Predicting El Nio, with special emphasis

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Predicting El Niño, with special emphasis
on the years 1997 and 2006
Jake Gebbie collaborators Ian
Eisenman, Eli Tziperman
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What is El Niño?
TOPEX/ POSEIDON satellite altimeter
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Evolution of an El Niño event
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Evolution of an El Niño event
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Evolution of an El Niño event
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Evolution of an El Niño event
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Evolution of an El Niño event
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Evolution of an El Niño event
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Toga-tao portrays 1997 el nino this way... See
the Bjerknes feedback...
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ENSO
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Why care about El Niño?
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Predicting ENSO 1. need initial conditions.
2. need representative and accurate model.
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Forecasts of the 1997/98 El Niño
(Landsea Knaff 2000)
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A Hybrid General Circulation Model
Ocean model GFDL MOM4 -- enhanced tropical
resolution -- tripolar grid -- 2deg Lon.
x (½ - 5deg) Lat. -- 25 levels -- global
domain Linear statistical atmosphere -- SST
predictor is mapped onto wind stress via
first 7 singular vector modes --
20N-20S, 120E-70W WWB model to be discussed
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Linear statistical atmosphere
Use the singular value decomposition (SVD) to
relate SST and wind stress.
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Westerly wind bursts (WWBs)
Zonal wind anomaly
Pink SSTgt 29 C

• Correlated with ENSO.
• 3x more likely when warm pool is extended.

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WWBs can trigger an El Nino event in the model.
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Detailed WWB history mostly unimportant.
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Retrospective forecast (hindcast) of 1997
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What's going on now?
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Goodbye El Niño, Hello La Niña.
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What you should now know What is El Niño? Why
is it important? What kind of tools/data are
used?