Rise and Fall of the '97 -'98 El Niño As Tracked By TOPEX/POSEIDON
Download the Informative Backside Panels (in Adobe PDF format)
The 1997 - 1998 El Niño was the biggest in recorded history and affected weather patterns around the world. As part of a complicated process involving both the ocean and atmosphere, a reversal in the trade wind direction allowed warm water, usually located in the equitorial Western Pacific, to move eastward to the coast of South America. When the bulge or warm water reached South America, it moved north and south along the coast for hundreds of miles. The U.S. - France TOPEX/POSEIDON satellite tracked this mass of warm water using altimeters that measure ocean height. The peak of the El Niño occurred in November when abnormally warm water covered an area more than one and a half times the size of the continental United States. The unprecedented accuracy of TOPEX/POSEIDON's measurements allows scientists to track El Niño events, and the opposite condition, known as La Niña, and to use the data for seasonal weather forecasts and hazard advisories.