Depth dependence of the vertical directionality of low‐frequency ambient noise in the ocean

1978 ◽  
Vol 64 (S1) ◽  
pp. S166-S166
Author(s):  
G. B. Morris ◽  
R. C. Tyce
Keyword(s):  
Ambient Noise ◽  
Low Frequency ◽  
Depth Dependence

scholarly journals Low‐frequency ocean ambient noise depth dependence

1980 ◽  
Vol 68 (S1) ◽  
pp. S73-S73
Author(s):  
Aubrey L. Anderson ◽  
Robert L. Martin
Keyword(s):  
Ambient Noise ◽  
Low Frequency ◽  
Depth Dependence

Meteorological conditions influence on quantification of site effects at low frequency using the seismic ambient noise

2015 ◽  
Author(s):  
Rabah Bensalem* ◽  
Djamal Machane ◽  
Jean-Luc Chatelain ◽  
Mohamed Djeddi ◽  
Hakim Moulouel ◽  
...  
Keyword(s):  
Site Effects ◽  
Ambient Noise ◽  
Low Frequency ◽  
Meteorological Conditions ◽  
Seismic Ambient Noise

scholarly journals Low‐frequency propagation across the East Greenland and Frontal Zone: Depth dependence of transmission loss

1987 ◽  
Vol 82 (S1) ◽  
pp. S31-S31
Author(s):  
Leonard E. Mellberg ◽  
D. N. Connors ◽  
D. G. Browning ◽  
G. Botseas ◽  
O. M. Johannessen
Keyword(s):  
Frontal Zone ◽  
Transmission Loss ◽  
Low Frequency ◽  
East Greenland ◽  
Depth Dependence ◽  
Zone Depth

scholarly journals Detection of infrasound by the Atlantic cod

1986 ◽  
Vol 125 (1) ◽  
pp. 197-204 ◽  
Author(s):  
O. Sand ◽  
H. E. Karlsen
Keyword(s):  
Ambient Noise ◽  
Atlantic Cod ◽  
Low Frequency ◽  
Directional Pattern ◽  
Frequency Noise ◽  
Threshold Values ◽  
Sensory Inputs ◽  
A Value ◽  
Cardiac Conditioning ◽  
Lower Frequencies

Below about 50 kHz the level of ambient noise in the sea increases continuously towards lower frequencies. In the infrasound range the spectral slope is particularly steep. This low-frequency noise may propagate long distances with little attenuation, causing a directional pattern of infrasound in the sea. Using a standing-wave acoustic tube, we have studied the sensitivity of cod to infrasound down to 0.1 Hz by means of the cardiac conditioning technique. The threshold values, measured as particle acceleration, showed a steady decline towards lower frequencies below 10 Hz, reaching a value close to 10(−5)ms-2 at 0.1 Hz. The spectrum level at 0.1 Hz in the sea ranges between 120 and 180 dB (re 1 microPa), with corresponding particle accelerations from less than 10(−6) to more than 10(−4)ms-2. The sensitivity of cod is thus sufficient to detect the highest levels of ambient infrasound, and we put forward the hypothesis that fish may utilize information about the infrasound pattern in the sea for orientation during migration, probably in addition to an array of other sensory inputs.

Low Frequency Wind Generated Ambient Noise in Shallow Water

1988 ◽  
pp. 273-280
Author(s):  
Henrik Schmidt ◽  
Tuncay Akal ◽  
W. A. Kuperman
Keyword(s):  
Shallow Water ◽  
Ambient Noise ◽  
Low Frequency

scholarly journals Low‐Frequency Ambient Noise Autocorrelations: Waveforms and Normal Modes

2018 ◽  
Vol 89 (4) ◽  
pp. 1488-1496 ◽  
Author(s):  
M. Schimmel ◽  
E. Stutzmann ◽  
S. Ventosa
Keyword(s):  
Ambient Noise ◽  
Normal Modes ◽  
Low Frequency

scholarly journals MobiLab – A Mobile Laboratory for On-Site Listening Experiments in Virtual Acoustic Environments

2019 ◽  
Vol 105 (5) ◽  
pp. 875-887
Author(s):  
Florian Pausch ◽  
Janina Fels
Keyword(s):  
Ambient Noise ◽  
Low Frequency ◽  
Mobile Laboratory ◽  
Noise Levels ◽  
Acoustic Parameters ◽  
Research Areas ◽  
Test Conditions ◽  
Acoustic Environments ◽  
Study Participants ◽  
Insulation Performance

Virtual acoustic environments have demonstrated their versatility for conducting studies in various research areas as they allow easy manipulations of experimental test conditions or simulated acoustic scenes, while providing expansion possibilities to related interdisciplinary and multimodal fields. Although the evolution of auditory and cognitive models is consistently pursued, listening experiments are still considered the gold standard, usually necessitating a large amount of resources, including travel expenses of study participants. In order to facilitate practical and efficient study execution, we therefore implemented a mobile hearing laboratory by acoustically optimising the interior of a caravan. All necessary technical facilities were integrated to perform listening experiments in virtual acoustic environments under controlled conditions directly on site, for example, in front of schools or senior residential centers. The design and construction of this laboratory are presented and evaluated based on insulation properties, selected room acoustic parameters, and interior ambient noise levels that are to be expected during operation at representative test sites. Limitations, particularly in low-frequency insulation performance, should provide incentives for further optimisations in similar future projects.

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