Statistics of low-frequency normal-mode amplitudes in an ocean with random sound-speed perturbations : shallow-water environments
Colosi, John A.
Duda, Timothy F.
Morozov, Andrey K.
MetadataShow full item record
Second- and fourth-moment mode-amplitude statistics for low-frequency ocean sound propagation through random sound-speed perturbations in a shallow-water environment are investigated using Monte Carlo simulations and a transport theory for the cross-mode coherence matrix. The acoustic observables of mean and mean square intensity are presented and the importance of adiabatic effects and cross-mode coherence decay are emphasized. Using frequencies of 200 and 400 Hz, transport theory is compared with Monte Carlo simulations in a canonical shallow-water environment representative of the summer Mid-Atlantic Bight. Except for ranges less than a horizontal coherence length of the sound structure, the intensity moments from the two calculations are in good agreement. Corrections for the short range behavior are presented. For these frequencies the computed mode coupling rates are extremely small, and the propagation is strongly adiabatic with a rapid decay of cross-mode coherence. Coupling effects are predicted to be important at kilohertz frequencies. Decay of cross-mode coherence has important implications for acoustic interactions with nonlinear internal waves: For the case in which the acoustic path is not at glancing incidence with a nonlinear internal-wave front, adiabatic phase randomizing effects lead to a significantly reduced influence of the nonlinear waves on both mean and mean square intensity.
The article of record as published may be found at https://doi.org/10.1121/1.3666002
Showing items related by title, author, creator and subject.
2006 progress report on acoustic and visual monitoring for cetaceans along the outer Washington Coast Oleson, Erin M.; Hildebrand, John A.; Calambokidis, John; Schorr, Greg; Falcone, Erin (Monterey, California. Naval Postgraduate School, 2007); NPS-OC-07-003An acoustic and visual monitoring effort for cetaceans was initiated within the boundaries of the proposed expansion area for the Quinault Underwater Tracking Range in July 2004. Acoustic data collection consisted of ...
Coby, Weston R. T.; Fischer, Jacob A. (Monterey, California. Naval Postgraduate School, 2013-09);In 2009, a monthlong study was conducted in the Western Philippine Sea. This experiment collected oceanographic and acoustic data from two moorings, the Distributed Vertical Line Array (DVLA) and T1 moorings. The T1 mooring ...
Powers, John Patrick; Bahl, Rajendar (Monterey, California. Naval Postgraduate School, 1990-06); NPS-62-90-011A computer model of a high-resolution sector-scanning sonar used for imaging objects against the sea bottom is presented. The model accounts for the sonar parameters, bottom backscatter, reflections from the target's visible ...