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
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.
Sea Surface Temperature Anomaly Apr 2013
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
ENSO index NINO3
SSTA are available from Nov 1981 to Apr 2013