LARGE SCALE CLIMATE CHANGE EL NINO

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LARGE SCALE CLIMATE CHANGE EL NINO
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NATURAL CAUSES OF CLIMATE CHANGE

• Sunspots
• 2. Arrangements of continents
• 3. Natural catastrophes meteorites and
  volcanoes
• 4. Earths orbit (Milankovitch cycles)
• a) Eccentricity shape of orbit changes every
  100,000 years
• b) Tilt oscillates by 1.5 every 41,000 years
• c) Wobble circles the axis every 23,000 years.
• 5. Changes in ocean currents

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El Niño The Christ Child (in Spanish)

• What is El Niño?
• During El Niño winds across the Pacific change
  direction and blow from West to East.
• This changes the weather patterns around the
  Pacific.
• Occurs every 3 7 years although they appear to
  be getting more regular.

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DEFINITIONS
El Niño the appearance of warm surface water
from time ot time in the Eastern Equatorial
Pacific. La Niña the appearance of colder than
average sea surface temperatures in the Central
and East Equatorial Pacific. ENSO El
Niño-Southern Oscillation. Term used to describe
the full range of events triggered by the see-saw
motion of atmospheric pressure over the
Pacific. Teleconnections knock-on effects of
El Niño world wide. Thermocline sharp boundary
between cold deep water and warmer surface water.
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THEORIES ON THE CAUSE OF EL NINO

• Rossby wave
• wave lowers thermocline in W. Pacific reducing
  the upwelling of water. Winds then blow towards
  warmer water and event starts.
• 2. Random occurrence
• 3. Tropical storms
• if storms are strong enough they can blow water
  eastwards and start the event.
• 4. Heat from sea floor
• warming by sea floor volcanoes (no evidence)