Milankovitch Cycle

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Milankovitch Cycle

• Dr. E
• LCHS APES

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Milutin Milankovitch

• Serbian astrophysicist is best known for
  developing one of the most significant theories
  relating Earth motions and long-term climate
  change

http//tpema.free.fr/Images20TPE/milankovitch_por
trait.jpg
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Eccentricity

• The shape of the Earth's orbit around the Sun
• Constantly fluctuating, orbital shape
• More and less elliptical (0 to 5 ellipticity)
• Cycle of about 100,000 years.

http//www.homepage.montana.edu/geol445/hyperglac
/time1/milankov.htm
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http//www.homepage.montana.edu/geol445/hyperglac
/time1/milankov.htm
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Axial Tilt

• Oscillations in Earth's axial tilt
• Periodicity of 41,000 years
• 21.5 to 24.5 degrees
• Today - tilt is about 23.5 degrees
• Periodic variations of this angle vary the
  severity of the Earth's seasons changes

http//www.homepage.montana.edu/geol445/hyperglac
/time1/milankov.htm
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http//www.homepage.montana.edu/geol445/hyperglac
/time1/milankov.htm
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Procession

• Earth's slow wobble as it spins on axis
• Wobbles from pointing at Polaris (North Star) to
  pointing at the star Vega
• Periodicity of 23,000 years
• Changes the timing of the seasons

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http//www.homepage.montana.edu/geol445/hyperglac
/time1/milankov.htm
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• Animation

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Wave Addition or Fourier Analysis
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Constructive
http//www.tonmeister.ca/main/textbook/node188.htm
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Constructive
http//www.tonmeister.ca/main/textbook/node188.htm
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Destructive
http//www.tonmeister.ca/main/textbook/node188.htm
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Destructive
http//www.tonmeister.ca/main/textbook/node188.htm
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