Monitoring the oceanic environment through passive underwater acoustics

Underwater ambient noise plays a fundamental role in the analysis of marine acoustics as well as of acoustical oceanography since it is an integral part of the marine environment and a key parameter for improving its sustainability and preserving the ecosystem. Furthermore, the detection and quantification of wind and rainfall events on a long-term basis from underwater sound measurements could greatly improve the knowledge of these atmospheric processes in open-ocean where environmental conditions limit our ability to obtain in-situ observations through surface buoys. This paper shows results on wind, rainfall and ship passages detection and the quantification of natural sound sources from a Passive Aquatic Listener (PAL) sensor deployed in the Ligurian Sea on the W1-M3A spar buoy. Validation of the estimates from the PAL data are provided by direct comparison with in-situ wind speed and precipitation measurements collected by the meteorological sensors onboard the buoy, hourly rainfall accumulations from a C-band weather radar, and ship traffic data in the Ligurian basin.