Low-frequency bottom backscattering data analysis using multiple constraints beamforming
MetadataShow full item record
The data analysis of a deep-sea bottom backscattering experiment, carried out over a sediment pond on the western flank of the Mid-Atlantic Ridge in July 1993 with a 250- 650 Hz chirp source and a vertical receiving array suspended near the fiat seafloor, is presented in this thesis. Reflected signals in the normal incidence direction as the output of endfire beamforming are used to determine the sediment structure. The sediment is found to be horizontally stratified, except for two irregular regions, each about 20 m t hick, located around 18 m and 60 m beneath the water-sediment interface. Multiple constraints beamforming is shown to be effective in removing coherent reflections from internal stratified layers, which is critical to the analysis of bottom backscattering. With backscattered signals obtained by beamforming, the above-mentioned two inhomogeneous regions are found to be the dominant factors on the bottom backscattered field, both in the normal incidence and oblique directions. The backscattering strength as a function of grazing angle is estimated for each of the two regions.
Submitted in partial fulfillment of the requirements for the degree of Ocean Engineer at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution May 1995
Showing items related by title, author, creator and subject.
Modeling of monostatic bottom backscattering from three-dimensional volume inhomogeneities and comparisons with experimental data Li, Dan (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1997-09)Acoustic propagation in the ocean inevitably encounters inhomogeneities of various types, which give rise to scattering. Acoustic scattering from rough water /bottom interfaces comprised of exposed rocks and sea mountains ...
Irish, James D.; Lynch, James F.; Newhall, Arthur E.; Witzell, Nick; Traykovski, Peter A.; Glenn, Scott M. (Woods Hole Oceanographic Institution, 1995-12)The NOAA National Underseas Research Program at Rutgers University is establishing a Long-term Ecosystem Observatory off New Jersey in 15 meters of water. As part of a bottom boundary layer study at this site, WHOI deployed ...
Chu, Dezhang; Stanton, Timothy K.; Pierce, Allan D. (Acoustical Society of America, 2007-12)A cw solution of acoustic diffraction by a three-sided semi-infinite barrier or a double edge, where the width of the midplanar segment is finite and cannot be ignored, involving all orders of diffraction is presented. The ...