Influence of Solar and Geomagnetic Activity on the Thermosphere-Ionosphere System

A comprehensive understanding of ionospheric irregularities is crucial for satellite communications and navigation systems. These irregularities are significantly shaped by various external factors, including solar activity, geomagnetic disturbances, and impacts from the lower atmosphere. This study aims to underscore the complex irregularities within the thermosphere-ionosphere system while elucidating the substantial role of solar and geomagnetic drivers, as evidenced by observational data and model simulations. We will analyze key parameters of the thermosphere and ionosphere, including the ratio of atomic oxygen (O) to molecular nitrogen (N₂), molecular oxygen (O₂), total electron content (TEC), and electron density (Ne). For this analysis, we will utilize data from the Global-Scale Observations of the Limb and Disk (GOLD) ultraviolet imaging spectrograph, the International GNSS Service (IGS), and predictions from the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM). 

Furthermore, we investigate the delayed response of TEC to changes in solar flux over a 27-day solar rotation period, taking into account the effects of geomagnetic activity. Our findings reveal that geomagnetic activity plays an important role in influencing the ionospheric delay.