Improving E-region Neutral Wind Variability in Numerical Models Using LEO Magnetometer Data

The strongest ionospheric currents flow in general in the E‑region (~90-135 km) due to the high conductivities produced by dayside ionization. The solar quiet (Sq) current system arises from neutral winds pushing plasma across Earth’s magnetic field, generating electric fields and ionospheric currents. The strongest current at low latitude is the daytime equatorial electrojet (EEJ). While magnetic perturbations associated with these ionospheric currents are measured globally—both from ground-based observations and from low Earth orbit (LEO)—direct measurements of E‑region neutral winds remain extremely sparse. This gap limits our ability to quantify neutral wind variability on day-to-day timescales and hinders a full understanding of lower–upper atmospheric coupling and its influence on space weather phenomena such as neutral density and plasma variations. These challenges motivate the use of magnetic observations to better constrain neutral wind variability.

In this presentation, we introduce atmospheric tides embedded in the neutral wind and their role in driving the wind dynamo. We illustrate how major tidal components contribute to the dynamo and the resulting magnetic signatures. We then present a data‑driven framework that combines ground-based magnetometer observations with ensemble modeling using the Thermosphere–Ionosphere–Electrodynamo General Circulation Model (TIEGCM) and an ionospheric electrodynamo model that simulates the full 3D current system and associated magnetic perturbations. This approach enables the estimation of hourly tidal variations at the TIEGCM lower boundary (~97 km altitude) and improves the representation of global EEJ variability. The simulation with improved winds is validated against LEO magnetic perturbation measurements, demonstrating that the agreement improves even in regions with limited data coverage. The results highlight the potential of magnetometer data to constrain tidal dynamics and enhance global modeling of equatorial electrodynamics.