Supplemental Reading (previously assigned)

• Basic background on electromagnetic radiation, provided as a handout
  (from Danielson, Levin and Abrams, Meteorology, 1998, pp. 80-87).
  

At least two, and possibly three, pre-class quizzes based on these reading questions will be posted on iLearn. Consult the course schedule on the class Web site for more information.

From The Earth System, 3rd Ed., Chapter 3:
"Global Energy Balance: The Greenhouse Effect" (pp. 36-48)

• Key Questions: #'s 1 and 2.
  
  
• Chapter Overview
  
  
  1. How is the Earth heated and how does it cool? [Note that the text is only partly correct about what heats the Earth; the sun emits more than just visible radiation (light), and the other wavelengths of radiation that the sun emits also heat the Earth, though it is true that these other wavelengths do little to heat the Earth's surface directly.]
  2. What determines the (global average) surface temperature of the Earth?
     
     
• Introduction
  
  
  3. How does the global average surface temperature of the Earth compare to that of Mars and of Venus?
  4. What is the "Goldilocks Problem" of comparative planetology?

• Electromagnetic Radiation
  
  
  5. What proportion of the radiation emitted by the sun consists of visible light?
     
     Properties of Electromagnetic Radiation
  6. What is electromagnetic radiation?
  7. What properties of electromagnetic characterize it? Are they independent of each other?
     
     Photons and Photon Energy
     (skip)
     
     The Electromagnetic Spectrum
  8. What is the electromagnetic spectrum?
  9. What distinguishes visible light, infrared (IR) radiation, and ultraviolet (UV) radiation? What proportion of the energy emitted by the sun is IR radiation? UV radiation?
  10. What types of radiation are the most important to climate?
  11. What type(s) of radiation does the Earth emit, mostly?
      
      
  Flux
  12. How is a flux defined? In particular, how is radiative flux defined? In the metric system, what are the units of radiative flux?
  13. Why does the radiative flux, or intensity of radiation, that strikes a piece of paper vary when the angle between the paper and the radiation striking it varies?
      
      
  The Inverse-Square Law
  14. How does the radiative flux, or radiative intensity, vary with distance from a "point source" of radiation such as a light bulb or the sun (or the Earth)?
  15. In the mathematical expression for the inverse-square law, what does each symbol represent, and what are its units (in the metric system)?
  16. What is an "astronomical unit" (AU)? What is the flux of solar radiation at a distance of 1 AU from the sun (in metric units)?
  17. What is the authors' reason for asserting that the inverse-square law is fundamentally important to the study of planetary climates?
      

• Temperature Scales
  
  
  18. What is temperature? What is heat energy (also sometimes called "sensible heat" or "internal energy")?
  19. What physically significant events define the Fahrenheit temperature scale? The Celsius scale? The Kelvin scale?
  20. How is a temperature in degrees Celsius converted to Kelvins (and vice-versa)? How does this compare to converting a change in temperature expressed in °C to the equivalent change in temperature expressed in Kelvins?
      
      
• Blackbody Radiation
  
  
  21. What is a blackbody?
  22. What determines how the radiative energy emitted by a blackbody is distributed over different wavelengths? What is a "blackbody radiation curve"?
      
      Wien's Law
  23. Blackbodies emit more radiative energy at one wavelength (the wavelength of peak emission) than any other wavelength. How does the wavelength of peak emission vary with absolute temperature? (That is, what is Wien's Law?)
  24. According to Wien's Law, what is the wavelength peak emission of the sun? The Earth? Why can't we see the radiation emitted by the Earth?
      
      
  The Stefan-Boltzmann Law
  25. The radiative energy emitted by a blackbody at different wavelengths can be summed to give a total radiative emission intensity. How does the total radiative emission intensity of a blackbody vary with absolute temperature? (That is, what is the Stefan-Boltzmann Law?)
      
      
• Planetary Energy Balance
  
  
  26. In the context of a whole planet in space, what is meant by energy balance? Is the Earth in energy balance? What happens to the average planetary temperature when the planet achieves energy balance?
  27. What three factors determine the Earth's global average surface temperature?
  28. About what proportion of the solar energy arriving at the top of the Earth's atmosphere is reflected back to space? What does most of the reflecting? What is meant by a planet's albedo? How is it defined quantitatively?
  29. How is the effective radiating temperature of a planet defined?
      
      Magnitude of the Greenhouse Effect
  30. How can we interpret the meaning of a planet's effective radiating temperature?
  31. What two factors determine a planet's effective radiating temperature? Where does the factor of 4 come from in the expression for a planet's effective radiating temperature?
  32. What is the effective radiating temperature of the Earth? What is the magnitude of the greenhouse effect on the Earth?
      
      
• Atmospheric Composition and Structure
Atmospheric Composition
33. Of gases does air consist, mostly? Do these gases contribute to the greenhouse effect?
34. What proportion of the atmosphere does water vapor compose? Carbon dioxide?
35. What are the two most important greenhouse gases? What are some other important greenhouse gases, although they are merely trace gases in the atmosphere?
    
    
Atmospheric Structure
36. What is atmospheric pressure? How does it vary with altitude in the atmosphere? What is the Earth's average sea-level pressure (expressed in millibars)?
37. How does atmospheric temperature vary with altitude (on the average)? What atmospheric layers are defined, based on this behavior?
38. In which atmospheric layer does most of what we regard as "weather" occur? What is convection? How does it differ from conduction? Which plays the more important role in heat transfer within the atmosphere and oceans?
39. Why is the lowest atmospheric layer (the troposphere) convective?
40. What is latent heat?
41. How does the stratosphere differ from the troposphere?
42. Why is the atmosphere warmest near the Earth's surface? What accounts for the increase in temperature with altitude in the stratosphere?
43. Why isn't the stratosphere convective? Why are clouds almost nonexistent in the stratosphere?
    
    
• Chapter Summary: Item #1
• Review Questions: #'s 3-8
• Critical Thinking Problems: #'s 1-5 (Recommended unless explicitly assigned.)