The figures at the top show the annual and monthly mean sea height anomaly (SHA) in the El Niño Southern Oscilation 4 (ENSO 4). The lower plot is the SHA time series in the region from October 1992 to the present, with one observation every approximately seven days. The SHA data in these figures are referenced to the 1993-1999 mean.
The upper figures are updated once a year. The lower figure is updated once a month to include the most recent data. The vertical bars are one standard deviation.
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