Observationally constrained modeling of sound in curved ocean internal waves: Examination of deep ducting and surface ducting at short range
Duda, Timothy F.
Reeder, D. Benjamin
MetadataShow full item record
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 parabolic equation computational code, and the results are compared to measured propagation along fixed 3 and 6 km source/receiver paths. The measurements were made on the shelf of the South China Sea northeast of Tung-Sha Island. Construction of the time-varying three-dimensional sound-speed fields used in the modeling simulations was guided by environmental data collected concurrently with the acoustic data. Computed three-dimensional propagation results compare well with field observations. The simulations allow identification of time-dependent sound forward scattering and ducting processes within the curved internal gravity waves. Strong acoustic intensity enhancement was observed during passage of high-amplitude nonlinear waves over the source/receiver paths, and is replicated in the model. The waves were typical of the region (35 m vertical displacement). Two types of ducting are found in the model, which occur asynchronously. One type is three-dimensional modal trapping in deep ducts within the wave crests (shallow thermocline zones). The second type is surface ducting within the wave troughs (deep thermocline zones).
The article of record as published may be found at https://doi.org/10.1121/1.3605565
Showing items related by title, author, creator and subject.
Reeder, D.B. (2014);Investigations of near-shore and in-shore environments have, rightly, focused on geological, thermodynamic and hydrodynamic parameters. A complementary acoustical characterization of the estuarine environment provides ...
Rogers, Jessica A. (Monterey, CA; Naval Postgraduate School, 2020-06);The James River Estuary hosts a salt wedge during its tidal cycle that is typical in estuarine environments but is atypical in its V-shape. Linear frequency-modulated acoustic signals in the 500–5000 Hz range were transmitted ...
Characterizing the Effects of Non-stationarity on the Marine Atmospheric Surface Layer during CASPER-West Ortiz-Suslow, David G.; Wang, Qing; Yamaguchi, Ryan (AMS, 2018-06-12);The Monin-Obukhov similarity theory (MOST) proposed that: given a logarithmic boundary layer, the gradients of the mean wind velocity, temperature, and water vapor within the surface layer are self-similar and universal ...