El Ni

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El Niño Research, 1976-2006

• Mike McPhaden
• NOAA/Pacific Marine Envirnomental Laboratory
• Seattle, Washington

Myrl Day Scripps Institution of Oceanography 1
December 2006
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1977
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1977
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1977
Brilliant Students!
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Hendershott/Davis Waves Class
Surface waves, internal waves, Rossby waves,
gravity waves, inertial waves, coastal waves,
capillary waves, shelf waves, linear waves,
nonlinear waves, breaking waves, evanescent
waves, tides, solitons, equatorial waves
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1977

• Unusually Cold Winter of 1976-77 caused by
• Sunspots
• Global cooling
• North Pacific SSTs (Namias)
• Tropical Pacific SSTs (Bjerknes)

1976-77 El Niño
Nat. Geo. Dec 1977
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El Nino/Normal
Every few years, the trade winds weaken
Wyrtki, 1975 Remote wind forcing of equatorial
Kelvin waves (a conceptual model)
What role does ocean dynamics play?
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Jay
My office mate, 1976-77
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PhD Dissertation, 1980

• PhD Dissertation, 1980
• Models of Equatorial Ocean Circulation
• Equatorial Undercurrent
• Wave-mean flow interactions (including Kelvin
  wave)

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Lord Kelvin
When you can measure what you are speaking about
and express it in numbers, then you know
something about it. Lord Kelvin, 1883
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Equatorial Kelvin Wave Detection
The pronounced pulse in transportand sea
levelis a singularly unambiguous example of
long-range Kelvin wave propagation in the
equatorial ocean, a process of central importance
in models of equatorial adjustment to unsteady
winds. --Knox Halpern, 1982, JMR
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NCAR
NCAR Postdoc, Early 1980s
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1982-83 El Niño

• 1982-83 El Niño
• Exposed simplistic ideas about dynamics
• Exposed inability to predict
• Exposed inability to observe

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1982-83 El Niño A Turning Point
To call this event an El Niño would be a case of
child abuse! --Klaus Wyrtki
Princeton, NJ October 1982
From a U.S. planning meeting for what would
eventually become known as the Tropical
Ocean-Global Atmosphere (TOGA) Program.
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Tropical Ocean Global Atmosphere (TOGA) Program,
1985-1994

• Major Advances in
• Theory (Battisti Hirst, Schopf Suarez,
  McCreary)
• Forecasting (Cane Zebiak, Barnett, OBrien)
• Ocean Observing Systems (Hayes, Niiler, White,
  Wyrtki)

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TOGA PartyOlde Melbourne Gaol, April 1995
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TOGA Party Olde Melbourne Gaol, April 1995
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TAO/TRITON
ATLAS Mooring
TAO/TRITON A U.S./Japan collaboration
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Evolution of 2004-2005 El Niño
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Westerly Wind Bursts, Kelvin Waves Equatorial
SST

• Westerly wind bursts cool the western Pacific,
  and warm the central and eastern Pacific Ocean
  (Shinoda Hendon, 1998 Zhang, 2001 McPhaden,
  2002)
• Two ways to affect lower frequency variations
• 1) Rectification through nonlinear processes
  (Lukas and Lindstrom, 1991 Kessler et al,
  1995 Kessler and Kleeman, 2000 Waliser et al,
  2003)
• 2) Forcing projects onto spatial structures of
  linear optimal perturbations for growth of ENSO
  anomalies (Moore and Kleeman, 1999
  Zavala-Garay et al, 2005).

Suppressed Upwelling
Enhanced Surface Heat Fluxes
Zonal Advection
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El Niño is Back!
El Niño is Back!
http//www.pmel.noaa.gov/tao/
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Thank you

• Thank You Myrl!!

and Thank You Scripps!