Forward Sound Propagation around Seamounts: Application of Acoustic Models to the Kermit-Roosevelt and Elvis Seamounts
Hyun Joe Kim, Ph.D., 2009
Arthur Baggeroer, Advisor
The Basin Acoustic Seamount Scattering Experiment (BASSEX) of 2004 was conducted to measure forward sound propagation around the Kermit-Roosevelt and the Elvis seamounts in the Northeast Pacific, focusing on bathymetric effects on sound propagation. In this thesis, the reconciliation between the measured broadband pulses and the simulated pulses using various two-dimensional (2D) and three-dimensional (3D) theoretical models is carried out to investigate the physical characteristics of the sound propagation around seamounts. First, the shadow and convergence zones behind the seamounts are explored using the 2D and 3D sound propagation models. Second, the broadband pulses using the 2D parabolic equation (PE) for the SPICEX source are reconciled with the measurement in the BASSEX experiment, which shows good correlation within the convergence zone. Those pulses are identified with the help of the 2D ray tracing method. Third, the 3D spectral coupled-mode model (W. Luo, PhD Thesis, MIT, 2007) is applied to sound propagation around the seamount showing wider shadow zone than the Nx2D computation. The increase of computational efficiency of the 3D spectral coupled-mode model is achieved using parallel computing. Through these analyses, we examine the characteristics of the sound propagation around the seamount as well as the limit of the application of the acoustic models.