1. Theoretical basis of physical phenomena

"Does the wind carry the sound? "Does sound rise upwards?" "Why do we hear more noise at night?" "Why is sound muffled when it's foggy? It's to these kinds of naïve – but not always trivial – questions that the next sections attempt to answer, in a way that's both rigorous and synthetic. Beyond a pure understanding of the physics of these phenomena, the aim is also to develop methods for experimental characterization, statistical analysis and numerical modelling of the effects of the environment (i.e. the atmospheric state) on acoustic propagation.

Whatever the sound source under study (road, rail, wind, industrial noise, etc.), this first article focuses on the physical phenomena associated with acoustic propagation in urban or peri-urban (open country) environments. At these spatial scales, whether sound propagation takes place in "open" space (i.e. in the presence...