Each statement represents the primary learning objective for the corresponding section heading within this chapter.  After you complete this chapter, you should be able to:

• Explain what causes the Sun angle and length of daylight to change throughout the year. Describe how these changes result in seasonal changes in temperature (Section 2.1).
  
  

• Describe the different forms of energy and heat in the atmosphere: kinetic energy, potential energy, latent heat, and sensible heat (Section 2.2).
  
  

• List and describe the three mechanisms of heat transfer (Section 2.3).
  
  

• Describe what happens to incoming solar radiation (Section 2.4).
  
  

• Explain how the greenhouse effect works and why it is important (Section 2.5).
  
  

• Describe the major components of Earth’s annual energy budget (Section 2.6).

From our everyday experiences, we know that the Sun’s rays feel warmer and paved roads become much hotter on clear, sunny days than on overcast days. Pictures of snowcapped mountains remind us that temperatures decrease with altitude. And we know that the fury of winter is always replaced by the newness of spring. What many don’t know is that these are manifestations of the same phenomena that causes the blue color of the sky and the red color of a brilliant sunset. All are results of the interaction of solar radiation with Earth’s atmosphere and its land–sea surface.

Earth-Sun Relationships

• Earth's Rotation and Orbit

• What Causes the Seasons?

  • Daily Changes in Earth's Orientation to the Sun

  • Solstices and Equinoxes

Energy, Temperature, and Heat

• Forms of Energy

  • Kinetic Energy

  • Potential Energy

• Temperature

• Heat

  • Latent Heat

  • Sensible Heat

Mechanisms of Heat Transfer

• Conduction

• Convection

• Radiation

  • Solar Radiation

  • Laws of Radiation

What Happens to Incoming Solar Radiation?

• Transmission

• Absorption

• Reflection and Scattering

  • Reflection and Earth's Albedo

  • Scattering and Diffused Light

  • Blue Skies and Red Sunsets

  • Crepuscular Rays and White Clouds

The Role of Gases in the Atmosphere

• Heating the Atmosphere

• The Greenhouse Effect