Ionospheric Response to the 21 May 2012 Annular Solar Eclipse Over Taiwan

J. Y. Liu, S. S. Yang, P. K. Rajesh, Y. Y. Sun, J. Chum, C. J. Pan, Y. H. Chu, C. K. Chao, L. C. Chang

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


An annular solar eclipse swept over Taiwan in the early morning on 21 May 2012. This provides an excellent opportunity to study ionospheric response to the solar eclipse mainly due to photochemical effects. Local ground-based Global Positioning System receivers, an ionosonde, high frequency-continue wave Doppler sounding systems, and very low frequency receivers are used to observe ionospheric eclipse signatures. These multiinstrument observations show that the extreme total electron content (TEC) depression lags the maximum obscuration by about 5–20 min, while the Doppler frequency shift decreases and increases (i.e., the ionosphere ascends and descends) during first contact-maximum obscuration and maximum obscuration-last contact, respectively. The ionosonde data well agree with the TEC and Doppler frequency shift observations. The results show that the extreme TEC depression lag (i.e., delay time) being inversely proportional to the associated maximum obscuration confirms that the photochemical process is essential in Taiwan during the 21 May 2012 annular solar eclipse. A theoretical derivation is proposed for the first time to explain the delay time due to pure photochemical process during solar eclipses.

Original languageEnglish
Pages (from-to)3623-3636
Number of pages14
JournalJournal of Geophysical Research: Space Physics
Issue number5
Publication statusPublished - 2019 May

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Space and Planetary Science


Dive into the research topics of 'Ionospheric Response to the 21 May 2012 Annular Solar Eclipse Over Taiwan'. Together they form a unique fingerprint.

Cite this