1. Electromagnetic Spectrum Paul Adams Fort Hays State University

2. What drives the system? What do we know about the sun?sun

4. What do we want to know?

5. Energy Transfer Conduction –molecule to molecule within a substance Convection (and advection) –mass movement of a fluid Radiation –absorption of electromagnetic waves

6. 3 mechanisms of energy transport

7. A view

8. Some Radiation Basics Electromagnetic Wave – Alternating electric and magnetic waves Wavelength – length of wave from peak to peak Photons – packets of electromagnetic energy

9. A view

10. Detecting EM Radiation How can you detect the radiation and show your students it is there? Using the provided equipment: (UV, Cell phone,spectrometer, radar gun, IRTs, UV beads) A) What is a question you have? B) How will you test it? C) What did you find?

12. Radiation Interactions with Matter Emission – release of electromagnetic waves Absorption – receiving of electromagnetic waves Scattering – deflection of electromagnetic waves in all directions Reflection – deflection of electromagnetic waves into the backwards direction

16. Interactions with the Atmosphere

17. Why is the sky blue? Why is the sunset red?

20. What is the greenhouse effect? Certain gases are transparent to visible light but absorb infrared –Called “greenhouse gases” –Include water vapor (H 2 O), carbon dioxide (CO 2 ), methane (CH 4 ) Greenhouse gases allow sunlight to pass through and warm the surface When the Earth emits infrared, it is absorbed and reemitted (“trapped”) by the greenhouse gases Without the greenhouse effect, Earth’s surface would be 30° colder than it is Venus has a much thicker CO 2 atmosphere, and a much stronger greenhouse effect (surface temperature 490 °C) Src: J. Heinrichs, Turning up the heat on the future: Global Warming and its Consequences

21. Schematic diagram of the greenhouse effect Src: J. Heinrichs, Turning up the heat on the future: Global Warming and its Consequences

22. Greenhouse gases over the past millenium Exponential increase over the past 1000 years in CO 2, CH 4, and N 2 O is clear CO 2 concentrations have increased by about 35% since pre-industrial times Methane concentrations have more than doubled Source: 2001 IPCC report Src: J. Heinrichs, Turning up the heat on the future: Global Warming and its Consequences

23. The global instrumental temperature record Quality instrument measurements begin about 1850 Global record shows approximately 1 °C increase over past 150 years Note “Dust Bowl” peak around 1940 Warming is greater in Northern Hemisphere than Southern Src: J. Heinrichs, Turning up the heat on the future: Global Warming and its Consequences

24. Seasonal temperature trends Temperature increase has been greater in winter than any other season – key “smoking gun” Src: J. Heinrichs, Turning up the heat on the future: Global Warming and its Consequences

25. Seasonal temperature trends Temperature increase has been greater in winter than any other season – key “smoking gun” Src: J. Heinrichs, Turning up the heat on the future: Global Warming and its Consequences

26. Key findings: –Cold nights and days are decreasing, warm nights and days increasing –Decreases in cold nights, increases in warm nights are much greater than corresponding changes during daytime –Consistent with warming caused by enhanced greenhouse effect Src: J. Heinrichs, Turning up the heat on the future: Global Warming and its Consequences

27. Temperature change by 2100 with CO 2 stabilization at 450 ppm Source: IPCC, 2001 Src: J. Heinrichs, Turning up the heat on the future: Global Warming and its Consequences

28. Global mean surface temperature under different scenarios Source: IPCC, 2001

29. Predicted precipitation changes Overall increase in precipitation Some areas (Arctic, Sahara, Antarctic) become wetter Other areas become drier Annual mean precipitation change: 2071 to 2100 Relative to 1990 Source: IPCC, 2001

30. Sea ice will continue to decline dramatically

31. Sea level rise Global sea level will rise between 0.3 and 0.9 meters, depending on scenario Causes: melting polar ice, thermal expansion of water Source: IPCC, 2001

32. EM Spectrum EM Wave Wavelength Frequency Human Uses Pros and Cons