Ionospheric total electron content response to September-2017 geomagnetic storm and December-2019 annular solar eclipse over Sri Lankan region

Jenan, Rajavarathan; Dammalage, Thilantha Lakmal; Panda, Sampad Kumar

doi:10.1016/j.actaastro.2021.01.006

Cited by 28 publications

(5 citation statements)

References 43 publications

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“…The effects of a solar eclipse on TEC is due to the reduction in solar radiation, which lowers the ionospheric TEC, the decreased total electron concentration is consequently observed over both stations. Our plots show similar trend in TEC variation as in the previous studies (Cherniak & Zakharenkova, 2018; Jenan et al., 2021).…”

Section: Resultssupporting

confidence: 90%

Variation in Total Electron Content Over Ethiopia During the Solar Eclipse Events

Uga,

Gautam,

Edward

et al. 2024

Radio Science

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This work studies variations of ionospheric total electron content (TEC) during four distinct solar eclipse events over the Ethiopia region. Dual‐frequency global positioning system (GPS) data obtained from UNAVCO over Addis Ababa (9.036°N, 38.76°E) and Bahir Dar (11.6°N, 37.34°E) stations are used to examine the ionospheric variability during two annular solar eclipses on 15 January 2010 and 1 September 2016, a partial solar eclipse on 4 January 2011, and a hybrid solar eclipse (the eclipse path starts out as annular but later changes to total) on 3 November 2013. The results show a significant decrease in TEC values during the occurrence of the solar eclipses. Specifically, the TEC values are reduced to −20% and −10% during the annular eclipse on 15 January 2010, −33% and −38% during the partial solar eclipse on 4 January 2011, −26% and −24% during the annular solar eclipse on 1 September 2016, over the Addis Ababa and Bahir Dar stations, respectively. There is only minimal change in TEC of −8% and −9% at Addis Ababa and Bahir stations, respectively, during the 3 November 2013 solar eclipse even if the obstruction rate is high over the study area. Furthermore, the study shows that the spatial gradient of TEC reduction varies at different locations, which is attributed to the distinct amount of reduction in solar radiation reaching the Earth's surface, resulting in reduced photo‐ionization. Overall, this study provides insightful information about the behavior of the ionospheric TEC during solar eclipses over Ethiopia and emphasizes the use of dual‐frequency GPS data in tracking the variations of the TEC.

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Section: Resultssupporting

confidence: 90%

Variation in Total Electron Content Over Ethiopia During the Solar Eclipse Events

Uga,

Gautam,

Edward

et al. 2024

Radio Science

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“…The obtained results in the Jenan's study showed that the four major features such as pre-ascension, major depression, sunset ascension, and secondary depression were perceptible in the total electron content variation at all stations. Maurya suggested interplay between eclipse effects on the ionosphere plasma density and the eclipse generated atmospheric gravity waves (AGWs) induced plasma density perturbation provided the peculiar features [32,33]. In another study conducted by Liu et al (1998) on the AGWs excited during solar eclipse events at F region altitude, it was revealed that the AGWs generation contributed to changes in the height of the peak of electron production [34].…”

Section: Resultsmentioning

confidence: 98%

“…Recently, the comprehensive studies have been conducted on the ionosphere interaction with Total/Annual solar eclipse effects, especially over the American and Indian equatorial low latitudes. In these studies, the relationship between ionospheric perturbations and physical mechanisms such as lunar tides, atmospheric gravity waves, electric field induced counter electrojets, total/vertical electron content, neutral winds and diffusion effects, has been examined in detail both during and before and after the solar eclipse [2,[30][31][32][33][34][35].…”

Section: Resultsmentioning

confidence: 99%

Investigation of ionospheric losses for the ‘O⁺ + O₂ → O₂ ⁺ + O’ reaction during the solar eclipse

Yaşar¹

2021

Phys. Scr.

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In this study, the response of the loss terms for the 'O + +O 2 →O 2 + +O' reactive reaction, which is an important charge transfer process in the upper ionosphere, to the partial solar eclipse on March 29, 2006 over Kharkov city located in the European mid-latitude was analyzed together with the reference days of 28 and 30 March. The measurement data were obtained from the Kharkov incoherent scatter radar. The loss terms for O + +O 2 reaction increased at the time of maximum covering and changed inversely proportional to the ionospheric height. The maximum loss terms were obtained at heights of 252, 303 and 353 km on the eclipse day, while it was seen at the 399 km on March 30. For the four altitudes, the maximum and minimum (except 353 and 399 km) values on the eclipse day were seen at different time intervals. The important finding of this analysis is that the solar eclipse effect on the loss terms gives different results at the upper and lower heights and the complexity of the ionospheric behaviour with the increase in altitude. Another important result of this analysis reveals that the effect of solar eclipse on ionospheric loss terms is greater on the day after the eclipse compared to the day before the eclipse. The results of this study show that eclipse-induced mechanisms such as electric field, neutral wind changes, lunar tides, atmospheric gravity waves (AGWs) and diffusion can continue to impact the ionosphere during and after the solar eclipse. REVISED

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“…First, the equatorward disturbance winds blew the ionosphere to higher altitudes, and hmF2 was positive disturbance. Then, new electrons were produced by photoionization of solar radiation in daytime, and filled the uplifted ionosphere (Jenan et al., 2021). The foF2 and TEC began to be positive disturbance.…”

Section: Resultsmentioning

confidence: 99%

“…Jenan et al. (2021) studied an ionospheric storm at the equatorial region. The positive response during the initial phase was attributed to the PPEF, while the effects of the later phase were due to the disturbance dynamo electric fields.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Ionospheric Storm on October 13, 2016 at the Greenwich Meridian

Wan

Maruyama

et al. 2021

JGR Space Physics

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The geomagnetic storms are the disturbances of the Earth's magnetic field, and the impact of solar wind particles enhancement (Buonsanto, 1999;Gonzalez et al., 1994;Kumar & Kumar, 2019). Following geomagnetic storms, the ionosphere also has obvious disturbance. It shows the critical frequency of F2-layer (foF2) or total electron content (TEC) changes obviously. The large decrease of foF2 or TEC is the ionospheric negative storm, and the significant increase of foF2 or TEC is referred to as positive storms (Fagundes et al., 2016;Maruyama et al., 2004). In general, 𝐴𝐴 𝐴𝐴 region ionization is positively correlated to the density ratio of atomic oxygen [O] to the molecular nitrogen 𝐴𝐴 [N2] . Prölss (1987) showed that the negative storm was caused by the change of neutral gas composition. The enhanced ratio of 𝐴𝐴 [N2] /[O] would lead to the chemical loss rate increase, so the ionospheric electron density decreased.There are two main physical mechanisms of ionospheric positive storms. The first is the equatorward wind surge or disturbance wind (Fuller-Rowell et al., 1994). Joule heating raises the temperature of the upper thermosphere and ion drag drives high velocity neutral winds. The heat source drives a global disturbance wind. It propagates to low latitudes and even into the opposite hemisphere. The equatorward wind pushes the ionosphere up to high altitudes where the recombination is ineffective. As a result, the electron density increases under sunlit conditions (Maruyama et al., 2004;Zhao et al., 2008). Because the equatorward wind surge blows from high to low latitudes, the ionospheric disturbance has time delay. During quiet days, the neutral winds (or background winds) are poleward in daytime and turn equatorward after sunset. During storms, the neutral winds are the combination of background and disturbance winds. The daytime neutral wind, which is caused by Joule heating in the auroral region, even turns to equatorward (Fuller-Rowell et al., 1994). Different storms have different intensity, local time, and latitude coverage. de Jesus et al. ( 2016) studied a positive ionospheric storm at equatorial, low and middle latitudes in African sector. The factor was the equatorward disturbance winds and huge wind circulations.

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Ionospheric total electron content response to September-2017 geomagnetic storm and December-2019 annular solar eclipse over Sri Lankan region

Cited by 28 publications

References 43 publications

Variation in Total Electron Content Over Ethiopia During the Solar Eclipse Events

Variation in Total Electron Content Over Ethiopia During the Solar Eclipse Events

Investigation of ionospheric losses for the ‘O⁺ + O₂ → O₂ ⁺ + O’ reaction during the solar eclipse

Characteristics of Ionospheric Storm on October 13, 2016 at the Greenwich Meridian

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Ionospheric total electron content response to September-2017 geomagnetic storm and December-2019 annular solar eclipse over Sri Lankan region

Cited by 28 publications

References 43 publications

Variation in Total Electron Content Over Ethiopia During the Solar Eclipse Events

Variation in Total Electron Content Over Ethiopia During the Solar Eclipse Events

Investigation of ionospheric losses for the ‘O+ + O2 → O2 + + O’ reaction during the solar eclipse

Characteristics of Ionospheric Storm on October 13, 2016 at the Greenwich Meridian

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Investigation of ionospheric losses for the ‘O⁺ + O₂ → O₂ ⁺ + O’ reaction during the solar eclipse