Simulation of the 21 August 2017 Solar Eclipse Using the Whole Atmosphere Community Climate Model‐eXtended

We performed simulations of the atmosphere-ionosphere response to the solar eclipse of 21 August 2017 using the Whole Atmosphere Community Climate Model-eXtended (WACCM-X v. 2.0) with a fully interactive ionosphere and thermosphere. Eclipse simulations show temperature changes in the path of totality up to -3 K near the surface, -1 K at the stratopause, 4 K in the mesosphere, and -40 K in the thermosphere. In the F region ionosphere, electron density is depleted by about 55%. Both the temperature and electron density exhibit global effects in the hours following the eclipse. There are also significant effects on stratosphere-mesosphere chemistry, including an increase in ozone by nearly a factor of 2 at 65 km. Dynamical impacts of the eclipse in the lower atmosphere appear to propagate to the upper atmosphere. This study provides insight into coupled eclipse effects through the entire atmosphere from the surface through the ionosphere. Plain Language Summary We used a computer model called the Whole Atmosphere Community Climate Model-eXtended (WACCM-X v. 2.0) to investigate what happens to the atmosphere from the surface of Earth up to space during the "Great American Eclipse" of 21 August 2017. During the eclipse, for a location in the path of totality, the model produces different changes in temperature from the ground up to hundreds of kilometers, with the largest decrease in temperature around 250 km. Also, at this altitude, the electron density of the ionosphere decreases by about 55% during the eclipse. Later on during the day of the eclipse, we see changes not only near the eclipse path but also all over the world. The chemistry in the atmosphere is also affected by the eclipse, including an increase in ozone in the middle atmosphere. Finally, changes that happen in the lower atmosphere affect what happens in space after the eclipse is over. This study helps us to understand how an eclipse can affect both the atmosphere and ionosphere, and how these changes are coupled together.