scholarly journals Electromagnetic Induction Sounding of Sea Ice Thickness

1996 ◽  
Author(s):  
Austin Kovacs ◽  
Deborah Diemand ◽  
John J. Bayer ◽  
Jr
Keyword(s):  
Sea Ice ◽  
Electromagnetic Induction ◽  
Ice Thickness ◽  
Sea Ice Thickness ◽  
Induction Sounding

Sounding sea ice thickness using a portable electromagnetic induction instrument

Geophysics ◽  
1991 ◽  
Vol 56 (12) ◽  
pp. 1992-1998 ◽  
Author(s):  
Austin Kovacs ◽  
Rexford M. Morey
Keyword(s):  
Sea Ice ◽  
Electromagnetic Induction ◽  
Direct Determination ◽  
Conductivity Measurement ◽  
Field Trials ◽  
The Arctic ◽  
Ice Thickness ◽  
Remote Measurement ◽  
Sea Ice Thickness ◽  
Processing Module

Field trials using a man‐portable, commercially available, electromagnetic induction (EMI) sounding instrument, with a plug‐in data processing module for the remote measurement of sea ice thickness, are discussed. The processing module was made to allow for the direct determination of sea ice thickness and to show the result in a numerical display. The processing module system was capable of estimating ice thickness within 10 percent of the the true ice value for ice from about 0.7 to 3.5 m thick, the thickest of undeformed ice in our study area. However, since seawater under the Arctic pack ice has relatively uniform conductivity (2.55 ± 0.05 S/m), a simplified method can be used for estimating sea ice thickness using just an EMI instrument. This technique uses only the EMI 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.

The footprint/altitude ratio for helicopter electromagnetic sounding of sea‐ice thickness: Comparison of theoretical and field estimates

Geophysics ◽  
1995 ◽  
Vol 60 (2) ◽  
pp. 374-380 ◽  
Author(s):  
Austin Kovacs ◽  
J. Scott Holladay ◽  
Clyde J. Bergeron
Keyword(s):  
Sea Ice ◽  
Ice Thickness ◽  
Remote Measurement ◽  
Sea Ice Thickness ◽  
Airborne Measurements ◽  
Sensing Technology ◽  
Induction Sounding ◽  
Coil Antenna ◽  
Ice Water ◽  
Lateral Variations

Helicopter‐towed electromagnetic (HEM) induction sounding systems are typically used for geologic surveys. More recently, HEM systems have been used for the remote measurement of sea‐ice thickness and shallow sea bathymetry. An important aspect of this remote sensing technology is the area, or footprint, in which the secondary field is predominantly generated by induced currents. A knowledge of the size of the footprint is important to understanding the accuracy of HEM sounding results over lateral variations in relief or conductivity. Conventional wisdom among workers in the field held that the footprint diameter is a few times the HEM antenna altitude. We confirm this view using airborne measurements over sea ice to calculate the footprint size/antenna altitude ratio. These findings are compared to various theoretical estimates and are found to be in reasonable agreement. For a vertical coaxial coil antenna arrangement, the apparent footprint diameter was found to be about 1.3 times the antenna height above the sea‐ice/water interface, and for a horizontal coplanar coil figuration the ratio is about 3.8 times the antenna height.

scholarly journals Ship-borne electromagnetic induction Sounding of Sea-ice thickness in the Southern Sea of Okhotsk

2006 ◽  
Vol 44 ◽  
pp. 253-260 ◽  
Author(s):  
Shotaro Uto ◽  
Takenobu Toyota ◽  
Haruhito Shimoda ◽  
Kazutaka Tateyama ◽  
Kunio Shirasawa
Keyword(s):  
Sea Ice ◽  
Sea Of Okhotsk ◽  
Theoretical Calculations ◽  
Multilayered Structure ◽  
Ice Thickness ◽  
Total Thickness ◽  
Sea Ice Thickness ◽  
Inductive Instrument ◽  
The Difference ◽  
Induction Sounding

AbstractRecent observations have revealed that dynamical thickening is dominant in the growth process of Sea ice in the Southern Sea of Okhotsk. That indicates the importance of understanding the nature of thick deformed ice in this area. The objective of the present paper is to establish a Ship-based method for observing the thickness of deformed ice with reasonable accuracy. Since February 2003, one of the authors has engaged in the core Sampling using a Small basket from the icebreaker Soya. Based on these results, we developed a new model which expressed the internal Structure of pack ice in the Southern Sea of Okhotsk, as a one-dimensional multilayered Structure. Since 2004, the electromagnetic (EM) inductive Sounding of Sea-ice thickness has been conducted on board Soya. By combining the model and theoretical calculations, a new algorithm was developed for transforming the output of the EM inductive instrument to ice + Snow thickness (total thickness). Comparison with total thickness by drillhole observations Showed fair agreement. The probability density functions of total thickness in 2004 and 2005 Showed Some difference, which reflected the difference of fractions of thick deformed ice.

Sea‐ice thickness measurement using a small airborne electromagnetic sounding system

Geophysics ◽  
1990 ◽  
Vol 55 (10) ◽  
pp. 1327-1337 ◽  
Author(s):  
A. Kovacs ◽  
J. S. Holladay
Keyword(s):  
Sea Ice ◽  
Current Model ◽  
Field Evaluation ◽  
Field Testing ◽  
Thickness Measurement ◽  
Ice Thickness ◽  
Sea Ice Thickness ◽  
Pressure Ridge ◽  
Ice Floes ◽  
Induction Sounding

The evaluation of a small electromagnetic induction sounding system for use in airborne measurement of sea‐ice thickness is discussed, as are the results from arctic field testing. Also outlined are the system noise and drift problems encountered during arctic field evaluation, problems which adversely affected the quality of the sounding data. The sea‐ice sounding results indicate that for ice floes with moderate relief it should be possible to determine thickness to within 5 percent, but that because of sounding footprint size and current model algorithm constraints, steep‐sided pressure ridge keels cannot be well defined. The findings also indicate that with further system improvement the day of routine sea‐ice thickness profiling from an airborne platform is close at hand.

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