Challenges to Modeling the Ionosphere-Thermosphere-Mesosphere System at Solar Minimum

Abstract:

The ionosphere-thermosphere-mesosphere (ITM) system is driven by energy and momentum forcing from above and below. The forcing from above includes solar irradiance and high latitude energy and momentum forcing of magnetospheric origin, whereas the forcing from below consists of upward propagating waves and tides that are originated from the lower atmosphere. During solar minimum, it can be easier to unravel how the forcing from below drives the ITM system and its variability since the forcing from above is relatively weaker than it is at high solar activity. This makes solar minimum a good time to investigate how ITM internal processes and the external forcing impact the system, and how they precondition the system and affect its response to geomagnetic storms. However, recent observations have shown us that many challenges remain in modeling even the quiet-time ITM system at solar minimum. We discuss these challenges from a vantage point of comparing modeled and observed phenomena in the ITM system during the most recent solar minimum.