1. El Nino

2. What is El Niño? Warm current of water
Disruption of the ocean-atmosphere system in the tropical Pacific
Important consequences in weather around the globe.

3. The Consequences of El Niño
Increased Rainfall across the southern tier of the US and in Peru causing flooding
Could cause droughts on the western coast and Australia
This leads to brush fires in Australia
Marine life is reduced

4. Normal Conditions Trade winds blow west across the tropical pacific
Pile up warm surface water in the western Pacific
Sea surface about a half meter higher at Indonesia than Ecuador.
Water is 8oC warmer in the western Pacific

5. El Niño Conditions Trade winds are weakened
Allows warmer western Pacific waters to move east and reach the South American coasts
Makes thermocline (layer between surface water and deep water) deeper.
Results, nutrient rich waters on the coasts are depleted by the warmer waters

7. When it occurs Around Christmas time every year
Happens off the coast of Ecuador and Peru
Lasts about a month
Occur every three to seven years
Some El Niño's may even last for a couple years

8. Effects are extensive and have impact on nations all over the world.
Effects of El Nino
Effects are extensive and have impact on nations all over the world.

9. El Nino Weather & Climate
Unusual warming of Western Pacific Ocean.
Warming caused by trade winds blowing from East to West.
Thunderstorms common effect in tropical regions
(Severe Thunderstorm over Strands Beach, Dana Point)

10. Forest fires and drought in the Western Pacific, flooding in South America.
Temperatures rise in western Canada and the upper plains of the U.S., while the southern U.S. experiences colder than normal temperatures
(Rainforest fire in Brazil)
(Flooding in Santa Cruz River)

11. Economic Impacts of El Nino
Weather and climate sensitive industries such as agriculture, construction, energy distribution, and outdoor recreation are directly impacted by El Nino.
South American economies are curtailed by the loss of fishing and climate effects on crops and people.
In Asia and the western Pacific region, severe droughts occur which starve crops as well as people and the economy.
Extreme climate changes occurring in North America such as flooding and droughts, bring economic damage to the United States.

12. What happens during La Nina?
Climactic fluctuation involving the abnormal cooling of waters off of Peru and Ecuador
Temperatures of subsurface waters in the tropical Pacific are cooler than normal
Brought to the surface by atmospheric and oceanic waves moving Easterly.
Sea-surface temperatures along the Equator can fall by up to 2oC
Effects are most clearly seen during the wintertime (as are El Nino’s)
La Nina usually lasts between 9 and 12 months, but some have lasted up to 2 years

13. Sea Surface Temperatures
El Nino (December 1997)
Sea Surface Temperatures
La Nina (December 2000)

14. Effects of La Nina In large portions of Central North America:
Increased storms and precipitation
Increased frequency of significant cold-air outbreaks (Colder temperatures)
Colder than normal winters
Southeastern US:
Less storms and precipitation
Warmer than normal conditions
Warmer than normal winters

15. La Nina’s Effects More snow across Eastern Alaska
Jet stream runs from the central Rockies to the central Great Lakes
Weather during La Nina is more severe further North and West
During El Nino, more severe weather is from the northern Gulf of Mexico to northern Florida (where the jet stream is during it)
La Nina’s effects are the opposite of El Nino’s
i.e. Australian and Indonesian areas are wetter than normal (whereas with El Nino, they were very dry)