1. Structure of the Atmosphere

2. Atmospheric Composition
The atmosphere mostly consists of nitrogen (78%), oxygen (21%), and argon.
99% composed of
Nitrogen and Oxygen
Remaining 1% made up of
small amounts of other gases

3. Atmospheric Thermodynamics
Why does the temperature change from one layer to the next?

4. Troposphere Closest to Earth Altitude 0-10 km
Contains most of the mass of the atmosphere
Weather occurs here, pollution collects
Upper limit called tropopause
Tropopause is where gradual decrease in temperature stops

5. Stratosphere -Above troposphere -Altitude 10-50 km
-Contains mostly ozone
-Ozone absorbs more UV radiation, so this layer is heated
-Upper limit called stratopause
-Stratopause is where gradual increase in temperature stops

6. Mesosphere Above stratosphere Altitude 50-80 km
No concentrated ozone here, so temperature drops again
Upper limit called mesopause
Mesopause is where gradual decrease in temperature stops

7. Thermosphere Above mesosphere
Altitude 80 km and above until outermost boundary of atmosphere
Contains a small part of the atmosphere’s mass
Little air that is in this layer increases in temperature again to greater than 1000C

8. The Ionosphere
The thermosphere can be identified in two parts- the ionosphere and the exosphere.
Ionosphere: 80 km- 640 (about 400 miles = 640 km).
It contains many ions and free electrons (plasma).
Auroras occur in the ionosphere.

9. Auroras
A beautiful display of light in the sky that come from interactions between particles from the sun's atmosphere and gases in the ionosphere.

10. Exosphere Outermost layer of Earth’s atmosphere
Light gases like helium and hydrogen found here
Above exosphere is outer space
No clear boundary between atmosphere and space

11. Atmosphere Energy
The Sun is the source for all energy in the atmosphere.
Three ways the energy transfer occurs:
Radiation
Conduction
Convection
Flash Animation

12. Radiation
Radiation is the transfer of energy through space by visible light, UV radiation, and other forms of electromagnetic waves

13. Conduction
Conduction is the transfer of heat energy that occurs when particles collide
Through conduction, Earth’s surface transfers energy to nearby air particles in troposphere.
Conduction only affects small layer of atmosphere.

14. Convection
Convection is the transfer of heat energy by the flow of a heated substance
Pockets of air near Earth’s surface are heated, become less dense and rise
As warm air rises, it expands and starts to cool. As it cools, its density increases and the cooler air sinks. As it sinks, it warms again and process starts over.

15. Temperature and Heat
Temperature-measurement of energy of a substance; interprets atmospheric processes.
Heat-transfer of energy from two objects of different temperatures; fuels atmospheric processes.

16. Pressure and Density
Air pressure increases towards Earth’s surface because of the greater mass of the atmosphere above you.
Atmospheric pressure decreases with height because there are fewer gas particles above you.
Density is proportional to amount of particles.

17. Atmospheric Relationships

18. Atmospheric Pressure & Density Dynamics
What happens to pressure and density as you go higher in the atmosphere?
Why do changes in pressure & density occur?

19. Temperature Inversion
A condition in which cold air underlies warmer air that is at a higher altitude.
This occurs when the air near the ground rapidly loses it heat on a clear night. In this situation, the ground becomes cooled quickly while the air above it retains the heat the ground was holding during the day.

20. Temperature Inversion