Polar and midlatitude ionosphere–atmosphere studies through ground-based observations

Convener: Maxime Grandin | Co-conveners: Veronika HaberleECSECS, Gaël Cessateur, Jia Jia, Mathieu Barthelemy

The Earth’s atmosphere and ionosphere are subject to significant variability associated with solar and space forcing. While this is predominantly relevant at high latitudes, midlatitudes can also be affected as observed during severe geomagnetic storms that occurred e.g. in 2024–2025. While in situ observations of the ionosphere and mesosphere–lower-thermosphere are only possible with spacecraft and sounding rockets, a wealth of information is obtained thanks to remote sensing techniques using ground-based instruments.
For instance, ground-based magnetometers, used in dense networks, routinely enable the derivation of ionospheric currents and geomagnetic indices. Optical instruments not only encompass imagers observing auroral and airglow emissions, but also consist of scanning Doppler imagers, Fabry-Perot interferometers, and lidars which measure upper atmospheric winds and temperatures, in particular in the thermosphere and mesosphere. Besides, visible spectrometers disentangle the spectral signatures of different auroral processes, enabling discrimination between precipitation-driven emissions and signatures of thermospheric heating. Ionospheric parameters can also be measured with radars, spanning a wide range of active (ionosondes, meteor radars, coherent and incoherent scatter radars, VLF transmitters) and passive (riometers, VLF receivers, GNSS receivers) systems. With increased interest in understanding space weather and atmosphere coupling as a system, polar atmospheric composition measurements of the middle atmosphere are also valuable. Finally, citizen science data such as images taken by aurora chasers are increasingly used to complement observations from instruments.
Combining ground-based observations from various instruments enables the development of novel data analysis methodologies that can provide access to physical quantities previously difficult to quantify, such as Joule heating. Ground-based measurements are also increasingly valuable for data assimilation into numerical models, thanks to which we can both enhance our understanding of the underlying physics of ionosphere–atmosphere processes and improve our space weather forecasting capability.
In this session, we invite contributions featuring the use of ground-based instruments in studies of the ionosphere–atmosphere system at polar and mid-latitudes. We welcome contributions of space weather and ionospheric–atmospheric physics processes of various time and spatial scales.