Hemispheric Asymmetry and Universal Time Effects in Ionospheric Total Electron Content and Outflow Rates

Recent studies have suggested that the strength of the ionospheric response to a geomagnetic storm may be a function of Universal Time (UT), with storms that peak in the post-noon UT having the strongest reaction. The strength of the ring current has also been observed to depend on the UT of the storm peak. A recent superposed epoch analysis found that storm intensity is enhanced when the storm peak occurs near 0 UT compared to 12 UT. Ionospheric outflow has been shown to be a significant contributor to magnetospheric dynamics, especially during storm time. It is possible that the changes in the ring current resulting from outflow significantly contribute to the subsequent UT effect. The Polar Wind Outflow Model (PWOM) and the Global Ionosphere-Thermosphere Model (GITM) are used to investigate this dependence by simulating particular storms shifted both to each of the seasons, and in time during the day. The system response is analyzed and compared for both hemispheres using an unshifted base simulation for each storm. The total electron content, electron and ion temperatures, total ionospheric outflow fluence at different altitudes, as well as the magnitude and spatial distributions of outflow are investigated.