The ionospheric behavior in conjugate hemispheres during the 3 October 2005 solar eclipse

Le, Huijun; Liu, Liuming; Yue, Xinan; Wan, Weixing

doi:10.5194/angeo-27-179-2009

Cited by 51 publications

(49 citation statements)

References 15 publications

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“…Thus, the ionospheric response in this case, revealed by the DFSs, is equivalent to an effective postponement of sunrise by about 90 min. The changes in DFS and increase/decrease of the F ‐layer height during the eclipse are consistent and agree with previous reports (Afraimovich et al, ; Cheng et al, ; Cohen, ; Farges et al, ; Jakowski et al, ; Le et al, ; MacPherson et al, ). Figure e reveals that the apparent velocity derived by the virtual height at the sounding frequency of 5.26 MHz divided by 5 min generally is out of phase with the DSFs in Figures f–j.…”

Section: Discussionsupporting

confidence: 92%

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

et al. 2019

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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.

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Section: Discussionsupporting

confidence: 92%

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

et al. 2019

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“…During the 3 October 2005 solar eclipse, decreases in electron temperature ( T e ), increases in F2‐layer critical frequency ( fo F2) and TEC, and an uplift in F2‐layer peak height ( hm F2) were also captured for further investigation [ Jakowski et al ., ; Le et al . ] in which the fo F2 and TEC increases were explained as a consequence of top ionospheric downward plasma flux and that resulted from the large magnetic inclination at middle‐high latitudes.…”

Section: Introductionmentioning

confidence: 99%

Nighttime ionospheric enhancements induced by the occurrence of an evening solar eclipse

Chen

Ning

et al. 2013

JGR Space Physics

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[1] The solar eclipse on 15 January 2010 traversed Asia and completed its travel on the Shandong Peninsula in China at sunset. Two vertical incidence ionosondes at Wuhan and Beijing and the oblique incidence ionosonde network in North China were implemented to record the ionospheric response to the solar eclipse. Following the initial electron density decrease caused by the eclipse, the ionosphere was characterized by a strong premidnight enhancement, and a subsequent ionospheric decay, and a~10 h later postmidnight enhancement. Neither geomagnetic disturbance occurred during the eclipse day nor did obvious nighttime peak appear for the 10 day mean of the F2-layer critical frequency (foF2). The electron density profilogram of the Beijing ionosonde indicates that the two enhancements were the result of the plasma flux downward from the top ionosphere, possibly due to the steep decrease of the ionospheric electron density and plasma temperature during the solar eclipse. The two-dimensional differential foF2 maps present the regional variations of the nighttime electron density peaks and decay. Both the pre-and postmidnight enhancements initially appeared in a belt almost in parallel with the eclipse track and then drifted southward. The different magnitudes of greatest eclipse in the umbra and outside tend to account for the different occurrence times of the plasma flux. The ionospheric decay following the premidnight enhancement is also considered as a consequence of the eclipse shade.

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“…The results show that the larger dip angle would cause the larger downward diffusion flux which makes up the ion losses and subsequently results in the smaller changes in electron concentration in the F region. In addition, Le et al [2009] reported that there were distinct ionospheric disturbances including decrease in electron temperature, increase in foF2 and uplift in hmF2, in the magnetic conjugate points of the eclipse regions during the 3 October 2005 total solar eclipse.…”

Section: Introductionmentioning

confidence: 99%

Latitudinal dependence of the ionospheric response to solar eclipses

Liu

Yue

et al. 2009

J. Geophys. Res.

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[1] In this study, we statistically analyze the latitudinal dependence of F2-layer peak electron densities (NmF2) and total electron content (TEC) responses to solar eclipses by using the ionosonde observations during 15 eclipse events from 1973 to 2006 and the GPS TEC observations during six solar eclipse events from 1999 to 2006. We carried out a model study on the latitudinal dependence of eclipse effects on the ionosphere by running a theoretical ionospheric model with the total eclipse occurring at 13 latitudes from 0°N to 60°N at intervals of 5°. Both the observations and simulations show that the NmF2 and TEC responses have the same latitudinal dependence: the eclipse effects on NmF2 and TEC are smaller at low latitudes than at middle latitudes; at the middle latitudes (>40°), the eclipse effect decreases with increasing latitude. The simulations show that the smaller NmF2 responses at low latitudes are mainly because of much higher heights of hmF2 at low latitudes and electron density response decreasing rapidly with increasing height. For the eclipse effects at the middle latitudes (>40°), the simulations show that the smaller NmF2 or TEC response at higher latitude is mainly ascribed to the larger downward diffusion flux induced by the larger dip angle at this region, which can partly make up for the plasma loss and alleviate the depression of electron density in the F region. The simulated results show that there is an overall decrease in electron temperature throughout the entire height range at the middle latitude, but for the low latitudes the eclipse effect on electron temperature is much smaller at high heights, which is mainly because of the much smaller reduction of photoelectron production rate at its conjugate low heights where only a partial eclipse with small eclipse magnitude occurs.

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The ionospheric behavior in conjugate hemispheres during the 3 October 2005 solar eclipse

Cited by 51 publications

References 15 publications

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

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

Nighttime ionospheric enhancements induced by the occurrence of an evening solar eclipse

Latitudinal dependence of the ionospheric response to solar eclipses

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