The snow has finally arrived and whilst there are less cars on the road and people in the streets contributing to sound around us, the falling of snow and the temperature also plays its own part.
Whilst hard surfaces are highly reflective, a thick covering of snow acts as an impressive acoustic absorber. A great way to reduce all that noise around us. And we are left with that slightly eerie feeling particularly when in a place which would be ordinarily quite noisy.
This may seem fairly obvious to some but there is more. Temperature can also affect the level of sound near us. Sound speed is a function of temperature. What this means is that the higher the temperature, the higher the sound speed. Sound tends to refract, curving towards regions of lower sound speed. They key here is not the absolute temperature but how the temperature changes as it moves upwards from the ground. So if the air near the ground is colder than the air above it, as is the case when the ground is covered in a thick layer of snow, sound is downward refracting ie: sound bends downwards towards the ground making background noise more easily heard. In contrast, when the air near the ground is warmer, as it might be when snow is falling or at night, the atmosphere will be upward refracting and sound will travel up into the atmosphere and disappear leaving only lower noise levels being heard at the listeners position.
For most of us, we enjoy the snow, it’s magical and beautiful to look at. But what adds to this picture is the ambience and peace it brings also….physically! Hooray for snow!
