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Chris Bassett

Senior Mechanical Engineer

Email

cbassett@uw.edu

Phone

206-543-1263

Research Interests

Passive noise studies, acoustic scattering, sea ice, marine renewable energy, fisheries acoustics, anthropogenic noise

Biosketch

Chris applies passive and active acoustic techniques to a variety of underwater applications. Some of his previous and ongoing studies include fisheries acoustics; high-frequency scattering from sea ice, crude oil, and physical oceanographic processes; measurements of anthropogenic noise; and ambient noise studies.

Department Affiliation

Ocean Engineering

Education

B.S. Mechanical Engineering, University of Minnesota, 2007

M.S. Mechanical Engineering, University of Washington, 2010

Ph.D. Mechanical Engineering, University of Washington, 2013

Publications

2000-present and while at APL-UW

Classification of broadband target spectra in the mesopelagic using physics-informed machine learning

Cotter, E., C. Bassett, and A. Lavery, "Classification of broadband target spectra in the mesopelagic using physics-informed machine learning," J. Acoust. Soc. Am., 149, 3889-3901, doi:10.1121/10.0005114, 2021.

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1 Jun 2021

Broadband echosounders measure the scattering response of an organism over a range of frequencies. When compared with acoustic scattering models, this response can provide insight into the type of organism measured. Here, we train the k-Nearest Neighbors algorithm using scattering models and use it to group target spectra (25–40 kHz) measured in the mesopelagic near the New England continental shelf break. Compared to an unsupervised approach, this creates groupings defined by their scattering physics and does not require significant tuning. The model classifies human-annotated target spectra as gas-bearing organisms (at, below, or above resonance) or fluid-like organisms with a weighted F1-score of 0.90. Class-specific F1-scores varied — the F1-score exceeded 0.89 for all gas-bearing organisms, while fluid-like organisms were classified with an F1-score of 0.73. Analysis of classified target spectra provides insight into the size and distribution of organisms in the mesopelagic and allows for the assessment of assumptions used to calculate organism abundance. Organisms with resonance peaks between 25 and 40 kHz account for 43% of detections, but a disproportionately high fraction of volume backscatter. Results suggest gas bearing organisms account for 98.9% of volume backscattering concurrently measured using a 38 kHz shipboard echosounder between 200 and 800 m depth.

Comparison of mesopelagic organism abundance estimates using in situ target strength measurements and echo-counting techniques

Cotter, E., C. Bassett, and A. Lavery, "Comparison of mesopelagic organism abundance estimates using in situ target strength measurements and echo-counting techniques," J. Acoust. Soc. Am. EL, 1, 040801, doi:10.1121/10.0003940, 2021.

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2 Apr 2021

Recent studies using acoustic techniques suggest that the biomass of mesopelagic fishes may be an order of magnitude higher than previously estimated from trawls. However, there is uncertainty surrounding these estimates, which are derived from shipboard echosounder measurements using necessary, but poorly constrained, assumptions. Here, an echosounder is used to measure individual target strengths at depth. These measurements are used to infer mesopelagic organism density through echo-counting. Measured target strengths are used to estimate organism density by inverting shipboard echosounder measurements. The two sampling methods agree well, but highlight the importance of accurate target strength measurements.

Risk to marine animals from underwater noise generated by marine renewable energy devices

Polagye, B., and C. Bassett, "Risk to marine animals from underwater noise generated by marine renewable energy devices," in OES-Environmental 2020 State of the Science Report: Environmental Effects of Marine Renewable Energy Development Around the World, A.E. Copping and L.G. Hemery, eds., 67-85, doi:10.2172/1633082 (Ocean Energy Systems, 2020).

30 Sep 2020

More Publications

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center
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