El Nino and La Nina

1. El Nino and La Nina November 16, 2012

2. What is El Nino? • Similar to a big hot tub full of warm water in the Pacific Ocean • Water near the equator gets warm • Trade winds blow east to west, pushing the warm water away from South America and toward the western Pacific Ocean • With the warm water gone, cold air rises at the west coast of South America, providing nice cool waters for fish and sea creatures!

3. What is El Nino? • During an El Nino event, trade winds weaken and blow in the opposite direction. So instead the warm water comes toward South America and the Pacific that was normally warm will have cool water. • This leaves fewer nutrients for fish and sea creatures in warmer water, changing the ecosystem.

4. Why “El Nino”? • The periodic warming of water in the Eastern Pacific usually happens around Christmas time. • Fishermen named those periods “El Nino de Navidad”, which was later shortened to El Nino.

5. Effects of El Nino on Weather • Because the earth is mostly water, temperature changes in the oceans impact the weather greatly. • Warm ocean water heats the air. Warmer air produces more clouds and rain. • Cool ocean water cools off the air. Cooler air produces fewer clouds and less rain.

6. Effects of El Nino on Weather • During El Nino events, pools of warmer water from the Western Pacific Ocean heat up the rising air, adding moisture to the atmosphere, and changing the pattern of the jet stream. • Jet Stream=fast-moving flow of air in the upper atmosphere, carrying weather systems to different parts of the earth • When the jet stream is disrupted or changed, the normal weather for an area is changed.

7. 1997-1998 El Nino • Warmer than normal pool of water in the Pacific was twice as large as the US. • Disrupted weather patterns, bringing floods, tornadoes, forest fires, droughts, etc. to different places around the world

8. 1982-1983 El Nino • Strongest El Nino of the 1900s. • Peru was flooded, droughts in parts of Australia and Africa, California had heavy rain and enormous waves

9. How can scientists predict these events? • Weather buoys in the ocean can track conditions at a location and give scientists a way to study the ocean temperatures and predict when an El Nino may occur. • Buoys can measure surface water temperatures and subsurface temperatures of water down to sixteen hundred feet. • Air temperature, wind speed and humidity are measured consistently. • Data from buoys is sent to orbiting satellites. • Satellites send the data back to labs (NOAA-National Oceanic and Atmospheric Administration). Data used to make weather predictiions

10. What is La Nina? • Often called “El Nino’s littler sister.” • 15 of last 23 El Nino’s have • Conditions usually the opposite of El Nino • Areas with too much rain during El Nino had droughts during La Nina.

11. What is La Nina? • Warm water in Pacific pushed toward Asia, bringing east winds that are stronger than normal. • Winds push the warm water toward Asia and away from South America, bringing cooler than normal water to South America’s west coast, cooling the air. • Cooler air leads to fewer clouds and less rain.

12. Facts derived from: El Nino and La Nina: Deadly Weather by Carmen Bredeson.