1 MET 112 Global Climate Change MET 112 Global Climate Change - Lecture 5 Clouds and the Earth’s energy budget Dr. Eugene Cordero San Jose State University Outline  Water in the earth system  Clouds: what are they  Cloud identification: quick view  Clouds and the radiation budget

2 MET 112 Global Climate Change Questions  What role do clouds play on the Earth’s climate?  What would happen to our climate if clouds were to increase/decrease?

3 MET 112 Global Climate Change

5 Water in the atmosphere  Definitions: –Evaporation: –Condensation: –Precipitation:

6 MET 112 Global Climate Change 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

Water freely evaporating and condensing

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

Lid on:

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

11 MET 112 Global Climate Change 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. a. b. b. c. c.  Condensation occurs primarily as temperature cools

12 MET 112 Global Climate Change 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

15 MET 112 Global Climate Change Clouds and radiation Cloud - Climate Interactions Albedo effect - COOLING   The cloud droplet size and total water content determine the overall reflectivity. Greenhouse effect - WARMING 

16 MET 112 Global Climate Change 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.

17 MET 112 Global Climate Change 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 cloudy, while on the second day (and evening) it is clear. Based on this information alone: Which day would be warmer? Which evening would be warmer? Explain your answers.

18 MET 112 Global Climate Change Which day would be warmer? 1.First day (clear) 2.Second day (cloudy) 3.Both the same 0 of 70

19 MET 112 Global Climate Change Which evening would be warmer? 1.First day (clear) 2.Second day (cloudy) 3.Both the same 0 of 70

21 MET 112 Global Climate Change 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?

22 MET 112 Global Climate Change Clouds and Climate Cloud A: Low level, (dark, thick) Cloud B: High level, light (sub visible or thin) (sub visible or thin)

23 MET 112 Global Climate Change 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. Together, though, clouds act to cool the earth

24 MET 112 Global Climate Change Changes in clouds  Increases in low level clouds will: –  Increases in high level clouds will:

25 MET 112 Global Climate Change 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)

32 MET 112 Global Climate Change Explain how the earth’s climate would change as a result of aircarft contrails.

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35 MET 112 Global Climate Change

36 MET 112 Global Climate Change 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.What percentage of the energy received by the earth’s surface comes directly from greenhouse gas emissions? 3.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

37 MET 112 Global Climate Change What percentage of the Sun’s radiation is absorbed by the Earth’s surface? 1.19% 2.51% 3.70% 4.117% 0 of 70

38 MET 112 Global Climate Change What percentage of the Sun’s radiation is absorbed by the Earth’s atmosphere? 1.19% 2.51% 3.70% 4.117% 0 of 70

39 MET 112 Global Climate Change What percentage of the sun’s radiation is reflected out to space? 1.19% 2.30% 3.64% 4.70% 5.111% 0 of 70

What percentage of the energy gained by the earth’s surface comes directly from greenhouse gas emissions? 0 of % 2.43% 3.51% 4.65% 5.70%

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 0 of 70

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 0 of 70

If the Sun’s radiation was to increase by 10% the energy 0 of 70 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

44 MET 112 Global Climate Change Example: 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 Activity 3: Water Concept Map

Draw a diagram indicating the earth’s energy balance. Use arrows to indicate energy in versus energy out. Include the following terms in your diagram Clouds Water Vapor Carbon Dioxide Albedo Infrared radiation Shortwave radiation Greenhouse gases Activity 2 (continued): The earth’s energy balance

47 MET 112 Global Climate Change Which way does water flow down the drain here in San Jose? 0 of 70 1.Clockwise 2.Counterclockwise 3.Both