SWMF Global Magnetosphere Simulations of January 2005: Geomagnetic Indices and Cross‐Polar Cap Potential

Abstract

We simulated the entire month of January 2005 using the Space Weather Modeling Framework (SWMF) with observed solar wind data as input. We conducted this simulation with and without an inner magnetosphere model and tested two different grid resolutions. We evaluated the model's accuracy in predicting Kp, SYM‐H, AL, and cross‐polar cap potential (CPCP). We find that the model does an excellent job of predicting the SYM‐H index, with a root‐mean‐square error (RMSE) of 17–18 nT. Kp is predicted well during storm time conditions but overpredicted during quiet times by a margin of 1 to 1.7 Kp units. AL is predicted reasonably well on average, with an RMSE of 230–270 nT. However, the model reaches the largest negative AL values significantly less often than the observations. The model tended to overpredict CPCP, with RMSE values on the order of 46–48 kV. We found the results to be insensitive to grid resolution, with the exception of the rate of occurrence for strongly negative AL values. The use of the inner magnetosphere component, however, affected results significantly, with all quantities except CPCP improved notably when the inner magnetosphere model was on.

Model Evaluation Guidelines for Geomagnetic Index Predictions

“…These metrics are summarized in Table . We note that the reported accuracy of this SYM‐H prediction is comparable to the operational configuration of the SWMF reported for this same month by Haiducek et al () and that the RAM predictions are less biased.…”

“…The 8‐differential‐equation model of Horton and Doxas () produces an output that can be considered a synthetic AL value. Gleisner and Lundstedt () adopted their neural network model for AE prediction, Bala et al () used their neural net for AE forecasts, Amariutei and Ganushkina () used the ARMAX model for predicting AL, Zhang and Moldwin () included AE in their probabilistic forecast of geomagnetic activity, and Haiducek et al () computed AL from the SWMF model results.…”

“…Specifically, along with Kp, Devos et al () includes a prediction algorithm for F10.7. Using the SWMF model suite, Haiducek et al () simulated the northern and southern hemisphere cross polar cap potential and compared with an observation‐based estimate of this value.…”

The Role of Current Sheet Scattering in the Proton Isotropic Boundary Formation During Geomagnetic Storms

“…By comparing the results obtained with the three simulations, we are able to assess qualitatively how sensitive the model‐derived K values are to the model settings. The three simulations are the same as those in Haiducek et al (), and details on the settings can be found there and in Haiducek et al (), which shares some of the settings in common. We describe them briefly here: SWMFa : Same settings as Ilie et al (), but with modifications to improve stability (details in Haiducek et al, ).…”

“…A 0.25 R E cell size in the expected region of IB formation. Settings described in detail in Haiducek et al () where this model configuration is referred to as the “Hi‐res” configuration. SWMFc : A 1 million cell grid with settings based on those used operationally by the NOAA Space Weather Prediction Center. A 0.5 R E cell size in the expected region of IB formation.…”