Experimental and Numerical Studies of Sound Propagation Over a Submarine Canyon Northeast of Taiwan

Lin, Ying‐Tsong; Duda, Timothy F.; Emerson, Chris; Gawarkiewicz, Glen; Newhall, Arthur E.; Calder, Brian R.; Lynch, James F.; Abbot, Philip; Yang, Yiing Jang; Jan, Sen

doi:10.1109/joe.2013.2294291

Cited by 18 publications

(9 citation statements)

References 20 publications

(27 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The high variability is consistent with the strong currents, barotropic tides, and internal waves. A canyon acoustics paper (Lin et al, 2013) finds weak point-to-point navigated sound transmission in a canyon that does not agree with 3D model predictions. It may be that the bathymetry that governs the spatial TL pattern in the model is not correct, or internal waves cause the sound to be deflected away from the receiver.…”

Section: Shallow-water Effort Qpementioning

confidence: 95%

See 1 more Smart Citation

Experimentally-Based Ocean Acoustic Propagation and Coherence Studies

Duda¹

2013

Self Cite

View full text Add to dashboard Cite

The goal is to better understand fluctuating sound propagation in two distinct ocean acoustic regimes: Stratified shallow water, where sound is highly bottom interacting, and the temperate deep-ocean sound channel. Acoustic field fluctuations have time scales varying from less than a minute to hours, and horizontal spatial scales from tens of meters to kilometers, comparable to processing time scales and system spatial scales, and thus impact exploitation of underwater sound. With proper understanding, reliable predictions of temporal and spatial variability of received underwater sound may be possible, thus improving processing and handling of signals of interest. Processing could include remediation of signal degradation and/or exploitation of available sonic information. OBJECTIVES An objective is to quantify and explain underwater sound fluctuation behavior that has been observed in both shallow and deep regimes, for the purpose of meeting the stated goals. For shallow water, transmission loss and phase data are available at frequencies from 50 to 3000 Hz. For the deep-ocean sound channel, data are in hand for propagation at 50 to 100 Hz over 100's to 1000's of kilometers. Propagation and forward scattering models, both theoretical and computational, will be used to test hypotheses regarding the origin of signal variations. Therefore, making better models is a second (enabling) objective. APPROACH The approach toward understanding the fundamentals of ocean sound propagation variability in numerous environmental regimes is to study the propagation together with the local environmental conditions. First, acoustically important features, such as nonlinear internal waves in the shallow seas and quasi-homogeneous internal waves in the deep seas, must be identified in the coupled studies. Next, the acoustic phenomena caused by those features are studied in detail, to identify the feature properties that are relevant to acoustics. Next, those properties are investigated, with a purpose of extrapolating (predicting) acoustic behavior in parameter regimes that may not have been encountered. The investigations of physical ocean phenomena that are critical to this approach are likely to differ from studies of the features motivated by other branches of ocean science, such as studies of biogeochemical/physical cycling, fisheries, or climate.

show abstract

Section: Shallow-water Effort Qpementioning

confidence: 95%

“…One paper covered acoustic signals transmitted from an OASIS Inc. Mobile Acoustic Source (OMAS) to three receivers located near the west branch of North Mien Hua Canyon (Lin et al, 2013). The frequency range is 800-1000 Hz.…”

Section: Shallow Water Effortmentioning

confidence: 99%

Experimentally-Based Ocean Acoustic Propagation and Coherence Studies

Duda¹

2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…An axially independent two-dimensional (Nx2-D) and a 3-D PE model using the split-step Fourier algorithm with a wide-angle PE approximation was used to calculate the pressure fields in this study (Lin et al, 2013;Lin et al, 2015). The 3-D model solves the forward propagating PE equation simplified from the Helmholtz wave equation by neglecting backward propagating energy in a cylindrical coordinate system with a one-way marching algorithm originating from the source position, allowing horizontal propagation between radial marching directions.…”

Section: Three-dimensional Ambient Noise Field Modellingmentioning

confidence: 99%

Mapping of surface-generated noise coherence

2022

Self Cite

View full text Add to dashboard Cite

The performance of a hydrophone array can be evaluated by its coherent gain, which depends on the spatial correlation of both the signal of interest and the background noise between different array elements, where one hopes to maximize the former while minimizing the latter with array signal processing. In this paper, a computational vertical noise coherence map of the first zero-crossing is generated near Alvin Canyon, south of Martha’s Vineyard, Massachusetts, to study its dependence on the spatial variation in bathymetry, water column sound speed and sediment type. A two and three-dimensional Parabolic Equation propagation model based on reciprocity theory were used for the simulation. The results showed that the seabed parameters have the greatest impact on vertical noise coherence at the array location in the Alvin Canyon area, when compared to 3-D bathymetric and water column sound speed profile variability, especially in the shallower water. The analysis reveals the ideal spacing for a vertical hydrophone array for better signal detection in acoustic experiments. In the continental shelf and slope regions, the ideal spacing lies between 3λ⁄8 in deep water and λ⁄2 in shallow water, and for areas with strong bathymetric variations the ideal spacing can be determined by comprehensive numerical models.

show abstract

“…The wave equation reduces to the Helmholtz equation for a harmonic signal of angular frequency ω, i.e., for the case p = p 0 exp(−iωt). In many instances, three-dimensional (3D) solutions are necessary due to seafloor interaction (Finette et al 2007;Lin et al 2015) or to strong lateral gradients of c (Finette et al 2007;Lynch et al 2010;Duda et al 2011a, b) so that the modeling of sound from individual sources and the modeling of noise (meant to characterize sound from numerous, imprecisely localized sources), can be computationally intensive and subject to large uncertainties. The sound speed in water is generally treated with a high degree of accuracy as a realvalued quantity that is independent of ω, but depends in a known manner on temperature, salinity and pressure (Del Grosso 1974;Dushaw et al 1993).…”

Section: A Equations and Approximationsmentioning

confidence: 99%

Modeling and Forecasting Ocean Acoustic Conditions

Duda¹

2017

j mar res

Self Cite

View full text Add to dashboard Cite

Modeling acoustic conditions in an oceanic environment is a multiple-step process. The environmental conditions (features) in the area first must be measured or estimated; relevant features include seabed geometry, seabed composition, and four-dimensionally (4D) variable sound-speed and density variations related to evolving or wave motions. Often the dynamical wave modeling depends on first obtaining correct seabed and mean stratification conditions (for example, nonlinear internal wave modeling). Next, this information must be included in sound propagation modeling. A selection of the many methods and tools available for these tasks are described, with a focus on modeling sounds of 20 to 1000 Hz propagating through water-column features that are time-dependent and variable in three dimensions (i.e., 4D variable). An example of a 3D parabolic equation acoustic calculation shows how variability caused by evolving internal tidal waves affects sound propagation. Different propagation and scattering regimes are discussed, including the theoretically delineated weak scattering and strong scattering regimes, as well as the empirically examined regime found in nonlinear internal waves. The histories and the current state of our oceanographic knowledge (the input to acoustic modeling) and of our ability to effectively model complex acoustic conditions are discussed. Example acoustic simulation applications are also discussed; these are ocean acoustic tomography, coherence prediction, and signal-to-noise ratio prediction. Types of ocean models and acoustic models and how they are interfaced are also examined. These include deterministic, statistical analytic feature models.

show abstract

Experimental and Numerical Studies of Sound Propagation Over a Submarine Canyon Northeast of Taiwan

Cited by 18 publications

References 20 publications

Experimentally-Based Ocean Acoustic Propagation and Coherence Studies

Experimentally-Based Ocean Acoustic Propagation and Coherence Studies

Mapping of surface-generated noise coherence

Modeling and Forecasting Ocean Acoustic Conditions

Contact Info

Product

Resources

About