Multiscale multiphysics data-informed modeling for three-dimensional ocean acoustic simulation and prediction.

Area of Science:

• Ocean Acoustics
• Oceanography
• Computational Fluid Dynamics

Background:

• Three-dimensional (3D) underwater sound field computations are crucial for understanding sound propagation in complex ocean environments.
• Existing regional ocean models have resolution and physics limitations, excluding impactful features like submesoscale fronts and nonhydrostatic nonlinear internal waves (NNIWs).
• These excluded features significantly affect acoustic forecasts.

Purpose of the Study:

• To develop and report on a method for predicting NNIW fields to enhance 3D acoustic forecasts.
• To investigate ocean dynamical processes, particularly intermittent phenomena like internal tides and NNIWs, that influence sound propagation.
• To improve deterministic prediction capabilities for challenging acoustic environments.

Main Methods:

• Implemented an NNIW model nested within a tide-inclusive, data-assimilating regional ocean model.
• Utilized operational data-driven regional ocean models for generating 3D sound-speed fields.
• Focused on modeling intermittent phenomena (high kurtosis) impacting sound propagation.

Main Results:

• Successfully integrated NNIW modeling to improve the prediction of sound-speed fields.
• Demonstrated the potential for enhanced 3D acoustic forecasts by incorporating NNIW dynamics.
• Identified successful aspects of the modeling approach as well as its limitations.

Conclusions:

• Predicting NNIW fields is essential for accurate 3D underwater acoustic forecasting.
• The nested NNIW modeling approach shows promise but requires further refinement.
• Internal tides are identified as significant precursors and energy sources for NNIWs.