scholarly journals Distribution and height of methane bubble plumes on the Cascadia Margin characterized by acoustic imaging

2003 ◽  
Vol 30 (12) ◽  
Author(s):  
Katja U. Heeschen ◽  
Anne M. Tréhu ◽  
Robert W. Collier ◽  
Erwin Suess ◽  
Gregor Rehder
Keyword(s):  
Acoustic Imaging ◽  
Bubble Plumes ◽  
Cascadia Margin ◽  
Methane Bubble

scholarly journals Observations of Shallow Methane Bubble Emissions From Cascadia Margin

2021 ◽  
Vol 9 ◽  
Author(s):  
Anna P. M. Michel ◽  
Victoria L. Preston ◽  
Kristen E. Fauria ◽  
David P. Nicholson
Keyword(s):  
Water Column ◽  
Water Depth ◽  
Dissolved Methane ◽  
Multibeam Sonar ◽  
Surface Ocean ◽  
Transient Nature ◽  
Technological Approach ◽  
Open Questions ◽  
Cascadia Margin ◽  
Methane Bubble

Open questions exist about whether methane emitted from active seafloor seeps reaches the surface ocean to be subsequently ventilated to the atmosphere. Water depth variability, coupled with the transient nature of methane bubble plumes, adds complexity to examining these questions. Little data exist which trace methane transport from release at a seep into the water column. Here, we demonstrate a coupled technological approach for examining methane transport, combining multibeam sonar, a field-portable laser-based spectrometer, and the ChemYak, a robotic surface kayak, at two shallow (<75 m depth) seep sites on the Cascadia Margin. We demonstrate the presence of elevated methane (above the methane equilibration concentration with the atmosphere) throughout the water column. We observe areas of elevated dissolved methane at the surface, suggesting that at these shallow seep sites, methane is reaching the air-sea interface and is being emitted to the atmosphere.

scholarly journals Sonar Gas Flux Estimation by Bubble Insonification: Application to Methane Bubble Fluxes from the East Siberian Arctic Shelf Seabed

2016 ◽  
Author(s):  
Ira Leifer ◽  
Denis Chernykh ◽  
Natalia Shakhova ◽  
Igor Semiletov
Keyword(s):  
Power Law ◽  
Mass Flux ◽  
Methane Flux ◽  
Bubble Plume ◽  
Single Beam ◽  
Bubble Plumes ◽  
Bubble Dispersion ◽  
Methane Fluxes ◽  
Methane Bubble

Abstract. Sonar surveys provide an effective mechanism for mapping seabed methane flux emissions, with Arctic submerged permafrost seepage having great potential to significantly affect climate. We created in situ engineered bubble plumes from 40-m depth with fluxes spanning 0.019 to 1.1 L/s to derive the in situ calibration curve, Q(σ). Non-linear curves relating volume flux, Q, to sonar return, s, for a multibeam echosounder (MBES) and a single beam echosounder (SBES) for a range of depths demonstrated significant bubble-bubble acoustic interactions – precluding the use of a theoretical calibration function, Q(σ), wherein bubble σ(r) scales with the radius, r, size distribution. Bubble plume sonar occurrence, Ψ(σ), with respect to Q found Ψ(σ) for weak σ well described by a power law that likely correlated with small bubble dispersion and strongly depth dependent. Ψ(σ) for strong s largely was depth-independent, consistent with bubble plume behavior where large bubbles in a plume remain in a focused core. As a result, Ψ(σ) was bimodal for all but the weakest plumes. Ψ(σ) was applied to sonar observations of natural arctic Laptev Sea, seepage including accounting for volumetric change with a numerical bubble plume. Based on MBES data, values of total mass flux, Qm, the mass flux, were 5.56, 42.73, and 4.88 mmol/s with good to reasonable agreement between the SBES and MBES data (4–37 %) for total Qm. Seepage occurrence, Ψ(Q) was bimodal, with weak Ψ(Q) in each seep area well described by a power law, suggesting primarily minor bubble plumes. Seepage mapped spatial patterns suggested subsurface geologic control attributing methane fluxes to the current state of subsea permafrost.

Simulation of the effect of methane bubble plumes on vertical mixing in Mono Lake

1996 ◽  
Vol 58 (3) ◽  
pp. 210-223 ◽  
Author(s):  
Jos� R. Romero ◽  
John C. Patterson ◽  
John M. Melack
Keyword(s):  
Vertical Mixing ◽  
Mono Lake ◽  
Bubble Plumes ◽  
Methane Bubble

Using video images to study Haima cold seep bubble plumes

2021 ◽  
Author(s):  
Kun Zhang ◽  
Haibin Song ◽  
Hongbin Wang ◽  
Yi Gong ◽  
Wenhao Fan ◽  
...  
Keyword(s):  
Flow Field ◽  
Optical Methods ◽  
Cold Seep ◽  
Bubble Plume ◽  
Video Images ◽  
Piv Method ◽  
Manual Analysis ◽  
Bubble Plumes ◽  
Methane Bubble ◽  
Plume Flow

<p>Cold seep is a widespread geological process mainly caused by hydrocarbon fluid migration. Methane bubble plumes released from cold seeps are often observed at the seafloor. These methane bubbles might be released into the atmosphere and have a huge effect on climate changes. It is of great significance for understanding the fate of these methane bubble plumes.</p><p>Many kinds of methods have been used to observe the methane bubble plumes, e.g., acoustical, geochemical, and optical methods. Video imaging is a kind of optical methods widely used in methane bubble plume studies. Compared to other methods, video imaging is a non-intrusive, high-resolution, and quick-collected method. Many studies have estimated bubbles' size, rise velocities, behavior, and the fate of bubbles by analyzing video images manually. However, manual analysis is time-consuming, one dimension, and has not been able to determine temporospatial changes in a two-dimension profile perspective.</p><p>In this study, we applied the manual analysis method and the particle image velocimetry (PIV) method to analyze in-situ video image sequences of Haima cold seep bubble plumes, a newly discovered, active cold seep in the Qiongdongnan Basin of the northern South China Sea during 2019. Quantitative and temporospatial change information about the plume flow filed is obtained. The results show that the sizes of bubbles in the plume range from 2.556 ~ 4.624 mm, with a rising velocity of ~ 0.26 m/s. The flux for an individual bubble stream is ~ 94.8 ml/min. The flow velocity field of the bubble plume is consistent with the manual analysis, and it reveals that the bubble plume's flow field is a multiscale turbulent flow field. The bubble plumes are usually V-shaped. Through carrying the adjacent water column, the bubble plumes swell and change rapidly. The direction and velocity of the bubble plume flow change with time, and its streamlines are sinuous. The max velocity of the bubble plume flow field changes at a 6.6 s period cycle.</p><p>Although there is some indetermination, our results show that the PIV method is feasible for calculating the bubble plume flow field and that it has some unique advantages, e.g., it is fast, non-invasive, it provides two-dimension temporospatial change images, and it has a high resolution. The images of the bubble plume flow field provide a new perspective to observe the cold seep systems. We hope that this method can be improved and widely applied in cold seep plume studies in the future.</p>

Dipole Shear Imaging behind casing: Extending the borehole Acoustic Imaging envelope to Brown-fields

2014 ◽  
Author(s):  
Ashok Srivastava ◽  
Hiroaki Yamamoto ◽  
Shabbir Ahmed ◽  
Jonathon Roberts ◽  
Fabrice Cantin ◽  
...  
Keyword(s):  
Acoustic Imaging

EXPERIMENTAL STUDIES ON AIR BUBBLE PLUMES IN CROSSFLOW

2016 ◽  
Author(s):  
Douglas de Almeida Garcia ◽  
Maria Helena Farias ◽  
Alessandra Santos ◽  
Samuel Araújo ◽  
Lucas Factor ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Air Bubble ◽  
Bubble Plumes

Borehole Acoustic Imaging Using 3D STC and Ray Tracing to Determine Far-Field Reflector Dip and Azimuth

2019 ◽  
Vol 60 (2) ◽  
pp. 335-347 ◽  
Author(s):  
Nicholas Bennett ◽  
◽  
Adam Donald ◽  
Sherif Ghadiry ◽  
Mohamed Nassar ◽  
...  
Keyword(s):  
Ray Tracing ◽  
Acoustic Imaging ◽  
Far Field

Electronic Package Failure Analysis Using TDR

2000 ◽  
Author(s):  
Dima A. Smolyansky
Keyword(s):  
Failure Analysis ◽  
Fault Location ◽  
Measurement Accuracy ◽  
Time Domain Reflectometry ◽  
Acoustic Imaging ◽  
X Ray ◽  
Analysis Techniques ◽  
Bga Packages ◽  
Impedance Profile ◽  
Nature Of Time

Abstract The visual nature of Time Domain Reflectometry (TDR) makes it a very natural technology that can assist with fault location in BGA packages, which typically have complex interweaving layouts that make standard failure analysis techniques, such as acoustic imaging and X-ray, less effective and more difficult to utilize. This article discusses the use of TDR for package failure analysis work. It analyzes in detail the TDR impedance deconvolution algorithm as applicable to electronic packaging fault location work, focusing on the opportunities that impedance deconvolution and the resulting true impedance profile opens up for such work. The article examines the TDR measurement accuracy and the comparative package failure analysis, and presents three main considerations for package failure analysis. It also touches upon the goal and the task of the failure analysts and TDR's specific signatures for the open and short connections.

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