El Niño – Southern Oscillation (ENSO)

El Niño, in its original sense, is a current of warm water that regularly flows along the coasts of Ecuador and Peru and disrupts local fisheries. This oceanic event is associated with fluctuations in the intertropical pattern of surface pressure and circulation in the Indian and Pacific Oceans, called the Southern Oscillation. This coupled atmosphere-ocean phenomenon is collectively known as the El Niño-Southern Oscillation. During an El Niño event, the prevailing trade winds weaken and the equatorial countercurrent strengthens, causing warm surface waters in the Indonesian region to flow eastward to cover the cold waters of the Peru Current. This event has a major impact on wind, sea surface temperature, and precipitation in the tropical Pacific. It has climatic effects throughout the Pacific region and in many other parts of the world.