Aircraft noise models generally simplify the atmosphere as homogenous and constant over time. However, momentary local conditions of wind, humidity and temperature influence the sound exposure level and become relevant for the calculation of single flights.
This paper presents a method to classify the atmospheric conditions with idealized vertical profiles derived from weather data of a monitoring station in combination with a radiation balance. The differences of the propagation in a homogenous and a stratified atmosphere are analyzed by exemplary overflights. Additionally, the attenuations due to idealized profiles are compared to those of vertical profiles obtained from flight data records and profiles from a meteorological prediction model.
The comparison between the different profiles shows good agreement for temperature, except for the transition between stable and unstable stratification, but larger deviations for humidity. Furthermore it can be shown that the reproduction of a stratified atmosphere in the propagation calculation has a beneficial effect on the accuracy of the resulting sound exposure level and should therefore be taken into account for sophisticated aircraft noise modelling. Therefore, input data of a meteorological prediction model should be used where available, as idealized profiles do not always reproduce the atmosphere accurately.