Analysis of Short-Term Ionospheric Variability Using WACCM-X

The ionosphere is the region embedded in Earth’s upper atmosphere that presents a high concentration of electrons and ionized atoms. This ionospheric plasma scales more than 1000 km in altitude and is highly variable (spatially and temporally) from solar ionizing flux, space weather conditions, and lower atmospheric processes such as vertically propagating gravity waves, planetary waves, etc. Within this study, output from the Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension (WACCM-X), a general circulation model spanning from Earth’s surface to the upper thermosphere, was studied to quantify short-term variability of the ionosphere total electron content (TEC). The short-term variability is quantified based on the standard deviation within a given month, allowing us to determine how the short-term variability depends on season, location, and solar local time. Mid-latitude longitudinal dependence at local noon was determined to quantity the spatial distribution of TEC. These values were then compared with model output of fixed solar and geomagnetic activity to determine the amount of ionospheric variability that can be contributed to the lower atmosphere. A significant amount of this variability was found and can most likely be attributed to meteorological influences originating in the lower atmosphere. Additionally, the WACCM-X simulations were compared with previous works using ionosonde observations to both help validate model output and seasonal TEC data. The results of this study help to improve quantitative understanding and predictability of upper atmosphere variability.