The hydroacoustic method for the quantification of the gas flux from a submersed bubble plume

Muyakshin, S. I.; Sauter, Eberhard-Jürgen

doi:10.1134/s0001437010060202

Cited by 30 publications

(32 citation statements)

References 9 publications

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“…Accurately calculating gas flow rates using hydroacoustic methods is needed but different research groups still use very different approaches (Artemov et al ; Nikolovska et al ; Ostrovsky et al ; Muyakshin and Sauter ; Jerrem et al in press). To date, no standard methodology exists for analyzing free gas flow rates of large bubbles in deep water (> 100 m) with ship‐based hydroacoustic systems alone.…”

Section: Materials and Proceduresmentioning

confidence: 99%

A new methodology for quantifying bubble flow rates in deep water using splitbeam echosounders: Examples from the Arctic offshore NW‐Svalbard

Veloso

Greinert

Mienert

et al. 2015

Limnology & Ocean Methods

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Quantifying marine methane fluxes of free gas (bubbles) from the seafloor into the water column is of importance for climate related studies, for example, in the Arctic, reliable methodologies are also of interest for studying man-made gas and oil leakage systems at hydrocarbon production sites. Hydroacoustic surveys with singlebeam and nowadays also multibeam systems have been proven to be a successful approach to detect bubble release from the seabed. A number of publications used singlebeam echosounder data to indirectly quantify free gas fluxes via empirical correlations between gas fluxes observed at the seafloor and the hydroacoustic response. Others utilize the hydroacoustic information in an inverse modeling approach to derive bubble fluxes. Here, we present an advanced methodology using data from splitbeam echosounder systems for analyzing gas release water depth (> 100 m). We introduce a new MATLAB-based software for processing and interactively editing data and we present how bubble-size distribution, bubble rising speed and the model used for calculating the backscatter response of single bubbles influence the final gas flow rate calculations. As a result, we highlight the need for further investigations on how large, wobbly bubbles, bubble clouds, and multi-scattering influence target strength. The results emphasize that detailed studies of bubble-size distributions and rising speeds need to be performed in parallel to hydroacoustic surveys to achieve realistic mediated methane flow rate and flux quantifications.

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Section: Materials and Proceduresmentioning

confidence: 99%

A new methodology for quantifying bubble flow rates in deep water using splitbeam echosounders: Examples from the Arctic offshore NW‐Svalbard

Veloso

Greinert

Mienert

et al. 2015

Limnology & Ocean Methods

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“…The use of remote acoustic methods is preferable here. The conventional methods of determining the methane flux in a gas flare [15,28] are based on estimating the methane volume carried by bubbles from data on the backscattering level, and, hence, they also determine the upward methane flux. In addition, to obtain such an estimate, the acoustic data should be supplemented with data on the distribution functions characterizing the distributions of bubbles in their upward velocity, size, and shape at individual depths.…”

Section: Methodsmentioning

confidence: 99%

An acoustic estimate of methane concentration in a water column in regions of methane bubble release

et al. 2014

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A remote acoustic method is presented for estimating the methane flux into water from rising bub bles. With the proposed method and data of hydroacoustic measurements in the Sea of Okhotsk, the dissolved methane concentration profile that forms in the water column in regions of methane bubble release is esti mated. Comparison of the aforementioned methane concentration profile with results of direct measure ments shows good quantitative and qualitative agreement. This testifies to the fair accuracy of the proposed acoustic method and is indicative of the dominant role of bubble transport in the formation of the concentra tion of dissolved methane in the water column in such regions.

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“…The dependence on flow rate and bubble size matched predictions from an analytical model of the expected sonar response to a constant bubble stream rising through a horizontally oriented multibeam sonar. The expected response from a bubble stream with a wide but constant bubble size distribution was calculated by adapting a method that was developed for single and split beam sonar [Muyakshin and Sauter, 2010;Veloso et al, 2015], assuming a constant bubble size distribution measured in UML with an optical bubble sizer [Delwiche et al, 2015] and assuming that plumes are too sparse to be influenced significantly by multiple scatter reflections (see supporting information). The relative uncertainty in flux estimates is estimated to be ∼70% (see supporting information).…”

Section: A2 Calibrationmentioning

confidence: 99%

Ephemerality of discrete methane vents in lake sediments

Scandella

Pillsbury

Weber

et al. 2016

Geophysical Research Letters

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Methane is a potent greenhouse gas whose emission from sediments in inland waters and shallow oceans may both contribute to global warming and be exacerbated by it. The fraction of methane emitted by sediments that bypasses dissolution in the water column and reaches the atmosphere as bubbles depends on the mode and spatiotemporal characteristics of venting from the sediments. Earlier studies have concluded that hot spots—persistent, high‐flux vents—dominate the regional ebullitive flux from submerged sediments. Here the spatial structure, persistence, and variability in the intensity of methane venting are analyzed using a high‐resolution multibeam sonar record acquired at the bottom of a lake during multiple deployments over a 9 month period. We confirm that ebullition is strongly episodic, with distinct regimes of high flux and low flux largely controlled by changes in hydrostatic pressure. Our analysis shows that the spatial pattern of ebullition becomes homogeneous at the sonar's resolution over time scales of hours (for high‐flux periods) or days (for low‐flux periods), demonstrating that vents are ephemeral rather than persistent, and suggesting that long‐term, lake‐wide ebullition dynamics may be modeled without resolving the fine‐scale spatial structure of venting.

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The hydroacoustic method for the quantification of the gas flux from a submersed bubble plume

Cited by 30 publications

References 9 publications

A new methodology for quantifying bubble flow rates in deep water using splitbeam echosounders: Examples from the Arctic offshore NW‐Svalbard

A new methodology for quantifying bubble flow rates in deep water using splitbeam echosounders: Examples from the Arctic offshore NW‐Svalbard

An acoustic estimate of methane concentration in a water column in regions of methane bubble release

Ephemerality of discrete methane vents in lake sediments

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