Call number:
ZSP-201-89/2
In:
CRREL Report, 89-2
Description / Table of Contents:
A brash ice jam in the South Channel of the St. Clair River was profiled in February 1987 using a helicopter-borne short-pulse radar operating in the UHF band near 500 MHz. During the same time, measurements of the brash ice depth and water temperature were made from a Coast Guard icebreaker. The returned radar pulses consisted of a strong coherent reflection from the water surface, preceded (and followed) by incoherent returns from the brash ice. The measured waveform time delays were then converted to mean freeboard height of the brash ice pieces above the water surface. Given the mean freeboard height, an estimate of the total brash ice thickness was made. This estimate was greater than the range of the direct shipboard measurements. The difference is believed due to differences between ice porosity above and below the water line, to melting within the ice and to partial submergence of some of the surface pieces. It is concluded that this technique could be used for mapping relative brash ice depth if the complexities of automating waveform analysis could be overcome.
Type of Medium:
Series available for loan
Pages:
iv, 25 Seiten
,
Illustrationen
Series Statement:
CRREL Report 89-2
URL:
https://apps.dtic.mil/dtic/tr/fulltext/u2/a206868.pdf
URL:
https://hdl.handle.net/11681/9064
Language:
English
Note:
CONTENTS
Abstract
Preface
Introduction
Objectives and procedures
Equipment
Radar
Brash ice probe
Temperature measurements
St. Clair River ice conditions
Results and discussion
Thickness and temperature
Size distribution
Radar survey
Discussion of errors
Porosity
Phase state of the ice
Partial submergence of individual pieces
Spectra of reflected energy
Conclusions and recommendations
Literature cited
Appendix A: Laboratory verification of surface scattering from a simulated ice jam
Appendix B: Display of digitized and processed data
Location:
AWI Archive
Branch Library:
AWI Library
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