Ionospheric irregularities observed during the St. Patrick’s Day 2015 severe geomagnetic storm over the southern high latitude polar cap region: a case study from Antarctic Circle (original) (raw)
Related papers
TEC fluctuation during magnetically disturbed events of April 2010 on high latitude station
IOSR Journal of Applied Geology and Geophysics, 2014
The ionospheric parameters, strongly dependent on the solar conditions and on the complex behavior of the magnetosphere, are very interesting for studying the complex phenomena and high degree of space time variability of the ionosphere occurring at the high latitude regions. In order to see the behavior of the high latitude ionosphere during the geomagnetically active events of extreme minimum phase of solar cycle 23 and starting phase of 24 th solar cycle, in April 2010 moderate geomagnetic storms have been identified and represented in fairly well detail in the present investigation. The ionospheric observations have been obtained from dual frequency GPS, installed and operated at Indian scientific base station Maitri (71.45 0 S and 11.45 0 E) Antarctica, during December. 2009 to December 2010. Situated on auroral region mainly two parameters from the GPS observations, (I) Total Electron Content (TEC), (II) Total Electron Content Rate (TECR) have been considered for the present study. On storm days, the percentage deviations of TEC from geomagnetically quiet days at high latitudes shows the variations of ionosphere in terms of positive and negative ionospheric storms. The results therefore showed the dependence of occurrence characteristics of TEC on the solar activity.
Geodesy and Geodynamics, 2019
In this study, the global effects of the severe geomagnetic storm on the Earth's ionosphere on September 5e9, 2017 with Coronal Mass Ejections (CMEs) associated with X-9.3 flares on September 6, 2017 were investigated by the Rate of Total Electron Content (TEC) Index (ROTI). ROTI was used as a criterion of ionospheric irregularities that took place during the storm. This study was conducted with TEC values obtained from fifty stations connected to the International GNSS System (IGS)-GPS network for five different latitude regions. As a result, it was observed that the irregularities in the high latitude regions of the southern hemisphere were greater in number in comparison with those at the high latitude regions of the northern hemisphere during the storm. It was observed that these irregularities generally occurred during the main and recovery phases of the storm at all latitudes. The weak and moderate ionospheric irregularities that developed at high latitudes during the storm were more in the southern hemisphere. Especially, moderate ionospheric irregularities in high latitudes of both hemispheres took place in eastern longitudes (18 o E-160 o E). However, ionospheric irregularities in the mid-latitude regions were observed in more stations at the northern hemisphere than at the southern hemisphere. Generally, ionospheric irregularities during the storm developed at eastern longitudes in all sectors.
Moderate magnetically disturbed events of August 2010 on high latitude station
( IJOART.org ) - International Journal of Advancements in Research & Technology, 2014
The behavior of the high latitude ionosphere during the geomagnetically active events of extreme minimum phase of solar cycle 23 and starting phase of 24th solar cycle, in August 2010 moderate geomagnetic storms have been identified and represented in fairly well detail in the present investigation. The ionospheric observations have been obtained from dual frequency GPS, installed and operated at Indian scientific base station Maitri (71.450S and 11.450E) Antarctica, during December. 2009 to December 2010. Situated on auroral region mainly parameters from the GPS observations, Total Electron Content (TEC), Total Electron Content Rate (TECR) Scintillation (S4) have been considered for the present study. On storm days, the percentage deviations of TEC from geomagnetically quiet days at high latitudes shows the variations of ionosphere in terms of positive and negative ionospheric storms. The results are showing the dependence of occurrence characteristics of TEC and scintillation on t...
The paper presents a method for computing the ionospheric total electron content (TEC) using the combination of the phase and code measurements at the frequencies f1 and f2 of the global positioning system, and applies it to study the TEC variations and disturbances during the magnetic storm in March 2015 using GPS continuous data in the Southeast Asia region. The computation results show that the TEC values calculated by using the combination of phase and code measurements are less dispersed than the ones by using only the pseudo ranges. The magnetic storm whose the main phase was on the 17th March 2015, with the minimum value of the SYM/H index of-223 nT is the biggest during the 24th solar cycle. In the main phase, the crests of the equatorial ionization anomaly (EIA) expanded poleward with large increases of TEC amplitudes, that provides evidence of the penetration of the magnetospheric eastward electric field into the ionosphere and of the enhancement of the plasma fountain effect associated with the upward plasma drifts. In the first day of the recovery phase, due to the effect of the ionospheric disturbance dynamo, the amplitude of northern crest decreased an amount of about 25% with respect to an undisturbed day, and this crest moved equatorward a distance of about 11 o , meanwhile the southern crest disappeared completely. In the main phase the ionospheric disturbances (scintillations) developed weakly, meanwhile in the first day of the recovery phase, they were inhibited nearly completely. During the storm time, in some days with low magnetic activity (Ap<~50 nT), the ionospheric disturbances in the local night-time were quite strong. The strong disturbance regions with ROTI > 0.5 concentrated near the crests of the EIA. The latitudinal-temporal TEC disturbance maps in these nights have been established. The morphology of these maps shows that the TEC disturbances are due to the medium-scale travelling ionospheric disturbances (MSTID) generated by acoustic-gravity waves in the northern crest region of the EIA after sunset moving equatorward with the velocity of about 210 m/s.
The paper presents a method for computing the ionospheric total electron content (TEC) using the combination of the phase and code measurements at the frequencies f1 and f2 of the global positioning system, and applies it to study the TEC variations and disturbances during the magnetic storm in March 2015 using GPS continuous data in the Southeast Asia region. The computation results show that the TEC values calculated by using the combination of phase and code measurements are less dispersed than the ones by using only the pseudo ranges. The magnetic storm whose the main phase was on the 17th March 2015, with the minimum value of the SYM/H index of-223 nT is the biggest during the 24th solar cycle. In the main phase, the crests of the equatorial ionization anomaly (EIA) expanded poleward with large increases of TEC amplitudes, that provides evidence of the penetration of the magnetospheric eastward electric field into the ionosphere and of the enhancement of the plasma fountain effect associated with the upward plasma drifts. In the first day of the recovery phase, due to the effect of the ionospheric disturbance dynamo, the amplitude of northern crest decreased an amount of about 25% with respect to an undisturbed day, and this crest moved equatorward a distance of about 11 o , meanwhile the southern crest disappeared completely. In the main phase the ionospheric disturbances (scintillations) developed weakly, meanwhile in the first day of the recovery phase, they were inhibited nearly completely. During the storm time, in some days with low magnetic activity (Ap<~50 nT), the ionospheric disturbances in the local night-time were quite strong. The strong disturbance regions with ROTI > 0.5 concentrated near the crests of the EIA. The latitudinal-temporal TEC disturbance maps in these nights have been established. The morphology of these maps shows that the TEC disturbances are due to the medium-scale travelling ionospheric disturbances (MSTID) generated by acoustic-gravity waves in the northern crest region of the EIA after sunset moving equatorward with the velocity of about 210 m/s.
The Ionospheric Total Electron Content Behavior at Equatorial and Polar Stations
Journal of Telecommunication, Electronic and Computer Engineering, 2017
The characteristic of ionosphere behavior is of spatial and temporal variations. The ionosphere behavior was determined by identifying the total electron content (TEC) variation. The investigation on TEC variation had been made over an equatorial station, Libreville (NKLG) station (0.4162° N, 9.4673° E), and a polar station, Ny-Alesund (NYA1) station (78.9235° N, 11.9099° E) in year 2009 and 2013, each representing different level of solar activity. The hourly averaged vertical TEC (VTEC) is used to observe the TEC variation under diurnal, seasonal, and geomagnetic storm variations. The diurnal TEC variations in March and September 2009 experienced a double TEC peak structure. The TEC variation over the NKLG station in the low and high solar activity depicted the same observation where the TEC variation began to rise until it reached its maximum TEC peak around noon to the late evening, and it falls after the sunset hours until it reached its minimum TEC at pre-dawn hours. The diurnal TEC variations for all months at the NYA1 station showed rapid fluctuations of TEC by the presence of more peaks of TEC. The seasonal TEC variations showed its highest TEC peak in spring and lowest TEC peak in summer at NKLG station during both 2009 and 2013. The great fluctuations of TEC obviously observed during the winter and spring. The maximum seasonal TEC peak at NYA1 station mainly occurred around the late evening hours to the extent of pre-dawn hours. The moderate geomagnetic storm on 22 July 2009 caused an increment of TEC at both stations during the storm time meanwhile the moderate geomagnetic storm on 6 July 2013 caused a decrement of TEC at both stations during the storm time.
Ionospheric electron density perturbations during the 7–10 March 2012 geomagnetic storm period
Advances in Space Research, 2017
From 7 to 10 March 2012 a series of magnetospheric disturbances caused perturbations in the ionospheric electron density. Analyzing the interplanetary causes in each phase of this disturbed period, in comparison with the total electron content (TEC) disturbances, we have concluded that the interplanetary solar wind controls largely the ionospheric response. An interplanetary shock detected at 0328 UT on 7 March caused the formation of prompt penetrating electric fields in the dayside that transported plasma from the near-equatorial region to higher in attitudes and latitudes forming a giant plasma fountain which is part of the so-called dayside ionospheric super-fountain. The super-fountain produces an increase in TEC which is the dominant effect at middle latitude, masking the effect of the negative storm. Simultaneously, inspecting the TEC maps, we found evidence for a turbulence in TEC propagating southward probably caused by large scale travelling ionospheric disturbances (LSTIDs) linked to auroral electrojet intensification. On 8 March, a magnetospheric sudden impulse at 1130 UT accompanied with strong pulsations in all interplanetary magnetic field (IMF) components and with northward Bz component during the growth phase of the storm. These conditions triggered a pronounced directly driven substorm phase during which we observe LSTID. However, the analysis of DMSP satellite observations, provided with strong evidence for Sub-Auroral Polarization Streams (SAPS) formation that erode travelling ionospheric disturbances (TID) signatures. The overall result of these mechanisms can be detected in maps of de-trended TEC, but it is difficult to identify separately each of the sources of the observed perturbations, i.e. auroral electrojet activity and LSTIDs, super-fountain and SAPS.
The global evolution of two major ionospheric storms, occurring on November 4, 1993 and November 26, 1994, respectively, is studied using measurements of total electron content (TEC) obtained from a worldwide network of ground-based GPS receivers. The time-dependent features of ionospheric storms are identified on a global scale using TEC difference maps based on the percent change of TEC during storm time relative to quiet time. The onset of each ionospheric storm is indicated by the appearance of auroralhubauroral TEC enhancements which occur within one hour of the beginning of the geomagnetic storm main phase. Significant TEC enhancements (> 100%) are observed in the winter northern hemisphere. The rate at which TEC enhancements appear is found to correlate with gradients in the Dst index. The large scale ionospheric structures identified during the storms are: (1) nightside auroral/subauroral enhancements which surround the auroral oval; (2) dayside (around noon) high latitude and middle latitude enhancements associated with traveling ionospheric disturbances, and (3) conjugate latitudinal enhancements. For the November 93 storm, a short positive phase (about 15 hours) is followed by a long negative phase (-60 hours). In the November 94 storm, we have identified the clear signature of a traveling ionospheric disturbance (TID) which propagated at a speed of-460 m/s from-70" N to-50" N. The motion of this disturbance appears to conserve angular momentum.
Ionospheric Disturbances and Irregularities During the 25–26 August 2018 Geomagnetic Storm
Journal of Geophysical Research: Space Physics, 2022
We use ground-based (GNSS, SuperDARN, ionosondes) and space-borne (Swarm, CSES, DMSP) instruments to study ionospheric disturbances due to the 25-26 August 2018 geomagnetic storm. The strongest large-scale storm-time enhancements were detected over the Asian and Pacific regions during the main and early recovery phases of the storm. In the American sector, there occurred the most complex effects caused by the action of multiple drivers. At the beginning of the storm, a large positive disturbance occurred over North America at low and high latitudes, driven by the storm-time reinforcement of the equatorial ionization anomaly (at low latitudes) and by particle precipitation (at high latitudes). During local night-time hours, we observed numerous medium-scale positive and negative ionospheric disturbances at middle and high latitudes that were attributed to a storm-enhanced density (SED)-plume, mid-latitude ionospheric trough and particle precipitation in the auroral zone. In South America, total electron content (TEC) maps clearly showed the presence of the equatorial plasma bubbles, that, however, were not seen in data of Rate-of-TECchange index (ROTI). Global ROTI maps revealed intensive small-scale irregularities at high-latitudes in both hemispheres within the auroral region. In general, the ROTI disturbance "imaged" quite well the auroral oval boundaries. The most intensive ionospheric fluctuations were observed at low and mid-latitudes over the Pacific Ocean. The storm also affected the positioning accuracy by GPS receivers: during the main phase of the storm, the precise point positioning error exceeded 0.5 m, which is more than 5 times greater as compared to quiet days.
Antarctica SED/TOI associated ionospheric scintillation during 27 February 2014 geomagnetic storm
Astrophysics and Space Science
A geomagnetic storm occurred on 27 February 2014 and the shock related to it arrived at Earth's magnetosphere at ∼17:00 UT. Dayside cusp region scintillation over Antarctica have been studied along with the Global Positioning System (GPS) observed total electron content (TEC), and Defense Meteorological Satellite Program (DMSP) Precipitating Particles (SSJ), Bulk Plasma Parameters (SSIES) and Magnetic Fields (SSM) data. For the first time, similar variation trend in amplitude and phase scintillation has been found near the polar latitude. Amplitude scintillation index (S 4) and phase scintillation index (σ ϕ) show the similar enhancement trend at different numerical scale. During the southward interplanetary magnetic field (IMF) Bz condition there is a significant enhancement in the particle precipitation occurred through the dayside cusp region. During southward IMF Bz and dawnward By (By < 0), high convection velocity guide solar wind plasma into the polar cap which enhances the phase scintillation, but, no amplitude scintillation enhancement at the similar numerical scale. The Halley and Dome C East radar data show that at the small to medium ionospheric irregularity speed, S 4 , and σ ϕ variations are alike. If proper variation scale is chosen, S 4 also appears an appropriate scintillation index for the polar ionosphere. The possible mechanism for S 4 occurrence similar to the σ ϕ at a dissimilar level has been discussed.