Seabed Characterization using Acoustic Pressure and Particle Velocity Data

Acoustic pressure and three components of particle velocity were measured on bottom mounted Ocean Bottom Recorders (OBX) during an experiment conducted in Narragansett Bay, Rhode Island, USA. Intensity based algorithms were implemented to estimate the direction of arrival (DOA) using data from a source of opportunity. Time-frequency representation of the azimuth angles were constructed to understand the temporal and frequency dependance of the azimuth estimates. This visualization offers a useful tool, especially when used in conjunction with the spectrogram, to identify multiple sources and their frequency content and time of occurrences. The ambient noise data collected on the OBX was used to estimate the bottom parameters using the H/V ratio method. This bottom model was then used to predict the waveguide invariant. The predicted value of the waveguide invariant provides a reasonable match to the value calculated using the striation pattern in the spectrogram of the data.