Atmospheric Turbulence affects Noise Annoyance from Aircraft Flyovers

Auralization of outdoor sound propagation has become an important tool for studying noise perception in the contexts of aircraft, wind farm, and drone noise.  To achieve high realism, these auralizations consider amplitude fluctuations caused by atmospheric turbulence.  In a recent publication, a semi-empirical model was introduced which is applicable to relatively long outdoor sound propagation such as aircraft and wind farm noise, as it considers the saturation effect for amplitude fluctuations in the partially-saturated regime.  This article presents a study applying the semi-empirical model for investigating the impact of turbulence-induced amplitude fluctuations on annoyance in auralized aircraft flyovers.  For this, two 2-alternative-forced-choice listening experiments were conducted in a controlled laboratory setting: the first tested whether participants could reliably detect audible differences between aircraft flyovers under different meteorological conditions; the second assessed which condition was perceived as more annoying. The results show that strong differences in meteorological conditions and the respective atmospheric turbulence can lead to salient audible differences. Relative annoyance ratings tend to increase with stronger atmospheric turbulence. Further, the data suggest that amplitude fluctuations can interact with other characteristics of aircraft noise such as fan tones and alter the perceptual impact of these characteristics. Therefore, the study highlights the importance of modeling turbulence-induced amplitude fluctuations in realistic aircraft auralizations, and presumably also wind farm and drone noise auralization, as the perceptual impression can be affected in several ways.