Acoustic characterization of the James River Estuary

D Benjamin Reeder1, Christopher Bassett2, Merrick C Haller3, David Honegger4, John Joseph5 and Thomas A Rago1, (1)Naval Postgraduate School, Oceanography, Monterey, CA, United States, (2)Applied Physics Laboratory, University of Washington, Seattle, WA, United States, (3)Oregon State University, School of Civil and Construction Engineering, Corvallis, OR, United States, (4)Oregon State University, School of Civil & Construction Engineering, Corvallis, OR, United States, (5)Naval Postgraduate School, Oceanography, Monterey, United States
Abstract:
Investigations of near-shore and in-shore environments have, rightly, focused on geological, thermodynamic and hydrodynamic parameters. A complementary acoustical characterization of the estuarine environment provides another layer of information to facilitate a more complete understanding of the physical environment. To this end, afield experiment was carried out in the James River Estuary in April 2019, to investigate the acoustic characteristics of the estuary in terms of both ambient noise field statistics and acoustic propagation characteristics at low-to-mid-frequencies. Ambient noise and linear frequency-modulated (LFM) acoustic signals in the 500–5000 Hz band were collected during flood on several days. Analysis of acoustic, high-frequency radar surface backscatter, echosounder, CTD and ADCP data demonstrate that the acoustic field fluctuates on tidal and diurnal timescales, and correlates to the passage of the salt wedge with attendant subducted bubbles at the tidal intrusion front and the flow of vehicular traffic through the nearby underwater traffic tunnel.