Measurements and models of acoustic transmission loss on two Hawaiian coral reefs

Acoustic transmission loss was measured as a function of range on a coral reef to better understand the propagation environment at frequencies of 0.5, 2, 5, 10, and 15 kHz. Low-level signals were projected on two contrasting coral reef sites in Hawaii, and received by a hydrophone at ranges up to 500 m. A suite of transmission loss models are tested against the field data. Geoacoustic inversion methods are used to obtain a spreading and attenuation coefficient for each site. This work challenges conventional geometric spreading models in a coral reef setting and quantifies site-specific spreading and attenuation. This work is DISTRIBUTION A. Approved for public release: distribution unlimited. This research was developed with funding from the Defense Advanced Research Projects Agency. The views, opinions and/or findings expressed are those of the author and should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. Government.