M. A. Wolfson
J. L. Spiesberger
Dept. Meteorol. and ARL, Penn State Univ., 602 Walker Building, University Park, PA 16802
F. D. Tappert
Univ. of Miami, Miami, FL 33149
Full-wave numerical simulations of internal wave scattering of
low-frequency sound in the deep ocean are performed with an efficient broadband
PE model based on a new parabolic approximation that is second-order accurate,
and an internal wave model based on a new representation of the GM spectrum
that allows efficient generation of internal wave fields that evolve in
geophysical time. Results are displayed as plots of acoustic travel time versus
geotime for various source--receiver separations (up to 8 Mm), and various
center frequencies and bandwidths. Quantitative examination (coherent and
incoherent geotime averages) yields information about the temporal coherence
and stability of each multipath. It is found that the later near-axial arrivals
are unstable and unresolvable, and therefore not useful for tomography, at
ranges and frequencies that are consistent with the predictions of Dozier and
Tappert [