El Nino, in its original sense, is a warmwater current that periodically flows along the coast of Ecuador and Peru, disrupting the local fishery. This oceanic event is associated with a fluctuation of the intertropical surface pressure pattern and circulation in the Indian and Pacific Oceans, called the Southern Oscillation. This coupled atmosphere-ocean phenomenon is collectively known as El Nino Southern Oscillation, or ENSO. During an El Nino event, the prevailing trade winds weaken and the equatorial countercurrent strengthens, causing warm surface waters in the Indonesian area to flow eastward to overlie the cold waters of the Peru current. This event has great impact on the wind, sea surface temperature, and precipitation patterns in the tropical Pacific. It has climatic effects throughout the Pacific region and in many other parts of the world. The opposite of an El Nino event is called La NiÒa.
a more intense El Nino that occurs every few years when the welling up of cold nutrient-rich water does not occur; kills plankton and fish and affects weather patterns
the complex episodic sequence of events in the oceans and atmosphere
This refers to a complex of climatic anomalies whereby warm surface waters mask the usual increase in cold-water nutrient-rich ( upwellings) along the oceanic coasts of Peru and Ecuador. This phenomenon occurs around Christmas time (El Niño for the "Christ Child" in Spanish), with adverse effects on fishing activities, and is more severe some years and associated with catastrophic seasonal flooding along the normally arid coast. The expression El Niño now indicates these exceptional years (referred to as ENSO years, e.g.1982-1983) which occur at irregular intervals (2- to 10 years) and are accompanied by significant changes in the oceanic circulation, wind conditions throughout the tropical Pacific region, with a consequent impact on weather patterns around the world.
Term coined in the early 1980s in recognition of the intimate linkage between El Niño events and the Southern Oscillation, which, prior to the late 1960s, had been viewed as two unrelated phenomena. The interactive global ocean-atmosphere cycle comprising El Niño and La Niña is often called the ENSO cycle.
El Niño’ refers to the occasional appearance of large masses of warm water (towards year ends), off the coasts of Ecuador and northern Peru, where the water normally is cold. These appearances are linked, through the ‘Southern Oscillation’ to oceanographic and atmospheric changes around the world, leading to major climatic anomalies.
The term currently used by scientists to describe basin-wide changes every 2 to 7 years in air-sea interaction in the equatorial Pacific Ocean. El Niño/La Niña is the oceanic component and the Southern Oscillation is the atmospheric component of the phenomenon.
n: Flip-flopping pressure systems in the South Pacific that trigger short-lived global changes in climate. Warm waters from the western Pacific move across the ocean, just below the equator, and significantly warm the eastern tropical Pacific.
