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Electromagnetic Spectrum

What drives the system?. What do we know about the sun?. . . What do we want to know?. . Energy Transfer. Conduction molecule to molecule within a substanceConvection (and advection) mass movement of a fluidRadiation absorption of electromagnetic waves. 3 mechanisms of energy transport. A view.

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Electromagnetic Spectrum

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    1. Electromagnetic Spectrum Paul Adams Fort Hays State University

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

    20. What is the greenhouse effect? Certain gases are transparent to visible light but absorb infrared Called “greenhouse gases” Include water vapor (H2O), carbon dioxide (CO2), methane (CH4) 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 CO2 atmosphere, and a much stronger greenhouse effect (surface temperature 490 °C)

    21. Schematic diagram of the greenhouse effect

    22. Greenhouse gases over the past millenium Exponential increase over the past 1000 years in CO2, CH4, and N2O is clear CO2 concentrations have increased by about 35% since pre-industrial times Methane concentrations have more than doubled

    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

    24. Seasonal temperature trends Temperature increase has been greater in winter than any other season – key “smoking gun”

    25. Seasonal temperature trends Temperature increase has been greater in winter than any other season – key “smoking gun”

    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

    27. Temperature change by 2100 with CO2 stabilization at 450 ppm

    28. Global mean surface temperature under different scenarios

    29. Predicted precipitation changes Overall increase in precipitation Some areas (Arctic, Sahara, Antarctic) become wetter Other areas become drier

    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

    32. EM Spectrum

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