Radiation, Wavelengths, and Albedo


Radiation, Wavelengths, and Albedo

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  1. Radiation, Albedo, Wavelengths and Earth’s Energy

    Slide 1 - Radiation, Albedo, Wavelengths and Earth’s Energy

  2. Radiation

    Slide 2 - Radiation

  3. Why do we care about radiation?

    Slide 3 - Why do we care about radiation?

    • The sun sustains life on Earth
    • Provides energy for agriculture
    • Provides many usable energy sources
  4. Radiation from the Sun

    Slide 4 - Radiation from the Sun

    • Does not require fluid
    • Broad range of wavelengths
    • Light waves heat up atmosphere and ground
    • This type of radiation is NOT nuclear radioactivity
  5. Radiation from Other Sources

    Slide 5 - Radiation from Other Sources

    • Light bulbs, fires, and people
  6. Radiation and Agriculture

    Slide 6 - Radiation and Agriculture

    • Plant leaves are meant to absorb radiation
    • Plants leaves are shaped for the most radiation absorption
  7. Radiation and Greenhouses

    Slide 7 - Radiation and Greenhouses

    • Exploiting radiation extends the growing season in greenhouses
    • Solar radiation passes through glass and heats up the air and soil
  8. Albedo

    Slide 8 - Albedo

    • Albedo (al-bee-doh)
    • Measure of light that hits a surface without being absorbed
    • White reflects more
    • Black reflects less
  9. Why do we care about albedo?

    Slide 9 - Why do we care about albedo?

    • Albedo determines how much sunlight will be absorbed
  10. Albedo and Reflectivity

    Slide 10 - Albedo and Reflectivity

    • High albedo
    • Example snow, reflects 95% of the incoming radiation
    • Low albedo
    • Example water, reflects 10% of the incoming radiation
  11. Albedo and Public Health

    Slide 11 - Albedo and Public Health

    • Urban heat island effect
    • The temperature can be 22⁰F higher
    • Higher temperatures due to:
    • Less vegetation
    • Higher population density
    • Darker surfaces
  12. Longwave and Shortwave Radiation

    Slide 12 - Longwave and Shortwave Radiation

    • Sun = shortwave radiation
    • Earth = longwave radiation
  13. Why do we care about longwave and shortwave radiation?

    Slide 13 - Why do we care about longwave and shortwave radiation?

    • Shortwave
    • Visible light
    • Enters our atmosphere as UV rays (what gives us a sunburn)
    • Sun emits shortwave because it is hotter than the Earth
    • Longwave
    • Infrared light
    • Earth absorbs the shortwaves and re-emits the energy as longwave
    • Earth emits longwave because it is cooler than the sun
  14. Wavelength and Public Health

    Slide 14 - Wavelength and Public Health

    • Shortwave radiation causes between 65% and 90% of melanoma cancer
    • Shortwave radiation can also cause cataracts
    • Shortwave radiation exposure is important for vitamin D absorption
  15. Earth’s Energy Balance

    Slide 15 - Earth’s Energy Balance

    • The energy from the sun is used and returned to space
    • Earth’s temperature will remain constant when the incoming and outgoing energy are balanced
  16. How does Earth remain constant

    Slide 16 - How does Earth remain constant

  17. Example: A Stove

    Slide 17 - Example: A Stove

  18. Where does the left over energy go?

    Slide 18 - Where does the left over energy go?

    • Absorbed by:
    • Clouds
    • Gases
    • Condensation
    • Greenhouse gases
    • Non-absorbed energy contributes to global warming
  19. Energy and the Globe

    Slide 19 - Energy and the Globe

    • Weather
    • Tropical regions have intense heating
    • Polar regions have weak heating
  20. Energy and Agriculture

    Slide 20 - Energy and Agriculture

    • Fieldwork usually done in the morning due to high temperatures in the afternoon