Ionospheric responses to a total solar eclipse deduced by the GPS beacon observations

Chen, Anhua; Yu, Shengbing; Xu, Jisheng

doi:10.1007/bf02832278

Cited by 15 publications

(14 citation statements)

References 6 publications

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“…The occurrence of maximum TEC depletion before the maximum solar eclipse time at ALRT, SCH2, THU3, and QAQ1 is common and reported by other researchers such as An‐hua et al [1999] and Bamford [2001]. An‐hua et al [1999] observed obvious TEC depression in large scale of sub‐ionospheric points occurred on the neck of the first contact of the eclipse followed by deeper negative deviation while the area of optical disk obscured getting larger. They also show that the trend of TEC depression continues after the middle of solar eclipse at some stations and at most stations the time of restoration during the recovery phase is delayed behind the time of the fourth contact.…”

Section: Resultssupporting

confidence: 64%

“…The observation of TEC depletion before the first contact time of the solar eclipse can be explained based on previous observations made by other scientists such as An‐hua et al [1999], Bamford [2001], and Baran et al [2003]. An‐hua et al [1999] observed an interesting phenomenon during the 9 March 1997 total solar eclipse over eastern Asia. During this event, TEC started to drop before the first contact of the solar eclipse at stations with higher latitudes such as MOHE, IRKT, and TAEJ.…”

Section: Resultsmentioning

confidence: 63%

“…The average TEC curve obtained from eight GPS stations (Figure 6) shows two periods of TEC depletion; the main depletion was seen during the solar eclipse period while another period of depletion was seen before the solar eclipse starting time and after the end time. The occurrence of TEC depletion before the solar eclipse commence is probably due to earlier obscuration of the solar corona which precedes the obscuration of the optical disk and/or due to earlier occurrence of the first contact of the eclipse at ionospheric heights than the occurrence time on the ground as suggested by An‐hua et al [1999] and same for the observation after the eclipse end time. The observation of TEC depletion prior to the time of first contact of solar eclipse was reported by other scientists during different events [e.g., An‐hua et al , 1999; Bamford , 2001; Baran et al , 2003].…”

Section: Summary and Discussionmentioning

confidence: 65%

“…However, longer TEC depletion is generally seen at the stations of higher solar eclipse magnitude such as ALRT, THU3, RESO, and NYA1 sites. The inconsistent relationship of regional maximum depletion to maximum solar obscuration was reported by An‐hua et al [1999]. This inconsistency is probably due to the variations of geographic and geomagnetic latitudes of each GPS site where the electron density profile varies with geographic location.…”

Section: Resultsmentioning

confidence: 83%

“…The delay in the Z and total field response depletion (∼1 h) behind the fourth contact time can be explained by restoration process of electron and ions concentration of the E and F regions of ionosphere that takes several minutes to reach its normal level. An‐hua et al [1999] observed a delay in TEC recovery during the 9 March 1997 eclipse where the recovery phase persisted several minutes behind the last contact time at several stations. Similar delay is expected in the magnetic field, as the reduction or the increase in the number of ions and electrons in the E and F layers of the ionosphere implies a reduction or increase of their vertical integrated electric conductivity.…”

Section: Resultsmentioning

confidence: 93%

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Ionospheric and geomagnetic response to the total solar eclipse on 1 August 2008 over Northern Hemisphere

2010

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[1] The ionospheric and geomagnetic response to the total eclipse of the Sun on 1 August 2008 over Northern Hemisphere has been examined using 14 GPS, three ISR radar, and three magnetometer ground-based stations. Three different approaches were employed to examine the TEC depletion occurrence at the GPS stations: determination of the TEC depletion parameters during the solar eclipse with respect the quiet day TEC variations, comparison of the total TEC (STEC) during the solar eclipse period with respect to quiet day TEC measurements for the same period of time, and determination of the average daily TEC obtained from eight GPS stations and compares the values with the average quiet day TEC at these stations. The GPS observations indicate obvious TEC depression occurrence at all stations with the values was varying between 11% and 40%. The observations show that TEC depression at most GPS stations started on the neck of the first contact of the eclipse followed by deeper negative deviation while the area of optical disk obscured getting larger. Periods of TEC depletion were also observed before the first contact time of solar eclipse and after the fourth contact of solar eclipse due to earlier and later obscuration of the solar corona before and after the eclipse observation time. The incoherent scatter radar observations at Svalbard, Tromso, and Sondrestrom also show clear depletion occurrence in electron density, electron temperature, ion velocity, and plasma cutoff frequency during the solar eclipse passage at these stations. Radar measurements show obvious difference in the ionospheric response between the E and F layers of ionosphere and between ion and electron temperature in the F layer. The geomagnetic field response to the solar eclipse at CBB, RESO, and NUR stations was examined by using two different techniques, first by comparing the daily variations of geomagnetic field during the eclipse period with the variations on the day before and day after the eclipse, and second by determination the D magnetic field with respect to the average quiet geomagnetic field. The results show obvious decrease in the total field, X and Z components of geomagnetic field and obvious increase in the Y component at both CBB and RESO stations. The depletion in X, Z, and total field was in the range between 15 and 28 nT while the increase in the Y component was 18-22 nT.

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Section: Resultssupporting

confidence: 64%

Section: Resultsmentioning

confidence: 63%

Section: Summary and Discussionmentioning

confidence: 65%

Section: Resultsmentioning

confidence: 83%

Section: Resultsmentioning

confidence: 93%

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Ionospheric and geomagnetic response to the total solar eclipse on 1 August 2008 over Northern Hemisphere

2010

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Ionospheric vertical plasma drift and electron density response during total solar eclipses at equatorial/low latitude

2015

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The response of the vertical plasma drift (Vz) and the electron density (NmF2) during different solar eclipses was investigated. The diurnal values of the direct scaled measurement of F2 peak height and the one derived from M(3000) F2 data, acquired over an equatorial/low‐latitude stations, have been used to determine the vertical plasma drift. The ionosphere during a solar eclipse is significantly affected by the E × B vertical drift; the large depletion of electron density at low altitudes can be transported to high altitudes through the plasma vertical drift. The loss in ionization density during the eclipse phase decreases the electron density, which was accompanied by rapid increase in hmF2. This deviation in the NmF2 during eclipse compared to control days can be related to the increase in the loss rate due to recombination, as a result of reduction in thermal energy. However, the maximum reduction in NmF2 is not synchronous with the time of maximum totality but some minutes later. The differences in the solar epochs may contribute to the observed relative changes in the ionospheric F2 region behavior during the eclipse window. Lastly, it is very difficult to separate the influence of magnetic disturbances from solar eclipse. The deviation in NmF2 is higher during magnetic disturbed days than the quiet day. The reverse is the case for hmF2 observation. However, the NmF2 variation increases with an increase in solar activity.

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Storm-time ionospheric disturbances monitored by GPS beacon measurements

Pei

et al. 2001

Wuhan Univ. J. Nat. Sci.

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Ionospheric responses to a total solar eclipse deduced by the GPS beacon observations

Cited by 15 publications

References 6 publications

Ionospheric and geomagnetic response to the total solar eclipse on 1 August 2008 over Northern Hemisphere

Ionospheric and geomagnetic response to the total solar eclipse on 1 August 2008 over Northern Hemisphere

Ionospheric vertical plasma drift and electron density response during total solar eclipses at equatorial/low latitude

Storm-time ionospheric disturbances monitored by GPS beacon measurements

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