Solar Extreme Ultraviolet (EUV) irradiance is the primary energy input driving the dynamics, chemistry, and structure of the ionosphere-thermosphere (IT) system. For decades, the 10.7-cm solar radio flux (F10.7) has served as the baseline proxy for this energy. However, investigations over the past 20 years have exposed critical limitations, demonstrating that non-linearities in the F10.7 index make it an imperfect and sometimes misleading irradiance proxy. Concurrently, there is a growing realization that historical empirical irradiance models, such as HEUVAC, are based on early calibrations that are fundamentally inconsistent with modern, high-precision spectroradiometric measurements from TIMED SEE and SDO EVE. We welcome abstracts focusing on: Cross-calibrating and reconciling historical EUV models with modern observations from TIMED and SDO; and the sensitivity and response of upper atmospheric and ionospheric measurements and models to these revised historical and modern EUV irradiance inputs at Earth and other planets.

• IN - Informatics
• SH - SPA-Solar and Heliospheric Physics