van Vossen R, Ainslie MA. The effect of wind-generated bubbles on sea-surface backscattering at 940 Hz.
THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2011;
130:3413-3420. [PMID:
22088015 DOI:
10.1121/1.3626125]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Reliable predictions of sea-surface backscattering strength are required for sonar performance modeling. These are, however, difficult to obtain as measurements of sea-surface backscattering are not available at small grazing angles relevant to low-frequency active sonar (1-3 kHz). Accurate theoretical predictions of scattering strength require a good understanding of physical mechanisms giving rise to the scattering and the relative importance of these. In this paper, scattering from individual resonant bubbles is introduced as a potential mechanism and a scattering model is derived that incorporates the contribution from these together with that of rough surface scattering. The model results are fitted to Critical Sea Test (CST) measurements at a frequency of 940 Hz, treating the number of large bubbles, parameterized through the spectral slope of the size spectrum for bubbles whose radii exceed 1 mm, as a free parameter. This procedure illustrates that the CST data can be explained by scattering from a small number of large resonant bubbles, indicating that these provide an alternative mechanism to that of scattering from bubble clouds.
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