Cross-spectral analysis of midfrequency acoustic waves reflected by the seafloor

Laurent Guillon, Charles Holland, Christopher Barber

Research output: Contribution to journalReview article

2 Citations (Scopus)

Abstract

Direct path measurements of a single-bottom interacting path on a vertical array are used to probe the seabed structure. The phase of the cross-spectrum, commonly used in engineering acoustics, permits examination of the importance of subbottom paths. When the cross-spectral phase is linear with frequency it implies that source to receiver propagation is dominated by a single path. A linear cross-spectral phase would also satisfy the linear seabed reflection coefficient phase approximation sometimes employed in forward modeling and geoacoustic inversion approaches. Shallow water measurements of the cross-spectrum, however, evidence a strongly nonlinear phase, below about 1500 Hz at one site, and 600 Hz at another site, implying that: 1) the subbottom structure plays an important role (i.e., a seabed half-space approximation would be inappropriate); and 2) the linear reflection phase approximation would be violated at those frequencies.

Original languageEnglish (US)
Article number5766773
Pages (from-to)248-258
Number of pages11
JournalIEEE Journal of Oceanic Engineering
Volume36
Issue number2
DOIs
StatePublished - Apr 1 2011

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Spectrum analysis
Acoustic waves
Acoustics
Water

All Science Journal Classification (ASJC) codes

  • Ocean Engineering
  • Mechanical Engineering
  • Electrical and Electronic Engineering

Cite this

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abstract = "Direct path measurements of a single-bottom interacting path on a vertical array are used to probe the seabed structure. The phase of the cross-spectrum, commonly used in engineering acoustics, permits examination of the importance of subbottom paths. When the cross-spectral phase is linear with frequency it implies that source to receiver propagation is dominated by a single path. A linear cross-spectral phase would also satisfy the linear seabed reflection coefficient phase approximation sometimes employed in forward modeling and geoacoustic inversion approaches. Shallow water measurements of the cross-spectrum, however, evidence a strongly nonlinear phase, below about 1500 Hz at one site, and 600 Hz at another site, implying that: 1) the subbottom structure plays an important role (i.e., a seabed half-space approximation would be inappropriate); and 2) the linear reflection phase approximation would be violated at those frequencies.",
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Cross-spectral analysis of midfrequency acoustic waves reflected by the seafloor. / Guillon, Laurent; Holland, Charles; Barber, Christopher.

In: IEEE Journal of Oceanic Engineering, Vol. 36, No. 2, 5766773, 01.04.2011, p. 248-258.

Research output: Contribution to journalReview article

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