Comparative Solar Minima – Observed Effects on the Earth’s Mesosphere and Thermosphere

The past few decades have been a golden age in Heliospheric research. Numerous space-based observatories have provided a steady stream of observations the Heliosphere’s response to variable solar activity. For the past two decades observations from NASA’s TIMED satellite have offered unprecedented views of the effects of solar variability on Earth’s geospace system. The observations have been used to sort out the different (but complementary) effects of increasing carbon dioxide and decreasing solar variability on Earth’s upper atmosphere. In addition, observations have provided the first-ever solar-terrestrial index with direct, physical terrestrial context. The length of the dataset is enabling comparison of the two most recent solar minima in terms of the terrestrial response. This talk will give a brief overview of these observations and the observed effects of weakening solar activity over the past twenty years.