Computation of Horizontal Correlation of Sound in Presence of Internal Waves in Deep Water and Long Distances

TL;DR

This paper investigates the impact of internal gravity waves on horizontal acoustic correlation in deep water over long distances, finding that azimuthal coupling is negligible up to 4000 km, simplifying computational models.

Contribution

It demonstrates that azimuthal coupling can be ignored in modeling horizontal correlation of sound in deep water over long distances, enabling simpler computational approaches.

Findings

No significant azimuthal coupling up to 4000 km.

Horizontal correlation shapes align with theoretical predictions at higher frequencies.

Uncoupled vertical slice computations are sufficient for accurate modeling.

Abstract

Numerical solutions are given for a parabolic approximation of the acoustic wave equation at 200 and 250 Hz in two and three spatial dimensions to determine if azimuthal coupling in the cross-range coordinate significantly affects horizontal correlation in the presence of internal gravity waves in the sea. No evidence for coupling is found for distances of 4000 km and less. This implies that accurate solutions are possible using computations from uncoupled vertical slices. Shapes of horizontal correlation are closer to shapes given by two theories than at lower frequencies.