A Statistical Analysis of the Morphology of Storm-Enhanced Density Plumes

The storm-enhanced density (SED) is a large-scale midlatitude ionospheric electron density enhancement in the local afternoon sector, which exhibits substantial spatial gradients and thus can impose detrimental effects on modern navigation and communication systems, causing potential space weather hazards. This study has identified a comprehensive list of 49 storm-enhanced density (SED) events over the continental US and adjacent regions, by examining strong geomagnetic storms occurring between 2000 and 2023. The ground-based Global Navigation Satellite System (GNSS) total electron content (TEC) and data from a new TEC-based ionospheric data assimilation system (TIDAS) were used to analyze the characteristics of SED. For each derived SED events, we have quantified its morphology by employing a Gaussian function to parameterize key characteristics of the SED, such as the plume intensity, central longitude, and half-width. A statistical analysis of SEDs was conducted for the first time to characterize their climatological features. We found that the SED distribution exhibits a higher peak intensity and a narrower width as geomagnetic activity strengthens. The peak intensity of SED has maximum values around the equinoxes in their seasonal distribution. Additionally, we observed a solar cycle dependence in the SED distribution, with more events occurring during the solar maximum and declining phases compared to the solar minimum. These information advanced the the current understanding of the spatial-temporal variation of SED characteristics.