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Eric Thorsos

Sr. Principal Physicist--Retiree

Affiliate Associate Professor, Electrical Engineering





Research Interests

Shallow Water Acoustic Propagation, Sediment Acoustics, Rough Surface Scattering


Dr. Thorsos research addresses high-frequency sound penetration into, propagation within, and scattering from the shallow-water seafloor. One finding is that high-frequency acoustic penetration into sediments at grazing angles below the critical angle is possible--an important issue in detection of buried mines.

Dr. Thorsos is also presently leading a project to improve our understanding of the effects of sea surface and bottom roughness on shallow water propagation, and to determine the best approaches to modeling this propagation. A specialist in numerical studies of scattering theory and on the validity of scattering theory approximations, Dr. Thorsos publishes in the Journal of the Acoustical Society of America and the IEEE Journal of Oceanic Engineering.

Department Affiliation



B.S. Physics, Harvey Mudd College, 1965

M.S. Engineering & Applied Science, University of California, Davis-Livermore, 1966

Ph.D. Theoretical Nuclear Physics, MIT, 1972


2000-present and while at APL-UW

Open ocean ambient noise data in the frequency band of 100 Hz – 50 kHz from the Pacific Ocean

Yang, J., J.A. Nystuen, S.C. Riser, and E.I. Thorsos, "Open ocean ambient noise data in the frequency band of 100 Hz – 50 kHz from the Pacific Ocean," JASA Express Lett., 3, doi:10.1121/10.0017349, 2023.

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1 Mar 2023

Bubbles from wind generated breaking surface waves are the dominant ambient noise source. With ambient noise data collected in the open ocean between 100 Hz and 50 kHz from 1999 to 2022, the ambient noise level is observed to sharply decrease as wind speed increases beyond 15 m/s for frequencies higher than 4 kHz. Data-model comparisons show a mismatch, as existing models including the Wenz curves are monotonic in nature. The decrease at high wind speeds and frequencies is likely due to attenuation when ambient sound propagates through the deeper and denser bubble layer for high sea conditions.

Macroscopic observations of diel fish movements around a shallow water artificial reef using a mid-frequency horizontal-looking sonar

Lee, W.-J., D. Tang, T.K. Stanton, and E.I. Thorsos, "Macroscopic observations of diel fish movements around a shallow water artificial reef using a mid-frequency horizontal-looking sonar," J. Acoust. Soc. Am., 144, 1424-1434, doi:10.1121/1.5054013, 2018.

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18 Sep 2018

The twilight feeding migration of fish around a shallow water artificial reef (a shipwreck) was observed by a horizontal-looking, mid-frequency sonar. The sonar operated at frequencies between 1.8 and 3.6 kHz and consisted of a co-located source and horizontal line array deployed at 4 km from the reef. The experiment was conducted in a well-mixed shallow water waveguide which is conducive to characterizing fish aggregations at these distances. Large aggregations of fish were repeatedly seen to emerge rapidly from the shipwreck at dusk, disperse into the surrounding area during the night, and quickly converge back to the shipwreck at dawn. This is a rare, macroscopic observation of an ecologically-important reef fish behavior, delivered at the level of aggregations, instead of individual fish tracks that have been documented previously. The significance of this observation on sonar performance associated with target detection in the presence of fish clutter is discussed based on analyses of echo intensity and statistics. Building on previous studies of long-range fish echoes, this study further substantiates the unique utility of such sonar systems as an ecosystem monitoring tool, and illustrates the importance of considering the impact of the presence of fish on sonar applications.

On sensing nitro-group containing compounds using thin planar arrays of titanium dioxide nanowires

Asher, W.E., P. Colosimo, E.I. Thorsos, and A. Yao, "On sensing nitro-group containing compounds using thin planar arrays of titanium dioxide nanowires," IEEE Sens. J., 18, 6927-6936, doi:10.1109/JSEN.2018.2855110, 2018.

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1 Sep 2018

Previous laboratory results have suggested that unheated TiO2 nanowire arrays provide a means to detect trace level concentrations of nitro-group containing compounds in the gas phase with fast response and high chemical selectivity. The detection method is based on the chemiresistive effect, where an electron-deficient compound adsorbed to the surface of an n-type semiconductor causes a surface charge deficit on the semiconductor leading to an increase in its resistance. However, a major issue with this method is that chemiresistive sensors based on TiO2 are also sensitive to the presence of water vapor, and this cross-sensitivity could lead to artifacts for sensors used under environmental conditions. Results are presented here, where thin planar arrays of TiO2 nanowires were tested to determine the sensitivity towards water vapor, along with the detection limits and response times towards several nitrocontaining organic molecules as a function of gas-phase water vapor concentration. When water vapor concentrations were carefully controlled to ensure they remain constant throughout the testing cycle, it was found that TiO2 nanowire devices could detect 2,4,6-trinitrotoluene at a concentration as low as a few tens of part per trillion by volume with a response time in the range of 102 – 103 s, depending on experimental conditions.

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