1. All images courtesy of the National Weather Service unless otherwise indicated.

2. Chapter 18: Water in the Atmosphere
18.2 Clouds
High: Above 7000 meters
Cirrus
Cirrostratus
Cirrocumulus

3. Cirrus

4. Cirrostratus

5. Cirrocumulus

6. Chapter 18: Water in the Atmosphere
18.2 Clouds
Middle: About 2000 to 7000 meters
Altostratus
Altocumulus

7. Stratus

8. Altostratus

9. Chapter 18: Water in the Atmosphere
18.2 Clouds
Low: Below about 2000 meters
Stratus
Nimbostratus
Stratocumulus
Cumulus

10. Stratus

11. Nimbostratus

12. Stratocumulus

13. Cumulus

14. Cumulonimbus

15. (photo taken from a passenger jet)
Cumulonimbus
(photo taken from a passenger jet)

16. Thunderstorm Animation
Cloud Animation
Thunderstorm Animation

17. Cloud Formation & Satellite Imagery

18. Cumulus Cloud Formation
Condensation Level: the height at which clouds form
Dependent on a constant supply of warm, moist air
Also dependent on temperature and dew point temperature

19. Condensation Level

20. Cumulus Cloud Formation
Dry-adiabatic lapse rate: the rate at which unsaturated air cools with height (~10°C/km)
Moist-adiabatic lapse rate: the rate at which saturated air cools with height (~5 to 9°C/km)

21. Moist-adiabatic Lapse Rate
Dry-adiabatic Lapse Rate

22. Cumulus Cloud Formation
Why is the moist rate less than the dry rate?
Condensation releases heat
Warms the air around it, increasing the temperature
This is due to the high heat capacity of water

23. Cumulonimbus Clouds
Form the same way as cumulus clouds, except density differences between the surface air and the air aloft is greater (unstable)
Causes the air inside to rise more quickly and achieve greater heights

24. Cumulonimbus Cloud Diagram

25. Layer Clouds
Form in stable air; the density difference between the surface air and the air aloft is small
Causes the air inside to spread out horizontally rather than vertically like cumulus clouds

26. Layer Clouds Can form in 2 ways:
Air can be forced slowly upward to its condensation level
The layer of air can cool to its dew point by radiating heat or mixing with cooler air

27. Satellite Imagery

28. GOES Weather Satellites
There are a few satellites orbiting Earth gathering many types of weather data, including “pictures” of clouds
Satellites are centered over the equator, over 22,000 miles up
Geosynchronous: orbits Earth at same rate of Earth’s rotation

29. Satellite Imagery There are 3 main types of images:
Visible: visible light from the sun is reflected to the satellite
Infrared: infrared light (heat) is sensed
Water vapor: detects moisture in mid/upper troposphere

30. Compare 3 Images http://www.srh.noaa.gov/jetstream/remote/goes.htm