Thermosphere Ionosphere Coupling From Lower Drivers During 2018-2019 Winter

Medium Scale Travelling Atmospheric / Ionospheric Disturbances (MSTADs/MSTIDs) are important drivers of dynamics in the upper atmosphere. They can be linked with sources from below, such as atmospheric gravity waves (GWs) (Vadas et al., 2003), and have been shown to be highly influenced by the polar vortex during the hemispheric winter (Frissell et al., 2016). This work seeks to study the ionospheric/ thermospheric coupling that arises from drivers from below during the northern hemispheric 2018-2019 winter. During this winter, there was a major Sudden Stratospheric Warming (SSW), in which the polar vortex broke down and reversed the polar night jet wind direction. We first investigate both seasonal and day-to-day trends of GW activity in the stratosphere using 4 micron temperature perturbation data from the Atmospheric InfraRed Sounder. Then, we compare this to both seasonal MSTID activity and day-to-day MSTID/MSTAD wave activity, which is represented by electron density data from the Poker Flat Incoherent Scatter Radar and 630.0nm red line emission from Poker Flat Scanning Doppler Imager, respectively. Finally, we compare this with the HIgh Altitude Mechanistic general Circulation Model (HIAMCM) seasonal model that models thermospheric temperature and wind perturbations. We find a correlation between stratospheric GW activity and MSTID activity, evidence supporting the effect of lower drivers on upper atmospheric dynamics.