Acoustic Scattering of Large Wobbly Bubbles

TitleAcoustic Scattering of Large Wobbly Bubbles
Publication TypePoster - Conference
AuthorsPadilla, AM, Weber, TC
Conference NameBubbles 2017
Conference DatesJune 6-16
Conference LocationTromso, Norway
KeywordsAcoustic Scattering; Gas Bubbles;

Our research group uses acoustic systems, such as split-beam or multibeam echosounders found on most research vessels, to observe and quantify gas flux of methane bubbles released from both shallow and deep seafloor settings. Ebullition of methane gas from the seafloor plays an important role in climate forcing. The majority of methane bubbles released from the seafloor (especially deep water), while unlikely to survive transport through the water column to the atmosphere, export methane into the water column resulting in ocean acidification. Gaseous methane released in shallow water (<100 m) can facilitate the transport of methane directly to the atmosphere, resulting in direct climate forcing.

Flux measurements of methane gas can be obtained using gas traps and/or optical methods; however these single point source methods are often time consuming and expensive. Acoustic methods have proven to be an efficient alternative for methane gas flux measurements due to its versatility. Acoustic measurements can be calibrated and can be obtained at point sources or over large areas of interest.  We can obtain bubble size estimates by converting acoustic backscatter measurements of bubbles to bubble target strength using analytical models.

My general research interest is in refining acoustic techniques for measuring bubbles in the ocean using a variety of techniques including broadband, split-beam, and multibeam echosounders. Currently I am investigating the acoustic inversion errors associated with assuming that large bubbles are spherical when, in-fact, experimental and field observations show that bubbles with a radius greater than 1 mm are non-spherical.