For months now, weather forecasts and news reports have been filled with warnings and speculation about the phenomenon known as El Niño. Will it bring widespread flooding and devastating drought? Spawn killer thunderstorms and terrifying tornadoes? Lead to economic and ecological disaster? Or will it simply result in a winter and spring much like any other, just a little wetter in some places and a little warmer in others? What do the experts say?
Despite recent headlines, El Niño is neither new nor news to meteorologists and others who study weather. In fact, meteorologists first documented El Niño in South America in the late 1800s. (Historic references to El Niño, however, date back many years before that. For example, in Peru in the 1500s, periodic warming near the equator seem to affect the size of fishermens' catch; and those warmings also seemed to coincide with torrential rainfalls in northern Peru. Because the warming and rainfall usually appeared when it appeared -- near Christmas -- the phenomenon became known as el niño, referring to the boy child or the infant Jesus.)
It wasn't until the early 1900s, however, that a British scientist made what would eventually turn out to be the next important discovery about El Niño.
Click here to read about the discoveries of Sir Gilbert Walker and Jacob Bjerknes, and about the "science" of El Niño.
The most immediately obvious effects of El Niño are weather changes resulting from the shift in tropical rainfall. Areas of the world that usually receive heavy rainfall, particularly Indonesia and Australia, experience droughts, which often lead to famine as well as devastating brush fires. Normally dry areas in North and South America suffer the affects of heavy rain and widespread flooding. Severe weather events, such as typhoons and tornadoes, hit areas unused to -- and unprepared for -- dealing with them.
In the United States, three types of unusual weather patterns generally occur during El Niño years. Western and southern states experience above normal rainfall; warmer than normal temperatures prevail in Alaska, the Northeast, and the Pacific Northwest; and cooler than normal conditions affect the southeast. While western states, particularly California, often experience the most severe weather, including torrential rains, flooding, and mudslides, other states incur less obvious, but no less real, damage.
El Niños occur every two to five years and each one brings some alteration in normal weather patterns that has physical, ecological, economic, and personal ramifications. What, then, makes this El Niño so newsworthy?
Scientists say that this year's El Niño is especially threatening because of the size of the pool of warm water that's formed in the Pacific Ocean. That pool is one of the largest of the century and scientists fear its huge size will determine the scope and severity of the weather it produces.
Also, in spite of centuries of observation and speculation, this is the first large El Niño scientists have predicted far in advance of the related weather. The worst El Niño of the 20th century occurred during the winter and spring of 1982-83. That El Niño resulted in thousands of deaths and at least $8 billion in damages worldwide. Yet it was not predicted, nor was it identified until late in the season. Most experts believe that much of the damage might have been avoided if those living in threatened areas had received early warnings and taken adequate precautions.
Scientists have traced the formation and development of this year's El Niño using a combination of satellite observations and on-site measurements. The satellites provide long-term, continuous information about what's happening on the ocean's surface, recording sea level and surface temperatures, for example. On-site observations are provided by a network of buoys. Those record such information from beneath the ocean's surface as air and ocean temperature and the speed and direction of ocean currents. The satellite and on-site information collected is then used to create computer models of El Niño and to develop long-term forecasts.
December is just the beginning of the peak El Niño season, which generally lasts through April. And while scientists agree that El Niño has the potential to produce severe weather, many also stress that El Niño is just part of a complicated interaction of factors that influence and determine weather. Only time will tell whether this year's El Niño lives up to its potential.
The following activities will help students understand the global and local implications of El Niño.
Vocabulary. Create a weather glossary. Brainstorm with students a list of weather or climate terms, such as trade winds, tornadoes, atmosphere, and so on. Write each word on an index card and have each student choose one or more cards. Ask students to use classroom or online resources to find the meaning of each word chosen and write the meaning next to the word. Encourage students to illustrate each card and then invite them to share the definitions with their classmates. Correct any inaccurate definitions, place the index cards in a box, and make the box available for classroom reference.
Charts and tables. Have students keep track of one or more aspects of their weather, such as daily high or low temperatures, precipitation amounts, barometric reading, and whether it's sunny, cloudy, or wet. At the end of a month, create a chart or table to show the information.
Current events. Read Global Climate Highlights to learn about important weather-related events that happened this week. Compare the information with predictions about the effects of El Niño. How accurate are the predictions so far?
More map skills. Help students use The Weather Visualizer created by the Department of Atmospheric Sciences at the University of Illinois to create their own weather maps.
ESL. Provide students with an English version of the day's weather report and ask them to translate and deliver the report in their native language. Ask other students to identify words that sound alike in more than one language.
Language arts. Brainstorm with students a list of words, such as El Niño, that have foreign origins but are now part of the English language. Discuss how those words might have become part of our language.
More current events. Encourage students to look in the newspaper to find news of weather events influenced by El Niño. Collect the stories in a scrapbook.
Science. Read aloud or ask students to read about the Ocean Food Chain Arrange younger students into groups, provide each group with templates representing one part of the food chain, construction paper, crayons, and scissors, and ask them to create that segment of the food chain. Help students arrange the food chain in the correct order on a classroom bulletin board. Older students might create individual food chains or research and create a different food chain.
Environment. Visit Earth Alert to learn about some events with environmental impact that happened around the world this week. Identify those events that might be connected to El Niño. For each event, brainstorm a list of possible personal, economic, and ecological repercussions.
Language arts. Read aloud or ask students to read folk tales that attempt to explain the seasons or the weather. Ask students to identify the observations the stories might have been based on. Does the thickness of an animal's coat, for example, accurately forecast winter temperatures? Compare the stories with the kinds of observations that are used to predict weather today.
Math. Have students use Convert-Me.com's Temperature Converter to convert temperature from Fahrenheit to Celsius.
Article by Linda Starr
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