Basics of meteorology for outdoor sound propagation and related modelling issues

Abstract

Noise from industrial plants, wind farms, ports, and airports ranges long distances and merges with noise from linear transport infrastructures (i.e. roads and railways). A straightforward description of people’s long-term noise exposure is usually performed using simplified algorithms implemented in software packages. However, when focusing on the worst-case scenario in favourable sound propagation conditions, the prediction needs to be more accurate and requires the model’s calibration through actual measurements. In these cases, where the noise source under investigation, the concurrent sources, or all of them may be far away from the receivers, the correct choice of the temporal and meteorological windows to perform the measurements demands specific knowledge of weather-related phenomena. Such an approach is also essential in developing technically and economically sustainable mitigation strategies when required. This article first introduces some of the meteorological principles underpinning these phenomena. Within this framework, three of the most commonly used road-traffic noise calculation methods have been applied to identical scenarios, and their performances in accounting for weather-related effects on sound propagation have been analysed. The chosen methodological approach can be used for other environmental noise sources.

Keywords

• outdoor sound propagation
• noise modelling
• model calibration
• weather effects
• effective sound speed
• meteorological stability