Analysis of acoustic communication channel characterization data in the surf zone
Partan, James W.
MetadataShow full item record
LocationSan Diego, CA
A channel characterization experiment for the underwater acoustic communication channel was carried out at Scripps Pier in May 1999. The experiment investigated acoustic transmission in very shallow water and breaking waves. In analyzing the data, several questions arose. The majority of the acoustic channel probe data was corrupted by crosstalk in the receiver array cable. This thesis investigates methods to correct for the effects of the crosstalk, to attempt to recover the channel probe data. In selected regions, the crosstalk could be removed quite effectively using a linear least-squares method to estimate the crosstalk coefficients. The bulk of the data could not be corrected, however, primarily due to crosstalk from a receiver channel which was not recorded, and hence could not be well estimated. A second question addressed by this thesis is concerned with acoustic propagation in shallow water under bubble clouds. The breaking waves injected air deep into the water column. The resulting bubble clouds heavily attenuated acoustic signals, effectively causing total dropouts of the acoustic communication channel. Due to buoyancy, the bubbles gradually rise, and the communication channel clears. The channel clearing was significantly slower than predicted by geometric ray acoustic propagation models, however. Proposed explanations included secondary, unobserved, breaking events causing additional bubble injection; delayed rising of bubbles due to turbulent currents; or failure of the geometric ray model due to suppression by bubble clouds of acoustic signals which are not along the geometric ray paths. This thesis investigated the final hypothesis, modeling the acoustic propagation in Scripps Pier environment, using the full wave equation modeling package OASES. It was determined that the attenuation of the propagating acoustic signal is not accurately predicted by the bubble-induced attenuation along the geometric ray path.
Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2000
Showing items related by title, author, creator and subject.
Mikhalevsky, Peter N.; Sagen, Hanne; Worcester, Peter F.; Baggeroer, Arthur B.; Orcutt, John A.; Moore, Sue E.; Lee, Craig M.; Vigness-Raposa, Kathleen J.; Freitag, Lee E.; Arrott, Matthew; Atakan, Kuvvet; Beszczynska-Moller, Agnieszka; Duda, Timothy F.; Dushaw, Brian D.; Gascard, Jean-Claude; Gavrilov, Alexander N.; Keers, Henk; Morozov, Andrey K.; Munk, Walter H.; Rixen, Michel; Sandven, Stein; Skarsoulis, Emmanuel; Stafford, Kathleen M.; Vernon, Frank L.; Yuen, Mo Yan (Arctic Institute of North America, 2015)The dramatic reduction of sea ice in the Arctic Ocean will increase human activities in the coming years. This activity will be driven by increased demand for energy and the marine resources of an Arctic Ocean accessible ...
Slavinsky, Mark; Bogolubov, Boris; Alelekov, Igor; Pigalov, Konstantin; Spiesberger, John L.; Boutin, Paul (Woods Hole Oceanographic Institution, 1993-02)A compact electromagnetic monopole source, requiring pressure equalization, was evaluated at the Naval Underwater Systems Center at Lake Seneca during July 1992 by scientists from the Institute of Applied Physics of the ...
Quantification of the spatial and temporal evolution of stratified shear instabilities at high Reynolds number using quantitative acoustic scattering techniques Fincke, Jonathan R. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2015-02)The spatial and temporal evolution of stratified shear instabilities is quantified in a highly stratified and energetic estuary. The measurements are made using high-resolution acoustic backscatter from an array composed ...