TY - JOUR
T1 - Ionospheric Response to the 21 May 2012 Annular Solar Eclipse Over Taiwan
AU - Liu, J. Y.
AU - Yang, S. S.
AU - Rajesh, P. K.
AU - Sun, Y. Y.
AU - Chum, J.
AU - Pan, C. J.
AU - Chu, Y. H.
AU - Chao, C. K.
AU - Chang, L. C.
N1 - Funding Information:
The authors thank all the students, teaching assistants, postdoctoral researchers, and professors of the course “Space Instrumentation and Observation I—Spring 2012” in NCU. Eclipse parameters are obtained from the websites of National Aeronautics and Space Administration (NASA) Solar Eclipse Page via http://eclipse.gsfc.nasa.gov/solar.html and Ephemeris Computation Office of National Astronomical Observatory of Japan (NAOJ, http://eco.mtk.nao.ac.jp/koyomi/koyomix/eclipsex_s.html). The GPS data used in this paper were purchased from Central Weather Bureau of Taiwan (http://e-service.cwb.gov.tw/wdps/). The Chung-Li ionosonde was operated by National Communications Commission, Taiwan. All the ionosonde, Doppler sounding, and VLF data could be retrieved from Taiwan Space Science Database (TSSD, http://sdbweb.ss.ncu.edu.tw/). The total electron content (TEC) global ionosphere map (GIM) is obtained from CODE (Center for Orbit Determination in Europe, http://aiuws.unibe.ch/ionosphere/). This work was financially supported by the Center for Astronautical Physics and Engineering (CAPE) from the Featured Area Research Center program within the framework of Higher Education Sprout Project by the Ministry of Education (MOE) in Taiwan. This study is supported by the Taiwan Ministry of Science and Technology (MOST) grant MOST 106-2628-M-008-002 and the ISSI-Bern International Team of “Ionospheric Space Weather Studied by RO and Ground-based GNSS TEC Observations” (the team leader Liu, J. Y. Tiger [TW]).
Funding Information:
The authors thank all the students, teaching assistants, postdoctoral researchers, and professors of the course “Space Instrumentation and Observation I—Spring 2012” in NCU. Eclipse parameters are obtained from the websites of National Aeronautics and Space Administration (NASA) Solar Eclipse Page via http://eclipse. gsfc.nasa.gov/solar.html and Ephemeris Computation Office of National Astronomical Observatory of Japan (NAOJ, http://eco.mtk.nao.ac.jp/ koyomi/koyomix/eclipsex_s.html). The GPS data used in this paper were pur chased from Central Weather Bureau of Taiwan (http://e‐service.cwb.gov.tw/ wdps/). The Chung‐Li ionosonde was operated by National Communications Commission, Taiwan. All the iono- sonde, Doppler sounding, and VLF data could be retrieved from Taiwan Space Science Database (TSSD, http:// sdbweb.ss.ncu.edu.tw/). The total elec tron content (TEC) global ionosphere map (GIM) is obtained from CODE (Center for Orbit Determination in Europe, http://aiuws.unibe.ch/iono sphere/). This work was financially supported by the Center for Astronautical Physics and Engineering (CAPE) from the Featured Area Research Center program within the framework of Higher Education Sprout Project by the Ministry of Education (MOE) in Taiwan. This study is sup ported by the Taiwan Ministry of Science and Technology (MOST) grant MOST 106‐2628‐M‐008‐002 and the ISSI‐Bern International Team of “Ionospheric Space Weather Studied by RO and Ground‐based GNSS TEC Observations” (the team leader Liu, J. Y. Tiger [TW]).
Publisher Copyright:
©2019. American Geophysical Union. All Rights Reserved.
PY - 2019/5
Y1 - 2019/5
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=85065726809&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85065726809&partnerID=8YFLogxK
U2 - 10.1029/2018JA025928
DO - 10.1029/2018JA025928
M3 - Article
AN - SCOPUS:85065726809
SN - 2169-9402
VL - 124
SP - 3623
EP - 3636
JO - Journal of Geophysical Research: Space Physics
JF - Journal of Geophysical Research: Space Physics
IS - 5
ER -