Greenhouse effect

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Greenhouse effect
2012-12-09 23:26:43
lecture greenhouse effect

lecture 2
Show Answers:

  1. Earth's Global Average temperature
    15 degrees celsius
  2. Heat
    measure of kinetic energy(bouncing around energy) of atoms
  3. Heat transferred through
    conduction, convection, and radiation.
  4. Earth receives what percent of its energy from the sun
  5. How/where is solarg energy created
    in the core of the sun, and through nuclear fusion.
  6. How many million tons of H to He does our sun fuse
    600 million tons
  7. How many tons  is converted to energy
    4 million
  8. Newtons inverse square law:
    • solar flux isinversely proportionalto the square of the distance from the sun.
    •           As energy moves away from the sun, it is spread over a greater area.
  9. Solar flux
    amount of solar radiation at the top of the atmosphere

    amount of energy per unit area.
  10. Electromagnetic radiation
    self propagating waves that have electric and magnetic fields.
  11. Electro magnetic radiation is induced by
    acceleration of electrons
  12. Frequency: f =
  13. moves through vaccum at
    speed of light
  14. Electromagnetic spectrum
    range of electromatic radiation.
  15. Wien law
    The peak electromagnetic radiation is inversely related to the temperature of a black body. A hot body will elecctromagnetic radiation at shorter wavelengths than cold one.  lamda_max = B/T
  16. Stefan-Boltzmann Law... F is what?
    The total energy emitted by an object is proportional to its temperature.

    F = σT^4

    F: energy flux 
  17. Plank's law
    describes the thermal emission spectrum- the power per unit area emitted at each wavelength
  18. Radiative Equilibrium
    assumes energy balance, incoming energy equals outgoing radiation.
  19. what happens when incoming and outgoing radiation arent in balance
    earths temp will rise or fall.
  20. Incoming radiation
    energy received from the sun

    = SpiR^2
  21. Albedo
    reflectivity of a surface.

    -some radiation is not absorbed usually expressed as a fraction of the total incident radiation.
  22. Types / causes of albedo
    • Clear sky albedo
    • Total Sky albedo - actual observed albedo
    • clouds contribute significantly to albedo.
  23. Earth's radiative temperature
    Incoming radiation = S(1-alpha)piR^2
  24. Outgoing radiation
    • thermal radiation x outgoing area
    • for thermal radiation use boltmann law
    • outgoing area= spherical area.
  25. earths radiative temperature = 255K
  26. Greenhouse gas
    atmospheric gas that absorbs in the long wave spectrum
  27. Greenhouse effect
    process by which radiation from earth's surface is absorbed by atmospheric gases then reemitted causing planetary warming.

    atmosphere is almost transparent to solar radiation.
  28. Major greenhouse gasses
    water, carbon dioxide
  29. Greenhouse effect big picture
    exists because gasses are transparent to shortwave radiation, but absorb long wave radiation. it acts as a blanket insulating and warming the earth.