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dc.contributorUnited States. Department of Energy.-
dc.contributor.authorKovacs, Austin.-
dc.contributor.authorMorey, Rexford M.-
dc.descriptionCRREL Report-
dc.descriptionAbstract: Sounding of multi-year sea ice, using impulse radar operating in the 80- to 500-MHz frequency band, has revealed that the bottom of this ice cannot always be detected. This paper discusses a field program aimed at finding out why this is so, and at determining the electromagnetic (EM) properties of multi-year sea ice. It was found that the bottom of the ice could not be detected when the ice structure had a high brine content. Because of brlne's high conductivity, brine volume dominates the loss mechanism in first-year sea ice, and the same was found true for multi-year ice. A two-phase dielectric mixing formula. used by the authors to describe the EM properties of first-year sea ice, was modified to include the effects of the gas pockets found in the multi-year sea ice. This three-phase mixture model was found to estimate the EM properties of the multi-year ice studied over the frequency band of interest. The latter values were determined by: 1) vertical sounding to a subsurface target of known depth, where the two-way travel time of the EM wavelet in the ice is measured; 2) cross-borehole transmission. where the transit time of the EM wavelet is measured through a known thickness of sea ice; and 3) a wide-angle or common-depth-polnt reflection method. Preliminary findings also indicate that a representative value for the apparent bulk dielectric constant of multi-year sea ice over 2 and 1/2 m thick is 3.5. This represents an effective EM wavelet velocity of 0.16 m/ns, which may be used to estimate multi-year sea ice thickness in cases where the ice bottom is detected in ice profile data.-
dc.publisherCold Regions Research and Engineering Laboratory (U.S.)-
dc.publisherEngineer Research and Development Center (U.S.)-
dc.relation.ispartofseriesCRREL report ; 85-13.-
dc.rightsApproved for public release; distribution is unlimited.-
dc.sourceThis Digital Resource was created from scans of the Print Resource-
dc.subjectCold regions-
dc.subjectElectromagetic properties-
dc.subjectElectromagnetic measurements-
dc.subjectImpulse radar-
dc.subjectMarine geophysics-
dc.subjectSea ice-
dc.subjectSea ice measurement-
dc.titleElectromagnetic measurements of multi-year sea ice using impulse radar-
Appears in Collections:CRREL Report

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