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Source bearing estimation in the Arctic Ocean using ice-mounted geophones.
Stan E Dosso1, Garry J Heard, Michael Vinnins
1School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia V8W 3P6, Canada.
The Journal of the Acoustical Society of America
|January 2, 2003
Summary
This study uses Arctic sea ice geophones to locate underwater acoustic sources. Seismic polarization filters improve bearing accuracy to within 100 degrees for sources up to 250 Hz.
Area of Science:
- Geophysics
- Acoustics
- Arctic Oceanography
Background:
- Locating underwater acoustic sources is crucial for various applications.
- Arctic sea ice presents unique challenges for acoustic monitoring due to complex seismic wave propagation.
- Existing methods for bearing estimation can be complicated by multi-modal seismic wave behavior.
Purpose of the Study:
- To investigate the effectiveness of geophones on Arctic sea ice for estimating the bearing of underwater acoustic sources.
- To develop and validate a method for suppressing unwanted seismic wave components and resolving directional ambiguities.
- To assess the accuracy of the proposed method under realistic Arctic field conditions.
Main Methods:
- Utilizing three-dimensional (3D) geophone measurements of seismic wave particle motion on sea ice.
- Applying seismic polarization filters to isolate specific wave types and suppress transverse motion.
- Performing rotational analysis of particle motion and resolving 180-degree ambiguities using vertical-radial plane data.
- Conducting Arctic field trials with controlled hammer and impulsive acoustic sources at varying ranges (200-1000 m).
Main Results:
- Demonstrated that seismic polarization filters effectively suppress transverse seismic wave components.
- Showcased the ability of 3D measurements to resolve directional ambiguities inherent in rotational analysis.
- Achieved typical source bearing estimation accuracy within an average absolute error of approximately 100 degrees for frequencies up to 250 Hz.
Conclusions:
- Geophones on Arctic sea ice, combined with seismic polarization filtering and 3D analysis, provide a viable method for underwater acoustic source localization.
- The developed technique effectively mitigates complexities arising from multi-modal seismic wave propagation in sea ice.
- This approach offers a practical solution for acoustic monitoring in challenging Arctic environments, with potential for further refinement.