Topside Ionospheric Disturbances Detected Using Radio Occultation Measurements During the August 2017 Solar Eclipse

Abstract

The CASSIOPE (also known as Swarm‐E) satellite crossed the path of totality of the August 2017 eclipse at ~640‐km altitude ~10 min following the lunar umbra. Observations from CASSIOPE's Global Positioning System radio occultation receiver reveal total electron content variations of 0.2–0.3 total electron content units in the topside ionosphere—a signature of medium‐scale (100‐200 km) plasma disturbances in the lunar penumbra that were induced by the eclipse. The variations were only observed during the eclipse, their absence on preceding days being consistent with their very low (<10%) statistical occurrence probability. Their spectral characteristics match those of other contemporaneous measurements, and their detection is consistent with the simulated ionosphere‐thermosphere response to the eclipse. To capture the small‐scale size of the variations or to simulate those expected in the upcoming (July 2019) total eclipse, ionosphere‐thermosphere model runs with a spatial resolution of 50 km or better would be required.

Prediction of the Ionospheric Response to the 14 December 2020 Total Solar Eclipse Using SUPIM‐INPE

“…Previous in situ measurements at high altitudes have shown that model electron temperature differ from observations albeit following the height distribution overall shape (Hairston et al, 2018). Moreover, topside eclipse measurements of ion composition, velocity, and temperature (Yau et al, 2018) and TEC using the radio occultation technique (Perry et al, 2019) are also not well reproduced by various ionospheric models. Future work will be required to evaluate the model performance by comparing our results to satellite observations.…”

Coordinated Ground‐Based and Space‐Borne Observations of Ionospheric Response to the Annular Solar Eclipse on 26 December 2019

“…Recently, the Great American Eclipse, which passed through the continental United States from northwest to southeast on 21 August 2017, offered a rare opportunity to study the midlatitude ionosphere and thermosphere response in detail with unprecedented dense observational instruments. Besides the above‐mentioned eclipse effects, a number of interesting findings were reported as well, such as large‐scale TEC and NmF 2 depletion for more than 50% (e.g., Cherniak & Zakharenkova, 2018; Coster et al, 2017; Reinisch et al, 2018), traveling ionospheric disturbances and thermospheric wave (e.g., Eisenbeis et al, 2019; Harding et al, 2018; Mrak et al, 2018; Nayak & Yiǧit, 2018; Pradipta et al, 2018; Zhang et al, 2017), enhanced and long‐lasting posteclipse response (e.g., Lei, Dang, et al, 2018; Wu et al, 2018), and topside ionosphere composition change and interhemispheric ion flows (e.g., Perry et al, 2019; Yau et al, 2018).…”

Conjugate ionospheric perturbation during the 2017 solar eclipse

“…Coster et al, 2017;He et al, 2018;Cherniak & Zakharenkova, 2018). Examples of particularly notable regional effects include bow-shaped ionospheric waves (Zhang et al, 2017;Liu et al, 2011) and other atmospheric wave induced fluctuations (Sun et al, 2018;Nayak & Yigit, 2018;Perry et al, 2019;Eisenbeis et al, 2019), ionospheric features arising from radiation inhomogeneity on the solar disk (Mrak et al, 2018), and the polar region impact . Global scale eclipse effects, however, have to date been largely based on theoretical estimates and need to be validated with solid observational evidence.…”