ORLANDO, Fla. – Most of the fireworks across Central Florida were canceled due to Covid-19, but boy did our neighbors pick up the slack this year! You may have noticed after seeing professional fireworks displays late in the evening or launching some of your own that the smoke just seems to sit there long after the show ends.
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 escape. The ground cools first allowing the atmosphere just above the surface to be warmer than the ground.
This is known as a temperature inversion since the “normal” temperature profile of temperature decreasing the higher you go, think of climbing a mountain, is reversed so that the warm air is on top of the cooler air. This is known as a stable atmosphere. This layer of warm acts as a lid to trap things like smoke close to the surface. Since the afternoon mixing has stopped, the wind is also relatively calmer.
There are two layers of earth’s atmosphere where temperature typically increases with height. The stratosphere, about 10 miles above the surface and the thermosphere, about 60 miles above the surface both have temperatures that increase the higher you move through them. We live in the troposphere where temperature, for the most part, decreases with height until you enter the stratosphere.