Multilayered Sporadic-E Response to the Annular Solar Eclipse on June 21, 2020

摘要

A moon shadow of annular solar eclipse passed through East Asia in the afternoon on June 21, 2020, which was a good opportunity to study the rapid ionospheric response to the solar radiation variations. In the study, the high-frequency echoes recorded by the ionosondes at Wuhan (82.4 obscuration), Xiamen (97.8 obscuration), and Nanning (81.1 obscuration) are analyzed to examine the variations in sporadic-E (E-s) during the obscuration over the East China area. The echoes show not only the variations in the typical signal E-s layer below 130 km, but for the first time also the multilayered E-s at much higher altitudes (130-190 km) during the eclipse. Specifically, the multilayered E-s is only observed over Nanning, while different E-s behaviors are observed in the other two stations. The relationship between the formation of the multilayered E-s and the uplifted E-s near the center path of the moon shadow are examined in the study. The small-scale atmospheric gravity waves play a key role in modulating the E-s behaviors during the eclipse.