Effects of front width on acoustic ducting by a continuous curved front over a sloping bottom.

The behavior of sound near an ocean front in a region with wedge bathymetry is examined. The front is parameterized as a zone of variation with inshore and offshore boundaries parallel to a straight coastline. The importance of frontal width and frontal sound speed on the ducting of acoustic energy is examined.

Parameter dependence of acoustic mode quantities in an idealized model for shallow-water nonlinear internal wave ducts.

Nonlinear internal waves in shallow water have significant acoustic impacts and cause three-dimensional ducting effects, for example, energy trapping in a duct between curved wavefronts that propagates over long distances. A normal mode approach applied to a three-dimensional idealized parametric model [Lin, McMahon, Lynch, and Siegmann, J. Acoust.

Estimating the parameter sensitivity of acoustic mode quantities for an idealized shelf-slope front.

The acoustic modes of an idealized three-dimensional model for a curved shelf-slope ocean front [Lin and Lynch, J. Acoust. Soc.

Approximate formulas and physical interpretations for horizontal acoustic modes in a shelf-slope front model.

The structure and behavior of horizontal acoustic modes for a three-dimensional idealized model of a shelf-slope front are examined analytically. The Wentzel-Kramers-Brillouin-Jeffreys (WKBJ) method is used to obtain convenient simple expressions and to provide physical insight into the structure and behavior of horizontal modes as trapped, leaky, or transition types. Validity regions for WKBJ expressions in terms of slope and frontal parameters are found, and outside the regions the asymptotic formulas for large order and large argument Hankel functions are used.

Treatment of a sloping fluid-solid interface and sediment layering with the seismo-acoustic parabolic equation.

The parabolic equation method is extended to handle problems in seismo-acoustics that have multiple fluid and solid layers, continuous depth dependence within layers, and sloping interfaces between layers. The medium is approximated in terms of a series of range-independent regions, and a single-scattering approximation is used to compute transmitted fields across the vertical interfaces between regions. The approach is implemented in terms of a set of dependent variables that is well suited to piecewise continuous depth dependence in the elastic parameters, but one of the fluid-solid interface conditions in that formulation involves a second derivative that complicates the treatment of sloping interfaces.