Estimate of the bottom compressional wave speed profile in the northeastern South China Sea using "Sources of Opportunity"
Lynch, James F.
Newhall, Arthur E.
Schock, Steven G.
Bartek, Louis R.
MetadataShow full item record
The inversion of a broad-band "source of opportunity" signal for bottom geoacoustic parameters in the northeastern South China Sea (SCS) is presented, which supplements the towed source and chirp sonar bottom inversions that were performed as part of the Asian Seas International Acoustics Experiment (ASIAEX). This source of opportunity was most likely a "dynamite fishing" signal, which has sufficient low-frequency content (5-500 Hz) to make it complimentary to the somewhat higher frequency J-15-3 towed source (50-260 Hz) signals and the much higher frequency (1-10 kHz) chirp signals. This low frequency content will penetrate deeper into the bottom, thus extending the other inverse results. Localization of the source is discussed, using both a horizontal array for azimuthal steering and the "water wave" part of the pulse arrival for distance estimation. A linear broad-band inverse is performed, and three new variants of the broad-band inverse, based on: 1) the Airy phase; 2) the cutoff frequency; and 3) a range-dependent medium are presented. A multilayer model of the bottom compressional wave speed is obtained, and error estimates for this model are shown, both for the range-independent approximation to the waveguide and for the range-dependent waveguide. Directions for future research are discussed.
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): 1231-1248, doi:10.1109/JOE.2004.834681.
Showing items related by title, author, creator and subject.
Seasonal changes in gaseous elemental mercury in relation to monsoon cycling over the northern South China Sea Tseng, Chun-Mao; Liu, Char-Shine; Lamborg, Carl H. (Copernicus Publications on behalf of the European Geosciences Union, 2012-08-16)The distribution of gaseous elemental mercury (GEM) was determined in the surface atmosphere of the northern South China Sea (SCS) during 12 SEATS cruises between May 2003 and December 2005. The sampling and analysis of ...
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 ...
Shoaling of large-amplitude nonlinear internal waves at Dongsha Atoll in the northern South China Sea Fu, Ke-Hsien; Wang, YuHuai; St. Laurent, Louis C.; Simmons, Harper L.; Wang, Wang (2012-02-10)Shoaling of large-amplitude (~100 m) nonlinear internal waves over a steep slope (~3°) in water depths between 100 m and 285 m near Dongsha Atoll in the northern South China Sea is examined with an intensive array of ...