Interannual changes in sound propagation across the Gulf Streama)

Area of Science:

• Oceanography
• Acoustics
• Climate Science

Background:

• The Gulf Stream's changing ocean environment impacts underwater sound propagation.
• Understanding these changes is crucial for acoustic monitoring and research.

Purpose of the Study:

• To investigate the effects of a changing ocean environment on sound propagation across the Gulf Stream.
• To quantify changes in sound travel time and interference patterns over a 14-year period.

Main Methods:

• Utilized satellite altimetry and Argo float hydrographic profiles.
• Reconstructed Gulf Stream vertical structure using the altimetry-informed gravest empirical mode (AGEM) method.
• Employed ray tracing and parabolic equation sound propagation models.

Main Results:

• Observed a reduction in sound travel time to 120 km due to increased water temperatures.
• Identified changes in the sound speed gradient field structure.
• Found altered sound propagation interference patterns on the far side of the Gulf Stream.

Conclusions:

• Ocean warming significantly affects underwater sound propagation across the Gulf Stream.
• Changes in sound speed fields alter acoustic propagation patterns over decadal timescales.
• The AGEM method provides a robust way to estimate 3D sound speed fields from surface altimetry.