3. Statistical approaches

3.1 A statistical approach to the noise-meteorology relationship

Readers are referred to [73] .

Variations in long-distance sound levels are the result of the refraction of sound waves, produced by gradients in air temperature and wind speed. In reality, these phenomena are not stable, and vertical profiles of wind speed and temperature vary widely over time, due to random fluctuations in meteorological conditions. These fluctuations can occur over fractions of a second due to turbulence phenomena, or over longer periods corresponding to diurnal, seasonal, annual or even decades-long rhythms. It follows that long-distance sound levels must be considered as a random variable. So, like any variable...