Experimental Evidence of Horizontal Refraction by Nonlinear Internal Waves of Elevation in Shallow Water in the South China Sea: 3D Versus Nx2D Acoustic Propagation Modeling
Part Of
Advances In Underwater Acoustics, Structural Acoustics, And Computational Methodologies (In 4 Volumes)
Journal Volume
1-4
Start Page
1:419
End Page
1:430
ISBN (of the container)
9789819809714
9789819809707
ISBN
9789819809714
9789819809707
Date Issued
2025-01-01
Author(s)
Abstract
A joint Taiwanese-U.S. field experiment was conducted in the South China Sea (SCS), entitled the South China Sea Oceanic Processes Experiment (Taiwan)/Non-Linear Internal Waves Initiative (US) (SCOPE/NLIWI), the ocean acoustics portion of which occurred during April 12–22, 2007. The acoustics objective was to quantify the temporal and spatial variability in acoustic propagation characteristics on the continental shelf in the presence of locally-generated and trans-basin nonlinear internal waves (NLIW). Broadband (400 Hz center frequency) m-sequence signals transmitted nearly continuously by a source moored near the seabed were received by vertical line arrays at 3 and 6 km range. The acoustic transect was oriented approximately parallel to the wave fronts of the shoaling trans-basin NLIW’s which had crossed the deep basin from their origin in the Luzon Strait. The acoustic propagation variability due to strong vertical and horizontal refraction induced by the very large NLIW’s creates an extremely complex acoustic field as a function of time and space. Experimental data and numerical acoustic propagation modeling results are presented to (1) examine and estimate the contribution of internal wave induced horizontal refraction to the received acoustic field; and (2) to quantify the range of propagation angles relative to the internal wave fronts within which strong horizontal refraction occurs and 3D propagation models are required to accurately predict the range- and depth-dependent acoustic propagation.
Subjects
Acoustic ducting
elevation waves
FOR3D
horizontal refraction
NLIWI
nonlinear internal waves
South China Sea
SDGs
Publisher
World Scientific Publishing Co.
Type
book part