Gaussian beam method for computing outdoor acoustic fields

Recently, a method using superposition of Gaussian beams has been proposed in the seismological community for the solution of high-frequency wave problems [V. Cerveny et al., Geophys. J. R. Astron. Soc. 70, 109–128 (1982)]. The concept of the theory of Gaussian beams is to solve the wave equation in the neighborhood of the familiar rays by use of the parabolic approximation. The solution associates with the ray a beam with a Gaussian amplitude profile normal to the ray. The approximate global solution for a given source is then constructed by a superposition of Gaussian beams along nearby rays. The method has been applied to typical outdoor sound propagation problems: wind and temperature gradient effect, turbulence effect, diffraction by screen. Comparison with measurements performed in a wind tunnel and with other results of the literature show that the Gaussian beam method is a potentially useful approach.