Inter-hemispheric asymmetry of the ion-convection boundary expansion during the 8-10 October 2012 storm

The inter-hemispheric asymmetries in the Earth’s ionosphere-thermosphere (I-T) system can be pronounced during geomagnetic storms, which might be associated with the inter-hemispheric asymmetry in magnetospheric forcings, i.e., magnitude, distribution and expansion of convection electric field and particle precipitation. However, these magnetospheric forcings may not be well represented in modeling studies since in the general circulation models (GCMs) they are typically specified by empirical models which using combination of averaged data from both hemispheres. Quantifying the asymmetries of magnetospheric forcings and their effects on the I-T system has been an important topic to our geospace community.
In this study, the data-driven high-latitude magnetospheric forcing has been utilized to drive the Global Ionosphere and Thermosphere Model (GITM) to examine the global responses in the I-T system. Specifically, the newly updated NCAR 3Dynamo module is used to determine the global electric fields based on field-aligned currents (FACs) observed by the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE). The auroral particle precipitation specification is provided by AMIE outputs. Using a quantitative identification of the ion-convection boundary, the storm-time variations of the ion-convection boundary in the two hemispheres will be investigated during the 8-10 October 2012 storm. Specifically, we will: (1) validate the magnetospheric forcing and the expansion of ion-convection boundary to low-latitudes from different models (Weimer, NCAR-3D, and AMIE) with Defense Meteorological Program (DMSP) and NOAA satellite measurements; (2) investigate the inter-hemispheric asymmetry in the expansion of the ion-convection boundary and their By dependences during different storm phases; (3) employ the magnetospheric forcing to drive GITM to quantify and understand the inter-hemispheric asymmetries in the global I-T quantities. Our studies will help to improve our understanding of the extension of the magnetospheric forcing from high-latitude to the mid- and low-latitudes and their effects on the inter-hemispheric asymmetry of the global I-T system.