Versatile Three-Dimensional Hamiltonian Ray-Tracing Computer Program for Acoustic Waves in the Atmosphere

摘要

A FORTRAN computer program for tracing the paths of acoustic waves in the atmosphere is described. The program integrates Hamilton's equations for a medium that can be anisotropic (because of wind) and varies continuously in three dimensions. Several versions of the subroutines that specify the spatial variation of wind velocity, sound speed, temperature, and molecular weight are provided; the user can specify other atmospheric models by writing new subroutines following the examples. For each path, the program can calculate group path (group time delay as an equivalent path length), phase path (phase as an equivalent path length), Doppler shift due to a time-varying atmosphere, and geometrical path length. In addition to printing these parameters and the direction of the wave normal at various points along the raypath, the program can plot the projection of the raypath on any vertical plane or on the ground and output the main characteristics of each ray in machine-readable form. The organization of the program into subroutines allows it to be applied to the propagation of waves in other media with straightforward modifications. The documentation includes equations, flow charts, program listings with comments, definitions of program variables, descriptions of input and output, and a sample case.