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Passive Aquatic Listener: A state-of-art system employed in Atmospheric, Oceanic and Biological Sciences in the Marine Environment Prof. E. N. Anagnostou, Dr. M. N. Anagnostou & Prof. Jeff Nystuen Hellenic Center for Marine Research, Institute of Inland Waters firstname.lastname@example.org
Applications • Geophysical/Geological applications: wind speed, rainfall, drop size distribution, cold/warm seepage gas bubbles, volcanic eruption, seismic activities, ice-breaking, etc. • Biological monitoring for sound-producing animal populations (bioacoustics) • Anthropogenic activities
Technological overview of PAL • Relatively simple measurement • Robust technology (hydrophones) • Moorings, cabled networks, floats/drifters
Technological Overview of PAL Components Low-noise broadband hydrophone 100 Hz – 50,000 Hz TT8 micro-computer processor with 100 kHz A/D sampler 2 Gb memory card Electronic filter and 2-stage amplifier 65 amp-hour battery package
d 1 d 2 Sea Level 100-2000m 50m (d 2) 2000m (d 1) Listening Area of PAL – Spatial Averaging The expectation is that the listening area for each hydrophone is a function of the depth of the hydrophone. Roughly half of the energy arriving at the hydrophone comes from an listening area with radius equal to the depth of the hydrophone and 90% of the energy from an area with radius equal to 3 times the depth.
Sampling/Recording modes • Pre-configured Wake-up/Sleep modes • Record short time series (4.5 s at 100 kHz) • Examine time series • Fourier transform (0-50 kHz) • Store spectra, not the time series* • Identify sound source • Quantify source • Return to “sleep” mode Two Modes of Recording Spectral time series at intervals determined by the sound source Short 100 kHz time series (4.5 sec) of targeted sound source
Meteo, curents, waves 20-1000m Sal, Temp, 500m PAL(Passive Acoustic Listener) Pressure sensor Sal, Temp PAL/Deployment modes PYLOS
PAL/Poseidon system Analysis of PAL’s data after retrieving the instrument from the Pylos Buoy
PAL/Poseidon system Comparison of PAL’s wind speed retrievals with the Buoy’s surface anemometer showing high correlations and small biases
PAL/Poseidon system Sound intensity peaks, of dolphin or whale clicks and whistle; the pressure time series collected by PAL on 30 November 2008 at Pylos’ site. The lower panel shows a spectral analysis from 0 – 20 kHz as a function of time
Poseidon data baseSystem On line PAL data: using the Poseidon data base system averaged every three hours Number of marine mammals Wind speed (m/s) Buoy sites Rainfall rate (mm/hr) Pylos Parameters
Analyzing acoustic data-Detecting marine mamals Whale call“Transient killer whale”Cape Flattery Echo-location click
Analyzing acoustic data-Detecting marine mamals Engine whine Killer Whale Call - Ugamak Bone crunching Pacific Right Whale “gunshot”
Conclusion & Future work • Low duty cycle recorder can • Monitor the background sound budget • Measure background physical environment • Detect pods of killer whales • Identify specific pods from the sound bites • Provide evidence of the interaction of animals in the acoustic sounds cape
Acknowledgements • NOAA NWFSC • NOAA NMML • ONR Ocean Acoustics • NSF Physical Oceanography • For the Poseidon/PAL integrated system: The people of the Aegean R/V, Mr. Dionysis Ballas and Mr. Paris Pagonis for the designing and deployment of PAL to the two Poseidon Buoys. More info: email@example.com