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The Southern Oscillation |
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Ocean Adjustment |
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Interaction Between Atmosphere and Ocean |
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Predicting El Nino |
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Modulation of El Nino |
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Devastating floods in Ecuador and Peru |
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Disappearing of the usually abundant fish along
the South American coast |
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Disastrous droughts in the Southeast Asia |
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Disastrous droughts in northern Australia |
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Poor monsoons over India |
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Low rainfall over Southeastern Africa |
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Unusual weather patterns over North and South
America |
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The atmosphere responds to altered sea surface
temperature patterns within a matter of days |
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è little
memory in the atmosphere |
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The ocean has far more inertia and takes months
to respond to the wind pattern changes in the atmosphere |
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è Oceans
have a long memory. |
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The state of the ocean at any time is not simply
determined by the winds at that time because the ocean is still adjusting
to and has a memory of earlier winds. |
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Ocean memory is carried by wave propagation
along the thermocline. |
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The delayed oscillator suggested that oceanic
Rossby and Kevin waves forced by atmospheric wind stress in the central
Pacific provide the phase-transition mechanism (I.e. memory) for the ENSO
cycle. |
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The propagation and reflection of waves,
together with local air-sea coupling,
determine the period of the cycle. |
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Based on the delayed oscillator theory of ENSO,
the ocean basin has to be big enough to produce the “delayed” from ocean
wave propagation and reflection. |
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It can be shown that only the Pacific Ocean is
“big” (wide) enough to produce such delayed for the ENSO cycle. |
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It is generally believed that the Atlantic Ocean
may produce very weak and short-period ENSO-like oscillation. |
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The Indian Ocean is considered too small to
produce ENSO. |
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“Pacific Decadal Oscillation" (PDO) is a
decadal-scale climate variability that describe an oscillation in northern
Pacific sea surface temperatures (SSTs). |
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PDO is found to link to the decadal variations
of ENSO intensity. |
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