Seminar: Acoustic inference of sea ice mechanical properties

D. Benjamin Reeder, Ph.D.
Research Professor
Department of Oceanography
Naval Postgraduate School, Monterey, CA, USA

*Zoom only*
Meeting ID: 963 5962 3640
Passcode: OREseminar
https://hawaii.zoom.us/j/96359623640

Arctic climate is important globally and regionally, in terms of its effects on global temperatures, global sea level, commercial activities and native coastal communities.  The Arctic energy budget is driven by atmospheric temperatures, cloud cover, wind patterns, freshwater discharge, oceanic forcing and sea ice cover.  Sea ice cover is particularly important because it buffers air-sea heat flux and strongly influences Earth’s absorption of solar radiation through ice-albedo feedback mechanism.  Understanding the relative contributions of all these factors to Arctic climate is challenging; our observations and modeling are incomplete.  To that end, work in the 1980s demonstrated that mechanical properties of Arctic sea ice can be inferred by observation of the speeds of compressional, shear and flexural waves generated through in-ice conversion of impulsive energy.  The work presented here (a) advances the work from the 1980s and 1990s by making use of coherent sources with which broadband signals can be generated to replace the manually-generated hammer-drop signals, leveraging processing gain and improving temporal resolution via matched filter; and (b) demonstrates the potential for remote, autonomous monitoring of sea ice mechanical properties via acoustic inference of recently-observed compressional resonances in the ice sheet in the Beaufort Sea.

Seminar Flyer