Environmental‐acoustics analysis of sound‐speed fluctuations induced by internal waves

1976 ◽  
Vol 59 (S1) ◽  
pp. S43-S43
Author(s):  
J. G. Watson ◽  
W. L. Siegmann ◽  
M. J. Jacobson
Keyword(s):  
Internal Waves ◽  
Sound Speed ◽  
Environmental Acoustics ◽  
Speed Fluctuations

scholarly journals Observations of thermohaline sound-speed structure induced by internal waves and spice in the summer 2015 Canada Basin marginal ice zone

Elem Sci Anth ◽  
2018 ◽  
Vol 6 ◽  
Author(s):  
Dominic DiMaggio ◽  
John A. Colosi ◽  
John Joseph ◽  
Annalise Pearson ◽  
Peter F. Worcester ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Internal Wave ◽  
Internal Waves ◽  
Sound Speed ◽  
Canada Basin ◽  
The Arctic ◽  
Spectral Slope ◽  
Frequency Spectra ◽  
Sound Speed Structure ◽  
Speed Fluctuations

The Arctic seas are in a period of transition as they adjust to stimuli from anthropogenic climate change. The acoustic response to this adjustment is of fundamental interest, as acoustics provide an important means for Arctic remote sensing, communication and navigation, and there are important biological implications for marine mammals and other organisms that use sound. The Canada Basin Acoustic Propagation Experiment (CANAPE) is an effort to study Arctic acoustics; this paper reports on ocean sound-speed measurements from a pilot study undertaken between 30 July and 16 August 2015. Moored and shipborne observations of temperature and salinity were made in the upper 600 m of the ocean, allowing analysis along isopycnals (surfaces of constant density) to separate sound-speed structure due to internal-wave-induced vertical displacements from those originating from density-compensated temperature and salinity variations termed spice. Frequency spectra and vertical covariance functions were used to describe the space/time scales of displacements and spice. Internal-wave frequency spectra show a spectral slope much lower than the Garrett-Munk model, with the energy level roughly 4% of the standard Garrett-Munk value. Frequency spectra of spice show a form similar to the internal-wave spectra but with a slightly steeper spectral slope, presumably due to the horizontal advection of the spice by internal-wave currents. The root mean square sound-speed fluctuations from internal waves were small with values less than 0.1 m s–1. Spicy sound-speed fluctuations were much stronger, particularly in the upper 100 m where a maximum of 0.25 m s–1 was observed. Both processes have vertical decorrelation lengths less than 100 m. The observed strong variations in vertical and horizontal sound-speed structure will have significant impacts on acoustic applications, especially in the realm of communications, navigation, and remote sensing.

Spice, internal waves, and sound speed in the upper ocean

2004 ◽  
Vol 116 (4) ◽  
pp. 2634-2634 ◽  
Author(s):  
Daniel L. Rudnick
Keyword(s):  
Internal Waves ◽  
Sound Speed ◽  
Upper Ocean

scholarly journals Ocean sound speed fluctuations

Nature ◽  
1980 ◽  
Vol 284 (5754) ◽  
pp. 380-380
Author(s):  
John A. DeSanto
Keyword(s):  
Sound Speed ◽  
Speed Fluctuations

SIMULATION OF UNDERWATER ACOUSTICAL FIELD FLUCTUATIONS IN SHALLOW SEA WITH RANDOM INHOMOGENEITIES OF SOUND SPEED: DEPTH-DEPENDENT ENVIRONMENT

2014 ◽  
Vol 22 (01) ◽  
pp. 1440002 ◽  
Author(s):  
OLEG E. GULIN ◽  
IGOR O. YAROSHCHUK
Keyword(s):  
Shallow Water ◽  
Sound Speed ◽  
Scientific Literature ◽  
Water Layer ◽  
Statistical Simulation ◽  
Frequency Range ◽  
Shallow Sea ◽  
Field Fluctuations ◽  
Pekeris Waveguide ◽  
Speed Fluctuations

Statistical problems encountered in the study of the influence of random inhomogeneities in layered shallow water on the propagation of sound signal is considered. The study is carried out by the example of two-layer models of the sea — a stochastic Pekeris waveguide and a waveguide with a regular refraction in the water layer, which describes the presence of the thermocline. The results were obtained by statistical simulation without approximations and assumptions. In the middle frequency range for actual parameters of sound speed fluctuations in shallow sea with a loss penetrable bottom, the specific features of acoustic field statistical moments behavior have been discovered. They did not get adequate attention in the scientific literature.

scholarly journals Analyzing sound speed fluctuations in shallow water from group-velocity versus phase-velocity data representation

2013 ◽  
Vol 133 (4) ◽  
pp. 1945-1952 ◽  
Author(s):  
Philippe Roux ◽  
W. A. Kuperman ◽  
Bruce D. Cornuelle ◽  
Florian Aulanier ◽  
W. S. Hodgkiss ◽  
...  
Keyword(s):  
Phase Velocity ◽  
Shallow Water ◽  
Group Velocity ◽  
Sound Speed ◽  
Data Representation ◽  
Velocity Versus ◽  
Velocity Data ◽  
Versus Phase ◽  
Speed Fluctuations
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