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Quiz #2 Study Questions
Chapter 2, Chapter 3 pp. 54-57, 60-67
Turn in Monday, Feb. 21 by start of class.
This is worth up to 5 points extra credit towards Quiz #2

1. What is the definition of insolation? What factors affect the amount of insolation the earth receives?
   • Incoming solar radiation or "insolation" is the amount of solar energy striking a given area over time. The actual amount of insolation depends on latitude and season (or sun angle and atmospheric path length, which are functions of latitude and season. Absorption, scattering, etc are included in atmospheric path length effect.
   
   
   
2. What feature of the earth's orbit explains the seasons?
   • The tilt of the earth on its axis by 23.5 degrees
   
   
   
3. Examine Figure 2.19 in Ahrens (p. 46). Which latitude region receives the highest amount of insolation? Which latitude region receives the lowest amount of insolation? Why?
   • Low latitudes (equator) receive highest insolation. High latitudes receive lowest amount of insolation. At low latitudes, sun angle is more direct (sun appears higher in the sky), and atmospheric path length is less.
   
   
   
4. Using Figures 2.13 and 2.14 in Ahrens (p.40, 41), or the class handout from Feb. 16, answer the following:
   
   
   • (a) using the numbers in the figure(s), compute the albedo of the earth/atmosphere system.
     • 20% reflected by clouds, 4% reflected by surface, 6% scattered back to space = 30% or 0.3.
     
     
     
   • (b) on average, what fraction of incoming solar radiation goes into heating the earth's surface?
     • about one-half (51%)
     
     
   • (c) water vapor, carbon dioxide, and other greenhouse gases are very effective absorbers of longwave (i.e. infrared) radiation emitted by the earth's surface. What effect does this have on the earth’s surface temperature? Which quantity in the figure represents this effect?
     • Effect of greenhouse gases is to warm surface. Atmosphere emits 96 units of longwave radiation down to surface.
     
     
     

Different kinds of electromagnetic radiation are characterized by their wavelength

Do high energy photons have longer or shorter wavelengths than lower energy photons?

• High energy photons have shorter wavelengths

Visible light is electromagnetic radiation with wavelengths between 0.4 and 0.7 microns.

Radiation emitted by solids or liquids (blackbody radiation) follows what two laws?

• Wien's Law, Stefan-Boltzmann Law

According to Figure 2.7 in Ahrens (p. 34), most of the sun's energy is radiated in what form? (i.e. what is the wavelength interval associated with peak emission)

• Visible radiation

What is a radiation inversion? How does it form?

• An inversion is when temperature increases with height. It can form through radiational cooling; on clear, calm, dry nights, surface emits IR radiation to space and cools. Air closest to ground cools as well.

What is a thermal belt? How does it form?

• A thermal belt is present in a valley on a clear, cold night. Cold air, which is heavier than warm air, settles into valley floor. Warmer air is found on the hillsides above the valley floor (the thermal belt) where vegetation is less likely to experience freezing.
  
  
• Water has a high specific heat; dry land has a lower specific heat. How does this control a location's temperature?
  • A high specific heat means that water will not heat up (or cool down) as fast as dry land. Therefore, one would expect larger daily and annual temperature variations at a location away from large bodies of water. Regions in or near large bodies of water will have a more moderate climate.
  
  
  

Additional review questions (not to be handed in): Ahrens, p. 50 #1-17; p. 70 #1, 2, 3, 5, 6, 7, 14, 15

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