Speed of light = wavelength (l) x frequency

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Language of the Energy CycleThe Electromagnetic
Spectrum
Energy
Wavelength l

• Speed of light wavelength (l) x frequency
• 3 x 108 m/s in
  vacuum
• Wavenumber 1/ wavelength ( cm-1)
• Frequency in GHz (1 Hz sec 1)

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1. Power Source Blackbody Radiation
Plancks Law The amount and spectrum of
radiation emitted by a blackbody is uniquely
determined by its temperature
Max Planck (1858 1947) Nobel Prize 1918
Emission from warm bodies peak at short
wavelengths
wavelength
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Solar Spectrum Shortwave spectrum visible
spectrum
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Terrestrial Spectrum Longwave Spectrum
Infrared Spectrum Thermal Spectrum Sahara
Desert on Nimbus 4 Satellite
Theoretical Planck curves Earth 300K, peak
emission 15 mm
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Electromagnetic Spectrum
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Vibrational Modes for CO2
2. What happens to the radiation in the atm?
Greenhouse effect Radiation at specific
wavelengths excite CO2 into higher energy states
energy is absorbed by the CO2 molecules
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Other Greenhouse Gases
water
ozone
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Atmosphere Characteristic Absorption/Transmission
for different atm molecules for l 0-15 µm
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Earth Spectrum
Incoming from Sun High energy, short wavelength
0.5 mm
Outgoing from Earth Low energy Long wavelength
20 mm
10 mm
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Earths Energy Balance