Theoretical model of in-plane scatter from a smooth sediment seabed

Journal of the Acoustical Society of America

Volumn 99, Issue 2, 1996, Pages 836-844

  Hines, Paul C ^a  

^a Defence Research Establishment Atlantic   (Canada)

Author keywords

[No Author keywords available]

Indexed keywords

ACOUSTICS; ARTICLE; MODEL; PRIORITY JOURNAL; SEA; SEDIMENT; SOUND;

EID: 0030063597     PISSN: 00014966     EISSN: None     Source Type: Journal    
DOI: 10.1121/1.414659     Document Type: Article

References (21)

1. P. C. Hines, "Theoretical Model of Acoustic Backscatter From a Smooth Seabed," J. Acoust. Soc. Am. 88, 324-334 (1990).
2. For water-saturated sediments the coupling to shear is poor and can safely be neglected as discussed in Ref. 3. Shear waves have been shown to be an important contributor to scattering in Ref. 4 but this was for the case of a hard (basalt) bottom
3. F. B. Jensen, W. A. Kuperman, M. B. Porter, and H. Schmidt, Computational Ocean Acoustics (AIP, New York, 1994). p. 40.
4. S. A. Swift and R. A. Stephen, "The Scattering of a Low-Angle Pulse Beam From Seafloor Volume Heterogeneities," J Acoust. Soc. Am. 96, 991-1002 (1994).
5. D R Jackson, A. M. Baird, J. J. Crisp, and P A. G. Thomson, "High-Frequency Bottom Backscatter Measurements in Shallow Water," J. Acoust. Soc. Am. 80, 1188-1199 (1986).
6. H. Boehme, N. P. Chotiros, L. D. Rolleigh, S. P. Pitt, A. L. Garcia, T. G. Goldsberry, and R. A. Lamb, "Acoustic Backscattering at Low Grazing Angles from the Ocean Bottom. Part I. Bottom Backscattering Strength," J. Acoust. Soc. Am. 77, 962-974 (1985).
7. A. W. Nolle, W. A. Hoyer, J. F. Mifsud, W. R. Runyan, and M. B. Ward, "Acoustic Properties of Water-Filled Sands," J. Acoust. Soc. Am. 35, 1394 (1963).
8. e in Eqs. (15a), (21), (22a), (27), and (28) of Ref. 1 should be negative. The author apologizes for the errors in Ref. 1.
9. In general, scattering results from fluctuations in acoustic wave speed and acoustic density. In water-saturated sediments, porosity is an effective variable to tie both quantities to a single variable. The upper frequency limit for this occurs when the acoustic wavelength begins to interrogate the bottom at length scales small enough such that the concept of porosity as a bulk property, is no longer meaningful. The low-frequency limit of the model is driven primarily by the morphology of the bottom. That is to say, so long as the bottom province doesn't change from say, mud to very large sand for example, thereby introducing nonstationarity into the porosity variable, the model's validity remains intact
10. A V. Il'in, "Principle Geomorphological Features in the Atlantic Ocean Bottom," in Sedimentation Conditions in the Atlantic Ocean (in Russian), edited by A. P. Lisitsin (Nauka, Moscow, 1971).
11. Yu. P. Lysanov, "Geoacoustic Model of the Upper Sediment Layer in Shallow Seas." Dokl. Akad. Nauk SSSR 251, 200 (1979).
12. J. H. Stockhausen, "Scattering from the Volume of an Inhomogeneous Half-Space," NRE Report, 63/9, 1963.
13. R. J. Urick, Principles of Underwater Sound (McGraw Hill, New York, 1975), 2nd ed.. p. 215.
14. E. L. Hamilton and R. T. Bachman, "Sound Velocity and Related Properties of Marine Sediments," J. Acoust. Soc. Am. 72, 1891 (1982).
15. M. Gensane, "Sea-Bottom Reverberation: The Role of Volume Inhomogeneities of the Sediment," in Proceedings of the Ocean Reverberation Symposium, SACLANT Center, 1992, edited by D. D. Ellis, J. R. Preston, and H. G. Urban (Kluwer Academic, Dordrecht, 1993), pp. 59-64.
16. 0 is a reference length of 1 mm.
17. Note that in the definition of scattering strength in Eq. (19), sound absorption in the water column has been ignored since losses never exceed 1 dB for the frequencies and ranges modeled here.
18. The incident grazing angle is measured from the horizontal plane to the incident wave direction. The scattered grazing angle is measured from the horizontal plane to the scattered refracted wave direction. (See Fig. 2).
19. This phenomenological comparison of the in-plane model to backscatter data is made because the author is unaware of any experimental data for either the fully bistatic or the in-plane geometry in the frequency band under examination.
20. L. E, Kinsler, A. R. Frey, A. B. Coppens, and J. V. Sanders, Fundamentals of Acoustics (Wiley, Singapore, 1982), 3rd ed., p. 125.
21. c.