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Chris Bassett

Senior Mechanical Engineer





Research Interests

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


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


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

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

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


Connecting to the Ocean's Power: Marine Energy Research at APL-UW

The U.S. Navy's support of the University of Washington, one of the nation's preeminent research universities, leverages APL-UW capabilities with university academic expertise to address a wide range of topics in marine energy through experimentation and evaluation in laboratory settings and field deployments of prototype systems.
Companion to the technical report, APL-UW TR 2301.

5 Jul 2023

Turbulence Generated by Tides in the Canal de Chacao, Chile

At a proposed tidal energy conversion site in southern Chile, APL-UW researchers are measuring the magnitude and scales of turbulence, both to aid in the design of turbines for the site and to understand the fundamental dynamics of flows through the channel.

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7 Mar 2013

Principal Investigator Jim Thomson chronicled all phases of the Chilean experiment through posts to the New York Times 'Scientist at Work' blog.

Sound Sounds: Listening to the Undersea Noise in Puget Sound

Doctoral student researcher Chris Bassett is analyzing a long time series of ambient noise data from Puget Sound. Vessel traffic is the most significant noise source, but breaking waves, precipitation, biology, and sediment moving on the seabed are other common underwater noise sources. The research is being pursued in conjunction with a program to assess the environmental impacts from a tidal energy conversion system placed on the seafloor.

13 Mar 2012


2000-present and while at APL-UW

Motion tracking of fish and bubble clouds in synthetic aperture sonar data

Marston, T.M., B.R. Hall, C. Bassett, D.S. Plotnick, and A.N. Kidwell, "Motion tracking of fish and bubble clouds in synthetic aperture sonar data," J. Acoustic. Soc. Am., 155, 2181-2191, doi:10.1121/10.0025384, 2024.

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21 Mar 2024

Data captured by a Synthetic Aperture Sonar (SAS) near Mobile Bay during the 2021 Undersea Remote Sensing experiment funded by the Office of Naval Research reveals near surface bubble clouds from wave breaking events and a large aggregation of fish. Tools developed for using SAS data to image hydrodynamic features in the water column were applied to observations of the bubble clouds and fish aggregation. Combining imagery and height data captured by the sonar array with a detection and tracking algorithm enables the trajectories, velocities, and behavior of fish in the aggregation to be observed. Fitting the velocity and height data of the tracked objects to a Gaussian mixture model and performing cluster analysis enables an estimate of the near-surface ambient velocity via observation of the movement of the bubble traces and the general direction of motion of the fish aggregation. We find that the velocity traces associated with bubbles are consistent with ambient currents as opposed to the direction of propagating wave crests while velocities of fish indicate relatively large, pelagic species.

The structure and dynamics of an estuarine tidal intrusion front

Geyer, W.R., D.K. Ralston, M.C. Haller, C. Bassett, and D. Honegger, "The structure and dynamics of an estuarine tidal intrusion front," J. Geophys. Res., 129, doi:10.1029/2023JC020371, 2024.

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1 Feb 2024

Tidal intrusion fronts are surface convergences that occur at constrictions in estuaries during the flood tide, separating incoming higher-salinity water from lower-salinity, stratified estuarine water. Previous observations of tidal intrusion fronts describe a V-shaped planform, with the apex of the V pointing into the estuary, however the significance of this structure has not been previously explained. Observations near the mouth of the James River estuary during the flood tide reveal the development of a quasi-steady, V-shaped front. Considering a reference frame oriented normal to the front, the velocity and density structure are consistent with gravity-current dynamics, but the oblique orientation of the front relative to the impinging flow indicates strong, along-front shear, which results from vorticity produced by flow separation at the lateral boundaries as well as topographic torque from upstream. The combination of convergence and along-front shear leads to enhanced mixing, as revealed by acoustic backscatter images of shear instability and persistent subcritical gradient Richardson number in the frontal zone. Oblique fronts such as this tidal intrusion front are common features of estuaries, and they play an important role in vertical exchange due to subduction and mixing of surface water.

Calibration and Processing of Nortek Signature1000 Echosounders

Bassett, C., and K. Zeiden, "Calibration and Processing of Nortek Signature1000 Echosounders," Technical Report, APL-UW TR 2307, Applied Physics Laboratory, University of Washington, Seattle, December 2023, 40 pp.

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27 Dec 2023

The five-beam Nortek Signature series acoustic Doppler current profilers (ADCPs) include a vertical beam that can be operated as an echosounder. These echosounders record an echo intensity level as a function of range in hundredths of a decibel. While these recorded levels provide valuable qualitative information about scattering from the water column, without calibration the units’ recorded echo intensities cannot be linked quantitatively to scattering processes. In this report we summarize calibration results for six Nortek Signature1000 units. The echosounders were calibrated in the field while deployed on 4th generation Surface Wave Instrument Floats with Tracking (SWIFTs) by suspending 38.1-mm tungsten carbide spheres with 6% cobalt binder below. Here, we summarize the equations used to process Nortek Signature series echosounder data, general calibration procedures for echosounders, the methodology used to calibrate the six units, the results of the calibrations, and uncertainties and recommendations for future work. In addition, we present post-processed, calibrated echosounder data from a deployment of the SWIFTs equipped with the Signature1000s in Mobile Bay, Alabama.

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