Total solar eclipse of July 22, 2009: Its impact on the total electron content and ionospheric electron density in the Indian zone

Sharma, Siddharth; Dashora, N.; Galav, Praveen; Pandey, R.

doi:10.1016/j.jastp.2010.10.006

Cited by 31 publications

(26 citation statements)

References 17 publications

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“…The closer the PRN path is to the total eclipse path, the greater the decrease in the TEC is. This study also confirms previous research conducted by Sharma et al (2010) discussing the ionospheric response when an annular solar eclipse occurred in India. The magnitude of TEC decrease as the distance between the observation station and the eclipse pathway is farther.…”

Section: Resultssupporting

confidence: 92%

Decrease of total electron content during the 9 March 2016 total solar eclipse observed at low latitude stations, Indonesia

Srigutomo

Singarimbun

Meutia

et al. 2019

Preprint

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Abstract. The total solar eclipse on 9 March 2016 was a rare phenomenon that could be observed in 12 provinces in Indonesia. The decline in solar radiation to the earth during a total solar eclipse affects the amount of electron content (TEC) in the ionosphere. The ionospheric dynamics during the eclipse above Indonesia have been studied using data from 40 GPS stations distributed throughout the archipelago. It was observed that TEC decrease occurred over Indonesia during the occurrence of the total eclipse. This TEC decrease did not instigate ionoshperic scintillation. Moreover, the relationship between eclipse magnitude and TEC decrease throughout three GPS stations was analysed using PRN 24 and PRN 12 codes. Data analysis from each station reveals that the time required by the TEC to achieve maximum reduction since the initial contact of the eclipse is faster than the recovery time. The maximum TEC reduction came about several minutes after the maximum obscuration indicating that the recombination process was still ongoing even though the peak of the eclipse had happened. The magnitude of this decline is positively correlated with the geographical location of the stations and the relative satellite trajectory with respect to the total solar eclipse trajectory. The amount of TEC reduction is proportional to the magnitude of the eclipse which is directly related to the photoionization process. Because Indonesia is located in a low latitude magnetic equator region, the dynamics of the ionosphere above it is more complex due to the fountain effect. During the solar eclipse, the fountain effect declines disturbing the plasma transport from the magnetic equator to low latitude regions.

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Section: Resultssupporting

confidence: 92%

Decrease of total electron content during the 9 March 2016 total solar eclipse observed at low latitude stations, Indonesia

Srigutomo

Singarimbun

Meutia

et al. 2019

Preprint

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“…Earlier studies showed a decrease in TEC after the beginning of the partial solar eclipse, and TEC reached a minimum value after a lapse of time varying between 30 min and 2 h from the time of maximum obscuration (Yeh et al, 1997;Huang et al, 1999;Jakowski et al, 2008;Krankowski et al, 2008). For the solar eclipse of 22 July 2009, Sharma et al (2010) reported a significant decrease in electron density and TEC at Udaipur, Hyderabad and Bangalore stations. They have also reported that the reduction persisted up to 2 h past the last contact.…”

Section: Resultsmentioning

confidence: 92%

“…It takes more than 2 h after the eclipse for the TEC to reach its normal value with a slower rate of recovery. For the same eclipse, Sharma et al (2010) reported a time delay of 30 min from Udaipur station.…”

Section: Resultsmentioning

confidence: 94%

Ionospheric response to total solar eclipse of 22 July 2009 in different Indian regions

Kumar

Singh

2013

Ann. Geophys.

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The variability of ionospheric response to the total solar eclipse of 22 July 2009 has been studied analyzing the GPS data recorded at the four Indian low-latitude stations Varanasi (100% obscuration), Kanpur (95% obscuration), Hyderabad (84% obscuration) and Bangalore (72% obscuration). The retrieved ionospheric vertical total electron content (VTEC) shows a significant reduction (reflected by all PRNs (satellites) at all stations) with a maximum of 48% at Varanasi (PRN 14), which decreases to 30% at Bangalore (PRN 14). Data from PRN 31 show a maximum of 54% at Kanpur and 26% at Hyderabad. The maximum decrement in VTEC occurs some time (2–15 min) after the maximum obscuration. The reduction in VTEC compared to the quiet mean VTEC depends on latitude as well as longitude, which also depends on the location of the satellite with respect to the solar eclipse path. The amount of reduction in VTEC decreases as the present obscuration decreases, which is directly related to the electron production by the photoionization process. The analysis of electron density height profile derived from the COSMIC (Constellation Observing System for Meteorology, Ionosphere & Climate) satellite over the Indian region shows significant reduction from 100 km altitude up to 800 km altitude with a maximum of 48% at 360 km altitude. The oscillatory nature in total electron content data at all stations is observed with different wave periods lying between 40 and 120 min, which are attributed to gravity wave effects generated in the lower atmosphere during the total solar eclipse

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“…These early theoretical studies, however, did not self‐consistently solve the I‐T system with fully coupled chemistry, dynamics, energetics, and electrodynamics. The eclipse‐induced wind and ionospheric conductivity changes and their impacts on the I‐T system through electrodynamics (e.g., Madhav Haridas & Manju, ; Shweta Sharma et al, ) were not fed back to the ionospheric models to affect the modeled ionosphere during eclipses.…”

Section: Introductionmentioning

confidence: 99%

Physical Processes Driving the Response of the F₂ Region Ionosphere to the 21 August 2017 Solar Eclipse at Millstone Hill

et al. 2019

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The high-resolution thermosphere-ionosphere-electrodynamics general circulation model has been used to investigate the response of F 2 region electron density (Ne) at Millstone Hill (42.61°N, 71.48°W, maximum obscuration: 63%) to the Great American Solar Eclipse on 21 August 2017. Diagnostic analysis of model results shows that eclipse-induced disturbance winds cause F 2 region Ne changes directly by transporting plasma along field lines, indirectly by producing enhanced O/N 2 ratio that contribute to the recovery of the ionosphere at and below the F 2 peak after the maximum obscuration. Ambipolar diffusion reacts to plasma pressure gradient changes and modifies Ne profiles. Wind transport and ambipolar diffusion take effect from the early phase of the eclipse and show strong temporal and altitude variations. The recovery of F 2 region electron density above the F 2 peak is dominated by the wind transport and ambipolar diffusion; both move the plasma to higher altitudes from below the F 2 peak when more ions are produced in the lower F 2 region after the eclipse. As the moon shadow enters, maximizes, and leaves a particular observation site, the disturbance winds at the site change direction and their effects on the F 2 region electron densities also vary, from pushing plasma downward during the eclipse to transporting it upward into the topside ionosphere after the eclipse. Chemical processes involving dimming solar radiation and changing composition, wind transport, and ambipolar diffusion together cause the time delay and asymmetric characteristic (fast decrease of Ne and slow recovery of the eclipse effects) of the topside ionospheric response seen in Millstone Hill incoherent scatter radar observations. Key Points:• Changes in winds, composition, and diffusion play significant roles in temporal and spatial variations of the eclipse effects on F 2 region • The recovery of F 2 region electron density above the F 2 peak is dominated by the transport due to winds and ambipolar diffusion • Observations and model show time delay and asymmetric (fast decrease and slow recovery) response of topside plasma density to the eclipse The Millstone Hill ISR conducted 5-day observations centered on 21 August 2017. In this study, we used the zenith antenna data of electron density (Ne) profiles from interleaved 480-μs single pulse measurements above 250 km (black solid squares in Figures 1c-1f) and alternating code measurements below 250 km (gray solid circles in Figures 1c-1f). This allows for appropriate data quality in different altitude ranges. We have calibrated ISR Ne against the digisonde data.The TIEGCM solves time-dependent momentum, energy, and continuity equations for the neutrals and energy and continuity equations for the ions of the coupled I-T system on a global grid (Qian et al., 2014;Richmond et al., 1992;Roble et al., 1988). Recently, the TIEGCM V2.0 has been upgraded to high resolution with a 0.625°× 0.625°geographic latitude-longitude grid and 1/4 scale height in the vertical pressure coordinates to facil...

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Total solar eclipse of July 22, 2009: Its impact on the total electron content and ionospheric electron density in the Indian zone

Cited by 31 publications

References 17 publications

Decrease of total electron content during the 9 March 2016 total solar eclipse observed at low latitude stations, Indonesia

Decrease of total electron content during the 9 March 2016 total solar eclipse observed at low latitude stations, Indonesia

Ionospheric response to total solar eclipse of 22 July 2009 in different Indian regions

Physical Processes Driving the Response of the F₂ Region Ionosphere to the 21 August 2017 Solar Eclipse at Millstone Hill

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Total solar eclipse of July 22, 2009: Its impact on the total electron content and ionospheric electron density in the Indian zone

Cited by 31 publications

References 17 publications

Decrease of total electron content during the 9 March 2016 total solar eclipse observed at low latitude stations, Indonesia

Decrease of total electron content during the 9 March 2016 total solar eclipse observed at low latitude stations, Indonesia

Ionospheric response to total solar eclipse of 22 July 2009 in different Indian regions

Physical Processes Driving the Response of the F2 Region Ionosphere to the 21 August 2017 Solar Eclipse at Millstone Hill

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Physical Processes Driving the Response of the F₂ Region Ionosphere to the 21 August 2017 Solar Eclipse at Millstone Hill