Attenuation and Dispersion of Acoustic Energy by Atmospheric Dust

摘要

Insight into the role of atmospheric dust in the attenuation and dispersion of acoustic energy in the lower troposphere is gained by a comparison of theoretical attenuation coefficients and dispersion functions in the 1-10 million Hz range for the mechanisms of classical absorption, molecular absorption, turbulent scattering and dust absorption for three models of atmospheric dust conditions. Over most of this frequency range the attenuation due to dust absorption is masked by one or more of the other attenuating mechanisms, but at the lower frequencies there appear to be physically realizable conditions of high dust concentration and low turbulent scattering wherein dust absorption may become significant. Also, at the lower frequencies the absolute magnitude of the dispersion function due to dust is much greater than that due to classical and molecular absorption. (Author)