Effects Of Geomagnetic Storms Research Articles

Effect of geomagnetic storms on l-band scintillation over Ilorin, Nigeria

A study on the effects of geomagnetic storms on l-band scintillation at Ilorin (latitude = 8.48 °N, longitude = 4.67 °E, Geomagnetic Latitude = 1.89 °S) is presented using newly available data. Three storms with minimum Dst<-100nT(i.e. the storm of April 24, 2012, the St. Patrick’s day storm of March 17, 2015 and the storm of October 13, 2016) were selected for the study based on the availability of data and the season of frequent occurrence of scintillation at Ilorin. The indices used are the ring current index (Dst), the auroral electroject activity index (AE), the horizontal component of the Interplanetary Magnetic Field (IMFBZ) and the ratio of the atomic to molecular neutral species. Results showed that the main phase of the April 24, 2012 caused little enhancement in scintillation during the pre-midnight period while scintillation was suppressed during the post-midnight period. However, scintillation was inhibited on the night of the main phase of the storm of March 17, 2015 and slightly inhibited on the night of the main phase of the storm of October 13, 2016. During the recovery phase, little enhancement was observed for the storm of October 13, 2016 while scintillation was inhibited for one day for the April, 24 2012 and for two successive days for the storm of March 17, 2015. The most interesting results was that of St. Patrick’s day storm of March 17, 2015 in which scintillation was inhibited for three successive days. The Prompt Penetration Electric Field which brings about enhancement of E × B lifting of ionization based on the local time of the minimum Dst is good enough to explain the observation during April 24, 2012 storm. Whereas, northward turning in IMFBZ values and decay in AE values which causes damping of E × B lifting of ionization were used in explaining observations during the storms of March 17, 2015 and October 13, 2016. In addition, significant reduction is seen in the ratio of the atomic to molecular neutral species especially during the storm of March 17, 2015 in which scintillation was inhibited during the main phase and the first two successive days of the recovery phase.

Short- and Long-Term Changes in the Neurophysiological Status of Pilots Due to Radiation Exposure Caused by Geomagnetic Storms

Pilots who have completed successfully all the tests of cognitive and personality psychology have a strong commitment to their movements, and they influence their neural stimulation, such as the ability to acknowledge the right steps to follow in their tasks or dangerous situations. One of the branches of Aviation Psychology is dealing with the physical and mental effects of flight on aircrew personnel and passengers. Astronomical events, such as geomagnetic storms (GSs) that have a disruptive effect on Earth’s magnetosphere in certain periods, will cause negative effects on aircrew personnel and passengers. This article describes the expected damage to the different areas of the brain and nervous system in short- and long-term periods caused by the effects of GSs, based on the results of previous studies on GSs and neurophysiological studies. This is a very important topic for neurophysiological studies of pilots when we consider that aircraft accidents that may be geomagnetic in origin accounted for 26.36% of the total accidents which coincide with the days of GSs. Decision-making and judgment problems, abnormal attitudes such as anger, fearlessness, temerity, self-confidence, etc., decreasing problem-solving abilities, organization capabilities, and instantaneous decisions are the short-term changes while developing cancers of the brain, testis, bladder, breast, colon, melanoma, and Hodgkin’s type, in addition to Alzheimer’s and dementia diseases, hypoglycaemia, stroke, epileptic seizures, insomnia, stomach bleeding, appendicitis, hernia, asthma, and severe spinal pains can be lead in the long-term changes. We mentioned the psychological and medical application method of EEG in our article since it is the best technique that allows us to see the effects of these storms in the laboratory environment. This is because, the aircrew personnel and passengers flying at high latitudes will experience the effect of the GSs directly, whereas the response of the pilot, flight crew, and passengers flying in the middle latitudes, to these effects, can be measured only with tests in the laboratory environment. This paper has also special importance for the aviation literature because a theoretical recommendation regarding the possible laboratory environment for EEG measurements and application procedures necessary to investigate these effects is also presented.

Ionospheric anomalies probably related to the Mw 7.1 northern Mid-Atlantic Ridge earthquake

Discussions related to ionospheric anomalies ought to be carefully governed because of their dynamics. The anomalies in the ionosphere that happen before-after an earthquake play a crucial rule in estimations of earthquakes. The anomalies can be detected and discussed with the help of total electron content (TEC). This essay examines anomalies before and after the Mw 7.1 northern Mid-Atlantic Ridge (52.649° N-31.902° W) earthquake that occurred on February 13, 2015. This examination is performed with the help of the TEC (TECU) map. The paper employs the Global Navigation Satellite System-based TEC map. The TEC map obtained from the Center for Orbit Determination in Europe (CODE) is interpolated with the northern Mid-Atlantic at locations 52.250° N-52.500° N and 30.000° W-35.000° W. In the paper, the TEC map frequency-domain amplitudes are resolved by short-term Fourier transformation spectral analysis. To distinguish the anomaly reason from each other, the effect of solar activity with the F10.7 (sfu) index and the effect of geomagnetic storm with Bz (nT), v (km/s), P (nPa), E (mV/m), Kp (nT), and Dst (nT) parameters (index) is analyzed. The lower boundary and the upper boundary of interpolated CODE TEC map are specified with the help of median and standard deviation. The TEC data that does not locate within the specified limits are marked as an anomaly. According to the work, 9-day TEC anomalies (5-day of them belong to pre-earthquake) are detected. The anomalies observed on February 2, 3, 5, and 7 may relate to the Mid-Atlantic earthquake.

Analyzing the Effects of Geomagnetic Storms on the F2-region Ionosphere in South Pacific Region

Analyzing the Effects of Geomagnetic Storms on the F2-region Ionosphere in South Pacific Region

Modeling of the Subsolar Magnetopause Motion Under Interplanetary Magnetic Field Southward Turning

AbstractIn this study, a new analytical model to describe the time‐dependent subsolar magnetopause motion under interplanetary magnetic field (IMF) southward turning has been developed. This model, based on the scenario of magnetopause erosion due to magnetic reconnection, can be approximated by both linear and non‐linear functions. The linear function is simplified under the assumption of constant magnetopause erosion under southward IMF, and the non‐linear function is derived by assuming that the magnetopause erosion decays exponentially. In the limit of a short time, the non‐linear function is essentially the same as the linear function. By comparing with global magnetohydrodynamic simulations, the linear function performs well within the first 10 minutes, and the error then increases with time. The non‐linear function describes the magnetopause motion more accurately with respect to, and consistent with simulations for a time interval of ∼40 min. This model has also been successfully applied to data‐driven simulations of the 17 March 2015 geomagnetic storm event, suggesting the possible applicability of this model in reality.

Nightside 135.6 nm emission enhancements of mid/low latitudes during geomagnetic storms as observed by the ionosphere PhotoMeter (IPM) on the Chinese meteorological satellite FY-3D

IPM has detected nightside 135.6 nm emission enhancements over a wide latitude range, from the sub-auroral latitudes to the equatorial regions during geomagnetic storms. Our work, presented in this paper, uses the data of IPM to understand these 135.6 nm emission enhancements during of geomagnetic storms and studies the variations of total electron content (TEC) and the F2 layer peak electron density (NmF2) in the region of enhanced emissions. Middle and low latitude emission enhancements are presented during several medium storms in 2018. The variations of both the integrated electron content (IEC) derived from the nighttime OI 135.6 nm emission by IPM and TEC from the International GNSS Service (IGS) relative to the daily mean of magnetically quiet days of per each latitude bin (30°≦geographic latitude < 40°, 15°≦geographic latitude < 30°, 0°≦geographic latitude < 15°, −15°≦geographic latitude < 0°, −30°≦geographic latitude < -15°, −40°≦geographic latitude < -30°) are investigated and show that on magnetically storm day, IEC by IPM always increases, while TEC from IGC may increase or decrease. Even if both increase, the increase of IEC is greater than that of TEC. From the comparison of IEC and TEC during magnetic storms, it can be seen that the enhancement of the nighttime 135.6 nm emissions is not entirely due to the ionospheric change. The time of IEC enhancements at each latitude bin is in good agreement, which mainly corresponds to the main phase time of the geomagnetic storm event and lasts until the recovery phase. The available ground-based ionosonde stations provide the values of NmF2 which match the 135.6 nm emissions measured by IPM in space and time. The variations of NmF2 squared can characterize the variations of the OI 135.6 nm emissions caused by O+ ions and electrons radiative recombination. The study results show that the OI 135.6 nm emission enhancements caused by O+ ions and electrons radiative recombination (where NmF2 squared increases) are obviously a contribution to the measured 135.6 nm emission enhancements by IPM. The contribution accounts for at least one of all contributions to the measured 135.6 nm emission enhancements by IPM. However, where the NmF2 squared provided by ionosonde decrease or change little (where the OI 135.6 nm emissions cause by O+ ions and electrons radiative recombination also decrease or change little), the emission enhancements measured by IPM at storm-time appear to come from the contributions of other mechanisms, such as energetic neutral atoms precipitation, or the mutual neutralization emission (O+ + O-→2O + hʋ (135.6 nm)) which also occupies a certain proportion in 135.6 nm airglow emission at night.

Altitude Extension of the NCAR‐TIEGCM (TIEGCM‐X) and Evaluation

AbstractThe upper boundary height of the traditional community general circulation model of the ionosphere‐thermosphere system is too low to be applied to the topside ionosphere/thermosphere study. In this study, the National Center for Atmospheric Research Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model (NCAR‐TIEGCM) was successfully extended upward by four scale heights from 400–600 km to 700–1,200 km depending on solar activity, named TIEGCM‐X. The topside ionosphere and thermosphere simulated by TIEGCM‐X agree well with the observations derived from a topside sounder and satellite drag data. In addition, the neutral density, temperature, and electron density simulated by TIEGCM‐X are morphologically consistent with the NCAR‐TIEGCM simulations before extension. The latitude‐altitude distribution of the equatorial ionization anomaly derived from TIEGCM‐X is more reasonable. During geomagnetic storm events, the thermospheric responses of TIEGCM‐X are similar to NCAR‐TIEGCM. However, the ionospheric storm effects in TIEGCM‐X are stronger than those in NCAR‐TIEGCM and are even opposites at some middle and low latitudes due to the presence of more closed magnetic field lines. Defense Meteorological Satellite Program observations prove that the ionospheric storm effect of TIEGCM‐X is more reasonable. The well‐validated TIEGCM‐X has significant potential applications in ionospheric/thermospheric studies, such as the responses to storms, low‐latitude dynamics, and data assimilation.

The preliminary result of orbital atmosphere detector on board spherical satellite

<p indent="0mm">The spherical satellite is Chinese first spherical small satellite, integrating atmospheric composition, atmospheric density detection and precision orbit determination. The payload is the Orbital Atmosphere Detector, which was launched into near circular polar orbit with the orbit altitude of <sc>520 km</sc> and inclination angle of 97.4° on 14 October, 2021. The scientific objectives, operating principle and the ground calibration results of the Orbital Atmosphere Detector are presented in this paper. The preliminary <italic>in-situ</italic> observed results are analyzed and discussed. The observed mass densities are strongly correlated with <italic>F</italic>10.7 and <italic>Kp</italic>. The peak-to-valley ratio of observed mass densities during the quiet period of solar and geomagnetic activity on 3 November 2021 was 3.02; the peak of observed mass density increased from 2.8×10⁻¹³ to 8.0×<sc>10⁻¹³ kg/m³</sc> during the strong geomagnetic storm event on 4 November, 2021, an increase of 2.857 times compared to the MSIS00 model of 1.316 times. The observed data show that the increase in atmospheric density started at the South Pole and spread to the middle and low latitudes, while the MSIS00 model only show a weak symmetrically increase between the northern and southern hemispheres during the storm. The observed results show that the observed data objectively reflect the spatial and temporal distribution of thermosphere density during the quiet period and the geomagnetic storm event, and thermosphere atmospheric model correction can be implemented based on the large amount of observed data.

Effects of geomagnetic storms on the accuracy of orbit-derived atmospheric density measurements

We elucidated the effects of geomagnetic storms on the accuracy of orbit-derived densities. Two different methods were used to estimate densities along the Challenging Minisatellite Payload (CHAMP) satellite trajectory with two types of orbital data: low-accuracy high-spatial coverage mean orbital element (MOE) data, and high-precision low-quantity precise orbit ephemeris (POE) data. 12 cases under different geomagnetic conditions were selected. The biases in orbit-derived and empirical model densities with respect to three different sources of accelerometer-based density data sets were calculated. The main purpose of this research is to give a quantified analysis to the impact of different geomagnetic storm events on the precision of orbit-derived densities. Meanwhile, the influence of different integral time spans adopted in the density deriving procedures were also investigated and discussed, which might be helpful for other research teams on the selection of the optimal integral time spans. Results show that the POE data could induce higher precision and higher temporal resolution atmospheric density under all geomagnetic conditions, given that the Sutton densities are assumed as the baseline data.

North–South IMF Disturbance Detection via an Adaptive Filter Approach

Geomagnetic storm-detection algorithms are important for space-weather-warning services to provide reliable warnings (e.g., ionospheric disturbances). For that reason, a new approach using an adaptive filter (least mean squares algorithm) for the detection of geomagnetic storms based on the volatility of the north–south interplanetary magnetic field Bz is presented. The adaptive filter is not dependent on solar wind plasma measurements, which are more frequently affected by data gaps than Bz, and is less dependent on the magnitude of Bz disturbances compared with other detection algorithms (e.g., static thresholds). The configuration of the filter is discussed in detail with three geomagnetic storm events, and required optimization as well as possible extensions are discussed. However, the proposed configuration performs satisfactorily without further improvements, and good correlations are observed with geomagnetic indices. Long-term changes are also reflected by the filter (solar cycles 23 and 24), and thus the performance is not affected by different solar wind conditions during the solar minimum and maximum. Conclusively, the proposed filter provides a good solution when more complex approaches (e.g., solar-wind–magnetosphere coupling functions) that rely on solar wind plasma measurements are not available.

Characteristics of Low-Latitude Ionosphere Activity and Deterioration of TEC Model during the 7–9 September 2017 Magnetic Storm

Under the influence of space weather, abnormal disturbances in the ionosphere will distort the ionosphere model seriously and affect the global navigation satellite system negatively. This study analyzes the ionospheric activity characteristics and the ionospheric model performance in low latitude during a strong geomagnetic storm from 7 to 9 September 2017. The research goals are to determine the abnormal behavior of the ionosphere during the geomagnetic storm and to refine the ionosphere model in the low latitude. In the experiment, the vertical total electron content (VTEC) peak value at low latitudes caused by this geomagnetic storm was significantly higher than that on the geomagnetic quiet day, and the VTEC peak value increased by approximately 75%. In the main phase of the geomagnetic storm, the degree of VTEC variation with longitude is significantly higher than that of the geomagnetic quiet day. The VTEC variation trend in the northern hemisphere is more severe than that in the southern hemisphere. In the region where VTEC decreases with longitude, the VTEC in the northern hemisphere is higher than that in the southern hemisphere on the same longitude at low latitudes, and this phenomenon is not significantly affected by the geomagnetic disturbance of the recovery phase. During the geomagnetic storm, the daily minimum value of VTEC at different latitudes was basically the same, approximately 5 TECU, indicating that the nighttime VTEC of the ionosphere in low latitudes was weakly affected by latitude and geomagnetic storms. Geomagnetic disturbances during geomagnetic storms will lead to anomalous features of the “Fountain effect” in the ionosphere at low latitudes. In addition, this geomagnetic storm event caused the accuracy of spherical harmonics (SH), polynomial, and ICE models to decrease by 7.12%, 27.87%, and 48.56%, respectively, and caused serious distortion, which is negative VTEC values fitted by the polynomial model.

Diurnal Response of the Thermospheric radiative cooling to March 16–21, 2015 Geomagnetic Storm

It is well known that huge amount of energy is deposited into the high latitude thermosphere region during geomagnetic storm events. The energy deposition increases the thermospheric temperature by hundreds of degree kelvin. The radiative cooling by Nitric Oxide (NO) at 5.3 μm and CO2 at 15 μm emissions, being dominant coolants in the thermosphere, play important roles in regulating the thermospheric temperature during geomagnetic storm period. We utilized the NO 5.3 μm and CO2 15 μm radiative emissions, as observed by the SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) onboard NASA’s TIMED (Thermosphere Ionosphere Mesosphere Energetics Dynamics) satellite, to investigate the diurnal response of thermospheric cooling to March 16–21, 2015 storm. We also used the atomic oxygen density and temperature from the TIMED-SABER satellite to explore their correlations with the cooling flux. It is observed that the CO2 and NO cooling emissions respond differently to the March 16–21, 2015 storm during day and night. Both the NO (about five times) and CO2 (about 70%) emission show strong enhancement during storm period. A stronger enhancement and a quicker recovery is observed in the NO 5.3 μm emission. Although the CO2 emission shows lesser enhancement than the NO emission, it lasts longer than the later. The CO2 emission takes about 5–6 days to return to its pre-onset value. The response of the NO 5.3 μm emission is short-term and lasts for about 3–4 days before returning to the pre-onset value. The NO and CO2 emission exhibit strong positive correlation with the storm’s intensity both during day and night suggesting that more intense is the storm more energy exits the thermosphere.

Ionospheric storm due to solar Coronal mass ejection in September 2017 over the Brazilian and African longitudes

Coronal mass ejection (CME) occurs when there is an abrupt release of a large amount of solar plasma, and this cloud of plasma released by the Sun has an intrinsic magnetic field. In addition, CMEs often follow solar flares (SF). The CME cloud travels outward from the Sun to the interplanetary medium and eventually hits the Earth’s system. One of the most significant aspects of space weather is the ionospheric response due to SF or CME. The direction of the interplanetary magnetic field, solar wind speed, and the number of particles are relevant parameters of the CME when it hits the Earth’s system. A geomagnetic storm is most geo-efficient when the plasma cloud has an interplanetary magnetic field southward and it is accompanied by an increase in the solar wind speed and particle number density. We investigated the ionospheric response (F-region) in the Brazilian and African sectors during a geomagnetic storm event on September 07–10, 2017, using magnetometer and GPS-TEC networks data. Positive ionospheric disturbances are observed in the VTEC during the disturbed period (September 07–08, 2017) over the Brazilian and African sectors. Also, two latitudinal chains of GPS-TEC stations from the equatorial region to low latitudes in the East and West Brazilian sectors and another chain in the East African sector are used to investigate the storm time behavior of the equatorial ionization anomaly (EIA). We noted that the EIA was disturbed in the American and African sectors during the main phase of the geomagnetic storm. Also, the Brazilian sector was more disturbed than the African sector.

Influence of geomagnetic storms on the quality of magnetotelluric impedance

Magnetotelluric (MT) field data contain natural electromagnetic signals and artificial noise sources (instrumental, anthropogenic, etc.). Not all available time-series data contain usable information on the electrical conductivity distribution at depth with a low signal-to-noise ratio. If variations in the natural electromagnetic signal increase dramatically in a geomagnetic storm, the signal-to-noise ratio increases. A more reliable impedance may be obtained using storm data in a noisy environment. The field datasets observed at mid-latitudes were used to investigate the effect of geomagnetic storms on MT impedance quality. We combined the coherence between the electric and magnetic fields and the result of the MT sounding curve to evaluate the MT impedance quality across all periods and combined the phase difference among the electric and magnetic fields, the polarization direction, and the hat matrix to discuss the data quality for a specific period simultaneously. The case studies showed that the utilization of the data observed during the geomagnetic storm could overcome the local noise and bring a more reliable impedance.Graphical

Effects of CME-induced Geomagnetic Storm on Geomagnetic Induced Current at High and Middle Latitudes

Geomagnetic storm has been one of greatest events in space weather studies. Apart from the formation of aurora, geomagnetic induced current (GIC) is also induced during the storm when the storm intensity gets severe. Coronal mass ejection (CME) is a massive eruption created by the Sun and is believed to be the driver of geomagnetic storm. This paper is aimed to examine the effects of CME-induced geomagnetic storm on geomagnetic induced current (GIC) at high and middle latitudes by studying four levels of storm: minor (Kp 5), moderate (Kp 6), strong (Kp 7) and severe (Kp 8). We applied qualitative analysis through descriptive approach to describe the relationship between the storm intensity and GIC activity. Since the exact value of GIC were inaccessible, we adopted horizontal component time derivative magnetic field (dH/dt) as the indicator for GIC activity. At the end of the study, we found that the GIC highly depends on the storm intensity, by which higher levels of storm triggers more actively induced current. Besides, high latitude ionosphere was showing strong reactions to the storm arrival compared to middle latitude ionosphere as the magnitudes of dH/dt recorded by Barrow station at high latitude fluctuated within wider and higher range.

The Study of Geomagnetic Activity from 2017 to 2020 Period

Geomagnetic storm has been extensively studied and observed because it can interfere satellite and radio communications. Some parameters, such as Dst index, Kp index, north-south interplanetary magnetic field (Bz) and speed of solar wind (Vsw), can be used to identify the level of geomagnetic storm and assess its potential risk. Therefore, this paper provides the analysis of geomagnetic parameters and their correlation to geomagnetic activities during 2017-2020 period. The geomagnetic data, i.e. Dst, Kp, Bz, and Vsw, were obtained from the website: https://omniweb.gsfc.nasa.gov. The results indicated that some significant geomagnetic storms occurred during 2017-2020, which were shown by the sharp increase of the Dst index, which was also followed by the increase of Kp index, the increase of Vsw, and the extreme fluctuations of Bz index. Three big events occurred on May 28th 2017, September 8th 2017, and August 26th 2018, which had the Dst increase to as high as -125 nT, -124 nT, and -174 nT (< -100 nT), respectively, followed by seventeen minor storm events with Dst between -45 nT until -76 nT. The geomagnetic storm events were probably driven by earth-directed coronal mass ejection (CME) or halo CMEs or high-speed solar wind flows from coronal holes. This result was also supported with the data of flux electron detected at outer radiation belt that have been increased. It can be concluded that the north-south interplanetary magnetic field (Bz) and speed of solar wind (Vsw) have a strong correlation to geomagnetic storm events in which the increasing of Bz followed the increasing of Vsw.

Long short-term memory and gated recurrent neural networks to predict the ionospheric vertical total electron content

This paper provides the application of deep learning models such as Long Short-Term Memory (LSTM) and a recently proposed Gated Recurrent Unit (GRU) in forecasting the ionospheric GPS_VTEC, and compare the performance of the results with that of Multilayer Perceptron (MLP) neural networks, GIM_TEC and the IRI-Plas 2017 models. GPS_VTEC time series data estimated from GPS measurement over low latitude equatorial station MAL2 with (geo.lat -2.70NandLong40.190E) located in Kenya is used in this study. The data span from January 1, 2010 to December 31, 2018 which covers 9 years of solar cycle 24. The data from the year 2010 to 2016 is used for the training, while the year 2017 data is used for validation and finally the data in the year 2018 is used to examine the performance of the models during the testing period. The performance of the models is based on statistical parameters such as root-mean-square error (RMSE) and correlation coefficient (R). The GRU unit shows a correlation coefficient of 0.971 with GPS_VTEC and a prediction error of 2.004 TECU while that of LSTM, MLP, GIM_TEC, and IRI-Plas 2017 models are 0.967, 0.951, 0.832 and 0.774 with a prediction error of 2.055 TECU, 2.336 TECU, 5.913 and 16.183 TECU, respectively. This shows that the predictions of the gated system models are better than the MLP, GIM_TEC and IRI-Plas models. Considering the prediction ability of these models to forecast the GPS-VTEC values under an intense Geomagnetic Storm event, it is observed that the GRU unit can achieve the best prediction accuracy and shows a strong performance for the trend prediction of this event more than the LSTM, MLP, GIM_TEC, and IRI-Plas models. In all, the three deep learning models perform better than the GIM_TEC and the IRI-Plas 2017 model.

High and mid latitude and near subsolar point ionospheric and thermospheric responses to the solar flares and geomagnetic storms during low solar activity periods of 2017 and 2020

The paper observes the super-imposed effects of intense and moderate solar flares and Coronal Mass Ejection (CME) and High Speed Solar Wind (HSSW) driven geomagnetic storm events on the ionosphere and thermosphere at mid and high latitudes during low solar activity periods. The observations are conducted over a fixed longitude (∼117°W geographic) during May 27–31, 2017 (duration with intense geomagnetic storm without any significant solar flare event), September 3–6, 2017 (duration with solar flare events), September 7–16, 2017 (duration with intense to moderate solar flares as well as geomagnetic storms) and November 28–30, 2020 (duration with a moderate solar flare event with no geomagnetic storm in association). It is found that the effects were the highest during May 27–31, 2017 among all of these events. From the observations of super-imposed effects of the geophysical events, it was found that the effects of an X-class solar flare on September 10–12, 2017 on mid-latitude ionization were suppressed by the Disturbed Dynamo Electric Field (DDEF) from high latitudes during the recovery phase of an intense CME driven geomagnetic storm. The weak effects were also explained by the position of origination of the flare at the Sun. Correlations were observed between the variations in O/N2, neutral wind velocities and the mid and high latitude Total Electron Content (TEC) during these periods. Possible explanation is given for those few cases (for example, September 14, 2017) when the variations in O/N2 mismatched with the local TEC especially in the mid-latitudes. The effects of the solar flare event on November 28–30, 2020 which were short-lived have also been also observed at locations near the subsolar point from low latitudes in the southern hemisphere.

Prediction of Global Ionospheric TEC Based on Deep Learning

AbstractThe accurate prediction of ionospheric Total Electron Content (TEC) is important for global navigation satellite systems (GNSS), satellite communications and other space communications applications. In this study, a prediction model of global IGS‐TEC maps are established based on testing several different long short‐term memory (LSTM) network (LSTM)‐based algorithms to explore a direction that can effectively alleviate the increasing error with prediction time. We find that a Multi‐step auxiliary algorithm based prediction model performs best. It can effectively predict the global ionospheric IGS‐TEC in the next 6 days (the mean absolute deviation (MAD) and root mean square error (RMSE) are 2.485 and 3.511 TECU, respectively) compared to the IRI (the MAD and RMSE are 4.248 and 5.593 TECU). The analyses of four geomagnetic storm events are completely separate from the time range of the training set, so as to further validate the performance of the model. The International Reference Ionosphere model is used as a reference for the performance of our predictive model, and a rotated persistence is estimated by time‐shift algorithm of IGS‐TEC. The result suggests that the Multi‐step auxiliary prediction model has a good generalization performance and can have a relatively good stability and low error during a geomagnetic storm and quiet time.

Дневная электронная плотность на высотах ионосферного слоя F1 во время геомагнитных возмущений на станции Иркутск

We have examined variations in electron density Ne at ionospheric F1-layer heights during geomagnetic storms at the Irkutsk ionospheric station (52° N, 104° E). We have selected geomagnetic storms of varying intensity as well as quiet days for each event for the winter and summer seasons of 2003. We have analyzed the electron density in the daytime during geomagnetic storms at 150–190 km heights. Different effects of geomagnetic storms on Ne in different seasons at these heights were found. There is a slight change in the electron density during summer geomagnetic storms. On the other hand, there is an interesting effect in winter indicating the summer-winter asymmetry of the Ne response to the geomagnetic storms at these heights in 2003: in winter there is a significant influence of disturbances on Ne at a height of 190 km and a smaller effect at lower heights.