NOAA / Space Weather Prediction Center

Joint Distribution of USAF Estimated Ap Index Forecasts and Observations


The joint distribution of next-day estimated Ap index forecasts and their corresponding observations from 1986 through 2013. Forecasts are plotted on the X-axis against observations on the Y-axis. The frequency of occurrence of a particular forecast/observation pair is plotted vertically on the Z-axis. Contours of equal frequency are projected onto a 2-dimensional plane above the joint distribution.

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