Evaluation of a Portable Electromagnetic Induction Instrument for Measuring Sea Ice Thickness.

摘要

Field trials using a man-portable Geonics, Ltd., EM31 electromagnetic induction sounding instrument, with a plug-in data processing module, for the remote measurement of sea ice thickness, are discussed. The processing module was made by Flow Research Inc., to directly measure sea ice thickness and show the result in a numerical display. The EM31-processing module system was capable of estimating ice thickness within 10% of the true value for ice from about 0.7 to 3.5 m thick, the oldest undeformed ice in the study area. However, since seawater under the Arctic pack ice has a relatively uniform conductivity (2.5 + or - 0.05 S/m), a simplified method, which can be used for estimating sea ice thickness using jet an EM31 instrument, is discussed. It uses only the EM31's conductivity measurement, is easy to put into use and does not rely on theoretically derived look-up tables or phasor diagrams, which may not be accurate for the conditions of the area.