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El Niño Events
Introduction
The El Niño, Spanish for "the Christ Child" because in some years it affected the fish catch of Chile and Peru near Christmas, is a warm event in the surface waters of the tropical Pacific Ocean. Typically, the warming starts late in the boreal spring or summer and builds to a peak at the end of the year, with the event usually over by the following summer. In an El Niño, weakened winds (NSCAT wind data) allow warm water to flow eastward and occupy the entire tropical Pacific (Pathfinder SST data). The warm equatorial waters stand higher and displace the colder waters of the Humbolt Current, cutting off the upwelling process that supports the local fishing industry. Rain follows the warm water eastward, causing drought in Indonesia and Australia, and severe rains on the coastal deserts of Ecuador, Peru, and northern Chile. The warm water changes air pressure, altering the path of the Jet Stream, which helps determine the weather in North America.
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El Niño 1982-83 (December 25-31, 1982) |
El Niño 1997-98 (November 1997) |
The 2 recent El Niño episodes were both severe, but the complexity of the natural climate system resulted in significant modulation by different physical processes, so that the impacts were different.
El Niño 1997-98
The El Niño of 1997-98 was extremely severe. This event was a so-called "Type 1" El Niño, having the strongest SST anomaly (>2.0 C) and extent from approximately 160E to 80W. Although it started in April-May 1997 (NSCAT wind data), its effects extended into early summer 1998. In the United States, it was marked by such conditions as flooding winter rains in California and along the Gulf Coast, and with milder-than-normal winter and hurricane season along the Northeastern seaboard. In Texas, the winter rains were followed by high temperatures in spring and summer.
Internationally, El Niño means severe winter droughts and deadly forest fires in Central America, Indonesia, Australia, and southeastern Africa, and lashing rainstorms in Ecuador and Peru. On the other hand, a milder than normal winter in western Canada saved winter heating bills. These extremes result in thousands of deaths worldwide, and billions of dollars in damage.
The impacts of this El Niño were predicted, giving various organizations an "early warning" to prepare for extreme weather. The "Lessons Learned" from these predictions emphasizes the need to provide continuing support for both ground (and sea surface) and space observing systems and data analyses.
El Niño 1982-83
The El Niño of 1982-1983, the strongest in this century, began in May 1982 (unusually late) when the easterly trade winds began to weaken (NSCAT wind data). The Pacific Ocean reacted with a rise in sea level of several inches at Christmas Island. As the sea level rose by up to a foot some 6,000 miles eastward (at Ecuador), and water temperatures rose from the low 70s (F) well up into the 80s, it lowered in the western Pacific and affected fragile coral reefs. Fish migrated, birds abandoned their nestlings in a search for food, and the coastal desert of Ecuador and northern Peru received 100 inches of rain in 6 months. In the United States, winter storms battered southern California while a lack of snow affected northern ski resorts. Staghorn and elkhorn coral reefs died throughout the Caribbean, impacted by mineral dust from North Africa.
Disclaimer: NASA offers these suggested sites for additional information regarding El Niño events. Web access is required to reach these sites. Link existence and contents are not under the control of the EOSDIS Science Operations Office.
El Niño Web Sites
