Imaging the structure of a large‐scale TID using ISR and TEC data

Nicolls, M. J.; Kelley, M. C.; Coster, A. J.; González, S. A.; Makela, J. J.

doi:10.1029/2004gl019797

Cited by 110 publications

(115 citation statements)

References 17 publications

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“…This event has been reported and discussed by Nicolls et al (2004) and Vlasov et al (2005). Nicolls and Kelley (2005) also showed that the final LSTID before sunrise caused the Arecibo ionosphere to rise to over 450 km, and subsequently led to plasma structuring presumably due to some sort of instability mechanism.…”

Section: Observational Evidencementioning

confidence: 88%

“…However, the apparent simultaneity of the events might be misleading because postmidnight ESF at Jicamarca normally occurs during this time period (Hysell and Burcham, 2002) and any disturbed electric fields, caused for example by the TID, could enhance pre-existing irregularities. The event on the night of 1-2 October 2002 was anomalous and coincident with a geomagnetic storm (Nicolls et al, 2004). However, the uplifts occur fairly regularly in the equatorial ionosphere with no strong correlation to Kp.…”

Section: Observational Evidencementioning

confidence: 97%

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Observations and modeling of post-midnight uplifts near the magnetic equator

et al. 2006

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Abstract. We report here on post-midnight uplifts near the magnetic equator. We present observational evidence from digital ionosondes in Brazil, a digisonde in Peru, and other measurements at the Jicamarca Radio Observatory that show that these uplifts occur fairly regularly in the post-midnight period, raising the ionosphere by tens of kilometers in the most mild events and by over a hundred kilometers in the most severe events. We show that in general the uplifts are not the result of a zonal electric field reversal, and demonstrate instead that the uplifts occur as the ionospheric response to a decreasing westward electric field in conjunction with sufficient recombination and plasma flux. The decreasing westward electric field may be caused by a change in the wind system related to the midnight pressure bulge, which is associated with the midnight temperature maximum. In order to agree with observations from Jicamarca and Palmas, Brazil, it is shown that there must exist sufficient horizontal plasma flux associated with the pressure bulge. In addition, we show that the uplifts may be correlated with a secondary maximum in the spread-F occurrence rate in the post-midnight period. The uplifts are strongly seasonally dependent, presumably according to the seasonal dependence of the midnight pressure bulge, which leads to the necessary small westward field in the post-midnight period during certain seasons. We also discuss the enhancement of the uplifts associated with increased geomagnetic activity, which may be related to disturbance dynamo winds. Finally, we show that it is possible using simple numerical techniques to estimate the horizontal plasma flux and the vertical drift velocity from electron density measurements in the post-midnight period.

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Section: Observational Evidencementioning

confidence: 88%

Section: Observational Evidencementioning

confidence: 97%

Observations and modeling of post-midnight uplifts near the magnetic equator

et al. 2006

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“…Other possible perturbations could be caused by winds (transport of energy from high latitudes in form of changes in global wind pattern and traveling atmospheric disturbances due to Joule heating or Lorentz forces; e.g. Burns and Killeen, 1992;Hajkowicz, 1990;Prolss, 1997;Nicolls et al, 2004) and composition changes (changes in the thermospheric composition (O/N 2 ) ratio; e.g. Greenspan et al, 1991;Zhang et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

The ionospheric response in the Brazilian sector during the super geomagnetic storm on 20 November 2003

et al. 2007

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Abstract.A very intense geomagnetic storm (superstorm) began with storm sudden commencement (SSC) at 08:03 UT on 20 November 2003, as a result of the coronal mass ejection (CME) by sunspot 484 hurled into space on 18 November 2003. The geomagnetic storm attained |D st | max =472 nT at 20:00 UT (20 November). In this paper we present the simultaneous ionospheric sounding observations, using the Canadian Advanced Digital Ionosondes (CADIs), carried out from Palmas (PAL; 10.2 • S, 48.2 • W; dip latitude 5.5 • S; a near equatorial station) and São José dos Campos (SJC; 23.2 • S, 45.9 • W; dip latitude 17.6 • S; station located under the crest of equatorial ionospheric anomaly), Brazil. In addition, total electron content (TEC) measurements from several GPS receiving stations in the Brazilian sector during this storm are presented. The simultaneous ionospheric sounding observations carried out at SJC and PAL, and TEC observations on 3 consecutive days viz., 19 November (quiet), 20 November (disturbed) and 21 November (recovery phase) are presented. Salient features from the ionospheric observations in the Brazilian sector during the superstorm are discussed. The difference in the observed ionospheric response at the two stations (PAL and SJC) is considerable. This is not surprising given that PAL is close to the magnetic equator and SJC is near the crest of the equatorial ionospheric anomaly (EIA). It should be pointed out that soon after the SSC (about 4 h later), the F-region critical frequency (foF2), the F-region peak height (hpF2), and variations of virtual heights at different frequencies (iso-frequency plots) all show Correspondence to: F. Becker-Guedes (fabio@univap.br) wavelike oscillations of the F-region during daytime at both the ionospheric sounding stations. Unusual rapid uplifting of F-region at PAL was observed during both the main and recovery phases of the storm.

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“…The method of creating two-dimensional TEC perturbation maps was introduced in detail by Ding et al (2007) which was similar to that of Tsugawa et al (2003) and Nicolls et al (2004). First, we obtained the vertical TEC time series (VTEC) from the original slant TEC time series by Eq.…”

Section: Generation Of Two-dimensional Tec Perturbation Mapsmentioning

confidence: 99%

Global propagation features of large-scale traveling ionospheric disturbances during the magnetic storm of 7~10 November 2004

et al. 2012

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Abstract. Larger-scale traveling ionospheric disturbances (LSTIDs) were studied using the total electron content (TEC) data observed from global GPS network in the regions of North America, Europe, and East Asia during the magnetic storm of 7∼10 November 2004. 4 LSTID events were detected in North America, 4 in Europe, and 3 in East Asia. The parameters of the 11 LSTID events, such as the propagation azimuth (the angle with respect to north, taking clockwise as positive), horizontal phase velocity and damping rate were determined. Our results showed two new propagation features of the LSTIDs. One was the latitudinal dependence of the LSTIDs' propagation azimuths. The LSTIDs tended to deflect more to west from south as they propagated to lower latitudes, which indicated that the Coriolis force was one of the main causes of the LSTIDs' southwestward deviation. The other was the different mean horizontal phase velocities of LSTIDs among different regions. The mean horizontal phase velocity of LSTIDs was 422 ± 36 m s −1 in North America, 381 ± 69 m s −1 in Europe, and 527 ± 21 m s −1 in East Asia, respectively. The results also indicated that the amplitudes of LSTIDs decreased during their propagation for every event, and the daytime damping rates were more than 1 time larger than the nighttime ones due to different ion drag between daytime and nighttime. The source regions of the LSTIDs were likely to be located between geomagnetic latitudes of 68 • N and 62 • N in North America, and between 65 • N and 57 • N in Europe, according to the variation of magnetic H component observed in these two regions.

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Imaging the structure of a large‐scale TID using ISR and TEC data

Cited by 110 publications

References 17 publications

Observations and modeling of post-midnight uplifts near the magnetic equator

Observations and modeling of post-midnight uplifts near the magnetic equator

The ionospheric response in the Brazilian sector during the super geomagnetic storm on 20 November 2003

Global propagation features of large-scale traveling ionospheric disturbances during the magnetic storm of 7~10 November 2004

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