The Annular Solar Eclipse on May 20 1966 and the Ionosphere

Anastassiades, Michael

doi:10.1007/978-1-4684-1839-2_16

Cited by 9 publications

(5 citation statements)

References 6 publications

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“…Both mechanisms disfavor the geomagnetic equatorial region. Actually, Anastassiades (1970b) stated, without justification, that the mag netic dip should be at least 60° (about 40° geomagnetic latitude) for the downward diffusion process to be effective. However, recent measurements using a thermal electron energy distri bution instrument on board the EXOS D satellite show a large diurnal swing in T c above the 1000 km altitude (Balan et al, 1996).…”

Section: Maxmentioning

confidence: 99%

Ionospheric Response to a Solar Eclipse in the Equatorial Anomaly Region

Yeh

Lin

et al. 1997

Terr. Atmos. Ocean. Sci.

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On October 24, 1995 a solar eclipse occurred with its path of totality passing over southern Asia, but the associated region of its partial eclipse covered almost all of Asia. It was therefore of interest to investigate how the ionosphere responded to this eclipse, especially because the region in cluded the equatorial anomaly region. For this purpose the authors col lected and processed ionosonde data from six stations in the region. These data reveal three effects that are coherent geographically in that they cover at least two of these six stations: (1) For the region with geomagnetic lati tudes higher than 20 degrees, the N increased slightly immediately folmax lowing the first contact for about 30 minutes. (2) In response to the eclipse, the largest depression occurring roughly 1112 hours after the maximum obscuration was observed at approximately 14 degrees geomagnetic lati tude even though the percent obscuration of the Sun at latitudes lower than 14 degrees was larger. (3) Around 6 hours after the maximum phase an other secondary depression in the Nmax was observed for geomagnetic lati tudes lower than 14 degrees. Physical mechanisms that may be responsible for causing these effects are proposed and examined in this paper. They are all related to eclipse-caused dynamic effects.

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Section: Maxmentioning

confidence: 99%

Ionospheric Response to a Solar Eclipse in the Equatorial Anomaly Region

Yeh

Lin

et al. 1997

Terr. Atmos. Ocean. Sci.

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“…One of the scientific goals in solar eclipse campaigns is to study the source-response relation between the ambient rates of production, chemical loss, and motion of ionization. Many scientists employed the beacon satellites to observe ionospheric changes during the solar eclipse (see the references listed in the works of Anastassiades [1970], Cohen [1984], and Yeh [1997]). Matsoukas [1969] used the satellite S-66 to examine the ionospheric total electron content (TEC) by the eclipse influence.…”

Section: Introductionmentioning

confidence: 99%

Ionospheric total electron content response to solar eclipses

Tsai¹,

Liu²

1999

J. Geophys. Res.

118

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Abstract. On October 24, 1995, and March 9, 1997, two solar eclipse events occur. It is therefore of interest to investigate how the ionosphere responded to the eclipses. Five global positioning system (GPS) ground-based receivers are specifically designed to observe large-scale ionospheric variations over the geomagnetic equatorial, equatorial anomaly crest, and midlatitude regions. Two-dimensional images of ionospheric total electron content (TEC) during the two eclipse periods are constructed. The deviations in the TEC images on eclipse days from those on reference days show that during the eclipse days the ionosphere experienced some large-scale changes. Four features of the TEC deviations, pre-ascension (PA), major depression (MD), sunset ascension (SA), and secondary depression (SD) have been observed. A detailed study shows that in geomagnetic low latitudes, PAs are possibly related to the locations of the equatorial anomaly crest. The latitudinal location, amplitude, and occurrence time of MDs suggest that the fountain effect is essential. SAs and SDs occurring in geomagnetic equatorial and low latitudes and appearing respectively before/around and after local sunset indicate that the prereversal enhancement plays an important role.

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“…It is known that the solar eclipse decreases the electron density in the E, F 1 and F2 layers. However, a slight increase in electron density as well as a significant decrease in the height of the F-layer (h'F) are also reported (Anastassiades, 1970). The salient features observed in the ionosonde measurements made at Waltair, a low latitude station, during the total solar eclipse of 24th October 1995, are presented in this paper.…”

Section: Introductionmentioning

confidence: 68%

Ionospheric Changes Observed Over Waltair(Dip 20 N) During the Total Solar Eclipse of 24th October 1995

Rao¹,

Prasad²,

Ram³

et al. 1997

Terr. Atmos. Ocean. Sci.

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The ionosonde measurements made at Waltair (20°N dip) during the solar eclipse of 24th October 1995 showed significant decreases in both the critical frequency and the height of the F-layer during the eclipse. Also, significant oscillatory variations were observed in h'F and f0F 2 during the course of the eclipse. When compared with the control days, f0F2 and f0F1 fell by about 15% and as much as 50%, respectively, on the eclipse day.The spectral components derived from the quasi-periodic variations ob served in f0F2 and h'F over Waltair (81 % obscuration) clearly showed the presence of an additional 30-minute component on the eclipse day, which was not present on the control days, indicating that the waves are observed away from the, totality path.

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The Annular Solar Eclipse on May 20 1966 and the Ionosphere

Cited by 9 publications

References 6 publications

Ionospheric Response to a Solar Eclipse in the Equatorial Anomaly Region

Ionospheric Response to a Solar Eclipse in the Equatorial Anomaly Region

Ionospheric total electron content response to solar eclipses

Ionospheric Changes Observed Over Waltair(Dip 20 N) During the Total Solar Eclipse of 24th October 1995

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