Detection and Quantification of Submerged Oil Droplets by a Broadband, High-frequency Echo Sounder

TitleDetection and Quantification of Submerged Oil Droplets by a Broadband, High-frequency Echo Sounder
Publication TypeConference Abstract
AuthorsLoranger, S, Weber, TC
Conference Name2016 Gulf of Mexico Oil Spill and Ecosystem Science Conference
Conference LocationTampa, FL
Conference DatesFebruary 1-4
Keywordsacoustics, oil fate, physical processes, submerged oil droplets

The evolution and fate of dispersed oil droplets in the marine environment is crucial to the development of response protocols and to the assessment of risk for areas surrounding a spill. Current models of the movement of submerged oil droplets suffer from a lack of in-situ data for verification. Current in-situ measurement depends on short range instrumentation that is only capable of evaluating small segments of a spill at a time. Very high-frequency acoustics (few MHz), mass spectrometers, fluorometers and water sampling systems have very small fields of view, creating observational challenges when trying to generate a synoptic view of a spill. As an alternative, the use of broad-band high-frequency acoustics (100-500 kHz) is being explored. Broad-band high-frequency acoustics are capable of measuring and quantifying oil droplets at ranges of tens to hundreds of meters in a single measurement. The frequency-dependent acoustic response of oil droplets is dependent on the size, sound speed and density of oil droplets. Broadband high-frequency acoustic measurements of a variety of oils have been measured in the laboratory setting to quantify the droplet size dependent acoustic response of oils of varying density and sound speed. This instrumentation was able to differentiate between droplets with different radii. Results indicate that broadband high-frequency acoustics can be used to map the location of submerged oil droplets and to evaluate changes in the physical properties of oil for large areas of a spill.