Effects Of Geomagnetic Storms Research Articles

Ionospheric Disturbances Observed Over the Peruvian Sector During the Mother's Day Storm (G5‐Level) on 10–12 May 2024

AbstractThis article presents the recent extreme and rare G5‐level geomagnetic storm (Mother's Day Storm) effects on the equatorial and low‐latitude ionosphere observed at the Peruvian sector by the Jicamarca (11.9°S, 76.8°W, magnetic dip 1°N) incoherent scatter radar and associated instruments. This storm was produced by multiple Earth‐directed coronal mass ejections, which generated significant modifications in the Earth's magnetic field, leading to the Sym‐H of ∼−518 nT. On the dayside, due to the strong eastward penetration electric field, vertical plasma drift and equatorial electrojet (EEJ) enhanced for 2–3 hr and remained consistent at values of ∼95 m/s and 260 nT between 1700 and 1900 UT (1200 and 1400 LT). At the same time, vertical E B plasma drift uplifted the equatorial ionosphere, producing the dusk‐side super plasma fountain and transferring electron density to higher latitudes. A huge increase (∼1,325%) in electron density (from 11 to 142 TECu) is observed at low and mid‐latitudes from ∼20°S to 50°S between 2000 and 0400 UT (1500–2300 LT). The strong westward penetration electric field suppressed pre‐reversal enhancement, leading to downward plasma drift (∼−96 m/s) at around 2400 UT (1900 LT). Overnight, vertical plasma drift fluctuated between ±90 m/s, and the combined effect of penetration and disturbance dynamo electric fields caused a significant increase (∼530 km) in ionospheric virtual height. In the main and early recovery phase, consistent short‐ and long‐duration electric field disturbances persisted for approximately 30 hr, with periods of ∼48 and 90 min.

The State of Solar Wind Heavy Ions in Interplanetary Coronal Mass Ejection–Driven Geomagnetic Storms

During geomagnetic storms, which are the primary periods for heavy ions from the solar wind to enter Earth’s magnetospheric space, the charge state of solar wind heavy ions during these storms has significant implications for studying the distribution and effects of heavy ions in the magnetosphere. We analyzed the states and variations of heavy ions during 158 interplanetary coronal mass ejection (ICME)–driven geomagnetic storm events using data from the Advanced Composition Explorer satellite and examined four of these events in detail. We found that the increase in the average charge state of heavy ions such as O, Mg, Si, and Fe is positively correlated with the intensity of the geomagnetic storm. Regarding the abundance ratio of heavy ions such as Ne, Mg, Si, and Fe relative to oxygen ions, the rate and magnitude of increase in abundance ratios during extreme geomagnetic storms (Kp = 9) triggered by ICME events are significantly higher than those during other levels of geomagnetic storms. Additionally, we observed that although the average charge states of heavy ions such as O and Fe are correlated with the geomagnetic storm intensity induced by ICMEs, there are significant individual differences in the charge state variations of heavy ions.

The Evolution of Earth's Outer Radiation Belt Over Geomagnetic Storm Phase in Van Allen Probe Era

AbstractEarth's outer radiation belts are highly dynamic during geomagnetic storms. Using electron flux data from 226 keV to 2.6 MeV measured by the Van Allen Probes, we statistically analyzed the peak flux position and inner boundary position of the outer radiation belt across different storm phases: pre‐storm quiet time, main phase, early recovery phase, and later recovery phase. This analysis covered 196 geomagnetic storm events from October 2012 to September 2019. Our results indicate that: (a) During the pre‐storm, decreases with increasing energy. From the pre‐storm to the early recovery phase, shifts inward for energies below 1 MeV and outward for energies above 1 MeV. For all energies, converges to approximately L = 4.3–4.6 in the early recovery phase. (b) Below approximately 1 MeV, generally move inward from the main phase to the early recovery phase. Above 1 MeV, remains nearly unchanged across different storm phases. (c) The half‐width (−) of the outer belt decreases during the main phase for energies below 1 MeV and increases during the recovery phase for energies above 1.5 MeV. (d) In the early recovery phase, and at 593–742 keV show a moderate correlation with storm intensity (CC 0.7–0.8), while and at energies greater than 1.1 MeV exhibit low correlations (CC0.4) during each phase. These results confirm the complex, energy‐dependent morphology of the outer radiation belt throughout geomagnetic storm phases.

Investigation of Thermospheric Response to Geomagnetic Storms Using GITM‐OVATION Prime and ‐FTA Model With Comparison to GOLD and SABER Observations

AbstractGlobal Ionosphere Thermosphere Model (GITM) results have been compared with measurements from Global‐scale observations of the limb and disk (GOLD) and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER). For the first time, GOLD‐derived exospheric temperature and column‐integrated ratio measurements have been used to validate GITM model results. We examine two geomagnetic storm events for which we drive GITM with space weather conditions to understand how well the model reproduces the thermospheric responses to geomagnetic activity. In this paper, a recently developed auroral model, the Feature Tracking of Aurora (FTA) model, has been employed to calculate auroral electron precipitation in GITM (GITM w/FTA), and results are compared with the OVATION prime (OP) driven GITM model (GITM w/OP). GITM w/FTA simulated temperature, neutral density, and nitric oxide (NO) density are generally higher compared to the GITM w/OP model. During the geomagnetic storm, the GITM model and GOLD‐derived exospheric temperature agree between and N latitude in the equatorial region. GOLD measurements show strong peaks on either side of the equator during the geomagnetic storm period, which is also observed in our model results. The NO cooling peaks estimated by GITM models are 20 km lower than SABER observations during geomagnetic storms. GITM w/FTA better matches SABER observations than GITM w/OP except at low latitudes during storm time. Our model‐model/data comparisons show that improved auroral models are needed to better capture the thermospheric variations during geomagnetic storms.

Identifying Ionospheric Small‐Scale Currents: A Spatial Correlation Study Using Closely‐Spaced Pairs of Ground Magnetometers

AbstractThe occurrence of small‐scale and intense ionospheric currents that can contribute to geomagnetically induced currents have recently been discovered. A difficulty in their characterization is that their signatures are often only observed at single widely spaced (typically 200–400 km) ground geomagnetic stations. These small‐scale structures motivate the examination of the maximum station separation required to fully characterize these small‐scale signatures. We analyze distributions of correlation coefficients between closely spaced mid‐latitude and auroral zone ground magnetometer stations spanning day to month long intervals to assess the separation distance at which geomagnetic signatures appear in only one station. Distributions were analyzed using periods that included low and high geomagnetic activity. We used data from pairs of magnetometer stations across North America within 200 km of each other, all of which were separated primarily latitudinally. Results show that while measurements remain largely similar up to separations of 200 km, large and frequent differences appear starting at around 130 km separation. Larger differences and lower correlations are observed during high geomagnetic activity, while low geomagnetic activity leads to frequent high correlation even past 200 km separation. Small but identifiable differences can appear in magnetometer data from stations as close as 35 km during high geomagnetic activity. We recommend future magnetometer array deployment in the auroral and sub‐auroral zone to have separations of 100–150 km. This enables the monitoring of large scale effects of geomagnetic storms, better temporal and spatial resolution of substorms, and observations of small‐scale current signatures.

Nighttime ionospheric irregularity during intense geomagnetic storm events over the Europe-African longitudinal sector

Radio communication and navigation systems can be severely impacted by irregularities in the ionosphere. There is still much to learn about how geomagnetic storms affect the occurrence of these irregularities. Ionosphere studies in different regions, particularly the equatorial and low-latitudes, are necessary to enhance the forecasting of this phenomenon. This study investigates the effect of intense geomagnetic storm events of August 27, October 7 and December 22, 2015, on nighttime ionospheric irregularities. Data collected from the receivers of the Global Navigation Satellite Systems (GNSS) in specific longitudinal sector of 15∘W – 0∘, 0∘ – 15∘E, 15∘E – 30∘E and 30∘E – 45∘E, as well as from the Swarm constellations in the longitude range of 30∘W – 70∘E and the latitude range of 50∘S – 50∘N, have been used. The rate of change of the total electron content (TEC) index (ROTI) and the rate of change of the electron density index (RODI) were analyzed. In the main phases of the storms, at equatorial and low-latitude regions we observed ionospheric irregularities in the African longitudinal sectors of 15∘W – 0∘, 0∘ – 15∘E and 30∘E – 45∘E in the three storm events. The observed ionospheric irregularities were more pronounced in the western than eastern regions. These irregularities were possibly driven by the Prompt Penetration Electric Fields (PPEFs) that point east to west during nighttime. Ionospheric irregularities were inhibited in the selected storm periods over the middle latitudes in the African sector. In the longitudinal sector of 15∘E – 30∘E, we obtained inhibition of irregularity in the study periods. In the case of the top-side ionosphere, we observed enhanced and depleted electron density during the storm in the low latitude and equatorial regions. In the low latitude and equatorial regions, there were electron density fluctuations within the range of 15∘N and 15∘S, indicating significant top-side irregularities.

Effects of the Super Intense Geomagnetic Storm on 10-11 May, 2024 on Total Electron Content at Bhopal

The responses of the ionosphere near the equatorial anomaly crest, as observed at Bhopal (23.2° N, 77.4° E, GMLAT 14.2° N), India, for super intense geomagnetic storms that occurred from May 10 to 11, 2024 (Sym-H: −518 nT) were studied using the vertical total electron content (VTEC). The study is based on the TEC data recorded by a multi-frequency multi-constellation GNSS receiver installed in Bhopal since April 2016. It was observed that the super intense geomagnetic storm produced positive and negative impacts on VTEC. Approximately + 61 % deviation in VTEC was observed at ∼ 0500 UT on May 12, 2024 whereas approximately −68.5 % deviation in VTEC was observed at ∼ 2045 UT on May 11, 2024. The increase in VTEC (+24 % to 50 %) during the main phase of the storm can be attributed to the prompt penetration of electric fields (PPEFs) and suppression of VTEC during recovery phase of the storm can be attributed to the changes in the thermospheric composition and ionospheric disturbance dynamo electric fields (DDEF). Increase in VTEC and wave-like structures in the VTEC on May 12, 2024 may be due to the combined effect of DDEF and traveling ionospheric disturbances (TIDs) generated by this geomagnetic storm; however, a separate study is needed to fully characterize these TIDs. We also compared IRI2020 TEC with the observed VTEC and found that IRI-TEC model accurately estimated the suppression in TEC on May 11 and 12, but could not reflect on the wave-like structure observed in VTEC on May 12. The results are compared with the earlier observations and possible mechanism is also discussed.

An investigation into the influence of solar flares and geomagnetic storms on the F2 layer of the ionosphere in Western Europe during March 2024

On March 23 and 24, 2024, the M-class and X-class solar storms significantly intensified. Subsequently, from March 24 to 26, the monitoring station’s Kp index notably increased, at times exceeding 8, indicating that a severe geomagnetic storm was occurring. During this period, the IGS Global Ionosphere Maps (GIMs) displayed a substantial decrease in Total Electron Content (TEC) in Western Europe due to the impact of the intense geomagnetic storms. To investigate this occurrence, data from the Lowell GIRO Data Center were utilized. The analysis revealed that a concentrated solar flare eruption on March 23, 2024, triggered geomagnetic storm events on Earth, causing significant ionospheric anomalies in Western European countries. Specifically, compared to typical levels, parameters such as foF2, m3000F2, and TEC values experienced significant reductions in Western European countries. Moreover, the hmF2 data exhibited higher values at night and lower values during the day, deviating from the expected diurnal pattern. Analysis of the Rate of TEC Index (ROTI) indicated varying effects of geomagnetic storms across different latitudes in Western Europe. Through detailed graphical analysis, this study elucidates the alterations in the ionosphere under geomagnetic storm conditions in Western Europe, shedding light on the dynamic behavior of the ionosphere during a specific timeframe.

Ionosonde Measurement Comparison during an Interplanetary Coronal Mass Ejection (ICME)- and a Corotating Interaction Region (CIR)-Driven Geomagnetic Storm over Europe

A comparison of three types of ionosonde data from Europe during an interplanetary coronal mass ejection (ICME)- and a corotating interaction region (CIR)-driven geomagnetic storm event is detailed in this study. The selected events are 16–20 March 2015 for the ICME-driven storm and 30 May to 4 June 2013 for the CIR-driven one. Ionospheric data from three European ionosonde stations, namely Pruhonice (PQ), Sopron (SO) and Rome (RO), are investigated. The ionospheric F2-layer responses to these geomagnetic events are analyzed with the ionospheric foF2 and h’F2 parameters, the calculated deltafoF2 and deltahF2 values, the ratio of total electron content (rTEC) and Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) satellite Global Ultraviolet Imager (GUVI) thermospheric [O]/[N2] measurement data. The storm-time and the quiet-day mean values are also compared, and it can be concluded that the quiet-day curves are similar at all the stations while the storm-time ones show the latitudinal dependence during the development of the storm. As a result of the electron density comparison, during the two events, it can be concluded that the sudden storm commencement (SSC) that characterized the ICME induced a traveling atmospheric disturbance (TAD) seen in the European stations in the main phase, while this is not seen in the CIR-driven ionospheric storm, which shows a stronger and more prolonged negative effect in all the stations, probably due to the season and the depleted O/N2 ratio.

Dynamic Characterization of Equatorial Plasma Bubble Based on Triangle Network‐Joint Slope Approach

AbstractThis paper introduces a Triangle Network‐Joint Slope (TN‐JS) approach to characterize the spatial and temporal dynamics of Equatorial Plasma Bubbles (EPBs) during geomagnetic storms. To collaboratively determine the EPB drift directions from multiple stations, a Delaunay triangle network is constructed, utilizing the distribution of Ionospheric Piercing Points (IPPs). The Time Difference of Arrival (TDOA) is extracted through cross‐correlating the Rate of Total Electron Content (ROT). The EPB drift direction can be approximately calculated by considering TDOA and IPP distances within each individual triangle of the network. This calculation is then refined through a joint statistical analysis. Using a reference station as the origin, the remaining stations within the network are projected along the estimated EPB drift direction. A spatial‐temporal color map illustrating regional ionospheric anomaly ROT observations is constructed. The EPB drift velocity among multiple stations can be collectively estimated by fitting the slope of this map, facilitating outlier exclusion. Accounting for satellite dynamic effects and the diverse orbit characteristics of GPS and BDS, corresponding IPP scan velocity compensation is performed and analyzed for EPB dynamic estimation. Using the geomagnetic storm event that occurred on September 8 as a case study, the spatial‐temporal kinetic properties of EPBs is characterized by analyzing Global Navigation Satellite System (GNSS) observations from 17 Hong Kong monitoring stations with the proposed TN‐JS approach. The results indicate during this magnetic event, that EPBs exhibit a westward drift trend with velocities ranging from a few tens to hundreds of meters per second in GPS and BDS observations.

A Comprehensive Classification and Analysis of Geomagnetic Storms Over Solar Cycle 24

A geomagnetic storm is a global disturbance of Earth's magnetosphere, occurring as a result of the interaction with magnetic plasma ejected from the Sun. Despite considerable research, a comprehensive classification of storms for a complete solar cycle has not yet been fully developed, as most previous studies have been limited to specific storm types. This study, therefore, attempted to present complete statistics for solar cycle 24, detailing the occurrence of geomagnetic storm events and classifying them by type of intensity (moderate, intense, and severe), type of complete interval (normal or complex), duration of the recovery phase (rapid or long), and the number of steps in the storm's development. The analysis was applied to data from ground-based magnetometers, which measured the Dst index as provided by the World Data Center for Geomagnetism, Kyoto, Japan. This study identified 211 storm events, comprising moderate (177 events), intense (33 events), and severe (1 event) types. About 36% of ICMEs and 23% of CIRs are found to be geoeffective, which caused geomagnetic storms. Up to four-step development of geomagnetic storms was exhibited during the main phase for this solar cycle. Analysis showed the geomagnetic storms developed one or more steps in the main phase, which were probably related to the driver that triggered the geomagnetic storms. A case study was additionally conducted to observe the variations of the ionospheric disturbance dynamo (Ddyn) phenomenon that resulted from the geomagnetic storm event of 2015 July 13. The attenuation of the Ddyn in the equatorial region was analyzed using the H component of geomagnetic field data from stations in the Asian sector (Malaysia and India). The variations in the Ddyn signatures were observed at both stations, with the TIR station (India) showing higher intensity than the LKW station (Malaysia).

Analysis of Ionospheric Delay Correction Model Performance During Geomagnetic Storms

AbstractIonospheric delay, as one of the largest error sources in radio propagation, can only be corrected for this error using the ionospheric delay correction model for Global Navigation Satellite System (GNSS) single‐frequency users. In this paper, the 2021 geomagnetic storm event is selected, and based on the measured ionospheric data from the GNSS observatory, the perturbation of the ionosphere by the geomagnetic storm event is analyzed, and it is found that the response of the ionosphere to the geomagnetic storm has obvious differences in the response characteristics and response time in different latitude regions. The performance of the global ionospheric map (GIM), the empirical model, and the broadcast ionospheric model during the geomagnetic storm‐induced ionospheric perturbation is analyzed and the change in the accuracy of each ionospheric model during the geomagnetic storm‐induced ionospheric perturbation is investigated, using the measured electron content of the GNSS as a benchmark. The results show that there is good agreement between the GIM products and the measured electron content during the period of ionospheric calm and the period of ionospheric perturbation. It is worth noting that geomagnetic storms do not necessarily lead to a decrease in the accuracy of ionospheric delay‐correction models, and in some cases, the models that were originally under‐accurate show a tendency to improve their accuracy during the period of perturbation instead. Neither the broadcast ionospheric model nor the electron content of the empirical model output responds to geomagnetic storm‐induced ionospheric perturbations.

Inner Radiation Belt Simulations During the Successive Geomagnetic Storm Event of February 2022

AbstractStarting from 29 January 2022, a series of solar eruptions triggered a moderate geomagnetic storm on 3 February 2022, followed subsequently by another. Despite the typically minimal impact of unintense storms on space technology, 38 out of the 49 Starlink satellites underwent orbital decay, re‐entering Earth's atmosphere. These satellite losses were attributed to enhanced atmospheric drag conditions. This study employs numerical simulations, utilizing our test particle simulation code, to investigate the dynamics of the inner radiation belt during the two magnetic storms. Our analysis reveals an increase in proton density and fluxes during the transition from the recovery phase of the first storm to the initial phase of the second, primarily driven by intense solar wind dynamic pressure. Additionally, we assess Single Event Upset (SEU) rates, which exhibit a 50% increase in comparison to initial quiet conditions.

Morphology of equatorial F-region irregularities over the Indian longitude sector using GPS-derived ROTI observations

The occurrence characteristics of Equatorial F-region Irregularities (EFIs) along the Indian longitude sector are investigated using GPS-derived ROTI observations from 2010 to 2023, under both quiet and disturbed geomagnetic conditions. The analysis of the results emphasizes a strong dependence of EFIs occurrence on solar cycle variation. Additionally, the EFIs are more intense at the EIA regions under maximum solar activity periods attributed to the high ambient electron density in the F-layer. The occurrence of EFIs is found to be severe and frequently observed in equinox seasons in contrast to solstice seasons. Also, the occurrence of EFIs exhibits equinoctial asymmetry with more intense EFIs in the spring equinox than autumn equinox during the peak and declining periods of the solar cycle. Conversely, severe EFIs are observed during autumn equinox than spring equinox in the ascending phase of the solar cycle. The seasonal occurrence probability of EFIs is highest in the equinox seasons, following the winter solstice, and summer solstice in high solar activity conditions. Investigations of EFIs during two prominent geomagnetic storm events (17 March 2015 and 08 September 2017) during the study period show that the storm-induced Prompt Penetration Electric Fields (PPEFs) modulated the regular intensity of dusk time Pre-Reversal Enhancement (PRE), resulting in poleward expansion of ionospheric irregularities up to mid-latitude regions with spatial time lag. However, storm-induced westward electric fields and oscillating IMF Bz created Counter Electrojet (CEJ) like conditions, suppressing the dusk time ionospheric irregularities over dip equatorial and low-latitude regions on 17 March 2013. This study provides a comprehensive understanding of how ionospheric irregularities manifest under varying conditions, thereby supporting further research on substantiating the spatiotemporal EFIs characteristics and their predictions over the region.

Analysis of global ionospheric scintillation and GPS positioning interference triggered by full-halo CME-driven geomagnetic storm: A case study

Currently, the 25th solar activity peak has commenced, driving frequent geomagnetic storms and causing irregular disturbances in the global ionosphere, leading to the scintillation of Global Positioning System (GPS) signals, consequently decreasing the accuracy of GPS positioning. Analyzing the patterns of global ionospheric scintillation and changes in GPS positioning accuracy caused by geomagnetic storms is crucial to mitigate the adverse effects of GPS positioning. Current research has primarily concentrated on analyzing the effects of geomagnetic storms on ionospheric scintillation disturbances and GPS positioning interference. However, there is a notable gap in studying the holistic impact of coronal mass ejections (CMEs)-driven geomagnetic storms on GPS performance as an integrated event complex. This study investigates the conditions under which a CME drives a severe geomagnetic storm to elucidate the space weather phenomena associated with CME-driven geomagnetic storms. The ionospheric scintillation induced by the geomagnetic storm is analyzed, while we also examine the accuracy variability in kinematic precision point positioning (PPP) and its possible leading reasons. The research findings suggest that factors such as a high-speed full-halo CME, a southward interplanetary magnetic field (IMF) Bz, and high-speed solar wind contribute to the onset of this geomagnetic storm. Ionospheric scintillation and the decrease in positioning accuracy in low-latitude regions are less pronounced compared to mid- and high-latitude areas. Geomagnetic-storm-induced scintillation increases cycle slips, leading to a decrease in PPP accuracy. Even in the cases where geomagnetic storms do not induce ionospheric scintillation, positioning accuracy can still be affected by cycle slips, deterioration of the precision of the GPS measurements, data outages, and the decrease in the number of available satellites.

Initial Study of Adaptive Threshold Cycle Slip Detection on BDS/GPS Kinematic Precise Point Positioning during Geomagnetic Storms

Global navigation satellite system (GNSS) provides users with all-weather, continuous, high-precision positioning, navigation, and timing (PNT) services. In the operation and use of GNSS, the influence of the space environment is a factor that must be considered. For example, during geomagnetic storms, a series of changes in the Earth’s magnetosphere, ionosphere, and upper atmosphere affect GNSS’s positioning performance. To investigate the positioning performance of global satellite navigation systems during geomagnetic storms, this study selected three geomagnetic storm events that occurred from September to December 2023. Utilizing the global positioning system (GPS)/Beidou navigation satellite system (BDS) dual-system, kinematic precise point positioning (PPP) experiments were conducted, and the raw observational data from 100 stations worldwide was analyzed. The experimental results show that the positioning accuracy of some stations in high-latitude areas decreases significantly when using the conventional Geometry Free (GF) cycle-slip detection threshold during geomagnetic storms, which means that the GF is no longer applicable to high-precision positioning services. Meanwhile, there is no significant change in the satellite signal strengths received at the stations during the period of the decrease in positioning accuracy. Analyzing the cycle-slip rates for stations where abnormal accuracy occurred, it was observed that stations experiencing a significant decline in positioning accuracy exhibited serious cycle-slip misjudgments. To improve the kinematic PPP accuracy during magnetic storms, this paper proposes an adaptive threshold for cycle-slip detection and designs five experimental strategies. After using the GF adaptive threshold, the station positioning accuracy improved significantly. It achieved the accuracy level of the quiet period, while the cycle-slip incidence reached the average level. During magnetic storms, the ionosphere changes rapidly, and the use of the traditional GF constant threshold will cause serious cycle-slip misjudgments, which makes the dynamic accuracy in high latitude areas and some mid-latitude areas uncommon, while the use of the GF adaptive threshold can alleviate this phenomenon and improve the positioning accuracy in the high-latitude regions and some of the affected mid-latitude areas during the magnetic storms.

The effect of continuous geomagnetic storms on enhancements of ultrarelativistic electrons in the Earth’s outer radiation belt

The effect of continuous geomagnetic storms on enhancements of ultrarelativistic electrons in the Earth’s outer radiation belt

MHD Waves in Solar Wind Plasma during Geomagnetic Storm Events in February–March 2023

MHD Waves in Solar Wind Plasma during Geomagnetic Storm Events in February–March 2023

Penetrating electric field during the Nov 3–4, 2021 geomagnetic storm

We simulated the Nov 3–4, 2021 geomagnetic storm event penetrating electric field using the Multiscale Atmosphere-Geospace Environment (MAGE) model and compared with the NASA ICON observation. The ICON observation showed sudden enhancement of the vertical ion drift when the penetrating electric field arrived at the equatorial region. The MAGE model simulated vertical ion drifts have the similarly fast enhancement that shown in the ICON data at the same UT time and satellite location. Hence, ICON ion drift data was able to verify MAGE simulation, which couples the magnetospheric model was able to simulate the penetrating electric field very well.

Geomagnetic storm effect on equatorial ionosphere over Sri Lanka through total electron content observations from continuously operating reference stations network during Mar–Apr 2022

Abstract The technological advancements in the current era have highlighted the increasing significance of satellite-based positioning, navigation, and timing services in a wide range of dynamic and critical applications. This has led to significant efforts towards enhancing the performance of global navigation satellite systems (GNSS) operating under challenging ionospheric conditions. The Sri Lankan ionosphere region is a focal point of equatorial aeronomy scientists, being situated in the southernmost landmass of the Indian longitude sector within the vicinity of the magnetic equator where a combination of electric, wind, and temperature dynamics exerts a substantial influence on the ionosphere but was relatively unexplored in the past. In the present work, we employed a Kriging interpolation technique on the total electron content (TEC) variables from ten GNSS receivers operating under the Continuously Operating Reference Stations (CORS) network in Sri Lanka first ever of its kind to deliver two-dimensional regional ionospheric TEC maps at hourly intervals, both during quiet and disturbed ionospheric conditions in the equinoctial March and April months of 2022. The latitudinal variation patterns are discernable from the hourly TEC maps. Furthermore, a comparative analysis of the performance of GNSS-derived TEC with that of the routinely published Global Ionospheric Maps (GIMs) confirms overestimation characteristics of the latter irrespective of the local time of observation. The generated regional ionospheric maps are fairly responsive to the onset of the storm and the recovery phase thereafter. The extent of nighttime ionospheric irregularity is also probed through the rate of TEC index (ROTI) variations, demonstrating that the irregularities were insignificant during the selected storm event.