First Global-Scale Synoptic Imaging of Solar Eclipse Effects in the Thermosphere

Saurav Aryal; J S Evans; John Correira; Alan G Burns; Wenbin Wang; Stanley C Solomon; Fazlul I Laskar; William E McClintock; Richard W Eastes; Tong Dang; Jiuhou Lei; Huixin Liu; Geonhwa Jee

doi:10.1029/2020JA027789

First Global-Scale Synoptic Imaging of Solar Eclipse Effects in the Thermosphere

J Geophys Res Space Phys. 2020 Sep;125(9):e2020JA027789. doi: 10.1029/2020JA027789. Epub 2020 Sep 18.

Authors

Affiliations

¹ Labrotary for Atmospheric and Space Physics University of Colorado Boulder CO USA.
² Computational Physics Inc Springfield VA USA.
³ High Altitude Observatory National Center for Atmospheric Research Boulder CO USA.
⁴ CAS Key Laboratory of Geospace Environment, School of Earth and Space Sciences University of Science and Technology of China Hefei China.
⁵ Department of Earth and Planetary Sciences Kyushu University Fukuoka Japan.
⁶ Division of Polar Climate Sciences Korea Polar Research Institute Incheon South Korea.

Abstract

A total solar eclipse occurred in the Southern Hemisphere on 2 July 2019 from approximately 17 to 22 UT. Its effect in the thermosphere over South America was imaged from geostationary orbit by NASA's Global-scale Observation of Limb and Disk (GOLD) instrument. GOLD observed a large brightness reduction (>80% around totality) in OI 135.6 nm and N₂ LBH band emissions compared to baseline measurements made 2 days prior. In addition, a significant enhancement (with respect to the baseline) in the ΣO/N₂ column density ratio (~80%) was observed within the eclipse's totality. This enhancement suggests that the eclipse induced compositional changes in the thermosphere. After the eclipse passed, a slight enhancement in ΣO/N₂ column density ratio (~7%) was also seen around the totality path when compared to measurements before the eclipse. These observations are the first synoptic imaging measurements of an eclipse's thermospheric effects with the potential to drastically improve and test our understanding of how the thermosphere responds to rapid, localized changes in solar short wavelength radiation.