Identifying the Drivers of Thermospheric Disturbance Winds with ICON

Résumé fourni par la source

The three years of wind observations from the NASA Ionospheric Connection Explorer (ICON) provide millions of wind profiles with altitude resolution between 5 and 30 km (depending on altitude), and 250 or 500 km sampling (depending upon local time). These observations are continuous in daytime with no spatial or temporal gaps outside of observatory resets. Launched during a deep solar minimum, nonetheless ICON observed many geomagnetic disturbances in its mission from 2019 to 2022. Review of the differences between data and numerical models, and how their agreement changes with modification of model parameters, offers a remarkable tool to advance our understanding of the system and to validate the final ICON product, the ICON-TIEGCM. Comparisons of wind disturbance are combined with analyses of ionospheric variability also measured by ICON. The statistics of storm-time winds are carefully considered in context of their drivers, as are the altitude and latitude of the penetration of disturbance winds that generally propagate and expand from the auroral zones. The remarkable features of individual storms show the diversity of storm effects, while the statistical nature of disturbance winds over the three year mission provides a critical reference. We find that globally-propagating atmospheric gravity waves are generated with almost every auroral disturbance, but that disturbance winds are uncommon, with their occurrence related to the persistence of the auroral inputs.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.