Observing the Coupled Ionosphere-Thermosphere System: From Solar Maximum to Solar Minimum and Beyond

TIMED has gone far beyond the coarse 0D and 1D understanding of the atmosphere generated by the DE and AE missions. TIMED has served as the catalyst for a greater understanding of the ionosphere/thermosphere (I/T) because it exists at a time of unprecedented resources such as the "5th Great Observatory" and the extensive ground-based instrument network supported by the world community. The TIMED/GUVI instrument has made the first systematic ultraviolet observations of the Earth's thermosphere and ionosphere from solar maximum to solar minimum. These unique observations provide us with routine data analysis results (thermospheric density profiles, O/N2, nightside ionosphere, auroral parameters, etc) that were envisioned when the TIMED mission was first conceived over 15 years ago. In addition, there are other high value products that we have only just begun to be able to provide to the community; for example, maps of ionospheric irregularities and the structure of ionospheric bubbles. There are, however, new analyses that are possible because of the length of the mission. Because TIMED has seen all local solar times over all seasons and over a broad range of solar and geomagnetic conditions (e.g. CMEs, CIRS, etc.) we can begin to systematic validate first principles models. The next years, as the solar activity passes through minimum and increases toward maximum, are vital to our understanding of what the quiescent state of the I/T system is and how readily it is perturbed away from that state by forcing from below (e.g. gravity waves, the QBO). In this talk, we provide an overview of what we have learned by looking the variability in the response of the coupled I/T system with GUVI and what remains to be learned by missions like ITSP and GEC.