Application of atmospheric absorption models for aircraft en route noise

摘要

Different atmospheric absorption models co-exist in the literature and it is thereforernhard to choose between one or the other when working on a sound propagation problem.rnThe full description of the refined algorithm and the ANSI standard algorithm wererncompared and it was shown that the sound pressure level on the ground for en route noisernissues was predicted to be 12 dB lower at 1 kHz using the ANSI standard algorithm.rnThen, the same atmospheric model (described in Refs. 2 and 3) was included in bothrnalgorithms, which reduced the difference on the ground to about 3 dB at 1 kHz. Thernaverage seasonal humidity profiles at Huntsville, AL were also computed using the ANSIrnalgorithm and led to much greater SPL differences.rnAlthough the two absorption algorithms lead to different SPL predictions on thernground, applying various humidity profiles to one algorithm or the other lead to muchrngreater differences for critical frequencies in the A-weighted scale used to predict thernimpact of en route noise on natural quiet areas.