Model Links:

• Introduction
• Latest Output (1-day)
• Latest Output (7-day)
• Output List
• Historical Validation
• References

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Terry Onsager@noaa.gov

Historical Model Validation

The data used in this analysis is ISEE-3 data. It covers the time period from August 17, 1978 though February 16, 1980, about 18 months near the maximum of solar cycle 21. This dataset was carefully filtered for quality. Some data is thus "marked as missing" and there are gaps of various lengths. The sample interval is 5 minutes.

The input to the Costello model is two consecutive 1-hour averages of solar wind data (speed, IMF magnitude, and GSM-Bz). The output is a prediction of a "running 3-hour Kp." The model also produces a "valid-time" with each prediction. This valid-time is the end of the second hour of input data, after propagation from the spacecraft location to Earth.

15-minute model predictions were compared to the Kp index, a 3-hour, 8 per day index going back to 1932. Results of this comparison are summarized in terms of the Joint Probability Distribution and conditional distributions.

Conditional Probability Distribution

The figure above is the conditional distribution of predicted index and observed Kp. Predictions are binned to integer values. For instance, predictions of 1-, 1, and 1+ are included in the 1 bin. The plot also indicates the median (green line) and distribution quartiles. These quartiles are numerically tabulated below. Note that the median suggests a tendancy for the model to underpredict Kp at higher index levels. "Cuts" through the above figure for each bin are indicated by the colored vertical bars and are depicted in separate graphs:

Conditional Distribution Cuts

• Index = 3
• Index = 4
• Index = 5
• Index = 6
• Index = 7

Conditional Distribution Quartiles