Passive ocean sensing and soundscape analysis of the Juan de Fuca plate using the Ocean Networks Canada NEPTUNE Array

The Ocean Networks Canada (OCN) deployment of a small set of acoustic recorders (4) in and around the Juan de Fuca plate provides the opportunity to observe the seasonal and long-term trends in the northeast Pacific ocean soundscape. With one receiver near the opening of the Straits of Juan De Fuca, two on the continental slope and one in deep water, we have the opportunity to evaluate the effects of local environment on the ambient sound. Wind waves and surface ships drive the low frequency ambient sound fields in most regions. These long-term recordings provide the opportunity to perform passive acoustic tomography, where the cross-correlation of the acoustic field over long time periods can provide estimates of the channel impulse response between the two hydrophones. This technique has been demonstrated experimentally at shorter ranges. The expected oceanographic observed signal from a “tomography experiment” is estimated using the ECCO4 model and the parabolic equation.