Passive Aquatic Listener: A Passive Aquatic Listener: A state-of-art system employed in state-of-art system employed in

Atmospheric, Oceanic and Atmospheric, Oceanic and Biological Sciences in the Biological Sciences in the

Marine EnvironmentMarine EnvironmentProf. E. N. Anagnostou, Dr. M. N. Anagnostou Prof. E. N. Anagnostou, Dr. M. N. Anagnostou

& Prof. Jeff Nystuen& Prof. Jeff Nystuen

Hellenic Center for Marine Research, Institute of Inland WatersHellenic Center for Marine Research, Institute of Inland Waters

managnostou@ath.hcmr.grmanagnostou@ath.hcmr.gr

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

ComponentsComponents

Low-noise broadband hydrophone 100 Hz – 50,000 Hz

TT8 micro-computer processor with 100 kHz A/D sampler 2 Gb memory card

65 amp-hour battery package

Electronic filter and 2-stage amplifier

Sea Level

100-2000m

2000m (d 1)

d 1

d 2

50m (d 2)

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.

I h I atten p dA( ) cos ( ) 02

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 RecordingTwo 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

PAL/Deployment modes

20-1000m Sal, Temp,

500m PAL(Passive

Acoustic Listener)

Pressure sensor

Sal, Temp

Meteo, curents, waves

PYLOSPYLOS

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

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

Paul R. Houser, November 7, 2005, Page 12

Poseidon data base SystemOn line PAL data: using the Poseidon data base system averaged every three hours

Number of marine mammals

Rainfall rate (mm/hr)

Wind speed (m/s)Buoy

sites

Pylos

Parameters

Analyzing acoustic data-Detecting marine mamals

Whale call“Transient killer

whale”Cape Flattery

Echo-location click

Engine whineKiller Whale Call - Ugamak

Bone crunching Pacific Right Whale “gunshot”

Analyzing acoustic data-Detecting marine mamals

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

AcknowledgementsAcknowledgements

• 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:

managnostou@ath.hcmr.gr

More info:

managnostou@ath.hcmr.gr