A major milestone was achieved this year with the inclusion of our sporadic E layer data product in the International Reference Ionosphere (IRI). The IRI is the globally recognized empirical standard model of the Earth's ionosphere applied by thousands of users worldwide across academia, government agencies, and industry for research, education and operational applications. 

Our sporadic E data set, derived from approximately 30 million GNSS radio occultation observations from multiple satellite missions, provides valuable information on the occurrence and characteristics of sporadic E layers on a global scale. The data record spans more than two decades of observations and includes measurements from several international satellite missions with strong GFZ involvement, including CHAMP, GRACE, TerraSAR-X, and TanDEM-X. Its incorporation into IRI reflects the scientific maturity, robustness, and international relevance of our long-term research efforts. The key person of these successful scientific activities is Dr. Christina Arras, who works currently within a joint research project of GFZ with Technische Universität Berlin. 

V. Truhlik, D. Bilitza, C. Arras, H. Haralambous, M. Moses: A global model of the occurrence probability of sporadic E for the International Reference Ionosphere, Advances in Space Research, 2026, https://doi.org/10.1016/j.asr.2026.09.071.

Arras, C., Resende Chagas, L. C., Senevirathna, G., Kepkar, A., Wickert, J. (2022): Sporadic E layer characteristics at equatorial latitudes as observed by GNSS Radio Occultation measurements. - Earth Planets and Space, 74, 163. https://doi.org/10.1186/s40623-022-01718-y