Estimating sediment properties using a new source level function for wind-driven underwater sound derived from...

Area of Science:

• Oceanography
• Acoustics
• Environmental Science

Background:

• Wind-driven breaking waves are a primary source of ambient sound in the ocean.
• Accurate source levels are crucial for sound exposure modeling, environmental impact assessments, and sonar performance evaluation.
• Existing models have limitations, particularly at lower frequencies (<1000 Hz) and varying wind speeds.

Purpose of the Study:

• To develop an accurate source level model for wind-driven breaking waves down to 100 Hz.
• To improve estimations of ambient sound levels in marine environments.
• To provide a tool for estimating sediment properties or wind speeds based on acoustic data.

Main Methods:

• Analysis of 16 long-term archival datasets with minimal anthropogenic noise.
• Estimation of site-specific areic propagation loss (APL) using a ray-based model.
• Calculation of source levels by adding APL to median received levels at different wind speeds.

Main Results:

• A novel equation for the areic dipole source level was derived.
• The source level increases with wind speed cubed, consistent with air-ocean coupling processes.
• The model provides accurate source levels down to 100 Hz.

Conclusions:

• The developed model accurately estimates wind-driven ambient sound levels for soundscape modeling.
• The model can be utilized for inferring sediment properties or wind speeds from acoustic measurements.
• An open-source implementation is available for broader application in marine acoustics research.