Abstract <p>Solar eclipses (SEs) are accompanied by both regular and a number of irregular effects as well as individual effects inherent in a particular SE. The following questions remain unanswered: can there be effects prior to an SE? How long do they last after the end of an SE? Do they appear on the night side of the planet? What effects occur in the magnetically conjugate region? What is the role of dynamic processes and geophysical fields in the interaction of subsystems in the Earth–atmosphere–ionosphere–magnetosphere system during an SE? These questions need to be addressed. The aim of this paper is to present the results of observations of temporal variations of total electron content (TEC) in the ionosphere over China obtained using Global Navigation Satellite System during the SE and reference days. The low-latitude ionosphere has certain features that could not fail to manifest themselves in the effects of the SE. Estimation of the ionospheric response to the annular SE was performed using recordings of GPS satellite signals obtained on dual-frequency receivers. The error of the TEC calculation technique used in the study does not exceed 0.1 TECU. To obtain acceptable results, the mutual motions of the TEC measurement point, lunar shadow, and Earth’s rotation were taken into account. The ionospheric effect of the SE, which consisted in a significant reduction in TEC, was confidently observed at all five stations and for all seven satellites. It was found that the deficit of TEC clearly followed the maximum magnitude value of the SE. The maximum TEC depletion reached 6–7 TECU at a magnitude of <i>M</i><sub>max</sub> ≈ 0.976–0.986. In this case, the relative TEC depletion was 35–37%. The time delay of the maximum reduction in TEC relative to the maximum magnitude of the SE was close to 15 min. This result is in good agreement with the known data. The moments of the beginning and end of the TEC depletion, in general, did not coincide with the changes in the SE magnitude. The duration of the ionospheric effect was usually longer than the duration of the eclipse. There was no clear dependence of the ionospheric effect on latitude and longitude. No increase in the wave activity during the SE was detected. The effects of the annular SE, which took place in the low-latitude ionosphere near the summer solstice, had a number of features.</p>

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Effects of the Solar Eclipse on June 21, 2020, in Low-Latitude Ionosphere Total Electron Content

  • L. F. Chernogor,
  • Y. Luo,
  • Yu. B. Mylovanov,
  • V. L. Dorokhov

摘要

Abstract

Solar eclipses (SEs) are accompanied by both regular and a number of irregular effects as well as individual effects inherent in a particular SE. The following questions remain unanswered: can there be effects prior to an SE? How long do they last after the end of an SE? Do they appear on the night side of the planet? What effects occur in the magnetically conjugate region? What is the role of dynamic processes and geophysical fields in the interaction of subsystems in the Earth–atmosphere–ionosphere–magnetosphere system during an SE? These questions need to be addressed. The aim of this paper is to present the results of observations of temporal variations of total electron content (TEC) in the ionosphere over China obtained using Global Navigation Satellite System during the SE and reference days. The low-latitude ionosphere has certain features that could not fail to manifest themselves in the effects of the SE. Estimation of the ionospheric response to the annular SE was performed using recordings of GPS satellite signals obtained on dual-frequency receivers. The error of the TEC calculation technique used in the study does not exceed 0.1 TECU. To obtain acceptable results, the mutual motions of the TEC measurement point, lunar shadow, and Earth’s rotation were taken into account. The ionospheric effect of the SE, which consisted in a significant reduction in TEC, was confidently observed at all five stations and for all seven satellites. It was found that the deficit of TEC clearly followed the maximum magnitude value of the SE. The maximum TEC depletion reached 6–7 TECU at a magnitude of Mmax ≈ 0.976–0.986. In this case, the relative TEC depletion was 35–37%. The time delay of the maximum reduction in TEC relative to the maximum magnitude of the SE was close to 15 min. This result is in good agreement with the known data. The moments of the beginning and end of the TEC depletion, in general, did not coincide with the changes in the SE magnitude. The duration of the ionospheric effect was usually longer than the duration of the eclipse. There was no clear dependence of the ionospheric effect on latitude and longitude. No increase in the wave activity during the SE was detected. The effects of the annular SE, which took place in the low-latitude ionosphere near the summer solstice, had a number of features.