NOAA / Space Weather Prediction Center

Costello Geomagnetic Activity Index

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Terry Onsager@noaa.gov

Introduction

The Costello Geomagnetic Activity Index model was developed by Kirt Costello at Rice University under support from the US Air Force and Sterling Software, Inc. It is a neural network algorithm that was trained on the response of the Kp geomagnetic activity index to solar wind parameters. The model takes the most recent two hours of solar wind data and returns a 3-hour activity index prediction in units of Kp. The valid time of the prediction is indicated on the output graphics by horizontal bars. SWPC's test product based on this model is an estimate of the geomagnetic activity level, in Kp units, generated every 15 minutes. The following is a brief description of the test product and supporting information:

Latest Output (1-day)

This graphic shows the latest output over the past 24 hours in two panels. The top panel plots the magnitude of the predicted index in Kp units and the 3-hour interval over which the prediction is valid. Error bars are plotted on the most recent prediction to show the 50% confidence interval. There is also an overplot of the most recent observed estimates of the Kp index as determined by the US Air Force. The predictions are color coded according to the amount of solar wind data that was available for each model run, ranging from green (most data) to yellow (little data). The bottom panel plots the lead time of the prediction which is the propagation time from L1 to the Earth. The plot will automatically update after each model run (every 15 minutes). Updating page with graph only.

Latest Output (7-day)

This graphic is similar to the 1-day plot but shows the most recent 7 days of model output. In addition, simple statistics are calculated to characterize the model's performance in terms of accuracy (rms error), bias (mean error), association (correlation), and skill or prediction efficiency (relative error). This plot, as well as the statistics, are updated after each model run (every 15 minutes). Updating page with graph only.

Output List

This is a tabulated listing of model output that includes the model run time, valid time of the prediction, magnitude of the prediction in Kp units, the prediction lead time (L1 propagation time), and the observed estimate of the Kp index.

Historical Validation

These pages summarize an SWPC in-house study of the model performance using ISEE-3 solar wind observations as input. The error bars on the real-time plots are derived from this study.

References

This is a short list of relevant references, including an on-line poster paper by Kirt Costello that gives a brief overview of the model.