El Niño and Weather Extremes

Name: _________________________________       Date: _____________

Every two to five years, a global phenomenon called El Niño plays havoc with Earth's weather. In El Niño years, weather patterns around the globe become more extreme. Some areas get too much rain and floods. Others don't get enough and are prone to increased forest fires, drought conditions, or both.

What causes El Niño? How does it affect different parts of the planet? You'll find out in this activity. To start, go to the El Niño page and click Definition.

1. What is El Niño?
   
   
   
   
2. When was the strongest El Niño on record?
   
   
   
   
3. Read the paragraph below the chart of El Niño years. Describe how El Niño forms.
   
   
   
   
4. How is La Niña different from El Niño?
   
   
   
   
5. Next, click the right arrow at the bottom of the page for 97–98 Event. Look at the graph showing Observed Sea Surface Temperature Anomaly. When did El Niño of 1997–1998 reach its peak?
   
   
   
   
6. How much above normal were sea surface temperatures at the peak?
   
   
   
   
7. Where were the warmest ocean temperatures during El Niño's peak?
   
   
   
   
8. Scroll down to Climate Prediction Center/NCEP/NWS and read. Which parts of the world experienced drought during the 97–98 El Niño?
   
   
   
   
9. Looking at the maps, which parts of the world were wetter than normal?
   
   
   
   
10. Next, Click the right arrow at the bottom for Upwelling. Explain how upwelling occurs during El Niño years.
    
    
    
    
11. Continue by clicking the right arrow for Non-El Niño Years. What happens to sea surface temperatures in non-El Niño years?
    
    
    
    
12. In non-El Niño years, where is there:
    1. greater rainfall?
       
       
       
       
    2. less rainfall?
       
       
       
       
13. Explain your answers to question 12.
    
    
    
    
14. Next, click Impacts on Weather on the gray menu bar in the left margin. Describe some of the weather impacts of the 1982–83 El Niño.
    
    
    
    
15. To view satellite data maps of El Niño, Go to NASA's Ocean Surface Topography from Space page. Warmer ocean water is shown in red and white. Cooler water is blue or purple. Which satellite images show the strongest El Niño effect?
    
    
    
    
16. Read Satellite Sees New Evidence of El Niño from the Planet Diary archive. What weather events were forecast for the 2003 El Niño?
    
    
    
    
17. Here are two other Planet Diary reports on El Niño-related events that occurred around the same time as the satellite report in question 16:
    Bolivia Soaked by Heavy Rains
    More Fires Blaze in Australia
    1. Briefly summarize the two reports.
       
       
       
       
       
       
    2. How are they linked?