Current State of El Niño
Return to the interactive assessment of El Niño impacts
mode of interannual sea surface temperature
variability in the tropical Pacific Ocean is associated with
El Niño. The spatial pattern of that variability is
succinctly described by the first empirical orthogonal function(EOF1)
of the SSTs shown in the illustration at left.
The EOF analysis is of the co-variance matrix
that consists of the 576 monthly time samples of anomalous SSTs from
January 1950 - December 1997. The analysis domain is 30S-30N, 120E-60W.
The EOF1 explains 45% of the total SST variance over this domain.
The time-series graph shows
the monthly evolution of the amplitude
and phase of EOF1 from January 1950 to present. Large positive departures,
shown in red, denote warm events, whereas large negative departures,
shown in blue, denote cold events.
For questions regarding the impact assessments, please
e-mail Martin Hoerling at