Issue |
Acta Acust.
Volume 6, 2022
|
|
---|---|---|
Article Number | 13 | |
Number of page(s) | 15 | |
Section | Atmospheric Sound | |
DOI | https://doi.org/10.1051/aacus/2022005 | |
Published online | 12 April 2022 |
Scientific Article
S-shaped dependence of the sound pressure level in outdoor propagation on the effective sound speed gradient
1
TGM – Institute of Technology, Department for Research and Testing, Wexstrasse 19-23, 1200 Wien, Austria
2
University of Natural Resources and Life Sciences Vienna (BOKU), Institute of Meteorology (BOKU-Met), Gregor Mendel-Haus, Gregor-Mendel-Strasse 33, 1180 Wien, Austria
3
Kirisits Consulting Engineers, Kolpinggasse 10, 7423 Pinkafeld, Austria
4
Medical University of Vienna, Department of Radiation Oncology, Waehringer Guertel 18–20, 1090 Wien, Austria
* Corresponding author: dhohenwarter@tgm.ac.at
Received:
17
January
2021
Accepted:
8
February
2022
The effective sound speed gradient is used to describe the meteorological conditions during sound measurements at roads and railways. Meteorological parameters were assessed up to a height of 10 m. The sound level differences between a reference point close to the passing vehicles and at distances of 100–500 m from motorways and railway tracks were determined. These differences were found to correlate well with the effective sound speed gradient determined from the measured temperature and wind speed gradients which follow the day/night cycle as a result of the reversing air temperature gradient, incoming solar radiation and wind conditions. The correlation with sound level differences can be approximated by an S-shaped function which is constant for large positive or negative gradients of the effective sound speed. These threshold values are a consequence of the local meteorological and attenuation conditions. The analysis shows that large effective sound speed gradients are mainly a result of the wind conditions whereas gradients without a substantial wind speed contribution are low and a result of the temperature gradient. In the distance range between 150 m and 250 m, the meteorological influences cause a level increase of 3–4 dB(A) for downward refracted sound rays (favourable sound propagation) compared to a situation without meteorological influence (effective sound speed gradient of zero). In the same distance range, meteorological conditions cause a maximum sound level attenuation of 5–10 dB(A) for upward curved sound rays (unfavourable sound propagation).
Key words: Sound propagation / Meteorology / Effective sound speed gradient / S-shaped sound level attenuation
© The Author(s), Published by EDP Sciences, 2022
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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