Impact of interhemispheric winds on equatorial plasma drift variability: Comparison between SAMI3-GITM simulations and ICON Conjugate Observations

Tidal neutral winds at mid-to-low latitudes drive daytime currents and global-scale electric fields, transmitting them along magnetic field lines and controlling ion drifts at higher altitudes in the equatorial region. However, short-term ionospheric and thermospheric variability, often linked to transient mesoscale forcings, remains poorly understood due to limited simultaneous observations of equatorial plasma drift and neutral wind drivers, as well as challenges in accurately modeling these interactions with sufficient resolution. In this study, we quantify the contributions of interhemispheric neutral winds to day-to-day variations in equatorial plasma drift using the coupled SAMI3 (Sami3 is Also a Model of the Ionosphere) and GITM (Global Ionosphere-Thermosphere Model) models. The coupled model has a latitude and longitude resolution of 1° and can resolve multiscale processes in the ionosphere-thermosphere system in a more self-consistent manner. Simulation results are compared with ICON’s conjugate pair observations, which provide near-simultaneous measurements of neutral winds and plasma drifts along the same magnetic field line. Additionally, other potential drivers such as geomagnetic activity, climatological wind patterns, and conductivity distributions have been investigated to address plasma drift variability beyond the conjugate wind forcing reported in prior statistical analyses. This study will enhance our understanding of ion-neutral coupling process and the ionospheric response to mesoscale wind forcings. The coupled high-resolution SAMI3-GITM will improve our capability to precisely simulate meso-scale ion-neutral coupling, offering clear insights into the dynamo process across the geospace system.