Lower ionosphere effect observed during the 30 June 1992 total solar eclipse

Costa, Aracy Mendes da; Leme, Neusa Maria Paes; Piazza, L. Rizzo

doi:10.1016/0021-9169(93)e0021-z

Cited by 19 publications

(8 citation statements)

References 9 publications

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“…The ionospheric height of reflection was usually 3-8 km. Many researchers (Reeve and Rycroft, 1972;Sen Gupta et al, 1980;Lynn, 1981;Mendes Da Costa et al, 1995) concluded that the effects caused by a solar eclipse largely depend on the signal frequency and path length. Therefore, the researchers continued studying the ionospheric parameters during solar eclipses.…”

Section: Introductionmentioning

confidence: 99%

Effect of the total solar eclipse of March 20, 2015, on VLF/LF propagation

et al. 2016

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Abstract-The analyzed amplitude and phase variations in electromagnetic VLF and LF signals at 20-45 kHz, received in Moscow, Graz (Austria), and Sheffield (UK) during the total solar eclipse of March 20, 2015, are considered. The 22 analyzed paths have lengths of 200-6100 km, are differently oriented, and cross 40-100% occultation regions. Fifteen paths crossed the region where the occultation varied from 40 to 90%. Solar eclipse effects were found only on one of these paths in the signal phase (-50°). Four long paths crossed the 90-100% occultation region, and signal amplitude and phase anomalies were detected for all four paths. Negative phase anomalies varied from -75° to -90°, and the amplitude anomalies were both positive and negative and were not larger than 5 dB. It was shown that the effective height of the ionosphere varied from 6.5 to 11 km during the eclipse.

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Section: Introductionmentioning

confidence: 99%

Effect of the total solar eclipse of March 20, 2015, on VLF/LF propagation

et al. 2016

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“…The eclipse produced a phase delay of 6.4 μs and an amplitude change of 1.3 dB. So to say, various authors (Crary and Schneible 1965;Reeve and Rycroft 1972;Sen Gupta et al 1980;Lynn 1981;Mendes Da Costa et al 1995) reported the solar eclipse effects were to be path and frequency dependent. Experimental measurements of the ionospheric parameters at the time of solar eclipses are needed to understand the behaviour and characteristics of the ionosphere (Buckmaster and Hansen 1986;Zeng et al 1997;Clilverd et al 2001;Sanders 2001;Founda et al 2007).…”

Section: Introductionmentioning

confidence: 98%

“…The time constant of ionospheric response was found to be four minutes. Costa et al (1995) received VLF radio signals (12.9 kHz) at Atibaia, Brazil (latitude: 23.18°S, longitude: 46.55°W) transmitted from Ω-Argentina (latitude: 43.2°S, longitude: 65.4°W) during the total solar eclipse of 30 June 1992. The surface path of the totality crossed the VLF propagation path during the sunrise transition period.…”

Section: Introductionmentioning

confidence: 99%

Effects of a Solar Eclipse on the Propagation of VLF-LF Signals: Observations and Results

De¹,

De²,

Bandyopadhyay³

et al. 2011

Terr. Atmos. Ocean. Sci.

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The results from the measurements of some of the fundamental parameters (amplitude of sferics and transmitted signal, conductivity of lower ionosphere) of the ionospheric responses to the 22 July 2009 solar eclipse (partial: 91.7%) are shown. This study summarizes our results from sferics signals at 81 kHz and subionospheric transmitted signals at 19.8 and 40 kHz recorded at Agartala, Tripura (latitude: 23°N, longitude: 91.4°E). We observed significant absorption in amplitude of these signals during the eclipse period compared to their ambient values for the same period during the adjacent 7 days. The signal strength along their propagation paths was controlled by the eclipse associated decrease in ionization in the D-region of the ionosphere. Waveguide mode theory calculations show that the elevation of the height of lower ionosphere boundary of the Earth-ionosphere waveguide to a value where the conductivity parameter was 10 6 unit. The absorption in 81 kHz sferics amplitude is high compared to the absorption in the amplitude of 40 kHz signal transmitted from Japan. The simultaneous changes in the amplitudes of sferics and in the amplitude of transmitted signals assert some sort of coupling between the upper atmosphere and the Earth's near-surface atmosphere prevailing clouds during solar eclipse.

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“…Increases in the effective reflection height of the ionosphere were estimated to be between 6 and 11 km. Many authors (Gupta et al, 1980;Lynn, 1981;Mendes Da Costa et al, 1995;Reeve & Rycroft, 1972) suggested that ionospheric effects related to the solar eclipse depend on both the length of the path and the signal frequency. Clilverd et al (2001) studied in detail ionospheric effects during the total solar eclipse observed in Europe on 11 August 1999.…”

Section: Introductionmentioning

confidence: 99%

The Effect of the 21 August 2017 Total Solar Eclipse on the Phase of VLF/LF Signals

Рожной

Solovieva

Шалимов

et al. 2020

Earth and Space Science

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An experimental study of the phase and amplitude observations of sub‐ionospheric very low and low frequency (VLF/LF) signals is performed to analyze the response of the lower ionosphere during the 21 August 2017 total solar eclipse in the United States of America. Three different sub‐ionospheric wave paths are investigated. The length of the paths varies from 2,200 to 6,400 km, and the signal frequencies are 21.4, 25.2, and 40.75 kHz. The two paths cross the region of the total eclipse, and the third path is in the region of 40–60% of obscuration. None of the signals reveal any noticeable amplitude changes during the eclipse, while negative phase anomalies (from −33° to −95°) are detected for all three paths. It is shown that the effective reflection height of the ionosphere in low and middle latitudes is increased by about 3–5 km during the eclipse. Estimation of the electron density change in the lower ionosphere caused by the eclipse, using linear recombination law, shows that the average decrease is by 2.1 to 4.5 times.

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Lower ionosphere effect observed during the 30 June 1992 total solar eclipse

Cited by 19 publications

References 9 publications

Effect of the total solar eclipse of March 20, 2015, on VLF/LF propagation

Effect of the total solar eclipse of March 20, 2015, on VLF/LF propagation

Effects of a Solar Eclipse on the Propagation of VLF-LF Signals: Observations and Results

The Effect of the 21 August 2017 Total Solar Eclipse on the Phase of VLF/LF Signals

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