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SHORT-PULSE RADAR INVESTIGATIONS OF FRESHWATER ICE SHEETS AND BRASH ICE

Short-pulse radar profiles and waveform traces were recorded over natural, freshwater ice sheets and an artificially made, 1.6-m-diameter column of brash ice. The purpose was to study the feasibility of this type of radar to detect ice thickness, determine ice properties and distinguish ice forms. The radar utilized two antennas: one with a spectrum centered near 900 MHz and a second more powerful one near 700 MHz. Distinct top and bottom reflections from several ice sheets were produced by both antennas, but the value of dielectric permittivity calculated from the time delay of the reflections varied between sheets as one ice sheet was ready to candle and contained free water. The brash ice distorted signals and allowed no discernible bottom return. The lower frequency antenna also gave returns from the lake bottom (separated from the ice bottom by about 1 m of water) which could allow ice thickness to be determined indirectly. The report concludes that these antennas can be used to determine sheet ice thickness and to supply information to help in the detection of brash ice. The water content of an ice sheet may also be estimated if independent sutdies show a correlation between dielectric permittivity and free water content.

  • Corporate Authors:

    U.S. Army Cold Regions Research and Engineering Laboratory

    72 Lyme Road
    Hanover, NH  United States  03755-1290

    Office of the Chief of Engineers

    Directorate of Military Programs
    Washington, DC  United States  20314
  • Authors:
    • Arcone, S A
    • Delaney, A J
    • Perham, R E
  • Publication Date: 1986-7

Media Info

  • Features: Figures; References;
  • Pagination: 15 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00461751
  • Record Type: Publication
  • Report/Paper Numbers: CRREL Rept. 86-6, CWIS 32284
  • Files: TRIS
  • Created Date: Jan 31 1987 12:00AM