Effect of 21 June 2020 solar eclipse on the ionosphere using VLF and GPS observations and modeling

Tripathi, Gaurish; Singh, Saurabh; Kumar, Sanjay; Singh, Ashutosh K.; Singh, Rajesh

doi:10.1016/j.asr.2021.11.007

Cited by 8 publications

(12 citation statements)

References 65 publications

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“…To examine if the best-fit h′ and β values were reasonable, we compared the inversion results with the FIRI model [60], previous studies [30,31,33,35,64,67,68], as well as theoretical calculations [69]. Figure 5a shows the comparison of electron density profiles between the FIRI profiles and the pre-eclipse profiles that we found for the 2019 and 2020 solar eclipses, whereas Figure 5b shows the profiles that were close to the best-fit profiles derived from VLF measurements.…”

Section: Validation Of the Inversion Resultsmentioning

confidence: 69%

“…Second, previous eclipse studies estimated the h and β change caused by solar eclipses without using this constraint. Although there existed a large discrepancy among previous studies, the β change was found to be 0.01-0.03 km −1 in most cases [30,31,33,35,64]. Moreover, Xu et al [18] modeled the electron density change in the Dand E-region ionosphere using measurements of solar input by the Solar Dynamic Observatory (SDO) satellite and a widely used D-region chemistry model: the Sodankylä Ion and Neutral Chemistry (SIC) model [65].…”

Section: Ionospheric Inversionmentioning

confidence: 99%

“…Xu et al [18] modeled this eclipse using a first-principles chemistry model and a Finite-Difference Time-Domain (FDTD) model, and the abnormal VLF measurements in Utah have been well explained. Moreover, Tripathi et al [35] studied the 2020 solar eclipse using both tweek and transmitter signals and emphasized that "each solar eclipse, depending upon its time of occurrence, duration, and geographical location has a particular impact on the Earth's ionosphere".…”

Section: Introductionmentioning

confidence: 99%

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A Comparative Study of VLF Transmitter Signal Measurements and Simulations during Two Solar Eclipse Events

Cheng

et al. 2023

Remote Sensing

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To monitor the Very-Low-Frequency (VLF) environment, a VLF detection system has been installed in Suizhou, China, a location with the longitude almost identical to that of the NWC transmitter in Australia. In the years 2019 and 2020, two solar eclipses crossed the NWC–Suizhou path at different locations. Each solar eclipse event represents a naturally occurring controlled experiment, but these two events are unique in that similar levels of electron density variation occurred at different locations along the VLF propagation path. Therefore, we conducted a comparative study using the VLF measurements during these two eclipses. Previous studies mostly estimated a pair of the reflection height (h′) and sharpness parameter (β) using the Long Wavelength Propagation Capability code, whereas, in this study, we use the VLF amplitude and phase as constraints in order to find the electron density change that best explains the VLF measurements. The eclipse measurements could be best explained if the path-averaged β value was 0.56 and 0.62 km−1 for the 2019 and 2020 eclipse, respectively. The VLF reflection height increased from 71.5 to 73.3 km for the 2019 eclipse and from 71.1 to 72.8 km for the 2020 eclipse. The best-fit β values were consistent with the Faraday International Reference Ionosphere model and statistical studies, and the h′ change was also consistent with previous studies and theoretical calculations. Moreover, present results suggested that VLF signals collected by a single receiver were not sensitive to where the electron density change occurs along the propagation path but reflected the average path condition. Therefore, a network of VLF receivers is required in order to monitor in real time the spatial extent of the space weather events that disturb the lower ionosphere.

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Section: Validation Of the Inversion Resultsmentioning

confidence: 69%

Section: Ionospheric Inversionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Comparative Study of VLF Transmitter Signal Measurements and Simulations during Two Solar Eclipse Events

Cheng

et al. 2023

Remote Sensing

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“…Wang et al (2021), X. Wang et al (2021), Şentürk et al (2021), Sun et al (2021), Shagimuratov et al (2021), Aa et al (2021), Chen et al (2021), andTripathi et al (2022); the ionospheric effects were observed to occur with the South Atlantic Anomaly in the background. Zhang et al (2020) detected effects from the solar eclipse in the magnetically conjugate region.…”

Section: Introductionmentioning

confidence: 95%

Ionospheric effects of the 5–6 January 2019 eclipse over the People's Republic of China: results from oblique sounding

Черногор

Гармаш²,

Guo³

et al. 2022

Ann. Geophys.

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Abstract. This paper deals with the variations in the Doppler spectra and in the relative amplitudes of the signals observed at oblique incidence over the People's Republic of China (PRC) during the partial solar eclipse of 5–6 January 2019 and on reference days. The observations were made using the multifrequency multipath radio system for sounding the ionosphere at oblique incidence. The receiver system is located at the Harbin Engineering University, PRC, and 14 HF broadcasting station transmitters are used for taking measurements along the following radio-wave propagation paths: Lintong/Pucheng to Harbin, Hwaseong to Harbin, Chiba/Nagara to Harbin, Hailar/Nanmen to Harbin, Beijing to Harbin (three paths), Goyang to Harbin, Ulaanbaatar/Khonkhor to Harbin, Yakutsk to Harbin (two paths), Shijiazhuang to Harbin, Hohhot to Harbin, and Yamata to Harbin. The specific feature of this partial solar eclipse was that it occurred during the local morning with a geomagnetic disturbance (Kp ≈ 3−) in the background. The response of the ionosphere to the solar eclipse has been inferred from temporal variations in the Doppler spectra, the Doppler shift, and the signal relative amplitude. The partial solar eclipse was found to be associated with broadening of the Doppler spectrum, up to ± 1.5 Hz, alternating sign Doppler-shift variations, up to ± 0.5 Hz, in the main ray, and quasi-periodic Doppler-shift changes. The relative amplitude of electron density disturbances in the 15 min period of atmospheric gravity wave field and in the 4–5 min period of infrasound wave field is estimated to be 1.6 %–2.4 % and 0.2 %–0.3 %, respectively. The estimates of a maximum decrease in the electron density are in agreement with the observations.

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“…(2022). GPS‐based measurements of total electron content have been used in majority of studies (Aa et al., 2021; Şentürk et al., 2021; Shagimuratov et al., 2021; Tripathi et al., 2022).…”

Section: Introductionmentioning

confidence: 99%

Some Features of the Ionospheric Radio Wave Characteristics Over China Observed During the Solar Eclipse of 21 June 2020

et al. 2022

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Solar eclipses give rise to a number of nonstationary processes in the Earth-atmosphere-ionosphere-magnetosphere system (Chernogor, 2013) when the parameters of all components of this system and their geophysical fields change. The electron density and electron and ion temperatures show a decrease, whereas the plasma transport and energetic particle precipitation from the magnetosphere are activated, and plasma instabilities and wave processes of different nature are generated in the atmosphere (see Chernogor, 2013).During the course of solar eclipses, the parameters of radio channels through the atmosphere and ionosphere are subjected to considerable changes practically in all frequency bands, which inevitably cause degradation of signals, especially of those in the VLF, LF, MF, and HF bands.Hundreds of scientific papers are concerned with the ionospheric disturbances that accompany solar eclipses.

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Effect of 21 June 2020 solar eclipse on the ionosphere using VLF and GPS observations and modeling

Cited by 8 publications

References 65 publications

A Comparative Study of VLF Transmitter Signal Measurements and Simulations during Two Solar Eclipse Events

A Comparative Study of VLF Transmitter Signal Measurements and Simulations during Two Solar Eclipse Events

Ionospheric effects of the 5–6 January 2019 eclipse over the People's Republic of China: results from oblique sounding

Some Features of the Ionospheric Radio Wave Characteristics Over China Observed During the Solar Eclipse of 21 June 2020

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