Ionospheric effects of major magnetic storms during the International Space Weather Period of September and October 1999: GPS observations, VHF/UHF scintillations, and in situ density structures at middle and equatorial latitudes

Basu, S.; Valladares, C. E.; Yeh, H.-C.; Su, S.‐Y.; MacKenzie, E.; Sultan, P. J.; Aarons, J.; Rich, F. J.; Doherty, Patricia H.; Groves, K. M.; Bullett, T. W.

doi:10.1029/2001ja001116

Cited by 210 publications

(165 citation statements)

References 52 publications

(15 reference statements)

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“…During the southward IMF B z condition, the penetration of eastward IEF to ionospheric altitudes is favored and this scenario may lead to enhanced ionospheric fountain effect. Observations of such enhancement are found in Basu et al (2001). The result is an enhanced EIA with prominent crests displaced to higher latitudes compared to quiet time patterns (Mendillo, 2006).…”

Section: November 2004mentioning

confidence: 69%

Storm-time total electron content and its response to penetration electric fields over South America

et al. 2011

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Abstract. In this work the response of the ionosphere due to the severe magnetic storm of 7-10 November 2004 is investigated by analyzing GPS Total Electron Content (TEC) maps constructed for the South America sector. In order to verify the disturbed zonal electric fields in South America during the superstorm, ionospheric vertical drift data obtained from modeling results are used in the analysis. The vertical drifts were inferred from H magnetometer data (Jicamarca-Piura) following the methodology presented by Anderson et al. (2004). Also used were vertical drifts measured by the Jicamarca ISR. Data from a digisonde located at São Luís, Brazil (2.33 • S, 44.2 • W, dip latitude 0.25 • ) are presented to complement the Jicamarca equatorial data. Penetration electric fields were observed by the comparison between the equatorial vertical drifts and the Interplanetary Electric Field (IEF). The TEC maps obtained from GPS data reflect the ionospheric response over the South America low-latitude and equatorial region. They reveal unexpected plasma distributions and TEC levels during the main phase of the superstorm on 7 November, which is coincident with the local post-sunset hours. At this time an increase in the prereversal enhancement was expected to develop the Equatorial Ionization Anomaly (EIA) but we observed the absence of EIA. The results also reveal well known characteristics of the plasma distributions on 8, 9, and 10 November. The emphasized features are the expansion and intensification of EIA due to prompt penetration electric fields on 9 November and the inhibition of EIA during post-sunset hours on 7, 8, and 10 November. One important result is that the TEC maps provided a bi-dimensional view of the ionospheric changes offering a spatial description of the electrodynamics involved, Correspondence to: P. M. de Siqueira (patricia.mara@dae.inpe.br) which is an advantage over TEC measured by isolated GPS receivers.

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Section: November 2004mentioning

confidence: 69%

Storm-time total electron content and its response to penetration electric fields over South America

et al. 2011

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“…4 and 6) may well be related to electric field penetration to lower latitudes in the ionosphere. Theoretical considerations (Buonsanto, 1999 and references therein) and earlier observations (Jakowski et al, 1999;Basu et al, 2001) show that the zonal electric field of magnetospheric origin may penetrate down to the ionosphere when the IMF turns southward and before the ring current has developed. In the case of the 22 September storm event the IMF turned southward dramatically at 19:30 UT, which is approximately the same time as the TEC enhancement commenced.…”

Section: Discussionmentioning

confidence: 99%

The Southern Hemisphere and equatorial region ionization response for a 22 September 1999 severe magnetic storm

2004

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Abstract. The ionospheric storm evolution process was monitored during the 22 September 1999 magnetic storm over the Australian eastern region, through measurements of the ionospheric Total Electron Content (TEC) from seven Global Positioning Systems (GPS) stations. The spatial and temporal variations of the ionosphere were analysed as a time series of TEC maps. Results of our analysis show that the main ionospheric effect of the storm under consideration are: the long lasting negative storm effect during a magnetic storm at mid-latitude regions; the strong, positive disturbances during the storm's main phase at auroral latitude regions; the effects of storm-induced equatorward directed wind causing a positive disturbance at high and mid-latitude stations with appropriate time shift between higher and lower latitudes; daytime poleward movement of depleted plasma that causes temporary suppression of the equatorial anomaly during the start of the storm recovery phase; and prompt penetration of eastward electric fields to ionospheric altitudes and the production of nearly simultaneous TEC enhancement at all latitudes. In general, we found dominant negative disturbance over mid and high latitudes and positive disturbance at low latitudes. A comparison of storm-time behaviour of TEC determined from GPS satellites, and f o F 2 derived from ionosondes at a range of latitudes, showed reasonable agreement between the two independent measurements.

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“…Similarities as well as asymmetries of conjugate auroras during auroral breakups and substorms have been observed (Sato et al, 1998(Sato et al, , 2005Laundal and Østgaard, 2009). The GPS phase scintillation at high latitudes during magnetic storms has been studied intensively in the past (Aarons et al, 2000;Basu et al, 2001). Studies of polar ionospheres during geomagnetic storms (e.g.…”

Section: Interhemispheric Asymmetry In Phase Scintillation Occurrencementioning

confidence: 99%

Interhemispheric comparison of GPS phase scintillation at high latitudes during the magnetic-cloud-induced geomagnetic storm of 5–7 April 2010

et al. 2011

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Abstract. Arrays of GPS Ionospheric Scintillation and TEC Monitors (GISTMs) are used in a comparative scintillation study focusing on quasi-conjugate pairs of GPS receivers in the Arctic and Antarctic. Intense GPS phase scintillation and rapid variations in ionospheric total electron content (TEC) that can result in cycle slips were observed at high latitudes with dual-frequency GPS receivers during the first significant geomagnetic storm of solar cycle 24 on 5-7 April 2010. The impact of a bipolar magnetic cloud of north-south (NS) type embedded in high speed solar wind from a coronal hole caused a geomagnetic storm with maximum 3-hourly Kp = 8-and hourly ring current Dst = −73 nT. The interhemispheric comparison of phase scintillation reveals similarities but also asymmetries of the ionospheric response in the northern and southern auroral zones, cusps and polar caps. In the nightside auroral oval and in the cusp/cleft sectors the phase scintillation was observed in both hemispheres at about the same times and was correlated with geomagnetic activity. while it was significantly higher in Cambridge Bay (77.0 • N; 310.1 • E) than at Mario Zucchelli (80.0 • S; 307.7 • E). In the polar cap, when the interplanetary magnetic field (IMF) was strongly northward, the ionization due to energetic particle precipitation was a likely cause of scintillation that was stronger at Concordia (88.8 • S; 54.4 • E) in the dark ionosphere than in the sunlit ionosphere over Eureka (88.1 • N; 333.4 • E), due to a difference in ionospheric conductivity. When the IMF tilted southward, weak or no significant scintillation was detected in the northern polar cap, while in the southern polar cap rapidly varying TEC and strong phase scintillation persisted for many hours. This interhemispheric asymmetry is explained by the difference in the location of solar terminator relative to the cusps in the Northern and Southern Hemisphere. Solar terminator was in the immediate proximity of the cusp in the Southern Hemisphere where sunlit ionospheric plasma was readily convected into the central polar cap and a long series of patches was observed. In contrast, solar terminator was far poleward of the northern cusp thus reducing the entry of sunlit plasma and formation of dense patches. This is consistent with the observed and modeled seasonal variation in occurrence of polar cap patches. The GPS scintillation and TEC data analysis is supported by data from ground-based networks of magnetometers, riometers, ionosondes, HF radars and all-sky imagers, as well as particle flux measurements by DMSP satellites.Published by Copernicus Publications on behalf of the European Geosciences Union.

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Ionospheric effects of major magnetic storms during the International Space Weather Period of September and October 1999: GPS observations, VHF/UHF scintillations, and in situ density structures at middle and equatorial latitudes

Cited by 210 publications

References 52 publications

Storm-time total electron content and its response to penetration electric fields over South America

Storm-time total electron content and its response to penetration electric fields over South America

The Southern Hemisphere and equatorial region ionization response for a 22 September 1999 severe magnetic storm

Interhemispheric comparison of GPS phase scintillation at high latitudes during the magnetic-cloud-induced geomagnetic storm of 5–7 April 2010

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