Layers of the Atmosphere

Our planet is surrounded by layers of atmosphere. These layers differ in composition density temperature pressure The differences within these layers allow life on earth to exist.

The atmosphere at the surface of the earth is very different from the atmosphere just a few kilometers up. How do you think these layers work together to maintain our current living conditions here on earth?

The layers of atmosphere act like a blanket to protect and insulate the earth. The layers are clearly visible from outer space.

Thickness The atmosphere is a very thin (relatively) layer of gas over the surface of the Earth Earth’s radius ~ 6400km Atmospheric thickness ~ 100km (If you travel 100km from McKinney you will only be in Ft Worth. If you do it vertically you’d be in space!)

As you move away from the earth’s surface, the temperature will initially drop. The air pressure will continue to decrease the higher you go.

We will begin at the surface of the earth and work our way into the outer limits of Earth’s atmosphere.

Troposphere

The layer closest to the earth is the troposphere. This layer is approximately 10 km thick. All life exists within this layer. Due to rising and falling currents of air, all weather takes place within this layer.

Stratosphere

The stratosphere reaches 50km above the earth. Temperatures increase as you enter the stratosphere. This is due to the ozone layer present at the upper edge of the layer. The stratosphere reaches 50km above the earth. ozone 10-50 km Stratosphere Troposphere 10km

It also keeps too much heat from escaping into the outer atmosphere. The ozone layer is a highly reactive form of oxygen that absorbs ultraviolet light. This layer acts like an insulator to protect the earth from harmful rays. It also keeps too much heat from escaping into the outer atmosphere. ozone 10-50 km Stratosphere Troposphere 10km

Mesophere

Most meteors burn up in this layer. “Meso” means middle; hence, this is the middle layer of our atmosphere. The temperature of this layer drops from comfortable 00 C. to a chilling -800 C ! Most meteors burn up in this layer. 50-80 km Mesosphere ozone 10-50 km Stratosphere Troposphere 10km

Thermosphere

Temperatures in this layer increase from -80°C to a hot, 800°C. The space shuttle orbits the earth in this layer. Thermosphere 80-500 km 50-80 km Mesosphere ozone 10-50 km Stratosphere Troposphere 10km

Ionosphere

The Ionosphere is located in the upper Thermosphere. 150-500 km Ionosphere Thermosphere 80-500 km 50-80 km Mesosphere ozone 10-50 km Stratosphere Troposphere 10km

Temperatures increase as we enter this layer Temperatures increase as we enter this layer. The atmosphere is very thin and becomes electrically charged; hence, the name ionosphere. This layer also absorbs photons (light particles) from the sun. 150-500 km Ionosphere Thermosphere 80-500 km 50-80 km Mesosphere ozone 10-50 km Stratosphere Troposphere 10km

This ionization causes a natural phenomena called the Aurora Borealis. 150-500 km Ionosphere Thermosphere 80-500 km 50-80 km Mesosphere ozone 10-50 km Stratosphere Troposphere 10km

Exosphere

The Exosphere is the outermost layer. 500- 800 km 150-500 km Ionosphere Thermosphere 80-500 km 50-80 km Mesosphere ozone 10-50 km Stratosphere Troposphere 10km

The temperature ranges from 800° to 2000°C in the Exosphere. 500- 800 km 150-500 km Ionosphere Thermosphere 80-500 km 50-80 km Mesosphere ozone 10-50 km Stratosphere Troposphere 10km

Molecules of gas are about 2km apart in the Exosphere. Ionosphere Thermosphere 80-500 km 50-80 km Mesosphere ozone 10-50 km Stratosphere Troposphere 10km

Satellites orbiting Earth are found in the Exosphere. 500- 800 km 150-500 km Ionosphere Thermosphere 80-500 km 50-80 km Mesosphere ozone 10-50 km Stratosphere Troposphere 10km

Composition of the Atmosphere

The atmosphere is composed of a variety of gases: Nitrogen 78% Oxygen 20.9% Argon 0.9% Carbon Dioxide 0.035% Trace amounts of Helium, Neon, Methane and Krypton

The composition of the atmosphere remains the same throughout, the layers just vary in density. All of life is dependent on the delicate balance of the gases found in Earth’s atmosphere. What do you think would happen if there was a sudden increase or decrease in a certain atmospheric gas? Is it happening now? Give examples.

Air Density and height

Pressure and Density Decrease with Height

Low Pressure Low Density High Pressure High Density