Monitoring Greek Seas Using Passive Underwater Acoustics

AbstractThe Hellenic Center for Marine Research POSEIDON ocean monitoring and forecasting system has included passive underwater acoustic measurements as part of its real-time operations. Specifically, low-duty-cycle long-term passive acoustic listeners (PALs) are deployed on two operational buoys, one off Pylos in the Ionian Sea and the second off Athos in the northern Aegean Sea. The first step toward the quantitative use of passive ambient sound is the classification of the geophysical sources—for example, wind speed and rain rate—from the noise of shipping, from other anthropogenic activities, and from the natural sounds of marine animals. After classification, quantitative measurements of wind speed and precipitation are applied to the ambient sound data. Comparisons of acoustic quantitative measurements of wind speed with in situ buoy anemometer measurements were shown to be within 0.5 m s−1. The rainfall detection and quantification was also confirmed with collocated measurements of precipitation f...