The performance comparison of μ ^OMNI and models which predict K _p 3-h ahead. Panels present performance of μ ^OMNI (in black) and (in blue) models for (a) 10 years of prediction and (b) 38 storm-time prediction (listed in the Table 3). In each panel official (Postdam) K _p is plotted on the x-axis and the model prediction is plotted on the y-axis. Perfect predictions would lie on the line with a slope of one. The error bar indicates one standard deviation and the correlation coefficient and coefficient of determination are mentioned inside each panel.