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The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Sun, 14 Apr 2024 11:39:16 GMT2024-04-14T11:39:16ZCross-Spectral Analysis of Midfrequency Acoustic Waves Reflected by the Seafloor
http://hdl.handle.net/10985/8768
Cross-Spectral Analysis of Midfrequency Acoustic Waves Reflected by the Seafloor
GUILLON, Laurent; HOLLAND, Charles; BARBER, Christopher
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
Sat, 01 Jan 2011 00:00:00 GMThttp://hdl.handle.net/10985/87682011-01-01T00:00:00ZGUILLON, LaurentHOLLAND, CharlesBARBER, ChristopherDirect 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