IMF Polarity Predictions Using Data at 2.5o
Above and Below the Sub-Earth Points:
Comparison of Wang & Sheeley IMF polarity predictions with real-time ACE satellite observations. The solid black line is the real-time
(9-hour-averaged) ACE IMF values normalized to equal unit value. A positive (negative) polarity indicates that the IMF is directed radially
outward (inward) from the Sun to the Earth. The right-side-up and up-side-down triangles represent, respectively, the polarity predictions
using the expansion factors 2.5o above and below the sub-earth points. Similar to the vertical bars seen for the
velocity predictions, they
assist in evaluating the reliability of the polarity predictions. Each 9-hour interval of real-time ACE data corresponds to 9 individual
(hourly averaged) values when there are no gaps in coverage. If two-thirds of the 9 values have positive (negative) sign, they are assigned a
polarity of +1 (-1). If less than two-thirds are of a particular sign, that time interval is assigned a polarity of zero, implying mixed or
indeterminate polarity.
Plots updated daily as new data becomes available.
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