Ocean Acoustic Propagation and Coherence
Abstract
Studies of fluctuating underwater sound propagation in complex 4-D variable environments are proposed. The main approach is to use t,heoretical and computational methods to describe propagation behavior, including comparison with available data. Typically our group, studies the acoustics of ocean processes and features that are common throughout the worlds ocean (e.g., effects on nonlinear inte,rnal waves on sound), but that approach will be combined in this project with focused effort on bottom-interacting sound and high-la,titude sound. Targets for study are the effects of internal tides, intermittent internal waves, eddy fields, fronts and their intrus,ions (including in the Canada Basin and the far north NORSE project area), including how these processes affect sound in regimes of,complicated seafloor interaction, including slopes and canyons. Goals are to understand mean acoustic field patterns, variation betw,een realizations, fluctuation statistics, horizontal coherency of realizations, and reliability of derived quantities like direction, to source or range rate of source. Task areas are: (1) Set up a source to supplement sound propagation data in the ONR NORSE progra,m in Oct-Nov 2022, to model propagation in the NORSE area, and to collaboratively examine data obtained by other PIs in that program,. (2) Continue studies of the details of the upper ocean environment in the Canada Basin/Beaufort Sea area, and studies of the sound, propagation physics under those conditions. (3) Further study sound temporal variations in canyons filled with internal waves, incl,uding study of fluctuating direction of arrival results from synthetic signal beamforming, and quantification of biases and errors f,or direction finding. (4) Study striation patterns of frequency-range plots from sound simulations, and find relationships between p,attern stability, pattern reversals, and sound channel conditions. (5) Study how sound propagation in environments with multiple fac,tors influencing sound (mode-stripping bottom interaction, out-of-plane reflection from steep bathymetry, internal tidal thermocline, heaving, a meandering curved front) depends on the whole environment for realistic prediction of the mean sound field and fluctuati,ons, or whether effects from individual processes can be separately computed and combined to form the complete picture to sufficient, accuracy.Approved for public release
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 13, 2022
- Source ID
- N000142212547
Entities
People
- Timothy F Duda
Organizations
- Office of Naval Research
- United States Navy
- Woods Hole Oceanographic Institution