1. Cloud Formation

2. CLOUDS FORM WHEN: Air rises Air cools Air condenses What is a cloud?
Clouds: groups of tiny water drops or ice.
Air rises
Air cools
Air condenses
CLOUDS FORM WHEN:

3. Adiabatic temperature changes
This change in temperature occurs even though heat isn’t added or subtracted.

4. When air expands it becomes cooler

5. Air Air Air Air When air is compressed it becomes warmer Simulation
Click to run

6. Cooling air causes it to Condense
Air cools by expanding.
Cooling air increases Relative Humidity.
Air becomes full of water } SATURATED
Water condenses out of the air. GAS  LIQUID
The temperature when condensation begins is called the Dewpoint Temperature.
Clusters of water drops are called clouds.

7. When does condensation occur to make clouds?
 For any form of condensation to occur, the air must be saturated.
 Types of Surfaces
• Generally, there must be a surface for water vapor to condense on.
• Condensation nuclei are tiny bits of matter that help water vapor condense into droplets.

8. Dust and salt in the atmosphere are examples of condensation nuclei

9. Dry Adiabatic Rate NO CLOUDS FORM!
As a volume of unsaturated air rises or sinks.
This volume of will cool or warm at a rate of 10°C/1000meters.
NO CLOUDS FORM!

11. Wet Adiabatic Rate CLOUDS FORM!
As a volume of saturated air rises or sinks, dew point is reached
Water vapor condenses to liquid water
This volume of air it will change temp at a slower rate of 5°C/1000meters to 9°C/1000meters.
CLOUDS FORM!

12. Cloud Formation by Adiabatic Cooling
Makes no sense without caption in book

13. What processes lift the air so it can expand and cool?

14. 4 Ways to get air to rise.

15. 18.2 Cloud Formation
• Orographic lifting occurs when mountains act as barriers to the flow of air, forcing the air to ascend.

16. Orographic Lifting
Air

21. Frontal Wedging
A front is the boundary or edge where two air masses meet.
Frontal Wedging occurs when warmer, less dense air, rises above the cooler air, causes condensation and storms

22. Frontal Lifting
Cold
Air
Warm
Air

23. 18.2 Convergence
Convergence is when air masses, with the same temperatures, crash into each other and rise.

24. Convergence
Air
Air

25. Localized Convective Lifting
This occurs when air is heated unequally due to different types of surfaces.
Air above a parking lot heats faster than air above a forest.
The warmer, rising, less dense air is called a thermal.
Thermals are used by birds to soar.

26. Convective Lifting
Air

27. Stable Air & Unstable Air
Cooler & denser
Resists moving up
Unstable air
Warmer & less dense
Tends to rise

28. Environmental lapse rate
The speed at which temperature decreases as you move up in altitude.
The Environmental Lapse Rate in the troposphere is 6.5 °C /1000 meters

29. Temperature Inversion
When air found at lower levels is actually cooler than the air above it.
It is more dense so it stays below:
This can happen on a cool night. Lands cools quickly causing the air above it to cool as well.

30. Temperature Inversions can Create smog in cities with high pollution

31. Created by a Temperature Inversion
“Morning Glory”
Created by a Temperature Inversion
YouTube
Clip

32. Mr. Fetch's Earth Science Class
Summary: Cloud Formation
AIR
CONDENSES
AIR RISES
AIR COOLS
Convection
Orographic Lifting
Frontal Lifting
Convergence
By expanding
(low pressure)
Cools to the dewpoint and water vapor condenses.
Mr. Fetch's Earth Science Class
Mr. Fetch’s Earth Science Classroom