What are the Layers of the Atmosphere? Learn the Structure of the Atmosphere and More

The earth’s atmosphere is very complex and it is composed of numerous layers. The following shows how each layer of the earth’s atmosphere works. The layers are listed from highest to lowest. The suffix “-pause” means the top of an atmospheric layer. For instance, the tropopause is the top of the troposphere.

Exosphere

The Exosphere is the thinnest and outermost layer of the earth’s atmosphere. The atoms are so far away from each other that they rarely collide in the exosphere. If a particle is moving at high vertical motion, it can even escape completely from the earth’s atmosphere.

Thermosphere

The thermosphere lies above the exosphere and it is very warm relative to the layers directly below it. The thermosphere has a temperature inversion in which the temperatures actually increases with height. According to the University of Washington, the thermopshere can actually reach daytime temperatures of 1500 degrees Celsius (see reference 1). The ionosphere also lies within thermosphere and extends to the exosphere. It is the “ionosphere” because a lot of the particles are ionized. Ionization occurs when a particle has a net charge (extra or missing electrons).

Mesosphere

The greek prefix “meso” means “in between” or “middle.” Therefore, the mesosphere is at the middle of the earth’s atmospheric layers. It lies direly below the thermosphere and on top of the stratosphere. The temperature decreases with height in the atmosphere. The cooling of the mesosphere is primarily due to the CO2 particles. After reaching the mesosphere, the warm air from the stratosphere cools adiabatically. Meteors and asteroids also begin to disintegrate in the mesosphere.

Stratosphere

The stratosphere extends about 30 miles above the earth, and it lies directly below mesosphere. The temperature varies little in the stratopshere. However, the temperature increases rapidly with height at the stratopause. The ozone layer is also highly concentrated within the stratosphere. At the very top of the stratospause, the temperature start decreases with height again.

Troposphere

The troposphere is the layer immediately above the earth’s surface. Its height varies from latitudes, season, and daytime. The height of the troposphere depends on its temperature. If it is warm, it will expand and increase in height. This is why the troposphere is higher at the equator than the poles. The troposphere has a variety of gases: 78 percent nitrogen, 21 percent oxygen, one percent argon, and the rest is carbon dioxide and other gases. The troposphere is also where the majority of the earth’s weather occurs. Nearly all clouds remain in the troposphere. In rare cases, potent cumulonimbus clouds can punch through the tropopause.

Earth's Atmosphere

References

University of Washington, “Outer Layers of Thermosphere and Ionosphere

University of Texas AT Dallas, “The Layers of Earth’s Atmosphere

University of Michigan, Joelle S. Busman and Cary Belen, “Ozone Layer