APPLICATION OF ACOUSTIC NOISE INTERFEROMETRY TO REMOTE SENSING OF A COASTAL OCEAN

As noted by Tan, Godin, Brown, and Zabotin in 2019, interferometry of ambient and shipping noise in the ocean provides a way to estimate physical parameters of the seafloor and the water column in a surreptitious and environmentally friendly manner, without employing any controlled sound sources. This dissertation builds upon Tan et al.’s findings reported in The Journal of the Acoustical Society of America. With noise interferometry, two-point cross-correlation functions of noise serve as the probing signals and replace the impulse response measured in active acoustic remote sensing. The amount of the environmental information that can be obtained with passive remote sensing, and the robustness of the estimates of the seafloor parameters increase when contributions of individual normal modes are resolved in the noise cross-correlation function. Using the data obtained in the 2012 Florida Straits and Shallow Water 2006 experiments, dispersion curves of normal modes have been obtained by application of the time-warping transform to noise cross-correlations. The passively measured dispersion curves are inverted for unknown geoacoustic properties of the seabed. It is demonstrated that, despite very strong variations of the water column parameters caused by nonlinear internal waves and tides, noise interferometry can be successfully used to acoustically characterize the seafloor on a continental shelf.Office of Naval ResearchNational Science FoundationOffice of Naval Researchhttp://archive.org/details/applicationofaco1094564081Lieutenant Commander, Taiwan NavyApproved for public release; distribution is unlimited