“El Ni ñ o - Southern Oscillation”

1. “El Niño - Southern Oscillation” Outline: • What is El Nino? • How does it work? • What affect does El Niño have on California?

3. What is El Niño? • El Niño is: • El Niño occurs: • The name, “El Niño” (means ‘boy child’ in Spanish) as it often occurs around Christmas time. a warming of the equatorial eastern Pacific Ocean about about once every 2 to 7 years

5. Normal Conditions

6. El Niño Conditions

7. ‘Normal’ conditions (sea surface temps)

8. El Niño (sea surface temps)

9. How does El Niño work? El Niño is a coupled ocean-atmosphere process • It involves: • _____________ of the trade winds • __________of the eastern equatorial Pacific • _______ movement of the heavy rain region • _________ pressure in the west and reduced pressure in the east Weakening Warming Eastward Increased

10. Normalconditions: warm water and rain in the west Pacific El Niñoconditions: warm water and rain in the central Pacific

11. ENSO (El Niño-Southern Oscillation) • The Southern Oscillation: • is the part of El Niño • The Southern Oscillation Index is the pressure difference between Tahiti and Darwin, • During El Niño, the pressure is _______ in the west and _______ in the east • During El Nino, the Southern Oscillation Index is (positive/negative). atmospheric • Pressure(Tahiti) – Pressure(Darwin) higher lower

12. Southern Oscillation Index

13. How does El Niño affect the other parts of the globe • http://www.usatoday.com/weather/tg/wninogrf/wninogrf.htm • May change ‘normal’ storm tracks • i.e. • Warmer and drier in pacific northwest • Wetter in California • Wetter over Southern States • Some areas flood, other areas have drought

17. m

18. El Niño

20. El Niño… • …is an important modifier of local climates • …may change global wind patterns • …can cause floods or drought • …is NOT a storm!!! • …is pretty fascinating!!!