Sound propagation around underwater seamounts
Sikora, Joseph J.
MetadataShow full item record
This thesis develops and utilizes a method for analyzing data from the North Pacific Acoustic Laboratory's (NPAL) Basin Acoustic Seamount Scattering Experiment (BASSEX). BASSEX was designed to provide data to support the development of analytical techniques and methods which improve the understanding of sound propagation around underwater seamounts. The depth-dependent sound velocity profile of typical ocean waveguides force sound to travel in convergence zones about a minimum sound speed depth. This ducted nature of the ocean makes modeling the acoustic field around seamounts particularly challenging, compared to an isovelocity medium. The conical shape of seamounts also adds to the complexity of the scatter field. It is important to the U.S. Navy to understand how sound is diffracted around this type of topographic feature. Underwater seamounts can be used to conceal submarines by absorbing and scattering the sound they emit. BASSEX measurements have characterized the size and shape of the forward scatter field around the Kermit-Roosevelt Seamount in the Pacific Ocean. Kermit- Roosevelt is a large, conical seamount which shoals close to the minimum sound speed depth, making it ideal for study. Acoustic sources, including M-sequence and linear frequency-modulated sources, were stationed around the seamount at megameter ranges. A hydrophone array was towed around the seamount to locations which allowed measurement of the perturbation zone. Results from the method developed in this thesis show that the size and shape of the perturbation zone measured coincides with theoretical and experimental results derived in previous work.
Submitted in partial fulfillment of the requirements for Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2005
Showing items related by title, author, creator and subject.
Forward sound propagation around seamounts : application of acoustic models to the Kermit-Roosevelt and Elvis seamounts Kim, Hyun Joe (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2009-06)The Basin Acoustic Seamount Scattering Experiment (BASSEX) of 2004 was conducted to measure forward-scattering around the Kermit-Roosevelt Seamount Complex in the Northeast Pacific. The BASSEX experiment was focused on ...
Cho, Walter W. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2008-09)The mechanisms of faunal dispersal across ocean basins are key unknowns toward understanding of the modern biogeography and biodiversity of deep-sea fauna. Seamounts are considered to play a defining role in faunal ...
Eustice, Ryan M. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2005-06)This thesis describes a vision-based, large-area, simultaneous localization and mapping (SLAM) algorithm that respects the low-overlap imagery constraints typical of autonomous underwater vehicles (AUVs) while exploiting ...