Arctic research

Since 2006 our lab has been involved in shallow-water Arctic acoustic research in the Beaufort Sea.  Several distinct topics/papers are listed below:

Automated processing of bowhead whale vocalizations

Robust ranging bowhead whale calls using a single vertical array

Long-range detection and analysis of Arctic air gun pulses

The impact of seismic air gun reverberation on the acoustic environment

Automated processing of bowhead whale vocalizations

Since 2007 we have been collaborating with Greeneridge Sciences and the Shell Exploration and Production Company to monitor the fall bowhead whale migration in the Beaufort Sea, as part of a long-term study to determine the potential impact of both seismic air gun and industrial operations on the species’ behavior.  Each year at least 35 Directional Autonomous Seafloor Recorders (DASARs) have been deployed at five “sites”.  These recorders have the ability to triangulate location.  Our lab has developed custom-built software for automatically detecting and localizing bowhead whale calls and seismic air gun signals:

A. Thode, K. Kim, S. Blackwell, C. R. Greene Jr., C. Nations, T. McDonald, A. M. Macrander, “Automated detection and localization of bowhead whale sounds in the presence of seismic airgun surveys”, J. Acoust. Soc. Am. 131(5), 3726-3747 (2012).

The paper contains the following map, comparing the performance of the automated procedure with human analysis:

Auto_manual_comp_09
Top: Spatial distribution of 20,216 whale call locations obtained by manual analysis of the last 12 hours of 8 non-contiguous days in 2009. Bottom: distribution of 18,024 whale call locations computed by automated detection algorithm over the same time periods. No manual data from the top subplot were used to train the software.

Robust ranging of bowhead whale calls using a single vertical array


As part of the DASAR deployments our lab has also deployed a vertical array, to explore whether dispersion-based methods for ranging calls can be achieved.   That is, is it possible to get ranges to baleen whale calls in shallow water using a single deployment (vs. a widely-distributed set of autonomous packages)?  Two papers on this topic have been accepted for peer-reviewed publication, and link to a sponsor report is also included:

Link to description of vertical array work to North Pacific Research Board

J. Bonnel, A.M. Thode, S. B. Blackwell, “Range estimation of bowhead whale (Balaena mysticetus) calls in the Arctic using time warping on a single hydrophone,” in press,  J. Acoust. Soc. Am., (Dec, 2013).

S. H. Abadi, A.M. Thode, S.B. Blackwell, D.R. Dowling, “Comparison of three methods of ranging bowhead whale calls in a shallow-water waveguide,” in press, J. Acoust. Soc. Am., (Jan, 2014).

 

Long-range detection and analysis of Arctic air gun pulses

 

In 2008 we used the DASARs to track a seismic vessel to ranges of over 1000 km:

A. Thode, K. Kim, C. R. Greene Jr., and E.H. Roth, “Long range transmission loss of broadband seismic pulses in the Arctic under ice-free conditions,” J. Acoust. Soc Am. 128, EL181-EL187 (2010).

 

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