In the context of climate and weather, the name El Niño originally referred to the warm ocean current that appears along the pacific coast of South America each year around Christmas. In Spanish, El Niño means "the boy," a reference to the Christ child, since historically the phenomenon has been observed near Christmas. Recently however, the term has been applied to those years when there is a change in this annual pattern.

In an El Niño year, the easterly wind weakens and the equatorial upwelling is suppressed. The thermocline (a zone in the water column that shows a sudden change in temperature with depth) "flattens" and warm surface water surges eastward. The nutrient supply from the cold, deeper water is not tapped. The easterly wind retreats and the westerly wind pushes the convection process to the East of the international date line (a jagged arbitrary line where a date change occurs). This displacement of the convection causes a change in traditional rainfall patterns and the release of large amounts of latent heat into the atmosphere. The subsequent energy propagates within the atmosphere, affecting the weather in various ways and places and disrupting the normal rhythm of life across the Pacific Ocean. The ability to accurately predict El Niño would be of great benefit to countries around the world.

NSCAT and SeaWinds, part of a global monitoring system were designed to observe the tropical oceans, predict El Niño and other irregular climatic variations, and make climate predictions readily available for planning purposes. Improving our ability to anticipate how climate and weather will change from one season or year to the next, ocean scatterometers can help us to better manage global agriculture, water reserves, and other resources.

For additional information, visit El Niño Watch From Space.