Summary of underwater ambient sound from wind and rain in the northeast Pacific continental margin

Abstract

Analyzing underwater ambient sound from various sources such as ships, marine mammals, rain, and wind is crucial for characterizing the ocean environment. While efforts to analyze ocean ambient sounds have been ongoing since the 1940s, networks such as the Ocean Observatories Initiative (OOI) provide modern large-scale recording setups for a more in-depth analysis. Here we will summarize results from analyzing over 11,000h of wind generated ambient sound and 280 h of ambient sound during rain collected between 2015 and 2019 by two OOI hydrophones deployed in the northeast Pacific continental margin. The hydrophones record continuously at depths of 81 and 581 m with a sample rate of 64 kHz. Meteorological data are provided by surface buoys deployed near the hydrophones. We compare our results to data obtained from a large-scale recording setup in the tropical Pacific Ocean (Ma et al., 2005). In contrast to their results, we found that sound levels during rain in the northeast Pacific Ocean are highly dependent on the wind speed over a wide frequency range. This implies that large-scale distributed sound measurements are necessary to accurately characterize underwater ambient sound from wind and rain across the globe. [Work supported by ONR.]