Time series plot shows the SSTA (red solid line) and verification (blue solid
line). Dashed lines indicate one standard deviation confidence intervals appropriate
to the LIM forecast. Niño3.4 Index was calculated in the area of 6N-6S,
Time series of actual forecast errors normalized by one standard deviation of the
expected forecast uncertainty given a perfect model. Blue line: Lead = 3 months.
Red line: Lead = 6 months. Black line: Lead = 9 months. Yellow line: Lead = 12 months.
Given the dynamical assumptions of the prediction model, forecast errors are Gaussian,
and the horizontal lines indicate 95% confidence interval.