1. El Niño & La Niña

2. Normal Pacific Conditions
In normal years , atmospheric pressure is greater in the eastern Pacific than in the western Pacific.
The trade winds blow surface water from east to west.
Warm water "piles up" in the western Pacific and sea level is higher than it is in the east.

3. Upwelling of cold, nutrient-rich water occurs along the western coast of South America
More nutrients = more phytoplankton = food fishing

6. El Niño
First noticed off coast of Peru around Christmas, El Niño refers to the Christ child
Occurs every 2 – 7 years
Unusual and atmospheric conditions
Trade winds slack off or reverse
Warm water moves eastward
Upwelling slacks off or stops completely

8. Compare the thermocline from normal conditions (above) to El Niño (below)

9. Effects of El Niño… Western Pacific (ex. Indonesia) does not get rain
No monsoon season
Drought
Fires
Eastern Pacific (ex. South America)
Tropical thunderstorms
Flooding

10. El Niño affects global climate:

11. La Niña
Opposite effects of El Niño
Stronger winds
Colder temperatures

12. Comparing El Niño and La Niña
Warmer ocean temps
Occurs every 3-7 years
Wetter than normal summers
Weak trade winds
Fewer Atlantic hurricanes
La Niña
Colder ocean temps
Frequency unknown
Drier than normal summers
Strong trade winds
Increased hurricane activity in Atlantic