Observation and modeling of sound propagation through a dynamic ocean on the continental shelf of the northeastern South China Sea

• Published in: The Journal of the Acoustical Society of America 2009-10, Vol.126 (4_Supplement), p.2304-2304
• Main Authors: Chiu, Ching-Sang, Miller, Christopher W., Chen, Chi-Fang, Chiu, Linus, Wei, Ruey-Chang
• Format: Article
• Language: English
• Subjects: Marine
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.3249497

In April 2005, a 3-day acoustic transmission experiment was carried out on the shelf of the northeastern South China Sea. A 400-Hz signal was transmitted every 5 min from a moored source to a moored vertical hydrophone array 17 km away. Additionally, a series of oceanographic moorings was deployed along the transmission path to sample the water-column variability that was dominated by the evolution of nonlinear internal tides and high-frequency nonlinear internal waves. Applying time-series filtering, principal component analysis, and a feature tracking technique to the oceanographic data, a continuous space-time empirical model for the sound-speed field was developed. Using a coupled-mode sound propagation model, interfacing with the sound-speed model, the temporal variations of the vertical distribution of signal intensity at the hydrophone array were computed. Analyzing the model results and comparing them to the measured signal intensities have allowed for quantification and comparison of the effects of the nonlinear internal tides, depression waves, and elevation waves on the sound transmission. The modeled sound-speed and sound-intensity fields and their comparisons to the measured data are discussed in this paper. [This research is jointly sponsored by the U.S. Office of Naval Research and the Taiwan National Research Council.]