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Predicting the Effects of Random Ocean Dynamic Processes on Underwater Acoustic Sensing and Communication.
Byunggu Cho1, Nicholas C Makris2
1Center for Ocean Engineering, Massachusetts Institute of Technology, 77 Mass. Ave., Cambridge, MA, 02139, USA.
Scientific Reports
|March 13, 2020
Summary
This study predicts how ocean conditions like waves and bubbles degrade underwater acoustics. New formulas accurately forecast acoustic signal loss and distortion, crucial for marine communication and sensing.
Area of Science:
- Ocean Acoustics
- Marine Physics
Background:
- Underwater acoustics are vital for marine life and human sensing.
- Oceanic fluctuations (waves, bubbles, internal waves) degrade acoustic signals unpredictably.
Purpose of the Study:
- Develop a predictive model for acoustic degradation in ocean environments.
- Quantify signal attenuation, dispersion, and temporal decorrelation.
Main Methods:
- Derived analytic expressions from physical principles.
- Modeled acoustic propagation through ocean waveguides with random 3D inhomogeneities.
- Incorporated Doppler effects from moving inhomogeneities.
Main Results:
- Accurate predictions of acoustic field statistics, including attenuation and decorrelation.
- Identified timescales for decorrelation: seconds (waves, bubbles), minutes (internal waves).
- Showed Doppler spread impacts high-frequency acoustics; sea state increases attenuation.
Conclusions:
- The model successfully predicts acoustic degradation based on ocean dynamics.
- Marine mammal vocalization durations align with quantified coherence timescales.
- Findings are vital for understanding and improving underwater acoustic sensing and communication.
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