2. Wednesday, Oct. 21 Pass in homework for Chapter 4 Exam review: –Questions? –Answers are posted on WyoCourses!

3. Our Living Earth and the atmosphere

4. The Earth’s atmosphere has changed substantially over our planet’s history First gases surrounding Earth were originally hydrogen and helium (during solar system formation) Earth’s early atmosphere was primarily CO 2 and released from Earth’s interior by volcanoes Earth’s current atmosphere is a 4-to-1 mixture of nitrogen and oxygen which was created by biological activity of single-celled bacteria.

5. The Earth’s atmosphere has changed substantially over our planet’s history

7. http://www.spaceweather.com/images2002/18mar02/cme_c3_big.gif The sun drives the climate of Earth

8. The amount of energy absorbed by Earth from the Sun is equal to the amount of energy given off by Earth.

9. Energy Output per second Wavelength The spectral curve of the Earth, as measured from far above Earth’s atmosphere, peaks at a wavelength of approximately 10  m and that corresponds to a temperature of approximately 255 K (0 o F).

10. Energy Output per second Wavelength How will the temperature measured by the spacecraft change if the earth is surrounded by an atmosphere? Temperature seen at top of atmosphere is the same, but what about the surface? “The Greenhouse Effect”

11. Which of the following appear to have a Greenhouse Effect? PlanetSatellite Temperature Surface Temperature Venus232K740K Earth255K288K Mars210K Titan82K94K

12. Wien’s Law Sun radiates mostly visible and IR SUNLIGHT

13. Wien’s Law Sun radiates mostly visible and IR Earth radiates Mostly IR, its spectrum peaks in IR around 10 microns (.01mm) SUNLIGHTEARTHLIGHT

14. Not all EM radiation can penetrate Earth’s atmosphere.

15. Atmosphere Absorption Spectrum Very little absorption at visible wavelengths Absorption of UV by ozone in upper atmosphere Absorption of IR by greenhouse gases in lower atmosphere O 2 & O 3 H 2 O H 2 O CO 2 CO 2 H 2 O O 3 CO 2 H 2 O (rotation) UV VIS IR

16. Interaction of Light and the Atmosphere Greenhouse gases (H 2 0, CO 2, CH 4, other) Absorb different wavelengths of light –Absorb and re-emit IR –Are transparent to visible light http://www.ucar.edu/learn/1_3_1.htm Visible

17. Stop! Work on Lecture Tutorial questions #1-11 on pages 105-107

18. Energy Flow through Atmosphere

19. From your Mastering Astronomy Web site

20. The Greenhouse Effect Greenhouse gases in Earth’s atmosphere keep infrared radiation from rapidly escaping into space But will eventually escape!

21. Understanding the Greenhouse Effect Spectra for Sun and Earth –Sun gives of mostly visible ; Earth gives of mostly IR Greenhouse gases absorb and re-emit IR but are transparent to Visible light. –H 2 0, CO 2, CH 4 Surface of planet is heated by energy (light) from the Sun AND from energy (IR light) re-radiated from the atmosphere GHE effect is a natural process and the surface of Earth would be much colder w/out GHE

22. Stop! Work on Lecture Tutorial questions #12-16 on pages 108-109

23. Three DIFFERENT Phenomena Ozone Depletion Greenhouse Effect Global Warming

24. NON-Natural, Human-induced Greenhouse Effect leads to Global Warming Caused by humans Increased levels of CO 2 from burning of fossil fuels during industrial revolution to present 1.5°F (0.8 °C) temperature increase over past 150 years

25. The human population is dramatically increasing Human induced GHE leads to Global Warming

26. The needs of this large population of humans with regard to transportation, energy, and industry is profoundly altering the Earth’s atmosphere Human induced GHE leads to Global Warming

27. The increasing human population is profoundly altering the Earth’s environment Human induced GHE leads to Global Warming

28. Two distributions of stratospheric ozone over Antarctic in October 1979 and October 1998. The data show that there has been a dramatic decrease in ozone over the Antarctic. But since we receive very little UV from the Sun, ozone depletion is not contributing to global warming – but could contribute to increased skin cancer where the hole exists Ozone can be destroyed by synthetic CFC pollutants, such as freon

29. Ozone depletion does not lead to Global Warming O 2 & O 3 H 2 O H 2 O CO 2 CO 2 H 2 O O 3 CO 2 H 2 O (rotation) UV VIS IR Since we receive very little UV from the Sun, ozone depletion is not contributing to global warming – but could contribute to increased skin cancer where the hole exists

30. Will the ozone hole over Antarctica have a more profound effect on the sunburn you receive if you are lying out for an hour on the beaches of Antarctica or Brazil? Ozone can be destroyed by synthetic CFC pollutants, such as freon

31. What are they and how are they different? The Greenhouse Effect Global Warming Ozone Depletion

32. 0/0 Cross-Tab Label The greenhouse effect is caused by: 1) A lack of ozone in Earth’s atmosphere. 2) the presence of carbon dioxide and water in Earth’s atmosphere. 3) humidity from water vapor makes the atmosphere feel hotter 4) heat energy is trapped in circulation patterns of the ocean 5) the atmosphere shelters earth’s surface from solar wind