Range-dependent waveguide scattering model calibrated for bottom reverberation in a continental shelf environment

Area of Science:

• Ocean acoustics
• Waveguide theory
• Scattering phenomena

Background:

• Ocean waveguides exhibit complex scattering from random inhomogeneities.
• Understanding seafloor acoustic properties is crucial for underwater surveillance and mapping.
• Existing models may not fully capture the nuances of range-dependent environments.

Purpose of the Study:

• To develop an analytic model for acoustic scattering in range-dependent ocean waveguides.
• To calibrate the model using real-world oceanographic and geophysical data.
• To establish a method for differentiating moving underwater targets from background reverberation.

Main Methods:

• Utilizing the Rayleigh-Born approximation to Green's theorem for analytic modeling.
• Calibrating the model with data from Ocean Acoustic Waveguide Remote Sensing (OAWRS) and geophysical surveys.
• Developing a computationally efficient numerical approach using the parabolic equation.
• Analyzing temporal and spatial fluctuations in OAWRS intensity images.

Main Results:

• Scattered intensity is linked to statistical moments of compressibility and density variations.
• Seafloor scattering strength follows a 10 log(10)(F(p)V(c)k(4)) dependence on wave number, coherence volume, and penetration factor.
• A numerical method efficiently computes wide-area bottom reverberation.
• A technique is presented for distinguishing moving clutter from stationary reverberation.

Conclusions:

• The developed model accurately describes acoustic scattering in complex ocean environments.
• The findings provide a quantitative understanding of seafloor scattering characteristics.
• The study offers a practical approach for target detection and environmental characterization in underwater acoustics.