ORLANDO, Fla. – You may have noticed after seeing fireworks displays late in the evening (or setting off your own) that the smoke just seems to sit there long after the show’s over.
There is a reason for that and it all has to do with the temperature at different levels of our atmosphere. During the day, temperature decreases with height in our atmosphere as the sun heats the ground and the ground heats the air around it.
This process keeps the atmosphere well-mixed and doesn’t let things like smoke settle in once place. The wind is generally stronger during the afternoon as well to help move things along.
Once we lose daytime heating in the evening, the warmth generated during the day begins to radiate back into space. The ground cools first, allowing the atmosphere just above the surface to be warmer than the ground.
This is known as a temperature inversion.
That sliver of warm air just above the surface acts as a lid and prevents anything beneath it from efficiently clearing out. Inversions are strongest when skies are clear and winds are calm, as temperatures can efficiently radiate away from the ground.
The next time you see smoke from fireworks, or fog for that matter clinging to the ground or just above it, know that it’s an invisible lid known as a temperature inversion at work.
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