Ray-acoustic caustic formation and timing effects from ocean sound-speed relative curvature
MetadataShow full item record
KeywordPacific Ocean; Ray-tracing; Sound waves; Wave propagation; Pulses; Acoustics; Sound velocity; Depth profiles; Wave front; Fluctuations; Underwater
Using deterministic ray-acoustic modeling of 1000-km propagation in the North Pacific, a depth-dependent parameter of ocean sound channels has been found to strongly influence geometrical ray propagation. This parameter is the sound speed times the second vertical derivative of sound speed divided by the square of the first derivative. Ray and wavefront timing and intensity can be influenced within realistic ocean sound channels by unpredictable wavefront triplications and caustics. These triplications are associated with large values of the parameter at ray turning points. The parameter, a relative curvature, behaves as a random variable because of ocean finestructure, causing the unpredictability. The relative curvature has a higher mean value near the sound-speed minimum for both an internal-wave model and actual data, so that this mechanism is a plausible explanation of poor multipath resolution and identifiability late in North Pacific pulse trains.
Author Posting. © Acoustical Society of America, 1994. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 96 (1994): 1033-1046, doi:10.1121/1.410380.
Showing items related by title, author, creator and subject.
Observationally constrained modeling of sound in curved ocean internal waves: Examination of deep ducting and surface ducting at short range Duda, Timothy F.; Lin, Ying-Tsong; Reeder, D. Benjamin (Acoustical Society of America, 2011-09)A study of 400 Hz sound focusing and ducting effects in a packet of curved nonlinear internal waves in shallow water is presented. Sound propagation roughly along the crests of the waves is simulated with a three-dimensional ...
Low-frequency broadband sound source localization using an adaptive normal mode back-propagation approach in a shallow-water ocean Lin, Ying-Tsong; Newhall, Arthur E.; Lynch, James F. (Acoustical Society of America, 2012-02)A variety of localization methods with normal mode theory have been established for localizing low frequency (below a few hundred Hz), broadband signals in a shallow water environment. Gauss-Markov inverse theory is employed ...
Udovydchenkov, Ilya A.; Stephen, Ralph A.; Duda, Timothy F.; Bolmer, S. Thompson; Worcester, Peter F.; Dzieciuch, Matthew A.; Mercer, James A.; Andrew, Rex K.; Howe, Bruce M. (Acoustical Society of America, 2012-10)Data collected during the 2004 Long-range Ocean Acoustic Propagation Experiment provide absolute intensities and travel times of acoustic pulses at ranges varying from 50 to 3200 km. In this paper a subset of these data ...