Airborne Electromagnetic Sounding of Sea Ice Thickness and Sub-Ice Bathymetry

• Main Authors: Kovacs, Austin, Valleau, Nicholas C, Holladay, J S
• Other Authors: COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH
• Format: Text
• Language: English
• Published: 1987
• Subjects: Snow; Ice and Permafrost; Electrical and Electronic Equipment; *SEA ICE; *SOUNDING; AIRBORNE; ALASKA; ELECTRICAL CONDUCTIVITY; DEPTH; ELECTROMAGNETIC RADIATION; ELECTRONIC RECORDING SYSTEMS; FEASIBILITY STUDIES; HELICOPTERS; ICE; MODULES(ELECTRONICS); RESOLUTION; SEA WATER; SURFACES; THICKNESS; UNDERICE; ALTIMETERS; LASER APPLICATIONS; BATHYMETRY; TOPOGRAPHY; PROFILES; SURFACE PROPERTIES; AIRCRAFT ANTENNAS; REMOTE DETECTORS; MAGNET COILS; Multifrequency; Laser altimeters; Geophysical surveys; Electromagnetic sounding; AEM(Airborne Electromagnetic Measurements); PE63704N; Ice; permafrost; Prudhoe Bay; Sea ice; Alaska
• Online Access: http://www.dtic.mil/docs/citations/ADA188939; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA188939

A study was made in May 1985 to determine the feasibility of using an airborne electromagnetic sounding system for profiling sea ice thickness and the sub-ice water depth and conductivity. The study was made in the area of Prudhoe Bay, Alaska. The multifrequency airborne electromagnetic sounding system consisted of control and recording electronics and an antenna. The electronics module was installed in a helicopter, and the 7-m-long tubular antenna was towed beneath the helicopter at about 35 m above the ice surface. For this electromagnetic system, both first-year and second-year sea ice could be profiled, but the resolution of ice thickness decreased as the ice became rough. This decrease was associated with the large footprint of the system, which effectively smoothed out the sea ice relief. Under-ice water depth was determined, as was seawater conductivity. The results of the feasibility study were encouraging, and further system development is therefore warranted.