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Geoacoustic inversion with ships as sources.
Robert A Koch1, David P Knobles
1Applied Research Laboratories, The University of Texas at Austin, Austin, Texas 78713-8029, USA. koch@arlut.utexas.edu
The Journal of the Acoustical Society of America
|March 12, 2005
Summary
This study estimates geoacoustic parameters in the Gulf of Mexico using surface ship acoustic data. Successful inversions determined sediment sound speed, thickness, and deeper layer properties for shallow waters.
Area of Science:
- Oceanography
- Acoustics
- Geophysics
Background:
- Geoacoustic parameter estimation is crucial for understanding shallow water environments.
- Acoustic data from surface ships offer a practical method for seabed characterization.
- Horizontal Line Arrays (HLAs) provide directional acoustic information.
Purpose of the Study:
- To estimate geoacoustic parameters in a shallow water Gulf of Mexico region.
- To develop and demonstrate an efficient geoacoustic inversion method using broadband beam cross-spectral data.
- To validate the inverted geoacoustic parameters through comparisons with existing data and models.
Main Methods:
- Utilized acoustic data recorded by hydrophones in a bottom-mounted Horizontal Line Array (HLA).
- Employed broadband beam cross-spectral data for geoacoustic inversion.
- Investigated the performance of various cost functions for inversion, considering frequency and time segments.
- Performed inversions using data from a surface ship at ranges of 20, 30, and 50 water depths.
Main Results:
- Successfully inverted for the sound speed and thickness of the first sediment layer.
- Obtained parameters for deeper sediment layers.
- Validated inverted geoacoustic parameters against geophysical observations and previous studies.
- Confirmed results by comparing measured and modeled transmission loss (TL).
Conclusions:
- The developed geoacoustic inversion techniques are effective for shallow water environments.
- Surface ship acoustic data and HLAs provide valuable information for seabed characterization.
- The inversion method demonstrated is efficient for broadband beam cross-spectral data.