TITLE: Passive Hydrocoustic Data Icy Bay

AUTHOR(S):

Erin Pettit
Department of Geology and Geophysics
900 Yukon Dr. Rm 308
PO Box 755780
University of Alaska Fairbanks
Fairbanks, Alaska 99775
907-474-5389
pettit@gi.alaska.edu
http://ice.gi.alaska.edu


Shad O'Neel
USGS Glaciologist
Alaska Science Center
4210 University Dr.
Anchorage AK 99508
907.786.7088
soneel@usgs.gov


Jeff Nystuen
Applied Physics Laboratory
University of Washington
1013 NE 40th Street
Box 355640
Seattle, WA 98105-6698
206-543-1343
nystuen@apl.washington.edu

FUNDING SOURCE AND GRANT NUMBER:

NSF OPP 0806317 : Collaborative Research: A New Method for Observing Variability in Freshwater Discharge from Arctic and Antarctic Marine-Terminating Glaciers using Passive Acoustic Measurements

DATA SET OVERVIEW:

These data are passive hydroacoustic recordings from an autonomous hydrophone (Passive Aquatic Listener, PAL) moored in Icy Bay Alaska. The mooring was deployed three times:

Deployment 1: 60.071295N 141.366233W
May 12, 2009 to July 18, 2009
Water Depth ~160m
Hydrophone depth: ~90m

Deployment 2: 60.081117N 141.386767W
July 19, 2009 to July 27, 2010
Water depth: ~160m
Hydrophone depth: ~90m

Deployment 3: 60.130125N 141.394786W
July 26, 2011 to July 29, 2011
Water depth: 125.27m
Hydrophone depth ~75m

http://ice.gi.alaska.edu/research/acoustics

INSTRUMENT DESCRIPTION:

The Passive Aquatic Listener (PAL), developed by Jeff Nystuen at Applied Physics Laboratory at the University of Washington, is a lightweight ocean acoustic sensor contained in a cylinder 76cm tall and 15cm in diameter that is deployable with a small mooring system at any depth in the water column. PAL integrates a broadband hydrophone (sensitivity -160dB) with signal pre-ampliers, a microprocessor, a 2Gbyte memory card, and batteries so that it can operate autonomously for up to a year or more.

DATA COLLECTION and PROCESSING:

At regular intervals as short as 30 seconds, the PAL records a 4.5 second sound bite of acoustic data at a sample rate of 100 kHz. Eight 512-point power spectral density estimates are computed from short samples within this sound bite, then stacked to characterize the overall acoustic spectrum of the sound bite. The sound bite spectrum is stored in memory. These eight spectra are spectrally compressed to 64 frequency bins, with frequency resolution of 200 Hz from 100-3000 Hz and 1 kHz from 3-50 kHz.
The raw 4.5 second sound bite is stored at randomly selected times.

Deployment 1: Data collected and processed onboard every 3 minutes and stored a spectrum in memory
Deployment 2: Data collected and processed onboard every 10 minutes and stored a spectrum in memory
Deployment 3: Only raw sound bit data at 3 min intervals

DATA FORMAT:

PAL Spectral Data:

Data are presented as a tab-delimited ASCII files.

All data are in Sound Pressure Level re uPa^2/Hz for 64 frequency bands from 100Hz to 40000Hz

Columns:
1: Time
2-65: SPL in Frequency Bands (64 columns across)

File Names:
Deployment1: PALIcyBay1.txt
Deployment2: PALIcyBay2.txt
Deployment3: N/A

PAL Sound Bite Data:
Data are presented in .wav files. The files for each deployment are collected in .zip archive file.

File Naming Convention:
SBYYYYMMDDHHMMSS.wav
'SB' - sound bite
The rest is a time stamp in UTC.

SB files are zipped in ~100 file groupings (1, 2, and 3 refer to deployment number)

Deployment 1:
PALwav1a.zip
PALwav1b.zip
PALwav1c.zip
PALwav1d.zip
PALwav1e.zip
PALwav1f.zip
PALwav1g.zip

Deployment 2:
PALwav2a.zip
PALwav2b.zip
PALwav2c.zip
PALwav2d.zip
PALwav2e.zip
PALwav2f.zip
PALwav2g.zip
PALwav2h.zip

Deployment 3:
PALwav3a.zip
PALwav3b.zip
PALwav3c.zip
PALwav3d.zip
PALwav3e.zip
PALwav3f.zip
PALwav3g.zip
PALwav3h.zip
PALwav3i.zip
PALwav3j.zip
PALwav3k.zip
PALwav3l.zip
PALwav3m.zip
PALwav3n.zip
PALwav3o.zip

DATA REMARKS:
.wav files can be read by any audio processing software package. Computer software and sound cards, however may be limited in sampling frequency they can work with. Matlab can be used to load and manipulate the data using the 'wavread' command.

REFERENCES: