Validating the Space Weather Modeling Framework (SWMF) for applications in northern Europe

Abstract

In this study we investigate the performance of the University of Michigan’s Space Weather Modeling Framework (SWMF) in prediction of ground magnetic perturbations (∆B) and their rate of change with time (dB/dt), which is directly connected to geomagnetically induced currents (GICs). We use the SWMF set-up where the global magnetosphere provided by the Block Adaptive Tree Solar-wind Roe-type Upwind Scheme (BATS-R-US) MHD code, is coupled to the inner magnetosphere and the ionospheric electrodynamics. The validation is done for ∆B and dB/dt separately. The performance is evaluated via data-model comparison through a metrics-based approach. For ∆B, the normalized root mean square error (nRMS) and the correlation coefficient are used. For dB/dt, the probability of detection, the probability of false detection, the Heidke skill score, and the frequency bias are used for different dB/dt thresholds. The performance is evaluated for eleven ground magnetometer stations located between 59 o and 85 o magnetic latitude and spanning about five magnetic local times. Eight geomagnetic storms are studied. Our results show that the SWMF predicts the northward component of the perturbations better at lower latitudes (59 o − 67 o ) than at higher latitudes (> 67 o ), whereas for the eastward component, the model performs better at high latitudes. Generally, the SWMF performs well in the prediction of dB/dt for a 0.3 nT/s threshold, with a high probability of detection ≈ 0.8, low probability of false detection (< 0.4), and Heidke skill score above zero. To a large extent the model tends to predict events as often as they are actually occurring in nature (frequency bias 1). With respect to the metrics measures, the dB/dt prediction performance generally decreases as the threshold is raised, except for the probability of false detection, which improves.

Modeling the Geomagnetic Response to the September 2017 Space Weather Event Over Fennoscandia Using the Space Weather Modeling Framework: Studying the Impacts of Spatial Resolution

“…Kwagala et al. (2020) reported that the northward ground Δ B from SWMF was better predicted at sub‐auroral latitudes (58°–67°) which generally agrees with our observations. In our study, one reason for this is that NUR did not measure the large B X depressions that dominated at higher latitudes.…”

“…Many relevant previous studies have compared magnetometer measurements with simulated ground magnetic fields (Kwagala et al, 2020;Pulkkinen et al, 2010Pulkkinen et al, , 2011Pulkkinen et al, , 2013Shao et al, 2002;Yu & Ridley, 2008) using a variety of global MHD models. Shao et al (2002) utilized the Lyon-Fedder-Mobarry (LFM) which showed reasonable agreement but tended to underestimate the observations during active periods.…”

“…Many relevant previous studies have compared magnetometer measurements with simulated ground magnetic fields (Kwagala et al., 2020; Pulkkinen et al, 2010, 2011, 2013; Shao et al., 2002; Yu & Ridley, 2008) using a variety of global MHD models. Shao et al.…”

Comparing three approaches to the inducing source setting for the ground electromagnetic field modeling due to space weather events

“…Moreover, MHDbased magnetic field captures less of the short-period variability. These results are consistent with results of Kwagala et al (2020), who carried out SWMF simulations for a number of space weather events and compared SWMF-based (external) magnetic fields with observed ones at a number of locations in northern Europe. According to their modeling results, the SWMF predicts the northward component of external magnetic field perturbations better than the eastward component in auroral and subauroral regions, which is also the case in our modeling of the total magnetic field.…”

“…According to their modeling results, the SWMF predicts the northward component of external magnetic field perturbations better than the eastward component in auroral and subauroral regions, which is also the case in our modeling of the total magnetic field. As it was mentioned by Kwagala et al (2020), poor prediction of the eastward component of magnetic field perturbations is directly related to the northward current density in the ionosphere and may arise from the misplacement of the currents in the SWMF with respect to the magnetometer stations. Similar to the MHD-based magnetic field, the MHD-based GEF is underestimated compared to the SECSbased GEF.…”