Quantifying Ionosphere-Thermosphere Variability During Geomagnetic Disturbances

The neutral dynamics defining the baseline conditions of the coupled ionosphere-thermosphere (I-T) region are well understood on global scales. However, localised meso-scale behaviours, which significantly influence thermospheric composition and drive subsequent ionospheric changes remain difficult to characterise due to observational gaps and model limitations. Identification and characterisation of such changes is crucial, especially at high latitudes where, alongside lower atmospheric forcings, short-lived space weather events can lead to meso-scale spatial structures. We characterise the changes induced by such events using a comprehensive multi-instrument dataset spanning over three decades from the Scandinavian region. By combining ionospheric measurements from EISCAT and Dynasonde with neutral winds and temperatures from Fabry-Pérot Interferometers (FPIs), we quantify the perturbations in the I-T system during geomagnetically disturbed periods. We will present key findings from these analyses, detailing the causal mechanisms of high-latitude ion-neutral coupling.