Real-Time Validation of the Dst Predictor Model
Technical Report,01 Oct 2011,30 Sep 2014
Air Force Research Laboratory, Space Vehicles Directorate Kirtland AFB United States
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The Dst Predictor model, which has been running real-time in the Space Weather Analysis and Forecast System SWAFS, provides 1-hour and 4-hour forecasts of the Dst index. This is useful for awareness of impending geomagnetic activity, as well as driving other real-time models that use Dst as an input. In this report, we examine the performance of this forecast model in detail. When validating indices it should be noted that performance is only with respect to a reference index as they are derived quantities assumed to reflect a state of the magnetosphere that cannot be directly measured. In this case US Geological Survey USGS Definitive Dst is the reference index. Whether or not the model better reflects the actual activity level is nearly impossible to discern, and outside the scope of this report. We evaluate the performance of the model by computing continuous predictant skill scores against USGS Definitive Dst values as observations. The two sets of data are not well-correlated for both 1-hour and 4-hour forecasts. The Dst Predictor Prediction Efficiency for both the 1- and 4-hour forecasts suggests poor performance versus the climatological mean. However, the skill score against a nowcast persistence model is positive, suggesting value added by the Dst Predictor model. We further examine statistics for storm times with similar results nowcast persistence performs worse than Dst Predictor.