Angular dependence of 12‐kHz seafloor acoustic backscatter

The angular dependence of seafloor acoustic backscatter, measured with a 12‐kHz multi narrow‐beam echo‐sounder at two sites in the central North Pacific with water depths of 1500 and 3100 m, respectively, has been determined for incidence angles between 0° and 20°. The acoustic data consist of quadrature samples of the beamformed echoes received on each of the 16 2.66° beams of a Sea Beam echo‐sounder. These data are subjected to adaptive noise cancelling for sidelobe interference rejection, and the centroid of each echo is determined. After corrections for the ship’s roll and raybending effects through the water column, the angles of arrival are converted to angles of incidence by taking athwartships apparent bottom slopes into account. For each beam, the mean echo power received is normalized by the corresponding insonified area that depends on the transmit and receive beam patterns, the ship’s roll angle and the local bottom slope. For lack of system calibration, the data are presented as relative mean...

[1]  M. Noble,et al.  Physical, geological and biological studies on four Pacific seamounts: introduction , 1989 .

[2]  D. Alexandrou,et al.  Adaptive noise canceling applied to Sea Beam sidelobe interference rejection , 1988 .

[3]  J. J. Crisp,et al.  High‐frequency bottom backscatter measurements in shallow water , 1986 .

[4]  A. Ishimaru,et al.  Application of the composite roughness model to high‐frequency bottom backscattering , 1986 .

[5]  Christian de Moustier,et al.  Beyond bathymetry: Mapping acoustic backscattering from the deep seafloor with Sea Beam , 1986 .

[6]  Nicholas P. Chotiros,et al.  Acoustic backscattering at low grazing angles from the ocean bottom. Part I. Bottom backscattering strength , 1984 .

[7]  E. Hamilton,et al.  Sound velocity and related properties of marine sediments , 1982 .

[8]  W. Chesterman,et al.  Bottom Backscattering near Grazing Incidence in Shallow Water , 1968 .

[9]  C. Moustier.  Coastal and Ocean Mapping Center for Coastal and Ocean Mapping 7-1988 State of the Art in Swath Bathymetry Survey Systems , 2018 .

[10]  M. Gensane.  A statistical study of acoustic signals backscattered from the sea bottom , 1989 .

[11]  C. de Moustier,et al.  A fully transportable Sea Beam complex acoustic data acquisition system , 1987 .

[12]  Robert J. Urick,et al.  Principles of underwater sound , 1975 .

[13]  Charles D. Hollister,et al.  The Face of the Deep , 1971 .

[14]  C. McKinney,et al.  Measurements of Backscattering of Sound from the Ocean Bottom , 1964 .

[15]  R. Urick.  The Backscattering of Sound from a Harbor Bottom , 1954 .