Tuesday, May 05, 2015

Michigan Tech News: Listening Under the Ice

By Allison Mills, Michigan Tech Science and Technology Writer
Posted April 28 and updated Apr. 30, 2015, on Michigan Tech News
Reprinted in part with permission.

Andrew Barnard, assistant professor in mechanical engineering studying acoustics at Michigan Tech, helped install this passive hydrophone system off the dock at the Great Lakes Research Center. "Passive acoustics is just listening to whatever is out there," he said. (Photo © Andrew Barnard and courtesy Michigan Tech University)

HOUGHTON -- Spring is finally here in Michigan's Upper Peninsula -- and the thaw marks the first season of under-ice acoustics studies completed at the Great Lakes Research Center by Michigan Technological University researchers.

The watery world under winter’s ice is a mystery. It’s also a world full of sound. Now, as the days lengthen and the ice is retreating, researchers at Michigan Technological University are wrapping up their first winter season of underwater acoustic studies.

Learning more about acoustic properties underwater -- and specifically under the ice -- is important for designing acoustic communication networks and quiet underwater vehicles. These networks and vehicles have a range of applications. Environment monitoring is an example, encompassing everything from ice movement to the habits of aquatic critters to keeping tabs on chemical conditions.

Michigan Tech researchers work with a hydrophone network on L'Anse Bay. Zhaohui Wang, assistant professor of electrical and computer engineering at Michigan Tech, studies underwater wireless communication networks. (Photo © Zhaohui Wang and courtesy Michigan Tech University)

Although the applications are broad, studying acoustics all comes back to sound: Beeps and chirps for network signals, the glassy crinkle of floating ice and even the underwater reverb of a snowmobile passing by. Each sound tells a story; each narrative helps researchers understand the icy-cold depths we can’t normally see. ...

Click here to read the rest of this article and to LISTEN to sounds under the ice recorded by Michigan Tech Professors Andrew Barnard and Zhaohui Wang.

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