Sound phase and amplitude fluctuations in an anisotropic ocean.

Download
Author
Alexander, Charles Homer
Date
1972-12Advisor
Medwin, H.
Second Reader
Thornton, Edward B.
Metadata
Show full item recordAbstract
Sound of constant amplitude and frequency was transmitted
simultaneously in three orthogonal beams over a
distance of 1.5 meters in the upper ocean. Time records
of the resulting phase and amplitude fluctuations of the
sound beams were studied by means of auto and cross spectral
analysis and correlation. The time lag between corresponding
peaks of the phase fluctuation autocorrelation functions
of vertical and horizontal beams indicate movement of inhomogeneities
between the sound fields due to water particle
motion caused by surface wave action. Envelope correlation
times of the phase fluctuations are found to be approximately
one-half as great in the mixed layer as in the thermocline,
and are greater in the vertical than in the horizontal direction in the thermocline. Anisotropy in the thermocline
is also indicated by the variance of phase fluctuation
being greater for sound paths in the horizontal than in the
vertical direction. The autocorrelation functions of
amplitude and phase fluctuations in any one direction are
similar.
Collections
Related items
Showing items related by title, author, creator and subject.
-
Horizontal Propagation Deep Turbulence Testbed
Corley, M.S.; Santiago, F.; T. Martinez; Agrawal, B.N. (2011);The Navy is interested in horizontal laser propagation studies in a maritime environment, near the ocean surface, for applications including imaging and high-energy laser propagation. The Naval Postgraduate School (NPS) ... -
Acoustic fluctuations due to shallow thermal microstructure
Hagen, James Burgess (Monterey, California. Naval Postgraduate School, 1974-12);Simultaneous measurements of waves, orthogonal water particle velocities, temperature, conductivity and acoustic phase and amplitude measurements at 20 and 40 kHz over horizontal and vertical, 2m paths were made at the NUC ... -
Shallow water acoustic backscatter and reverberation measurements using a 68-kHz cylindrical array: a dissertation
Gallaudet, Timothy C. (Timothy Cole), 1967- (2001);The characterization of high frequency, shallow water acoustic backscatter and reverberation is important because acoustic systems are used in many scientific, commercial, and military applications. The approach taken is ...