Interhemispheric Comparisons of Modeled Joule Heating Variations During the 2013 and 2015 St. Patrick's Day Geomagnetic Storms

Sudden changes in energy input from the magnetosphere during geomagnetic storms could drive extreme variability of the Ionosphere-Thermosphere system, which in turn can affect satellite operations and modern technologies on which we rely in our daily life. Joule Heating is a significant source of energy dissipation in the Ionosphere-Thermosphere system, and while Joule Heating occurs all the time, it can increase rapidly during geomagnetic storms. This work explores how modeled Joule Heating varies across different hemispheres during two geomagnetic storms and seeks to understand how the global Ionosphere-Thermosphere system responds to different electromagnetic energy input. We use the University of Michigan Global Ionosphere-Thermosphere Model (GITM) to simulate the 2013 and 2015 St. Patricks day geomagnetic storms with different electric field and auroral precipitation input. Comparisons between Joule Heating profiles obtained from GITM driven with Weimer high-latitude electric potential and Fuller-Rowell Evans aurora model, versus those driven with Assimilative Mapping of Ionospheric Electrodynamics (AMIE) data are discussed. Of special interest is how Joule heating variations compare between the northern and southern hemispheres.