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Author Schmidt, H.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword GEOSCIENCES ♦ ARCTIC REGIONS ♦ ACOUSTIC MEASUREMENTS ♦ ICE ♦ SOUND WAVES ♦ MULTIPLE SCATTERING ♦ FREQUENCY DEPENDENCE ♦ ELASTICITY
Abstract This paper investigates the three-dimensional acoustic scatter from large-scale features under the Arctic ice cover using field data collected during the CEAREX experiments in April 1989. The analysis involves the identification and isolation of the features under the ice canopy, and the simultaneous evaluation of their spatial scattering characteristics. A two-step matched-field processing (MFP) algorithm is used to solve this complex multiparameter estimation problem. Using one large ({approximately}1200m) and four short ({approximately}300m) vertical line arrays, and a crossed horizontal hydrophone array in a matched-field processing scheme, beamforming under the ice sheet was performed to obtain an approximate map of the rough interface between ice and water. This analysis yields estimates for scattering strengths for frequencies ranging between 25 and 105 Hz. It is shown that scatter from the elastic ice surface is a frequency selective phenomenon. This beamformed map is then used to isolate a single discrete scatterer, and subsequently, its scattering characteristics are evaluated. Simultaneously, an idealized environmental model is developed to compute scatter from a canonical protuberance. Matching the theoretical results from the analytical model with the experimental data, which consists of contributions from multiple scatterers, yields the statistics of the distribution of ice protuberances. {copyright} {ital 1997 Acoustical Society of America.}
ISSN 00014966
Educational Use Research
Learning Resource Type Article
Publisher Date 1997-08-01
Publisher Place United States
Journal Journal of the Acoustical Society of America
Volume Number 102
Issue Number 2


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