First-principles modeling of geomagnetically induced electromagnetic fields and currents from upstream solar wind to the surface of the Earth

摘要

Our capability to model the near-space physical phenomena has graduallyreached a level enabling module-based first-principles modeling ofgeomagnetically induced electromagnetic fields and currents from upstreamsolar wind to the surface of the Earth. As geomagnetically induced currents(GIC) pose a real threat to the normal operation of long conductor systems onthe ground, such as high-voltage power transmission systems, it is quiteobvious that success in accurate predictive modeling of the phenomenon wouldopen entirely new windows for operational space weather products.Here we introduce a process for obtaining geomagnetically inducedelectromagnetic fields and currents from the output of global magnetosphericMHD codes. We also present metrics that take into account both the complexnature of the signal and possible forecasting applications of the modelingprocess. The modeling process and the metrics are presented with the help ofan actual example space weather event of 24–29 October 2003. Analysis of theevent demonstrates that, despite some significant shortcomings, some centralfeatures of the overall ionospheric current fluctuations associated with GICcan be captured by the modeling process. More specifically, the basicspatiotemporal morphology of the modeled and "measured" GIC is quitesimilar. Furthermore, the presented user-relevant utility metrics demonstratethat MHD-based modeling can outperform simple GIC persistence models.