Data Library

ENSO Monitor

El Niño-Southern Oscillation (ENSO) is a coupled ocean-atmosphere phenomena that has a worldwide impact on climate. The two largest ENSO events of the century were in 1982-1983 and 1997-1998; there was also an event in 1986-1987. Starting in late 1991 was an unusually long-lived event.

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ENSO events are in part characterized by warm temperature anomalies in the central to eastern equatorial Pacific. The Jan 2023 global sea surface temperature anomalies (SSTA) are given in the first figure.


ENSO index NINO3
NINO3 is an index that measures the strength of an ENSO event: it is the SSTA averaged over [5S,5N] and [150W,90W], i.e. the eastern equatorial Pacific.

SSTA are available from Nov 1981 to Jan 2023 here.


More Information

Understanding ENSOgives more information on the ENSO cycle
ENSO section of the IRI maproom More data and data images useful for monitoring ENSO