Solar forcing of the Thermosphere-Ionosphere system from maximum to minimum (Invited) [presentation]
Solomon, S. C., Qian, L., & Woods, T. N. (2009). Solar forcing of the Thermosphere-Ionosphere system from maximum to minimum (Invited) [presentation]. In AGU Fall Meeting 2009. American Geophysical Union: San Francisco, CA, US.
A comprehensive data set of solar ultraviolet irradiance variability during the declining phase of solar cycle 23 has been obtained by measurements from the TIMED and SORCE satellites, and augmented by X-ray measurements from the GOES program. These measurements have been used to describe the var... Show moreA comprehensive data set of solar ultraviolet irradiance variability during the declining phase of solar cycle 23 has been obtained by measurements from the TIMED and SORCE satellites, and augmented by X-ray measurements from the GOES program. These measurements have been used to describe the variability of thermospheric density and composition [Qian et al., J. Geophys. Res., 114, A01312, 2009] on solar-cycle and seasonal time scales, using solar measurements as an input to the NCAR Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM). The long and very quiet solar minimum between solar cycles 23 and 24 presents new challenges to model calculations, as the thermosphere appears to be cooler and less dense than previously observed during the space age, and other periodic phenomena, including seasonal changes, the response to lower atmosphere processes, and the response to co-rotating interaction regions, become more apparent. There may also be a secular component to the current thermospheric state, as increasing levels of carbon dioxide play a long-term role in reducing temperature in the upper atmosphere. This talk will summarize the current state of solar ultraviolet irradiance measurements, the evidence with regard to solar forcing during solar minimum, and the response of the thermosphere and ionosphere as determined from multiple space-based observations. Show less