An overview of SAX99: acoustic measurements

Thorsos, Eric I.; Williams, Kevin L.; Chotiros, Nicholas P.; Christoff, James T.; Commander, Kerry W.; Greenlaw, Charles F.; Holliday, D. V.; Jackson, Darrell R.; Lopes, Joseph L.; McGehee, Duncan E.; Piper, John E.; Richardson, Michael D.; Tang, Dajun

doi:10.1109/48.917916

Cited by 94 publications

(48 citation statements)

References 35 publications

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“…Thus, spatial resolution has been at scales of tens of centimeters to ~15 m ). Sound wave reflection off of and propagation through the sand surface have been studied extensively Jackson et al 2002;Hefner et al 2009) with the goal of long-range detection of solid objects (e.g., simulated seabed mines) buried beneath the seafloor (e.g., Thorsos et al 2001;Piper et al 2009). Bubbles can distort sound wave reflection and propagation and thus confound the detection of seafloor objects.…”

Section: Discussionmentioning

confidence: 99%

Acoustic detection of gas bubbles in saturated sands at high spatial and temporal resolution

Wildman

Huettel

2012

Limnology & Ocean Methods

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Small gas bubbles embedded near the surface of submerged sand affect physical, chemical, and biological processes, and so their detection and characterization is important. So far, a noninvasive method for the detection of such bubbles has not been available. We developed a portable acoustic detection technique that offers high spatial and temporal resolution. The measuring system consists of a hand‐held ultrasonic transmitterreceiver that we operated with transducers generating 1 MHz and 2.27 MHz pulses. Bubble detection was based on changes in amplitude and travel time of backscatter data collected from bubbles that were either manually injected into sediment or created by sedimentary microalgal photosynthesis. Laboratory experiments showed that individual bubbles of 6 mm diameter can be detected as deep as 60 mm beneath the sediment‐water interface. Vertical and horizontal resolutions of 0.4–1 mm and 8–13 mm were achieved, depending on the transducer used. Measurements in a coastal bay demonstrated that our technique discriminates between sands with and without bubbles and locates embedded gas. We found that gas accumulations develop in the upper 10 mm of shallow sandy sediment in shallow water during daytime, revealing that the combination of photosynthetic oxygen production and porewater transport in permeable sands can lead to bubble generation below the photosynthetically active layer.

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Section: Discussionmentioning

confidence: 99%

Acoustic detection of gas bubbles in saturated sands at high spatial and temporal resolution

Wildman

Huettel

2012

Limnology & Ocean Methods

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“…These surfaces typically implement an isotropic roughness with a power-law spectrum and a surface size that is compatible with the acoustic or electromagnetic wavelength of interest. The surface topography we chose was to reflect the isotropic roughness and the anisotropic surface ripple observed during the high-frequency Sediment Acoustics Experiment (SAX99) (Thorsos et al, 2001;Briggs et al, 2004).…”

Section: Rough Surface Measurementmentioning

confidence: 99%

Design, Calibration and Application of a Seafloor Laser Scanner

Wang¹,

Tang²,

Hefner³

2011

Laser Scanning, Theory and Applications

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“…Our objective was to acoustically distinguish different shapes of migrating animals in the multi-frequency scattering signals observed at dawn and dusk, and sometimes throughout the night. This modeling, and the development of new computer code for making improved inverse calculations, allowed us to describe data collected at the sandy SAX-99 site (Thorsos et al 2001;Richardson et al 2001).…”

Section: Work Completedmentioning

confidence: 99%

Effects of Benthopelagic Animals on Seabed Properties

Holliday¹,

Greenlaw²,

McGehee³

2003

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ONR Contract Number: N00014-98-C-0442http://206.251.232.34 LONG-TERM GOALSThe long-term goals of this research are to improve the ability of benthic biologists and biological oceanographers to observe life on and in the seabed; to describe the interactions between the animals that live there, their neighbors and their food; to improve our understanding of the coupling between the benthic and the pelagic communities; and to assess biologically mediated changes in those physical properties of the seabed that affect scattering and penetration of sound into the bottom. OBJECTIVESDirect observation of animals that live on or in the seabed can be exceptionally difficult. This is especially true in areas with characteristically poor visibility or in water that is too deep to allow divers to spend much time near the bottom. Little attention has been given to developing instrumentation and sensors that would allow remote observation of benthic animals for long periods at high spatial and temporal resolution. Our short-and medium-term objectives involve developing high frequency acoustic sensors to fill this gap, thereby improving the information that benthic ecologists can access about benthic and benthopelagic animals and the seabed environment. In addition, the presence and 1

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An overview of SAX99: acoustic measurements

Cited by 94 publications

References 35 publications

Acoustic detection of gas bubbles in saturated sands at high spatial and temporal resolution

Acoustic detection of gas bubbles in saturated sands at high spatial and temporal resolution

Design, Calibration and Application of a Seafloor Laser Scanner

Effects of Benthopelagic Animals on Seabed Properties

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