HARPO: A Versatile Three-Dimensional Hamiltonian Ray-Tracing Program for Acoustic Waves in an Ocean with Irregular Bottom

摘要

HARPO stands for Hamiltonian Acoustic Ray-tracing Program for the Ocean. This FORTRAN computer program traces the three-dimensional paths of acoustic rays through model oceans by numerically integrating Hamilton's equations, which are a differential expression of Fermat's principle. The user specifies an ocean model by writing closed-form formulas for its three-dimensional current and sound-speed distribution, and by defining the depth of the bottom as a function of geographic latitude and longitude. Some general-purpose models are provided, or users can easily design their own. The report describes the ray-tracing equations and the structure of the program and provides complete instructions for using it, illustrated by a sample case. The program is modular and can be adapted to model propagation through other media by changing the routine that defines the medium's dispersion relation.