Current State of El Niño

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EOF illustration The principal 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.

Time series plot 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.

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