Speaker
Description
Monitoring the thermospheric state is a highly relevant problem due to its impact on ionospheric dynamics and satellite drag. A novel approach based on routine ionosonde observations, originally developed for mid-latitudes (Perrone and Mikhailov, 2018), has proven effective in retrieving a self-consistent set of key aeronomic parameters and is now widely used in our analyses.
The method, known as THERION (THERmospheric parameters from IONosonde observations), uses as input: (1) plasma frequency at 180 km derived at selected local times (10–14 LT) from automatically scaled bottom-side electron density profiles Ne(h) obtained with ionogram inversion codes such as AUTOSCALA; (2) the noon-time foF2 value; and (3) solar (F10.7) and geomagnetic (Ap) indices. An advanced version of the method additionally includes neutral density from satellite observations as fitted parameters.
The retrieved parameters include the neutral composition (O, O₂, N₂ concentrations), exospheric temperature (Tₑₓ), the total solar EUV flux at wavelengths λ ≤ 1050 Å, and the vertical plasma drift W, which at mid-latitudes is mainly related to the meridional thermospheric wind component.
The method has been recently extended to low-latitude and equatorial regions (Perrone and Mikhailov, 2025), where it is applicable around local noon at the geomagnetic equator. In this case, the retrieved vertical plasma drift is primarily controlled by the zonal electric field component (Eᵧ). This unified approach provides a potential valuable tool for monitoring thermospheric conditions using long-term, routinely available observations.
Refernces:
Perrone, L., Mikhailov, A. V. (2018). A New Method to Retrieve Thermospheric Parameters From Daytime Bottom-Side Ne(h) Observations. J. Geophys. Res., 123,10,200–10,212. https://doi.org/10.1029/2018JA025762.
Perrone, L., & Mikhailov, A. V. (2025). A method to retrieve aeronomic parameters from noontime bottom‐side equatorial Ne(h) and satellite neutral density observations. Space Weather, 23, e2025SW004398. https://doi.org/10.102/2025SW004398
| Numerical model | THERION |
|---|
