: 2010