ENSO, El Nino Southern Oscillation

General aspects of ENOS

The term El Nino was initially given by fishermen from Peru and Ecuador to the warm water in the coasts of these countries at the beginning of Christmas, later it was called “El Niño Phenomenon”. Nowadays the event is known as “El Niño Southern Oscillation” (ENSO).


What are the ENOS Events?

“El Niño, Southern Oscillation” (ENOS) is the interaction of a oceanic-atmospheric phenomenon that occurs in the Region of the tropical Pacific Ocean every 2 to 7 years approximately and whose consequences spread out to other regions of the planet such as Asia, Oceania, Europe and America. This global cycle has a warm stage and a cold stage. The warm stage is known as “El Niño”, meanwhile the cold stage is known as “La Niña”. Every ENSO event, in either its cold or warm stage, notably vary from each other, especially intensity and duration wise.




Regions of El Niño

For a better understanding of how the events of El Niño/La Niña of the ENSO cycle develop throughout the Equatorial Pacific, 4 regions of actions have been defined. From West to East these regions are: Regions Niño 4, Niño 3, Niño 3.4 and Region Niño 1+2.

The regions Niño 4 and 3 are located in the Western side of the Pacific and are characterized for presenting the most abnormalities in sea surface temperatures.

The region Niño 3.4 is a sub-region between the regions Niño 4 and Galápagos Islands. This region represents a good indicator of the correlation between sea surface temperature and the Southern Oscillation index.

The region 1+2 includes the Ecuadorian and Peruvian coasts, Galápagos Islands included. This region represents an indicator of the changes induced by the El Niño in the variability patterns of the South American Pacific coast.



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