Atmosphere and Temperature
How Do the Layers of the Atmosphere Affect Temperature?
Have you ever visited the mountains? What did you notice about the air around you? Did it seem cooler than the air from lower down in the valleys? When you climbed out of your tent in the morning, was the air crisp and chilly? Though you may not have realized it at the time, you were performing a science experiment. Since you do not own a personal rocket ship, the only way for you to travel higher into the atmosphere is to climb a mountain. As you do so, the temperature quickly drops, becoming cooler and cooler.
What do you think will happen as you continue to travel higher into the atmosphere? It is easy to suppose that the temperature will continue to decrease. For many years, scientists believed that this was the case. However, we now understand that the layers of the Earth’s atmosphere affect temperature in complex ways. Eventually, as you continue traveling outward through the atmosphere, you will find that as you approach the tropopause the temperature will stop decreasing, and for several miles will remain constant. It will then actually begin to increase again as you travel through the upper stratosphere. As you enter the mesosphere, the temperature will once again begin to drop, getting cooler and cooler. Then, as you travel up through the thermosphere, the temperature again begins to increase, eventually becoming even warmer than the temperature on the surface of the Earth. Finally, as you continue to travel outward leaving the atmosphere via the exosphere, the temperature drops again, becoming very cold.
What causes the temperature to rise and fall, increase and decrease throughout the layers of the Earth’s atmosphere? Have you ever stood by a camp fire? The closer you get to the fire, what happens? As you hold your hands in front of you near the flames, do you feel the heat? What happens as you pull away from the fire? The further you draw away from the fire, the less heat your body feels.
Each time the atmosphere warms up, there must be something that is warming it. The closer you get to the thing warming it up, the more you can feel the heat. The further away you get from that heat source, the cooler the air becomes. In the troposphere, the source of heat is the surface of the Earth as well as particles in the air which absorb heat and energy from the Sun and release it back into the atmosphere.
The ozone layer absorbs radiation from the Sun, helping to increase the temperature in the upper portion of the stratosphere. High in the thermosphere are found gases that absorb radiation from the Sun. This helps to warm the thermosphere.