A time-dependent model of the acoustic intensity backscattered by the seafloor is described and compared with data from a calibrated, vertically oriented, echo-sounder operating at 33 and 93 kHz. The model incorporates the characteristics of the echo-sounder and transmitted pulse, and the water column spreading and absorption losses. Scattering from the water–sediment interface is predicted using Helmholtz–Kirchhoff theory, parametrized by the mean grain size, the coherent reflection coefficient, and the strength and exponent of a power-law roughness spectrum. The composite roughness approach of Jackson et al. [J. Acoust. Soc. Am. 79, 1410–1422 (1986)], modified for the finite duration of the transmitted signal, is used to predict backscatter from subbottom inhomogeneities. It depends on the sediment’s volume scattering and attenuation coefficients, as well as the interface characteristics governing sound transmission into the sediment. Estimation of model parameters (mean grain size, roughness spectrum strength and exponent, volume scattering coefficient) reveals ambiguous ranges for the two spectral components. Analyses of model outputs and of physical measurements reported in the literature yield practical constraints on roughness spectrum parameter settings appropriate for echo-envelope-based sediment classification procedures.
REFERENCES
1.
National Defense Research Council, “Physics of sound in the sea,” Technical report, National Research Council, Peninsula Publishing, Los Altos, CA, 1946.
2.
R. J. Urick. Principles of Underwater Sound (McGraw-Hill, New York, 1983).
3.
D. R.
Jackson
, D. P.
Winebrenner
, and A.
Ishimaru
, “Application of the composite roughness model to high-frequency bottom backscattering
,” J. Acoust. Soc. Am.
79
(5
), 1410
–1422
(1986
).4.
C.
de Moustier
and D.
Alexandrou
, “Angular dependence of 12-kHz seafloor acoustic backscatter
,” J. Acoust. Soc. Am.
90
(1
), 522
–531
(1991
).5.
S. D.
Morgera
, “Signal processing for precise ocean mapping
,” IEEE J. Ocean. Eng.
OE-1
(2
), 49
–57
(1976
).6.
S. D.
Morgera
and R.
Sankar
, “Digital signal processing for precision wide-swath bathymetry
,” IEEE J. Ocean. Eng.
OE-9
(2
), 73
–84
(1984
).7.
M. V.
Berry
, “On deducing the form of surfaces from their diffracted echoes
,” J. Phys. A
5
, 272
–291
(1972
).8.
M. V.
Berry
, “The statistical properties of echoes diffracted from rough surfaces
,” Philos. Trans. R. Soc. London, Ser. A
273
, 611
–654
(1973
).9.
M. V.
Berry
and T. M.
Blackwell
, “Diffractal echoes
,” J. Phys. A
14
, 3101
–3110
(1981
).10.
N. F.
Haines
and D. B.
Langston
, “The reflection of ultrasonic pulses from surfaces
,” J. Acoust. Soc. Am.
67
(5
), 1443
–1454
(1980
).11.
E. H. Nesbitt, “Estimation of sea bottom parameters using acoustic backscattering at vertical incidence,” Master’s thesis, University of Washington, 1988.
12.
D. R.
Jackson
and E.
Nesbitt
, “Bottom classification using backscattering at vertical incidence
,” J. Acoust. Soc. Am.
Suppl. 1 83
, S80
(1988
).13.
E.
Pouliquen
and X.
Lurton
, “Identification de la nature du fond de la mer à l’aide de signaux d’écho-sondeurs. I. Modélisation d’échos réverbérés par le fond
,” Acta Acust. European Acoustics Assoc.
2
(2
), 113
–126
(1994
).14.
X.
Lurton
and E.
Pouliquen
, “Identification de la nature du fond de la mer à l’aide de signaux d’écho-sondeurs. II. Méthode d’identification et résulatats experimentaux
,” Acta Acust. European Acoustics Assoc.
2
(3
), 187
–194
(1994
).15.
R.
Chivers
, N.
Emerson
, and D. R.
Burns
, “New acoustic processing for underway surveying
,” Hydrographic J.
56
, 9
–17
(1990
).16.
A. S. Tsehmahman, W. T. Collins, and B. T. Prager, “Acoustic seabed classification and correlation analysis of sediment properties by QTC view,” in Proceedings of IEEE OCEANS 97, pp. 921–926, 1997.
17.
E. L.
Hamilton
, “Geoacoustic modeling of the sea floor
,” J. Acoust. Soc. Am.
68
(5
), 1313
–1340
(1980
).18.
E. L.
Hamilton
and R. T.
Bachman
, “Sound velocity and related properties of marine sediments
,” J. Acoust. Soc. Am.
72
(6
), 1891
–1904
(1982
).19.
Applied Physics Laboratory. High-Frequency Ocean Environmental Acoustic Models Handbook. Technical report APL-UW TR9407 AEAS 9501, University of Washington, 1994.
20.
D. D.
Sternlicht
and C. P.
de Moustier
, “Remote sensing of sediment characteristics by optimized echo envelope matching
,” J. Acoust. Soc. Am.
114
, 2727
–2743
(2003
).21.
A. Ishimaru, Wave Propogation and Scattering in Random Media (Academic, New York, 1978), Vol. 2.
22.
T. H.
Bell
, Jr., “Statistical features of sea-floor topography
,” Deep-Sea Res. Oceanogr. Abstr.
22
, 883
–892
(1975
).23.
J. M.
Berkson
and E.
Matthews
, “Statistical characterization of seafloor roughness
,” IEEE J. Ocean. Eng.
OE-9
(1
), 48
–51
(1984
).24.
C. G.
Fox
and C. E.
Hayes
, “Quantitative methods for analyzing the roughness of the seafloor
,” Rev. Geophys.
23
(1
), 1
–48
(1985
).25.
D. R.
Jackson
, J. J.
Crisp
, and P. A.
Thompson
, “High-frequency bottom backscatter measurements in shallow water
,” J. Acoust. Soc. Am.
80
(4
), 1188
–1199
(1986
).26.
K. B.
Briggs
, “Microtopgraphical roughness of shallow-water continental shelves
,” IEEE J. Ocean. Eng.
14
(4
), 360
–367
(1989
).27.
D. R.
Jackson
and K. B.
Briggs
, “High-frequency bottom backscattering: Roughness versus sediment volume scattering
,” J. Acoust. Soc. Am.
92
(2
), 962
–977
(1992
).28.
D. R.
Jackson
, K. B.
Briggs
, K. L.
Williams
, and M. D.
Richardson
, “Test of models for high-frequency seafloor backscatter
,” IEEE J. Ocean. Eng.
21
(4
), 458
–470
(1996
).29.
E. L.
Hamilton
, “Compressional wave attenuation in marine sediments
,” Geophysics
37
, 620
–646
(1972
).30.
A. N.
Ivakin
and Y. P.
Lysanov
, “Underwater sound scattering by volume inhomogeneities of a bottom medium bounded by a rough surface
,” Sov. Phys. Acoust.
27
(3
), 212
–215
(1981
).31.
J. H. Stockhausen, “Scattering from the volume of an inhomogenous half-space,” Technical Report 63/9, Naval Research Establishment, Dartmouth, N.S., Canada, August 1963.
32.
S. T.
McDaniel
and A. D.
Gorman
, “An examination of the composite-roughness scattering model
,” J. Acoust. Soc. Am.
73
(5
), 1476
–1486
(1983
).33.
J. E.
Moe
and D. R.
Jackson
, “Near-field scattering through and from a two-dimensional fluid–fluid rough interface
,” J. Acoust. Soc. Am.
103
(1
), 275
–287
(1998
).34.
P. Beckmann and A. Spizzichino, The Scattering of Electromagnetic Waves from Rough Surfaces (Macmillan, New York, 1963).
35.
L. M. Brekhovskikh and Y. P. Lysanov, Fundamentals of Ocean Acoustics, 2nd ed. (Springer, Berlin, 1991).
36.
L. A. Chernov, Wave Propagation in a Random Medium, Part 2 (McGraw-Hill, New York, 1960).
37.
D. Tang, “Small scale volumetric inhomogeneities of shallow water sediments: Measurements and discussion,” in High Frequency Acoustics in Shallow Water, CP-45, pp. 539–546, Lerici, Italy, July 1997. NATO SACLANT Undersea Research Centre.
38.
J. A.
Ogilvy
, “Computer simulation of acoustic wave scattering from rough surfaces
,” J. Phys. D
21
, 260
–277
(1988
).39.
J. A. Ogilvy, Theory of Wave Scattering from Random Rough Surfaces (IOP, London, 1991).
40.
D. D. Sternlicht, “High Frequency Acoustic Remote Sensing of Seafloor Characteristics,” Ph.D. thesis, University of California, San Diego, 1999.
41.
S.
Stanic
, K. B.
Briggs
, P.
Fleischer
, W. B.
Sawyer
, and R. I.
Ray
, “High-frequency acoustic backscattering
,” J. Acoust. Soc. Am.
85
(1
), 125
–136
(1989
).42.
S.
Stanic
, K. B.
Briggs
, P.
Fleischer
, R. I.
Ray
, and W. B.
Sawyer
, “Shallow-water high-frequency bottom scattering off Panama City, Florida
,” J. Acoust. Soc. Am.
83
(6
), 2134
–2144
(1988
).43.
D. D. Sternlicht and C. P. de Moustier, “Stacking and averaging techniques for bottom echo characterization,” in Proceedings: 16th International Congress on Acoustics and 135th Meeting Acoustical Society of America, Vol. IV, pp. 3023–3024, Seattle, Washington, June 1998.
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