An overview of ambient sound using OOI hydrophone network

The NSF-funded Ocean Observatories Initiative (OOI) is a large-scale project that provides a unique observation of the ocean, collecting acoustic, meteorological, and oceanic datasets. Specifically, for hydrophone data, there are five low frequency hydrophones (Fs = 200 Hz), and six broadband hydrophones (Fs = 64 kHz) dispersed around the north-east pacific. This acoustic dataset presents numerous potential areas of study in the field of ambient sound analysis. In this talk, we analysis 6 years of acoustic data to identify prominent features that are present in the OOI acoustic dataset. Some notable occurrences that are observed in the dataset include volcanic activity, rain and wind noise, fin whale vocalizations, and shipping events. For all low frequency hydrophones and four of the six broadband hydrophones, we will present long-term spectrograms, time-series trends for different spectral bands, different acoustic features that are present in the dataset, and different statistical metrics about the acoustic environment. We find that 6-year, acoustic, trends vary depending on the location of the hydrophone and the spectral band that is observed. Some locations and spectral bands see increases in spectral levels while others see decreases in spectral levels over the course of the 6 years. [Work supported by ONR.]