Measurement and modelling of the influence of the atmospheric structure on the sound exposure

Noise is one of the most important environmental problems especially in urban regions. The propagation of sound waves takes place in the atmosphere, apart from interactions with the ground surface, and is influenced by the atmospheric structure. Thereby, the spatial and temporal variability of meteorological quantities like temperature, wind vector and air moisture leads to refraction, scattering and absorption and thereupon to an increased or decreased noise exposure.

The applicability of currently operational methods is limited because the influence of the atmosphere on the sound propagation is only insufficiently taken into account. Thus, a sound propagation model was developed to include the state of the atmosphere into the forecast of noise immission.  The model SMART (Sound propagation model of the atmosphere using ray-tracing) calculates the modified sound propagation conditions due to sound-ray refraction for an area according to the given thermal stratification of the atmosphere and the vertical profiles of wind speed and wind direction.

 

 

Schallstrahlenverläufe für eine Atmosphäre mit Temperaturinversion und Windgeschwindigkeitszunahme mit zunehmender Höhe sowie höhenkonstanter Windrichtung. Ausbildung von geometrischen Schattenzonen in Gegenwindrichtung und Lärmzonen in Mitwindrichtung (Schallstrahlen werden zur Erdoberfläche zurück gebrochen).

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