1. Layers of the Atmosphere

2. Earth’s atmosphere is divided into four main layers based upon changes in temperature.

3. Troposphere Lowest layer of the atmosphere (closest to Earth)
You live here
Tropo means turning or changing (there is more change in this layer than any other)
Weather occurs here
Shallowest layer (thinnest)
Contains almost all the mass of the atmosphere
It is 16 km thick at equator and less than 9 km thick at poles
As altitude increases, temperature decreases
At the top, temp is about -60 ̊C. Water here forms clouds of ice

4. Stratosphere Second layer of the atmosphere
Reaches from troposphere to about 50 km above surface of Earth
Strato means layer or spread out
Ozone layer is here (remember it protects living things from ultraviolet radiation from Sun)
Jets often fly here because it is calm
As altitude increases, temperature increases (because ozone layer absorbs heat)

5. Mesosphere Third layer Meso means middle
Reaches from 50 km to 80 km above Earth’s surface
Protects Earth’s surface from being hit by meteoroids (chunks of stone and metal from space – but some still get through)
A shooting star is a trail of hot, glowing gases a meteoroid leaves behind in the mesosphere
Coldest layer - Temperatures reach – 90 ̊C at the top of the mesosphere
As altitude increases, temperature decreases

6. Thermosphere Outermost layer of our atmosphere
Reaches from 80 km above Earth’s surface into outer space. There is no definite upper limit
Thermo means heat
Thickest layer
Hottest layer, temperatures reach up to 1,800 ̊C, but you would not feel warm here (Find out Why?)
As altitude increases, temperature increases
Has two other layers

7. Ionosphere Lower layer of the Thermosphere
Reaches from about 80 km to 400 km above Earth’s surface
Energy from the sun causes gas molecules here to become electrically charged particles
Radio waves bounce off ions back to Earth (makes signals travel much farther at night)
Auroras happen near the poles because of the ionosphere – these are brilliant streaks of light in night skies

8. Exosphere Exo means outer Is the outer portion of the thermosphere
Reaches from about 400 km outward for thousands of kilometers
Space shuttles and satellites orbit Earth here

9. Remember:
Earth’s atmosphere is divided into four main layers based upon changes in temperature and density!!

10. Why the temperature changes?
Troposphere: The air is warmed by heat given off by Earth. The farther away from the surface, the less heat.
Stratosphere: Warmed up from the ozone layer absorbing UV rays.
Mesosphere: Little ozone to help keep the temperature warm.
Thermosphere: High oxygen molecules absorbs light from the sun.

11. - Layers of the Atmosphere

12. Temperature Changes
The air is warmed by heat given off by Earth. Farther away from the surface, less heat.
Warms up from the ozone layer absorbing UV Rays.