Outdoor Sound Propagation Ranging from Hundreds to Hundreds of Thousands of Meters

Abstract

Outdoor sound propagation is remarkably influenced by many physical factors. Source characteristics such as the intensity and spectrum affect the propagation distance of the sounds, and relate deeply to evaluation methods of the propagated sound to receivers as well. Meteorology and atmospheric condition are also important parameters for sound propagation outdoors. Due to the complexities, further investigations are necessary, though these parameters can be introduced and reflected to several prediction methods nowadays. In this report, excess attenuation of some different sounds after outdoor propagation ranging from hundreds to hundreds of thousands of meters are presented, and the effects of the meteorology and atmospheric conditions on the outdoor sound propagation are discussed. Especially, the measurements on asphalt are compared with the predictions by the parabolic equation (PE) method using vertical sound-speed profiles estimated from the meteorological data such as atmospheric temperature, wind speed and direction.