Ionospheric responses to two large geomagnetic storms over Japanese and Indian longitude sectors

Uma, G.; Brahmanandam, P. S.; Kakinami, Yoshihiro; Дмитриев, А. В.; Devi, N.S.M.P. Latha; Kiran, K. V. D.; Prasad, D. S. V. V. D.; Rao, P. V. S. Rama; Niranjan, K.; Babu, Ch. Seshu; Chu, Yen Hsyang

doi:10.1016/j.jastp.2011.10.001

Cited by 23 publications

(10 citation statements)

References 43 publications

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“…GIMs are updated every 2 h. GIMs are intended to provide a global coverage and are somewhat less efficient than the dedicated regional networks like GAGAN (GPS Aided Geo Augmented Navigation) and Wide Area Augmentation System. Nonetheless, GIMs do provide an efficient tool to study the latitudinal distribution [Ho et al, 1997;Mannucci et al, 1998;Buonsanto, 1999;Iijima et al, 1999;Kil et al, 2003;Zhao et al, 2007;Lei et al, 2008;Wan et al, 2008;Uma et al, 2012]. Also, the GIM data are openly accessible to researchers unlike the GAGAN data.…”

Section: Total Electron Content Over Indian Longitude Based On Gimmentioning

confidence: 99%

On the utility of the ionosonde Doppler‐derived EXB drift during the daytime

Joshi

Sripathi

2016

JGR Space Physics

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Vertical EXB drift measured using the ionosonde Doppler sounding during the daytime suffers from an underestimation of the actual EXB drift because the reflection height of the ionosonde signals is also affected by the photochemistry of the ionosphere. Systematic investigations have indicated a fair/good correlation to exist between the C/NOFS and ionosonde Doppler‐measured vertical EXB drift during the daytime over magnetic equator. A detailed analysis, however, indicated that the linear relation between the ionosonde Doppler drift and C/NOFS EXB drift varied with seasons. Thus, solar, seasonal, and also geomagnetic variables were included in the Doppler drift correction, using the artificial neural network‐based approach. The RMS error in the neural network was found to be smaller than that in the linear regression analysis. Daytime EXB drift was derived using the neural network which was also used to model the ionospheric redistribution in the SAMI2 model. SAMI2 model reproduced strong (weak) equatorial ionization anomaly (EIA) for cases when neural network corrected daytime vertical EXB drift was high (low). Similar features were also observed in GIM TEC maps. Thus, the results indicate that the neural network can be utilized to derive the vertical EXB drift from its proxies, like the ionosonde Doppler drift. These results indicate that the daytime ionosonde measured vertical EXB drift can be relied upon, provided that adequate corrections are applied to it.

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Section: Total Electron Content Over Indian Longitude Based On Gimmentioning

confidence: 99%

On the utility of the ionosonde Doppler‐derived EXB drift during the daytime

Joshi

Sripathi

2016

JGR Space Physics

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“…In a recent study by Uma et al . [] the ionospheric response to two storms of 31 March 2001 and 20 November 2003 over Japanese and Indian latitudes showed that equatorial ionization anomaly (EIA) is expanded and intensified during the main phase of the storms. Simi et al .…”

Section: Introductionmentioning

confidence: 99%

“…In a recent study by Uma et al [2012] the ionospheric response to two storms of 31 March 2001 and 20 November 2003 over Japanese and Indian latitudes showed that equatorial ionization anomaly (EIA) is expanded and intensified during the main phase of the storms. Simi et al [2013] showed the effect of induced O/N 2 apart from the prompt penetration electric field for the storm event of 8-10 November 2004 in Indian longitudes.…”

Section: Introductionmentioning

confidence: 99%

F₂ region response to geomagnetic disturbances across Indian latitudes: O(¹S) dayglow emission

2016

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The morphology of ionospheric storms has been investigated across equatorial and low latitudes of Indian region. The deviation in F2 region characteristic parameters (foF2 and h′F) along with modeled green line dayglow emission intensities is examined at equatorial station Thiruvananthapuram (8.5°N, 76.8°E, 0.63°S geomagnetic latitude) and low‐latitude station Delhi (28.6°N, 77.2°E,19.2°N geomagnetic latitude) during five geomagnetic storm events. Both positive and negative phases have been noticed in this study. The positive storm phase over equatorial station is found to be more frequent, while the drop in ionization in most of the cases was observed at low‐latitude station. It is concluded that the reaction as seen at different ionospheric stations may be quite different during the same storm depending on both the geographic and geomagnetic coordinates of the station, storm intensity, and the storm onset time. Modulation in the F2 layer critical frequency at low and equatorial stations during geomagnetic disturbance of 20–23 November 2003 was caused by the storm‐induced changes in O/N2. It is also found that International Reference Ionosphere 2012 model predicts the F2 layer characteristic (foF2 and h′F) parameters at both the low and equatorial stations during disturbed days quite reasonably. A simulative approach in GLOW model developed by Solomon is further used to estimate the changes in the volume emission rate of green line dayglow emission under quiet and strong geomagnetic conditions. It is found that the O(1S) dayglow thermospheric emission peak responds to varying geomagnetic conditions.

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“…Over the years, researches to understand the variability and complexity of the ionospheric environments during this solar event have been given much attention, with a large number of studies conducted at different latitudes using data from different ionospheric probing techniques (e.g. RAWAT et al 2010;MANSILLA 2014;HASBI et al 2009;CHOI et al 2011;BAGIYA et al 2009;ADEBIYI et al 2012;JOSHUA et al 2011, JAKOWSKI et al 1999FANG et al 2012;UMA et al 2012;ADEBESIN et al 2013). The ionospheric variations, due to geomagnetic storm, can be described by the enhancement or depletion of ionospheric electron content, designated as positive and negative storm effects, respectively, or a combination of both effects.…”

Section: Introductionmentioning

confidence: 99%

Latitudinal and Seasonal Investigations of Storm-Time TEC Variation

Adimula

Oladipo

Adebiyi

2016

Pure Appl. Geophys.

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The ionosphere responds markedly and unpredictably to varying magnetospheric energy inputs caused by solar disturbances on the geospace. Knowledge of the impact of the space weather events on the ionosphere is important to assess the environmental effect on the operations of ground-and space-based technologies. Thus, global positioning system (GPS) measurements from the international GNSS service (IGS) database were used to investigate the ionospheric response to 56 geomagnetic storm events at six different latitudes comprising the northern and southern hemispheres in the Afro-European sector. Statistical distributions of total electron content (TEC) response show that during the main phase of the storms, enhancement of TEC is more pronounced in most of the seasons, regardless of the latitude and hemisphere. However, a strong seasonal dependence appears in the TEC response during the recovery phase. Depletion of TEC is majorly observed at the high latitude stations, and its appearance at lower latitudes is seasonally dependent. In summer hemisphere, the depletion of TEC is more pronounced in nearly all the latitudinal bands. In winter hemisphere, enhancement as well as depletion of TEC is observed over the high latitude, while enhancement is majorly observed over the mid and low latitudes. In equinoxes, the storm-time TEC distribution shows a fairly consistent characteristic with the summer distribution, particularly in the northern hemisphere.

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Ionospheric responses to two large geomagnetic storms over Japanese and Indian longitude sectors

Cited by 23 publications

References 43 publications

On the utility of the ionosonde Doppler‐derived EXB drift during the daytime

On the utility of the ionosonde Doppler‐derived EXB drift during the daytime

F₂ region response to geomagnetic disturbances across Indian latitudes: O(¹S) dayglow emission

Latitudinal and Seasonal Investigations of Storm-Time TEC Variation

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Ionospheric responses to two large geomagnetic storms over Japanese and Indian longitude sectors

Cited by 23 publications

References 43 publications

On the utility of the ionosonde Doppler‐derived EXB drift during the daytime

On the utility of the ionosonde Doppler‐derived EXB drift during the daytime

F2 region response to geomagnetic disturbances across Indian latitudes: O(1S) dayglow emission

Latitudinal and Seasonal Investigations of Storm-Time TEC Variation

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Product

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F₂ region response to geomagnetic disturbances across Indian latitudes: O(¹S) dayglow emission