Acoustic intensity fluctuations induced by South China Sea internal tides and solitons
Ramp, Steven R.
Miller, Christopher W.
Lynch, James F.
Duda, Timothy F.
Tang, Tswen Yung
MetadataShow full item record
KeywordIntensity fluctuations; Nonlinear internal waves; Shallow water acoustics; South China Sea (SCS)
Between late April and May 23, 2001, a suite of acoustic and oceanographic sensors was deployed by a team of U.S., Taiwan, and Singapore scientists in the northeastern South China Sea to study the effects of ocean variability on low-frequency sound propagation in a shelfbreak environment. The primary acoustic receiver was an L-shaped hydrophone array moored on the continental shelf that monitored a variety of signals transmitted along and across the shelfbreak by moored sources. This paper discusses and contrasts the fluctuations in the 400-Hz signals transmitted across the shelfbreak and measured by the vertical segment of the listening array on two different days, one with the passage of several huge solitons that depressed the shallow isotherms to near the sea bottom and one with a much less energetic internal wavefield. In addition to exhibiting large and rapid temporal changes, the acoustic data show a much more vertically diffused sound intensity field as the huge solitons occupied and passed through the transmission path. Using a space-time continuous empirical sound-speed model based on the moored temperature records, the observed acoustic intensity fluctuations are explained using coupled-mode physics.
Author Posting. © IEEE, 2004. This article is posted here by permission of IEEE for personal use, not for redistribution. The definitive version was published in IEEE Journal of Oceanic Engineering 29 (2004): 1249-1263, doi:10.1109/JOE.2004.834173.
Suggested CitationIEEE Journal of Oceanic Engineering 29 (2004): 1249-1263
Showing items related by title, author, creator and subject.
Duda, Timothy F.; Lynch, James F.; Newhall, Arthur E.; Wu, Lixin; Chiu, Ching-Sang (IEEE, 2004-10)We present analyses of fluctuations seen in acoustic signals transmitted by two 400-Hz sources moored as part of the ASIAEX 2001 South China Sea (SCS) experiment. One source was near the bottom in 350-m deep water 31.3 km ...
Badiey, Mohsen; Katsnelson, Boris G.; Lynch, James F.; Pereselkov, Serguey (Acoustical Society of America, 2007-08)A theory and experimental results for sound propagation through an anisotropic shallow water environment are presented to examine the frequency dependence of the scintillation index in the presence of internal waves. The ...
Enhanced acoustic mode coupling resulting from an internal solitary wave approaching the shelfbreak in the South China Sea Chiu, Linus Y. S.; Reeder, D. Benjamin; Chang, Yuan-Ying; Chen, Chi-Fang; Chiu, Ching-Sang; Lynch, James F. (Acoustical Society of America, 2013-03)Internal waves and bathymetric variation create time- and space-dependent alterations in the ocean acoustic waveguide, and cause subsequent coupling of acoustic energy between propagating normal modes. In this paper, the ...