Nighttime Ionosphere Perturbed by the Annular Solar Eclipse on June 21, 2020

Abstract

Abstract This study analyzed the total electron content (TEC) observed by 337 ground‐based Global Navigation Satellite System (GNSS) receivers over China and South Asia, the critical frequency of the ionospheric F 2 layer ( f o F 2 ) and its height ( h m F 2 ) recorded by the ionosonde at Puer (22.7°N, 101.05°E, 72% obscuration), Yunnan province, during and after the annular solar eclipse on June 21, 2020. The observations show that the eclipse induced not only a daytime major depression but also nighttime perturbations in the ionosphere. The TEC perturbed intermittently from noon to midnight between 85° and 125°E on the eclipse day. The positive and negative changes of the prereversal enhancement respectively occur in the nearby longitudinal sectors of 100°and 115°E. The TEC perturbations behave as a terminator wave that propagates in a northwestward direction after sunset.