Temporal variability of atmospheric absorption of sound and its effect on aircraft noise propagation around an airport during a year

摘要

The attenuation of sound due to atmospheric absorption depends strongly on environmental temperature and humidity. Therefore it varies in response to changing actual meteorological conditions on a variety of time scales. At long distances, the effect of temporal fluctuations of atmospheric absorption cannot be ignored. The authors have calculated the attenuation coefficients due to atmospheric absorption from meteorological data observed using the meteorological observation tower at the Meteorological Research Institute of the Japan Meteorological Agency. The results show that the variability characteristics of the attenuation coefficients during a year depend strongly on the sonic frequency. In order to examine the effects of atmospheric absorption on aircraft noise propagation around an airport, the sound pressure levels were calculated from the attenuation coefficients at altitudes up to about 200m. It has been found that the sound levels of aircraft noise in the winter are highly variable as compared with those in the summer.