Karen G Bemis, Rutgers University, Marine and Coastal Sciences, New Brunswick, NJ, United States; Applied Physics Laboratory University of Washington, Seattle, NJ, United States, Guangyu Xu, Applied Physics Laboratory University of Washington, Acoustics, Seattle, WA, United States, Darrell R. Jackson, University of Washington Seattle Campus, Applied Physics Laboratory, Seattle, WA, United States and Anatoliy N. Ivakin, Applied Physics Laboratory University of Washington, Seattle, WA, United States