Global responses of the coupled thermosphere and ionosphere system to the August 2017 great American solar eclipse

Wednesday, August 1, 2018

It is commonly believed that solar eclipses have a great impact on the ionosphere-thermosphere (I-T) system within the eclipse shadow, but little attention has been paid to the global responses to them.

Global maps of differential TEC, neutral temperature, meridional winds, and E×B vertical plasma drifts image
Global maps of differential TEC, neutral temperature, meridional winds (northward positive), and E×B vertical plasma drifts (upward positive) at pressure level 2 (~300 km) between the TIEGCM simulations with and without eclipse (with Eclipse - without Eclipse) for two selected UTs (18:30 and 22:30 UT). The solid circle indicates the location of the totality at 18:30 UT and the solid and dashed lines show the umbra path and solar terminator, respectively.

In this study, we, for the first time, investigate the global upper atmospheric responses of the recent Great American Solar Eclipse that occurred on 21 August 2017 using a high-resolution ionosphere-thermosphere-electrodynamics coupled model. The simulation results show that the ionosphere and thermosphere response to the eclipse is not just local, but global. Large-scale travelling atmospheric disturbances (TADs), seen in the thermospheric temperature and winds, were triggered from the eclipse region and propagated in a southeast direction when the eclipse ended. A large total electron content (TEC) enhancement occurred over South America after the eclipse was over. The TEC enhancement was primarily the result of transport by the themospheric wind associated with the eclipse-induced TADs. The perturbations of TEC, neutral temperature and winds exhibit asymmetric distributions with respect to the totality path during the solar eclipse. Plasma drifts also show responses to the solar eclipse at middle- and low- latitudes, indicating that electrodynamic processes also play an important role in the global responses of the I-T system to the solar eclipse.

Publication Name: Geophysical Research Letters

First HAO Author's Name: Wenbin Wang