Sound propagation over ground under the influence of a sound speed profile in the atmosphere

Abstract

Sound propagation from a monopole point source located over a semi-infinite porous ground is investigated. The atmosphere is described as a generalized horizontally stratified medium in order to take vertical variations in the sound speed into account. In each layer a linearly varying sound speed is permitted, hence making it possible to simulate a piecewise linear vertical velocity variation. The mathematical problem is formulated in terms of the Hankel transform, and the sound field is determined by numerical integration of the inverse transform. However, the numerical approach is substantially different from the one used in previous work in this field [1–3]. Results of calculations for different atmospheric conditions are shown and discussed, and compared to measured data.