Preliminary mapping of void fractions and sound speeds in gassy marine sediments from subbottom profiles

Leighton, Timothy G.; Robb, G.B.N.

doi:10.1121/1.2993744

Cited by 34 publications

(27 citation statements)

References 49 publications

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“…These include harbour protection, the detection of bubbles in marine sediments (Leighton & Robb 2008) and manufacturing (Yim & Leighton 2010). Biomedical applications, in addition to UCA studies, include monitoring biomedical shunts and participating in the current debate on distinguishing nonlinearly scattering bubbles from large, linearly scattering ones in tumour treatment using ultrasound (ter Haar 1995;Kennedy 2005;Rabkin et al 2006;Coussios et al 2007;Farny et al 2008;Leighton et al 2008c;McLaughlan et al in press).…”

Section: Discussionmentioning

confidence: 99%

Clutter suppression and classification using twin inverted pulse sonar (TWIPS)

et al. 2010

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This paper describes the detection and classification of targets against clutter by distinguishing between linear and nonlinear scatterers and, further, by distinguishing those nonlinear targets that scatter energy at the even-powered harmonics from those that scatter in the odd-powered harmonics. This is done using twin inverted pulse sonar (TWIPS), which can also, in some manifestations, require no range correction (and therefore does not require the a priori knowledge of the environment needed for most remote detection technologies). The method applies, in principle, to a range of sensor technologies, including the use of radar to distinguish between circuitry, metal and soil; Light Detection and Ranging (LIDAR) to detect combustion products; and Magnetic Resonance Imaging (MRI). A sonar application is demonstrated, detecting objects in bubbly water (including in the wake of a ship of 3953 gross register tonnage). A manmade sonar that can operate in bubbly water is relevant: Cold War sonar is not optimized for the shallow coastal waters that typify many current operations. The US Navy use dolphins in such waters. TWIPS arose as a demonstration that echolocation was possible in bubbly water in response to a video showing dolphins generating bubble nets when hunting: if echolocation were impossible in these nets, then during this hunt, the dolphins would have blinded their sonar.

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Section: Discussionmentioning

confidence: 99%

Clutter suppression and classification using twin inverted pulse sonar (TWIPS)

et al. 2010

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“…Imaging active sonars can then confirm range and bearing from time-of-flight and beamforming (figure 8d) and, within limitation, quantify the gas flux (De Beukelaer et al 2003;Sauter et al 2006;Nikolovska & Schanze 2007;von Deimling et al 2007;Westbrook et al 2009), but the bubble size distribution would be an estimate limited by the bandwidth that is affordable (Maksimov & Sosedko 2002;Maksimov 2003a,b). However, the power required for an active capability can also be used to acquire bottom and sub-bottom sonar of the associated geological and gaseous features (Paull et al 1995;Krastel et al 2003;Naudts et al 2008): such techniques, which can detect (and even quantify; Leighton & Robb 2008) gas release into the sediment before the gas reaches the water column, are particularly valuable for CCS facilities. Subsidiary information (e.g.…”

Section: Practical Applicationsmentioning

confidence: 99%

“…The topic of gas bubbles in marine sediments is of increasing importance (Judd 2003), first, because of the impact those bubbles have on the structural integrity and load-bearing capabilities of the sediment (Wheeler & Gardiner 1989;Sills et al 1991;Briggs & Richardson 1996); second, because of the impact which the bubbles have on any acoustic systems used to characterize the sediment (Anderson & Hampton 1980a,b;Karpow et al 1996;Anderson et al 1998;Boyle & Chotiros 1998;Wilkens & Richardson 1998;Gardner 2000;Leighton 2007;Leighton & Robb 2008); and third, because the presence of bubbles can be indicative of a range of biological, chemical or geophysical processes. This includes the assessment of gas reserves for fuel and the climatologically important flux of methane from the seabed to the atmosphere (Judd 2003).…”

Section: Introductionmentioning

confidence: 99%

Quantification of undersea gas leaks from carbon capture and storage facilities, from pipelines and from methane seeps, by their acoustic emissions

Leighton

White

2011

Proc. R. Soc. A.

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In recent years, because of the importance of leak detection from carbon capture and storage facilities and the need to monitor methane seeps and undersea gas pipelines, there has been an increased requirement for methods of detecting bubbles released from the seabed into the water column. If undetected and uncorrected, such leaks can generate huge financial and environmental losses. This paper describes a theory by which the passive acoustic signals detected by a hydrophone array can be used to quantify gas leakage, providing a practical (as opposed to research), passive and remote detection system which can monitor over a period of years using simple instrumentation. The sensitivity in detecting and quantifying the flux of gas is shown to exceed by more than two orders of magnitude the sensitivity of the current model-based techniques used commercially for gas leaks from large, long pipelines.

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“…Other potential production mechanisms for bubbles include production by the respiration of phytoplankton (Medwin, 1970;Johnson and Wangersky, 1987), release from the sea bed (e.g. Leighton and Robb, 2008), gases coming out of solution as gas-saturated water warms (Norris et al, 2011), and where sea ice is present the release of bubbles trapped in melting ice or expelled during the freezing process (Wettlaufer, 1998).…”

Section: Introductionmentioning

confidence: 99%

Near-surface measurements of sea spray aerosol production over whitecaps in the open ocean

et al. 2013

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Abstract. Simultaneous measurements of near-surface aerosol (0.12 < R < 9.25 µm) and bubble spectra (13 < R < 620 µm) were made during five buoy deployments in the open ocean of the North Atlantic and used to estimate aerosol fluxes per unit area of whitecap. The measurements were made during two cruises as part of the Sea Spray, Gas Flux, and Whitecaps (SEASAW) project, a UK contribution to the international Surface Ocean Lower Atmosphere Study (SOLAS) program. The mean bubble number concentrations for each deployment are in broad agreement with other open ocean spectra and are consistently one to two orders of magnitude lower than surf zone studies. Production fluxes per unit area of whitecap are estimated from the mean aerosol concentration for each buoy deployment. They are found to increase with wind speed, and span the range of values found by previous laboratory and surf-zone studies for particles with radius at 80 % relative humidity, R 80 < 1 µm, but to drop off more rapidly with increasing particle size for larger particles. Estimates of the mean sea spray flux were made by scaling the whitecap production fluxes with in situ estimates of whitecap fraction. The sea spray fluxes are also compared with simultaneous individual eddy covariance flux estimates, and with a sea spray source function derived from them.

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Preliminary mapping of void fractions and sound speeds in gassy marine sediments from subbottom profiles

Cited by 34 publications

References 49 publications

Clutter suppression and classification using twin inverted pulse sonar (TWIPS)

Clutter suppression and classification using twin inverted pulse sonar (TWIPS)

Quantification of undersea gas leaks from carbon capture and storage facilities, from pipelines and from methane seeps, by their acoustic emissions

Near-surface measurements of sea spray aerosol production over whitecaps in the open ocean

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