Future shallow water low frequency (100–1000 Hz) acoustic signal propagation physics studies

2013 ◽  
Vol 134 (5) ◽  
pp. 4035-4035
Author(s):  
Marshall H. Orr
Keyword(s):  
Shallow Water ◽  
Acoustic Signal ◽  
Low Frequency ◽  
Signal Propagation

scholarly journals Researches on very low frequency acoustic signal propagation characteristics in different shallow elastic wedge bottoms

2019 ◽  
Vol 283 ◽  
pp. 02003
Author(s):  
Jun Zhu ◽  
Hanhao Zhu ◽  
Jun Tang ◽  
Guangxue Zheng
Keyword(s):  
Acoustic Signal ◽  
Low Frequency ◽  
Signal Propagation ◽  
Acoustic Energy ◽  
Propagation Characteristics ◽  
The Finite Element Method ◽  
Very Low Frequency ◽  
Extremely Low Frequency ◽  
Elastic Bottom ◽  
Sloping Bottom

Targeted at the issue of extremely low-frequency (<100Hz) acoustic propagation in complex shallow elastic bottom environments. The influence law of different complex elastic bottoms on the acoustic signal propagation at very low frequency by acoustic energy flux has been analyzed with the simulation, which is based on the finite element method. The elastic bottoms which have been studied are the shallow horizontal elastic bottom, and the up-sloping and the down-sloping elastic bottom. The results show that the acoustic signal propagating in the up-sloping and down-sloping elastic bottom environments is more complex than that propagating in the horizontal elastic bottom, and the acoustic energy leaking into those elastic bottoms has very different influence on the acoustic signal propagation, especially in the up-sloping bottom.

Low-frequency bottom reverberation in shallow-water ocean regions

2004 ◽  
Vol 50 (1) ◽  
pp. 37-45 ◽  
Author(s):  
V. A. Grigor’ev ◽  
V. M. Kuz’kin ◽  
B. G. Petnikov
Keyword(s):  
Shallow Water ◽  
Low Frequency

scholarly journals Variation of Low-Frequency Time-Code Signal Field Strength during the Annular Solar Eclipse on 21 June 2020: Observation and Analysis

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1216
Author(s):  
Xin Wang ◽  
Bo Li ◽  
Fan Zhao ◽  
Xinyu Luo ◽  
Luxi Huang ◽  
...  
Keyword(s):  
Field Strength ◽  
Solar Eclipse ◽  
Low Frequency ◽  
Signal Propagation ◽  
Normal Operation ◽  
Time Code ◽  
Long Distance ◽  
Time Service ◽  
Annular Solar Eclipse ◽  
Signal Field

Due to the occlusion of the moon, an annular solar eclipse will have an effect on the ionosphere above the earth. The change of the ionosphere, for the low-frequency time-code signal that relies on it as a reflection medium for long-distance propagation, the signal field strength, and other parameters will also produce corresponding changes, which will affect the normal operation of the low-frequency time-code time service system. This paper selects the solar eclipse that occurred in China on 21 June 2020, and uses the existing measurement equipment to carry out experimental research on the low-frequency time-code signal. We measured and analyzed the signal field strength from 20 June 2020 to 23 June 2020, and combined solar activity data, ionospheric data, and geomagnetic data, and attempted to explore the reasons and rules of the change of signal parameters. The results showed that the field strength of the low-frequency time-code signal changed dramatically within a short time period, the max growth value can reach up to 17 dBμV/m and the variation trend yielded ‘three mutations’. This change in signal field strength is probably due to the occurrence of a solar eclipse that has an effect on the ionosphere. When the signal propagation conditions change, the signal strength will also change accordingly.

scholarly journals Low‐frequency bottom scattering strengths for a shallow water site in the Gulf of Mexico

1993 ◽  
Vol 93 (4) ◽  
pp. 2395-2395
Author(s):  
Peter G. Cable ◽  
Theo Kooij ◽  
Mike Steele
Keyword(s):  
Gulf Of Mexico ◽  
Shallow Water ◽  
Low Frequency

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
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