Evaluation of the Magnetic Induction Conductivity Method for Detecting Frazil Ice Deposits

The ability to map frazil ice deposits and water channels beneath an ice-covered river in central Alaska using the magnetic induction conductivity (MI) technique has been assessed. The study was performed during the first week of March of 1986 on the Tanana River near Fairbanks and employed a commer...

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Bibliographic Details
Main Authors: Arcone, Steven A, Brockett, Bruce E, Lawson, Daniel E, Chacho, Edward F , Jr
Other Authors: COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH
Format: Text
Language:English
Published: 1987
Subjects:
Magnetic & Electric Fld Detection & Detectors
Snow
Ice and Permafrost
*MAGNETIC INDUCTION
*CHANNEL FLOW
*ICE FORMATION
ADVERSE CONDITIONS
ALASKA
ANTENNAS
CALIBRATION
CHANNELS
COLD WEATHER
CONDUCTIVITY
CROSS SECTIONS
FAIRBANKS(ALASKA)
FREQUENCY
GRAVEL
INSTRUMENTATION
MODELS
PHYSICAL PROPERTIES
POSITION(LOCATION)
PROFILES
RESISTANCE
RIVERS
SURVEYS
THEORY
WATER
MAGNETIC INDUCTION
WATER FLOW
UNDERICE
REMOTE DETECTORS
ERROR ANALYSIS
*Frazil ice
AST24
PE61102A
LPN-CWIS-31722
WU014
Fairbanks
Ice
permafrost
Alaska
Online Access:http://www.dtic.mil/docs/citations/ADA186940
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA186940
Description
Summary:The ability to map frazil ice deposits and water channels beneath an ice-covered river in central Alaska using the magnetic induction conductivity (MI) technique has been assessed. The study was performed during the first week of March of 1986 on the Tanana River near Fairbanks and employed a commercially available instrument operating at a fixed frequency with a fixed antenna (coil) spacing and orientation. Comparisons of the MI data with theoretical models based upon physical data measured along three cross sections of the river demonstrate the sensitivity of the MI technique to frazil ice deposits. The conductivity generally derived for the frazil ice deposits encountered is very low (approx. .00063 s/m) when compared with the measured value for water (approx. 0.011 S/m), and is similar to the calculated values for gravel and sandy gravel bed sediments. In all three cross sections, maxima in the apparent conductivity profiles correlated with frazil ice deposits. Difficulties, possibly due to adverse effects of cold weather upon instrument calibration, affected the quantitative performance of the instrument on one cross section, although the interpretation of the data (locations of open channels vs frazil deposits) was qualitatively unaffected. Keywords: Resistivity surveying.

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