Comment les facteurs environnementaux affectent-ils le bruit?

Atmospheric or environmental conditions have a major impact on aircraft noise. The reverberation of sound waves caused by weather may actually make noises seem louder, or quieter, than they are. This is due to the physics behind how aircraft noise travels to our ears, and why aircraft flying at altitudes that normally produce no noise may seem louder.

Wind

On a gusty day, airplane noise is moved around in the air. More people hear it but it’s not as intense because it’s being redistributed to a wider area.

Fog

Like wind, fog can absorb or reflect noise. This can either increase or decrease the perceived noise level.

Cloud coverage

Depending on the thickness of a cloud, airplane noise will bounce off the ground back up into the sky and bounce off the cloud right back down. It won’t be as intense the second time around, but it may amplify the original sound, depending on the cloud height.

Time of day

Noise, like heat, is energy, and energy sources are drawn to each other. During the day, when the air is warmer than the ground, noise energy from an airplane staying in the air, so while you can still hear it, it seems quieter. Conversely, at night, when the ground is warmer than the air, the noise is drawn down, making it seem louder.

Topography

Rich greenery absorbs sound, which means less of it gets to your ears. If you were standing in the middle of a forest as a plane flew over your head, it would seem quieter than if you were standing in a parking lot where the sound is reflected to your ears instead of being absorbed.

Direction of sound

And like sunlight, noise will bounce off hard surfaces, essentially amplifying it. This is also the case when a plane flies over water, and the same reason why you can sunburn faster in the water. Like noise, the sun’s rays will reflect off the water and get you twice.