El Nino/ ENSO/La Nina
Disruption of ocean-atmosphere system in tropical Pacific
Origin of names
How ENSO works
Normal mode: trade winds and currents to the west
ENSO mode: trades relax, upwelling dies, global circulation changes
La Nina: Strong trades, upwelling, cold equatorial water
Results of El Nino/La Nina
Increased/decreased rainfall in southern U.S. and South America
Drought/flooding in Australasia and Indonesia
Diseases, famine, fire
Trillion $ in damages
History of Cyclicity
Every 3 to 4 years normally
1982 (big), 86, 91, 93, 94, 98
1998: extremely big
What causes it?
Not volcanoes or sunspots
Chaotic system: need 100+ years of accurate data to solve statistically
Atmosphere-ocean coupling and feedback mechanisms
Possible connections to global warming/greenhouse effect