What We Do
The Acoustics Department studies the propagation and scattering of sound. Historically our primary focus has been the ocean and on structures in the ocean using theory and numerical modeling backed by ocean experiments. In the next ten years we plan to strengthen our non-ocean related research efforts.
Our research spans the frequency range from a few hertz to hundreds of kilohertz. We seek to understand and quantitatively predict propagation and scattering (the ‘forward’ problem). These predictions require detailed knowledge of the environment and the material properties of targets. To measure the ocean environment, we collaborate with physical, biological and geophysical oceanographers. Those same collaborations are essential to our development of acoustical oceanography techniques (the ‘inverse’ problem).
A forward problem in environmental acoustics asks, "Given the environment, what is the received signal?" High fidelity forward models then allow us to address the inverse problem, "Given recorded acoustic data, what is the environment?" Solving the forward problem requires a combination of physical understanding, theoretical development, and analytic and numerical modeling. The inverse problem offers many challenges as well, since it may be nonlinear, non-unique, and sensitive to uncertainty in environmental properties and the details of the acoustic data.
Acoustic propagation and scattering from volume heterogeneities and surface roughness
- Undersea acoustic communications
- Remote sensing of the environment
- Acoustical oceanography
- Scattering from objects deployed in the ocean
- Ambient noise in air and underwater environments
- Measurement and control of underwater industrial noise
- Arctic acoustics
Philip Marston, WSU
TREX13: Target and Reverberation EXperiment 2013
This ocean acoustics experiment measured mid-frequency reverberation and the abilities to detect and classify unexploded ordnance and mine-like targets on the seafloor using synthetic aperture sonar in a shallow water environment off Panama City, FL. More >>
Acoustic Color of Mines & Mine-Like Objects Kevin Williams, Steven Kargl, Aubrey España (PDF 3 MB)
Acoustic Detection of Unexploded Ordnance Aubrey España's presentation at the 31 Oct 2011 Acoustical Society of America's Webcast on Discoveries in Acoustics (Quicktime Movie, 64 MB)
Acoustic Intensity Properties in an Ocean Waveguide David Dall-Osto, Peter H. Dahl (PPT 2 MB)
Modeling a Spiral Wave Front Source in an Ocean Environment Brian T. Hefner, Benjamin R. Dzikowicz (PDF 15.6 MB)
Pressure-particle Velocity Coherence David Dall-Osto, Peter H. Dahl (PPT 3 MB)
Physics-Based Inversion of High-Frequency Multibeam Sonar Data Darrell Jackson and Brian T. Hefner (PDF 250 Kb)
In the News
Mystery of bowhead whale song
Everett Herald, Sharon Wootton
16 Mar 2014
Oceanographer Kate Stafford of the University of Washington%u2019s Applied Physics Laboratory, is researching the sounds of bowhead whales in Fram Strait off the coast of Greenland. Based on the song diversity, loudness and period over which the songs were recorded, western Fram Strait appears to be a wintering ground and potentially a mating area, as well.
Whales, ships more common through Bering Strait
UW News and Information, Hannah Hickey
26 Feb 2014
The Arctic is home to a growing number of whales and ships, and to populations of sub-Arctic whales that are expanding their territory into newly ice-free Arctic waters.
Scientists look to marine mammals to shed light on Arctic ice loss
Minnesota Public Radio, Kerri Miller
4 Jun 2013
University of Washington marine mammal ecologist Kristin Laidre and Kate Stafford, principal oceanographer at the Applied Physics Laboratory at Washington University, are using their studies of Arctic mammals to unlock some of the mysteries of ice loss. Kerri Miller held a conversation with the two scientists at the World Science Festival.
Marston, T.M., and D.S. Plotnick, "Semiparametric statistical stripmap synthetic aperture focusing," IEEE Trans. Geosci. Remote Sens., 53, doi:10.1109/TGRS.2014.2353515, 2086-2095.
1 Apr 2015, Link
Risch, D., et al., including K. Stafford, "Seasonal migrations of North Atlantic minke whales: Novel insights from large-scale passive acoustic monitoring networks," Movement Ecol., 2, doi:10.1186/s40462-014-0024-3, 2014.
18 Nov 2014, Link
Xu, G., D.R. Jackson, K.G. Bemis, and P.A. Rona, "Time-series measurements of hydrothermal heat flux at the Grotto mound, Endeavor Segment, Juan de Fuca Ridge," Earth Planet. Sci. Lett., 404, 220-231, doi:10.1016/j.epsl.2014.07.040, 2014.
15 Oct 2014, Link
Graduate and undergraduate students can work under the tutelage of the Acoustics Department investigators through their respective home UW academic colleges, including oceanography, engineering, and earth and space sciences. More >>
Dr. Peter Dahl, for example, teaches Applied Acoustics (Mechanical Engineering 525), which introduces acoustics through its various applications and sub-fields, such as underwater sound (inlcuding sonar), medical ultrasound, and noise control and vibration.