scholarly journals Diel variation in high-frequency acoustic backscatter fromCochlodinium polykrikoides

2013 ◽  
Vol 134 (2) ◽  
pp. EL140-EL146 ◽  
Author(s):  
Tae-Hoon Bok ◽  
Jungyul Na ◽  
Dong-Guk Paeng
Keyword(s):  
High Frequency ◽  
Acoustic Backscatter ◽  
Diel Variation

scholarly journals Effects of Noise and Absorption on High Frequency Measurements of Acoustic-Backscatter from Fish

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Masahiko Furusawa
Keyword(s):  
Measurement Error ◽  
Environmental Conditions ◽  
High Frequency ◽  
Signal To Noise Ratio ◽  
Target Strength ◽  
Acoustic Backscatter ◽  
Signal To Noise ◽  
Absorption Coefficients ◽  
Frequency Measurements ◽  
Multiple Frequencies

Quantitative echosounders operating at multiple frequencies (e.g., 18, 38, 70, 120, 200, 333, and 710 kHz) are often used to observe fish and zooplankton and identify their species. At frequencies above 100 kHz, the absorption attenuation increases rapidly and decreases the signal-to-noise ratio (SNR). Also, incomplete compensation for the attenuation may result in measurement error. This paper addresses the effects of the attenuation and noise on high frequency measurements of acoustic backscatter from fish. It is shown that measurements of a fish with target strength of −40 dB at 200 m depth are limited by SNR to frequencies up to about 100 kHz. Above 100 kHz, absorption coefficients must be matched to local environmental conditions.

Temporal model of high‐frequency seafloor acoustic backscatter

1994 ◽  
Vol 96 (5) ◽  
pp. 3287-3287
Author(s):  
Christian de Moustier ◽  
Daniel Sternlicht
Keyword(s):  
High Frequency ◽  
Acoustic Backscatter ◽  
Temporal Model

scholarly journals High‐frequency acoustic backscatter sea surface

1984 ◽  
Vol 75 (S1) ◽  
pp. S31-S31
Author(s):  
W. I. Roderick ◽  
R. K. Dullea ◽  
J. B. Chester
Keyword(s):  
High Frequency ◽  
Sea Surface ◽  
Acoustic Backscatter

scholarly journals Hurricane impacts on a coral reef soundscape

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0244599
Author(s):  
Kayelyn R. Simmons ◽  
David B. Eggleston ◽  
DelWayne R. Bohnenstiehl
Keyword(s):  
Coral Reef ◽  
Frequency Band ◽  
High Frequency ◽  
Sound Production ◽  
Low Frequency ◽  
Benthic Habitat ◽  
Diel Variation ◽  
High Frequency Band ◽  
Frequency Sound ◽  
Snapping Shrimp

Soundscape ecology is an emerging field in both terrestrial and aquatic ecosystems, and provides a powerful approach for assessing habitat quality and the ecological response of sound-producing species to natural and anthropogenic perturbations. Little is known of how underwater soundscapes respond during and after severe episodic disturbances, such as hurricanes. This study addresses the impacts of Hurricane Irma on the coral reef soundscape at two spur-and-groove fore-reef sites within the Florida Keys USA, using passive acoustic data collected before and during the storm at Western Dry Rocks (WDR) and before, during and after the storm at Eastern Sambo (ESB). As the storm passed, the cumulative acoustic exposure near the seabed at these sites was comparable to a small vessel operating continuously overhead for 1–2 weeks. Before the storm, sound pressure levels (SPLs) showed a distinct pattern of low frequency diel variation and increased high frequency sound during crepuscular periods. The low frequency band was partitioned in two groups representative of soniferous reef fish, whereas the high frequency band represented snapping shrimp sound production. Daily daytime patterns in low-frequency sound production largely persisted in the weeks following the hurricane. Crepuscular sound production by snapping shrimp was maintained post-hurricane with only a small shift (~1.5dB) in the level of daytime vs nighttime sound production for this high frequency band. This study suggests that on short time scales, temporal patterns in the coral reef soundscape were relatively resilient to acoustic energy exposure during the storm, as well as changes in the benthic habitat and environmental conditions resulting from hurricane damage.

Measurements of diel variation of acoustic backscatter power from phytoplankton

2013 ◽  
Vol 134 (5) ◽  
pp. 3990-3990
Author(s):  
Hansoo Kim ◽  
Tae-Hoon Bok ◽  
Juho Kim ◽  
Dong-Guk Paeng ◽  
Md Mahfuzur Rahman Shah ◽  
...  
Keyword(s):  
Acoustic Backscatter ◽  
Diel Variation

scholarly journals The dance of the nanobubbles: detecting acoustic backscatter from sub-micron bubbles using ultra-high frequency acoustic microscopy

Nanoscale ◽  
2020 ◽  
Vol 12 (41) ◽  
pp. 21420-21428
Author(s):  
Michael J. Moore ◽  
Filip Bodera ◽  
Christopher Hernandez ◽  
Niloufar Shirazi ◽  
Eric Abenojar ◽  
...  
Keyword(s):  
High Frequency ◽  
Acoustic Microscopy ◽  
Acoustic Backscatter ◽  
Agarose Gel ◽  
Acoustic Microscope ◽  
Ultra High Frequency

Detection of the motion of individual nanobubbles and microbubbles in an agarose gel using an ultra-high frequency acoustic microscope.

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