1. MET 112 Global Climate Change - CLOUDS and CLIMATE Prof. Menglin Jin Department of Meteorology, San Jose State University Outline Clouds Formation Clouds Climatology Clouds and the Radiation Budget

2. Clouds by Christina Rossetti White sheep, white sheep, On a blue hill, When the wind stops You all stand still When the wind blows You walk away slow. White sheep, white sheep, Where do you go?

3. A good repository of cloud photos in various categories can be found at www.cloudappreciationsociety.org/gallery

4. Questions  What role do clouds play on the Earth’s climate?  What would happen to our climate if clouds were to increase/decrease?

5. Earth System Water Cycle

6. 6 MET 112 Global Climate Change

7. Clouds are formed when air containing water vapor is cooled below a critical temperature called the dew point and the resulting moisture condensesdew into droplets on microscopic dust particles (condensation nuclei) in the atmosphere. Clouds Formation

8. 8 MET 112 Global Climate Change Video  http://www.met.sjsu.edu/metr112- videos/MET%20112%20Video%20Library- MP4/clouds/ http://www.met.sjsu.edu/metr112- videos/MET%20112%20Video%20Library- MP4/clouds/ DTS-5.mp4

9. A visible mass of liquid water droplets suspended in the atmosphere above Earth's surface. http://earthobservatory.nasa.gov/Library/glossary.php3 Clouds can form along warm and cold fronts, where air flows up the side of the mountain and cools as it rises higher into the atmosphere, and when warm air blows over a colder surface, such as a cool body of water.

11. Water in the atmosphere  Definitions: –Evaporation: –Condensation: –Precipitation:

12. Water in the atmosphere  Definitions: –Evaporation: –Condensation: –Precipitation: Process where a liquid changes into a gas Any liquid or solid water that falls from the atmosphere to the ground. (i.e. RAIN!) Process where a gas changes into a liquid

13. Water freely evaporating and condensing

14. Since more water molecules are evaporating than condensing, then net evaporation is occurring.

15. Lid on: The humidity is now 100%

16. Lid on: Now, evaporation and condensation are equal. The air above water is now called ‘saturated’. The humidity is now 100%

17. Condensation  The process by which water vapor changes to a cloud droplet  Water vapor molecules may ‘stick’ to condensation nuclei and grow (billions) to eventually form cloud droplet.  Examples of condensation nuclei include: a. Dust b. Salt c. Smoke  Condensation occurs primarily as temperature cools: -colder the molecules more likely they are to ‘stick’ to other molecules

19. Zonal Mean Cloud Effective Radius (M. D. King, S. Platnick et al. – NASA GSFC) July 2006 (Collection 5) Aqua

20. Clouds and radiation Cloud - Climate Interactions Albedo effect - COOLING  Clouds reflect incoming solar radiation.  The cloud droplet size and total water content determine the overall reflectivity. Greenhouse effect - WARMING  Clouds are good absorbers (and emitters) of long wave (infrared) radiation.

21. Clouds and day to day temperatures Imagine that you are going camping in the Sierras with your friends. On the first day (and evening) it is clear, while on the second day (and evening) it is cloud. Based on this information alone: Which day would be warmer? Which evening would be warmer? Explain your answers.

22. Which day would be warmer? 1.First day (clear) 2.Second day (cloudy) 3.Both the same

23. Which evening would be warmer? 1.First day (clear) 2.Second day (cloudy) 3.Both the same

24. Clouds types

25. Low and High clouds Consider two types of clouds: 1.Low levels clouds 2.High levels clouds Q: How is the Earth’s surface energy budget different for low clouds compared to high clouds?

26. Clouds and Climate Cloud A: Low level, (dark, thick) Cloud B: High level, light (sub visible or thin) (sub visible or thin)

27. Clouds and climate Cloud A: Low level, (dark, thick) Cloud B: High level, light (sub visible or thin) (sub visible or thin) Excellent reflector of incoming radiation; good absorber/emitter of infrared radiation Fair/poor reflector of incoming radiation; good/excellent absorber/emitter of infrared radiation  So, clouds both warm and cool the earth.  Overall, though, clouds act to cool the earth

28. Changes in clouds  Increases in low level clouds will: –  Increases in high level clouds will:

29. Changes in clouds  Increases in low level clouds will: –cool the surface (cooling outweighs warming)  Increases in high level clouds will: –warm the surface (warming outweighs cooling)

30. Cirrus

31. Altocumulus (possibly cirrocumulus, depending on altitude of the clouds)

32. Stratocumulus

33. Broken stratocumulus

34. Nimbostratus

35. Cumulus humilis (commonly called 'fair weather cumulus')

36. Cumulus

40. Cumulonimbus

41. Stratus

43. Cirrus

45. Clouds That Look Like Things

46. Explain how the earth’s climate would change as a result of aircraft contrails.

50. 1.What percentage of the sun’s radiation is a)absorbed by the Earth’s surface? b)absorbed by the atmosphere c)reflected out to space? 2.If the sun’s radiation was to increase by 10%, how would the following energy units change (increase, decrease or stay the same) a)Energy gained by the Earth’s surface. b)Energy lost by the Earth’s surface. c)Energy emitted by greenhouse gases. d)Energy lost to space. Questions

51. What percentage of the Sun’s radiation is absorbed by the Earth’s surface? 1.19% 2.51% 3.70% 4.117%

52. What percentage of the Sun’s radiation is absorbed by the Earth’s atmosphere? 1.19% 2.51% 3.70% 4.117%

53. What percentage of the sun’s radiation is reflected out to space? 1.19% 2.30% 3.64% 4.70% 5.111%

54. If the Sun’s radiation was to increase by 10%, how would the energy gained by the earth’s surface change? 1.Increase 2.Decrease 3.Stay the same

55. If the Sun’s radiation was to increase by 10%, how would the energy emitted by greenhouse gases change? 1.Increase 2.Decrease 3.Stay the same

56. If the Sun’s radiation was to increase by 10% the energy 1.Entering the top of the atmosphere would exceed the energy leaving 2.Entering the top of the atmosphere would be less than leaving 3.Entering and leaving would be the same

57. Class Participation Concept Map

58. Activity : Water Concept Map Draw a concept map using the following terms. You may add additional terms if you wish. Water vapor Ice Liquid water Condensation Evaporation Gas High Cloud Low Cloud Precipitation Condensation nuclei Temperature Warming Cooling Air