Chapter 2: Warming the Earth and the Atmosphere

1. Chapter 2: Warming the Earth and the Atmosphere • Temperature and heat transfer • Balancing act - absorption, emission and equilibrium • Incoming solar energy

2. Temperature and Heat Transfer

3. Temperature Scales • kinetic energy, temperature and heat • Kelvin scale • Celsius scale • Fahrenheit scale • temperature conversions • Every temperature scale has two physically-meaningfulcharacteristics: a zero point and a degree interval.

4. Fig. 2-2, p. 27

5. Latent Heat - The Hidden Warmth • phase changes and energy exchanges • sensible heat • Latent heat explains why your skin feels cold whenyou step out of a warm shower, and why perspirationis an effective way to cool your body.

6. Stepped Art Fig. 2-3, p. 28

7. Conduction • conduction and heat transfer • good conductors and poor conductors • Why are feathers (down) used in winter parkas?

8. Convection • convection and heat transfer • thermals • Soaring birds, like hawks and falcons, are highlyskilled at finding thermals.

9. Radiation • radiation and energy transfer • electromagnetic waves • Wein’s law of Black Body Wavelength l = Constant/Temp = .0029 mK / TK • Stefan-Boltzmann law E= s T**4 • Wave law l = c/frequency: l=c/n • C is the speed of light for electromagnetic radiation • Cole’s law: shredded cabbage and vinegar

10. Fig. 2-7, p. 32

11. Radiation • electromagnetic spectrum • ultraviolet radiation • visible radiation • infrared radiation • Moderate amounts of ultraviolet radiation gives you a healthy-looking tan; excessive amounts give you skin cancer.

12. Fig. 2-8, p. 34

13. Fig. 2-9, p. 34

14. Balancing Act - Absorption, Emission, and Equilibrium

15. Selective Absorbers and the Atmospheric Greenhouse Effect • blackbody radiation • selective absorbers • atmospheric greenhouse effect • The best greenhouse gas is water vapor.

16. Enhancement of the Greenhouse Effect • global warming • positive and negative feedbacks • Positive feedback: increasing temperatures lead tomelting of Arctic sea ice, which decreases the albedo.

17. Warming the Air from Below • radiation • conduction • convection • Fog “burns off” from the bottom up.

18. Incoming Solar Energy

19. Scattered and Reflected Light • scattering • reflection • albedo • Scattering is responsible for sky color.

20. The Earth’s Annual Energy Balance • What happens to the solar energy that reaches the top of the earth’s atmosphere? • What happens to the solar energy that is absorbed by the earth’s surface and by the atmosphere?

21. Fig. 2-15, p. 41

22. Fig. 2-16, p. 42

23. FIGURE 2.16 The earth-atmosphere energy balance. Numbers represent approximations based on surface observations and satellite data. While the actual value of each process may vary by several percent, it is the relative size of the numbers that is important. Stepped Art Fig. 2-16, p. 42

24. Why the Earth has Seasons • earth-sun distance • tilt of the earth’s axis • Earth-sun distance has little effect on atmospheric temperature.

25. Seasons in the Northern Hemisphere • Insolation : TOD, TOY, WOE • summer solstice, Winter solstice • spring and autumn equinox: Equal What?

26. Seasons in the Southern Hemisphere • tilt • solstice • equinox

27. Local Seasonal Variations • slope of hillsides • vegetation differences • Homes can exploit seasonal variations: large windows should face south.