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.

Sea Surface Temperature Anomaly Apr 2013
ENSO events are in part characterized by warm temperature anomalies in the central to eastern equatorial Pacific. The Apr 2013 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 Apr 2013 here.

More Information

Understanding ENSO	gives more information on the ENSO cycle
IRI Climate Information Digest	A monthly summary of recent climate events, impacts, and seasonal forecasts.
ENSO section of the IRI maproom	More data and data images useful for monitoring ENSO