Acoustic inversion methods using ship noise
| dc.contributor.author | Morley, Michael G. | |
| dc.contributor.supervisor | Chapman, N. Ross | |
| dc.contributor.supervisor | Dosso, Stan E. | |
| dc.date.accessioned | 2007-10-24T23:29:19Z | |
| dc.date.available | 2007-10-24T23:29:19Z | |
| dc.date.copyright | 2007 | en_US |
| dc.date.issued | 2007-10-24T23:29:19Z | |
| dc.degree.department | School of Earth and Ocean Sciences | en_US |
| dc.degree.level | Master of Science M.Sc. | en_US |
| dc.description.abstract | In this thesis, acoustic inversion methods are employed to estimate array element locations and the geoacoustic properties of the seabed using measured acoustic data consisting of noise from a surface ship in the Gulf of Mexico. The array element localization utilizes relative travel-time information obtained by cross-correlating the recorded time series of ship noise received at spatially separated hydrophones. The relative travel-time data are used in an inversion, based on the regularized least-squares method and the acoustic ray tracing equations, to obtain improved estimates of the receiver and source positions and their uncertainties. Optimization and Bayesian matched-field inversion methods are employed to estimate seabed geoacoustic properties and their uncertainties in the vicinity of a bottom-moored vertical line array using the recorded surface ship noise. This study is used to test the feasibility of matched-field methods to detect temporal changes in the geoacoustic properties of the seabed near a known gas hydrate mound in the Gulf of Mexico. Finally, a synthetic study is performed that demonstrates how ignoring environmental range dependence of seabed sound speed and water depth in matched-field inversion can lead to biases in the estimated geoacoustic parameters. The study considers the distributions of optimal parameter estimates obtained from a large number of range-independent inversions of synthetic data generated for random range-dependent environments. Range-independent Bayesian inversions are also performed on selected data sets and the marginal parameter distributions are examined. Both hard- and soft-bottom environments are examined at a number of scales of variability in sound speed and water depth. | en_US |
| dc.identifier.uri | http://hdl.handle.net/1828/244 | |
| dc.language | English | eng |
| dc.language.iso | en | en_US |
| dc.rights | Available to the World Wide Web | en_US |
| dc.subject | Ocean acoustics | en_US |
| dc.subject | Matched-field inversion | en_US |
| dc.subject | Array element localization | en_US |
| dc.subject | Geoacoustic inversion | en_US |
| dc.subject | Bayesian inversion | en_US |
| dc.subject.lcsh | UVic Subject Index::Sciences and Engineering::Earth and Ocean Sciences::Geophysics | en_US |
| dc.title | Acoustic inversion methods using ship noise | en_US |
| dc.type | Thesis | en_US |