Large enhancements in low latitude total electron content during 15 May 2005 geomagnetic storm in Indian zone

Dashora, N.; Sharma, Siddharth; Dabas, R. S.; Alex, S.; Pandey, R.

doi:10.5194/angeo-27-1803-2009

Cited by 68 publications

(70 citation statements)

References 48 publications

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“…The other interesting phenomenon that has been observed and reported in several studies during geomagnetic storms is the traveling atmospheric disturbances (TADs) (Crowley and McCrea, 1988;Prolss, 1997;Fuller-Rowell et al, 2002;Yizengaw et al, 2005;Bruinsma and Forbes, 2007;Dashora et al, 2009). The excessive and impulsive energy input at high latitudes during the storms may launch TADs that travel from high latitudes (Hines, 1960;Balthazor and Moffett, 1997) meridionally towards the equator with high speed.…”

Section: Introductionmentioning

confidence: 99%

“…This is the time when under shielding conditions developed and the interplanetary electric field penetrated to the low latitudes as an eastward PPEF. This PPEF significantly modified the existing electric fields and plasma dynamics in low and equatorial latitudes (Dashora et al, 2009). …”

Section: Longitudinal Variation Of Vtecmentioning

confidence: 99%

“…Storm time changes in these can lead to positive (Zhao et al, 2005;Basu et al, 2007;Dashora et al, 2009) or negative (Buonsanto, 1999;Mendillo, 2006;Dashora and Pandey, 2007) ionospheric storms. And therefore ionospheric studies related to space weather disturbed conditions are required to characterize all aspects of ionospheric behavior under the different storm conditions.…”

Section: Introductionmentioning

confidence: 99%

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Longitudinal study of the ionospheric response to the geomagnetic storm of 15 May 2005 and manifestation of TADs

Sharma¹,

Galav²,

Dashora

et al. 2011

Ann. Geophys.

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Abstract.Response of low latitude ionosphere to the geomagnetic storm of 15 May 2005 has been studied using total electron content (TEC) data, obtained from three GPS stations namely, Yibal, Udaipur and Kunming situated near the northern crest of equatorial ionization anomaly at different longitudes. Solar wind parameters, north-south component of the interplanetary magnetic field (IMF B z ) and AE index data have been used to infer the strength of the geomagnetic storm. A large value of eastward interplanetary electric field at 06:15 UT, during the time of maximum southward IMF B z has been used to infer the transmission of an eastward prompt penetration electric field (PPEF) which resulted in a peak in TEC at 07:45 UT due to the local uplift of plasma in the low latitudes near the anomaly crest over a wide range of longitudes. Wave-like modulations superposed over the second enhancement in TEC between 09:15 UT to 10:30 UT have been observed at all the three stations. The second enhancement in TEC along with the modulations of up to 5 TECU have been attributed to the combined effect of super plasma fountain and traveling atmospheric disturbances (TAD). Observed large enhancements in TEC are a cause of concern for satellite based navigation and ground positioning. Increased [O/N 2 ] ratio between 09:15 UT to 10:15 UT when modulations in TEC have been also observed, confirms the presence of TADs over a wide range of longitudes.

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Section: Introductionmentioning

confidence: 99%

Section: Longitudinal Variation Of Vtecmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Longitudinal study of the ionospheric response to the geomagnetic storm of 15 May 2005 and manifestation of TADs

Sharma¹,

Galav²,

Dashora

et al. 2011

Ann. Geophys.

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“…There is a time delay of~1-2 h between the underlying E field events indicated by the above described time series and the development of resultant ionospheric features tracked by the TEC maps. This is usual during disturbed time periods [Dashora et al, 2009]. …”

Section: Global Gps Tec Observationsmentioning

confidence: 99%

“…While the TEC time series constructed for Poligan (POL2; 33.72°N, geomagnetic) tracked daytime increases that were due to both storm time PPEF and storm-induced equatorward neutral winds, the TEC time series constructed for Algonquin (ALGO; 55.93°N) detected depletions that were attributed to the midlatitude trough [Galav et al, 2014]. Some earlier studies covering this geomagnetic superstorm focused on the low-latitude regions of the Indian zone [Dashora et al, 2009] and Southeast Asia [Sharma et al, 2011]. Although the findings of all these studies are significant and are potentially useful to system engineers and ionospheric model developers, the observational results are from specific locations.…”

Section: Introductionmentioning

confidence: 99%

Positive and negative ionospheric storms occurring during the 15 May 2005 geomagnetic superstorm

Horvath

Lovell

2015

JGR Space Physics

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This study focuses on the 15 May 2005 geomagnetic superstorm and aims to investigate the global variation of positive and negative storm phases and their development. Observations are provided by a series of global total electron content maps and multi‐instrument line plots. Coupled Thermosphere‐Ionosphere‐Plasmasphere electrodynamics (CTIPe) simulations are also employed. Results reveal some sunward streaming plumes of storm‐enhanced density (SED) over Asia and a well‐developed midlatitude trough over North America forming isolated positive and negative storms, respectively. The simultaneous development of positive and negative storms over North America is also shown. Then, some enhanced auroral ionizations maintained by strong equatorward neutral winds appeared in the depleted nighttime ionosphere. Meanwhile, the northern nighttime polar region became significantly depleted as the SED plume plasma could not progress further than the dayside cusp. Oppositely, a polar tongue of ionization (TOI) developed in the daytime southern polar region. According to CTIP simulations, solar heating locally maximized (minimized) over the southern (northern) magnetic pole. Furthermore, strong upward surges of molecular‐rich air created O/N2 decreases both in the auroral zone and in the trough region, while some SED‐related downward surges produced O/N2 increases. From these results we conclude for the time period studied that (1) composition changes contributed to the formation of positive and negative storms, (2) strengthening polar convection and increasing solar heating of the polar cap supported polar TOI development, and (3) a weaker polar convection and minimized solar heating of the polar cap aided the depletion of polar plasma.

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Ionospheric response to the geomagnetic storm of 15 May 2005 over midlatitudes in the day and night sectors simultaneously

Galav

Rao

Sharma³

et al. 2014

JGR Space Physics

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The ionospheric response to the geomagnetic storm of 15 May 2005 has been studied over midlatitude stations in the dayside and nightside, simultaneously. In the day side the ionospheric response has been studied using the ground-based GPS and ionosonde measurements from the stations POL2 and Alma-Ata, respectively. The dayside total electron content (TEC) and f o F 2 variations are characterized by two well-separated enhancements. Of which the first enhancement in both the parameters is attributed to the episode of prompt penetration electric field caused by the sudden southward turning of interplanetary magnetic field (IMF) B z around 0600 UT. The second enhancement which was also superposed by wave like modulations has been attributed to the storm-induced winds. The maximum peak-to-peak amplitude of modulation in TEC is found to be 5 TECU (total electron content unit, 1 TECU = 10 16 el m À2). The enhanced plasma density observed during the daytime at midlatitudes is found to be locally produced and not transported from the equatorial ionization anomaly region because the time of enhanced plasma density at midlatitude is earlier than that observed at low latitudes. During the storm main phase, the nightside GPS observations from the midlatitude station ALGO (Algonquin Park, Canada) show moderate to large TEC fluctuations and short duration depletions that occur in a narrow latitude zone. These fluctuations and depletions in TEC have been attributed to the combined effect of storm-induced equatorward movement of the midlatitude ionospheric trough due to the expansion of auroral oval and the storm time-enhanced density. The maximum amplitude of the TEC depletions is found to be of the order of 20 TECU. Rate of TEC Index is also found to be high with a maximum value of 2.

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Large enhancements in low latitude total electron content during 15 May 2005 geomagnetic storm in Indian zone

Cited by 68 publications

References 48 publications

Longitudinal study of the ionospheric response to the geomagnetic storm of 15 May 2005 and manifestation of TADs

Longitudinal study of the ionospheric response to the geomagnetic storm of 15 May 2005 and manifestation of TADs

Positive and negative ionospheric storms occurring during the 15 May 2005 geomagnetic superstorm

Ionospheric response to the geomagnetic storm of 15 May 2005 over midlatitudes in the day and night sectors simultaneously

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