Analyses of broadband and narrowband propagation measurements in Shallow Water 2006 (SW06)

Abstract

Acoustic measurements were made during the Shallow Water 2006 Experiment near the New Jersey continental shelf in 70–80 m of water. For a portion of the experiment, several L-arrays and a variety of broadband and narrowband sources were deployed for the purpose of investigating the nature of the dispersion of the acoustic propagation in the seabed. A geo-acoustic inversion methodology is used to infer the dispersion from the acoustic measurements in the water column. The waveguide possesses significant inhomogenities in range, azimuth, and time due to bathymetry, sound speed profile fluctuations resulting from internal waves, and variability in seabed properties. Physical oceanography measurements are used in part to obtain the best estimate for a water column description for the analyses of specific acoustic measurements. Various inversion methods along with different propagation models, such as two-way coupled modes and finite element parabolic equation algorithms, are used to obtain an accurate mean description and uncertainty estimates for the properties that control dispersion of the seabed. [Work supported by ONR.]