Level Of Geomagnetic Disturbance Research Articles

中国区域Dst指数数据集（2010–2022）

The axisymmetric disturbance of the Geomagnetic field caused by the ring current can be quantified using the Disturbance storm-time (Dst) index. Due to the asymmetry of the ring current during the storm time, there are s notable variations in the geomagnetic disturbance levels at different locations, which cannot be accurately reflected by the globally averaged Dst index. In this paper, we collected and calculated the geomagnetic data of the Chinese Meridian Project in Lasa, Chengdu, Wuhan and Hangzhou, so as to produce a dataset of Dst Indexes in China. This dataset includes Chinese Dst indexes from 2010 to 2022, with a total of 109,608 entries of data. In addition to the comprehensive collection of Dst indexes, this dataset can be used to better describe the geomagnetic disturbances in the Chinese region and is expected to furnish valuable data for regional space weather research in China.

Auroral oval reconstruction for historical geomagnetic storms in the 18th and 19th century

AbstractThe investigation of extreme space weather events can yield important information about the solar activity. Here, we present the reconstruction of the auroral oval position and size based on Bayesian inference for nine historical geomagnetic storms between 1716 and 1882, including the Carrington event in 1859, by using ground‐based observations, which enables us to derive the Kp index for historical events for the first time. The results for the latter show a very high level of geomagnetic disturbance (8.2 Kp 8.7, −929 nT Dst −1327 nT). Furthermore, we were able to derive the position of the pole in corrected geomagnetic coordinates, where especially the longitude is in good agreement with the position derived from the gufm1 model (Jackson et al., 2000). For the eight other historical storms, the Kp and Dst indices have been calculated here for the first time. In all cases, a very high Kp index was derived. The only exception is the geomagnetic storm from March 1716, which is, with a Kp index of , comparable with the St. Patrick's Day storm in 2015.

ОЦЕНКА ВЗАИМОСВЯЗИ МЕЖДУ ВОЗМУЩЕНИЯМИ ГЕОМАГНИТНОГО ФОНА И ОТВЕТОМ СО СТОРОНЫ СЕРДЕЧНО-СОСУДИСТОЙ СИСТЕМЫ С ИСПОЛЬЗОВАНИЕМ СТАНДАРТНЫХ СТАТИСТИЧЕСКИХ РЕШЕНИЙ

The purpose of this work is to present the mechanism of statistical data processing necessary to assess the sensitivity of the human cardiovascular system to geomagnetic disturbances. However, the approach proposed by us can be used not only to identify the relationship between the daily level of geomagnetic disturbance and the performance of the cardiovascular system, but also to solve other similar problems. Materials and methods, namely, standard statistical techniques, such as χ2, and Fisher’s exact test, allowed us to find the solution necessary to establish the relationship between the level of disturbance of the geomagnetic background (Kp-index) and indicators of the functional activity of the cardiovascular system (T-wave symmetry coefficient), when registering an ECG signal in the phase space of coordinates. This paper considers a case in which the data obtained from the study of the values o f the symmetry coefficient of the T wave of an anonymous patient appear, as well as a series of data reflecting fluctuations in the daily index of geomagnetic disturbance recorded daily for 24 days of the study. The result of the work carried out is a working and sufficiently original data processing algorithm that makes it possible to distinguish between people who are sensitive to geomagnetic background disturbances and those who are insensitive to this factor. In the case described as an example in this paper, a significant relationship was found between the presence of geomagnetic disturbance and deviations of the indicators of the activity of the cardiovascular system from normal values, of a functional nature, as evidenced by the significance level p<0.05 obtained for the χ2 criterion, and the exact criterion Fisher, whose value was 0.04977.

Study of the Average Ion Mass of the Dayside Magnetospheric Plasma

AbstractThe investigation of heavy ions dynamics and properties in the Earth's magnetosphere is still an important field of research as they play an important role in several space weather aspects. We present a statistical survey of the average ion mass in the dayside magnetosphere made comparing plasma mass density with electron number density measurements and focusing on both spatial and geomagnetic activity dependence. Field line resonance frequency observations across the European quasi‐Meridional Magnetometer Array, are used to infer the equatorial plasma mass density in the range of magnetic L‐shells 1.6–6.2. The electron number density is derived from local electric field measurements made on Van Allen Probes using the Neural‐network‐based Upper‐hybrid Resonance Determination algorithm. The analysis is conducted separately for the plasmasphere and the plasmatrough during favorable periods for which both the plasma parameters are observed simultaneously. We found that throughout the plasmasphere the average ion mass is ≃1 amu for a wide range of geomagnetic activity conditions, suggesting that the plasma mainly consist of hydrogen ions, without regard to the level of geomagnetic activity. Conversely, the plasmatrough is characterized by a variable composition, highlighting a heavy ion mass loading that increases with increasing levels of geomagnetic disturbance. During the most disturbed conditions, the average radial structure shows a broad maximum around 3–4 Earth radii, probably correlated with the accumulation of oxygen ions near the plasmapause. Those ions are mostly observed in the post‐dawn and pre‐dusk longitudinal sectors.

Fusion of wildlife tracking and satellite geomagnetic data for the study of animal migration

BackgroundMigratory animals use information from the Earth’s magnetic field on their journeys. Geomagnetic navigation has been observed across many taxa, but how animals use geomagnetic information to find their way is still relatively unknown. Most migration studies use a static representation of geomagnetic field and do not consider its temporal variation. However, short-term temporal perturbations may affect how animals respond - to understand this phenomenon, we need to obtain fine resolution accurate geomagnetic measurements at the location and time of the animal. Satellite geomagnetic measurements provide a potential to create such accurate measurements, yet have not been used yet for exploration of animal migration.MethodsWe develop a new tool for data fusion of satellite geomagnetic data (from the European Space Agency’s Swarm constellation) with animal tracking data using a spatio-temporal interpolation approach. We assess accuracy of the fusion through a comparison with calibrated terrestrial measurements from the International Real-time Magnetic Observatory Network (INTERMAGNET). We fit a generalized linear model (GLM) to assess how the absolute error of annotated geomagnetic intensity varies with interpolation parameters and with the local geomagnetic disturbance.ResultsWe find that the average absolute error of intensity is − 21.6 nT (95% CI [− 22.26555, − 20.96664]), which is at the lower range of the intensity that animals can sense. The main predictor of error is the level of geomagnetic disturbance, given by the Kp index (indicating the presence of a geomagnetic storm). Since storm level disturbances are rare, this means that our tool is suitable for studies of animal geomagnetic navigation. Caution should be taken with data obtained during geomagnetically disturbed days due to rapid and localised changes of the field which may not be adequately captured.ConclusionsBy using our new tool, ecologists will be able to, for the first time, access accurate real-time satellite geomagnetic data at the location and time of each tracked animal, without having to start new tracking studies with specialised magnetic sensors. This opens a new and exciting possibility for large multi-species studies that will search for general migratory responses to geomagnetic cues. The tool therefore has a potential to uncover new knowledge about geomagnetic navigation and help resolve long-standing debates.

A Substorm Injection Event and the Radiation Belt Structure Observed by Space Radiation Detectors onboard Next Generation Small Satellite-1 (NEXTSat-1)

In this paper, we present observations of the Space Radiation Detectors (SRDs) onboard the Next Generation Small Satellite-1 (NEXTSat-1) satellite. The SRDs, which are a part of the Instruments for the study of Stable/Storm-time Space (ISSS), consist of the Medium-Energy Particle Detector (MEPD) and the High-Energy Particle Detector (HEPD). The MEPD can detect electrons, ions, and neutrals with energies ranging from 20 to 400 keV, and the HEPD can detect electrons over an energy range from 0.35 to 2 MeV. In this paper, we report an event where particle flux enhancements due to substorm injections are clearly identified in the MEPD A observations at energies of tens of keV. Additionally, we report a specific example observation of the electron distributions over a wide energy range in which we identify electron spatial distributions with energies of tens to hundreds of keV from the MEPD and with energy ranging up to a few MeV from the HEPD in the slot region and outer radiation belts. In addition, for an ~1.5-year period, we confirm that the HEPD successfully observed the well-known outer radiation belt electron flux distributions and their variations in time and L shell in a way consistent with the geomagnetic disturbance levels. Last, we find that the inner edge of the outer radiation belt is mostly coincident with the plasmapause locations in L, somewhat more consistent at subrelativistic energies than at relativistic energies. Based on these example events, we conclude that the SRD observations are of reliable quality, so they are useful for understanding the dynamics of the inner magnetosphere, including substorms and radiation belt variations.

Comparison of the TEC-based ionospheric disturbance indices AATR and WTEC

Various ionospheric indices based on Global Navigation Satellite Systems data are widely used to study ionospheric disturbances. Two of them, produced from the Slant Total Electron Content measurements are studied in the paper: well known AATR index and relatively new WTEC index. A comparative statistical analysis of AATR and WTEC indices was made using ISTP SB RAS receivers network. We compared AATR and WTEC indices for studying small- and mid-scale ionospheric disturbances in different geophysical conditions and different geographical regions. The analysis was carried out at high, equatorial and middle latitudes during 2014–2017. It is shown that the contribution of diurnal variations of the background ionosphere to AATR is higher than to WTEC. It is shown that at high latitudes the WTEC and AATR dynamics correlates with the level of geomagnetic disturbance (Kp index). At mid-latitudes, the contribution of Vertical Total Electron Content prevails other effects. Preliminary statistical analysis of 25 earthquakes with magnitude >6.8 shown that effect of internal atmospheric waves prevails the effect of shock acoustic waves from ground vibrations. The analysis demonstrated that at low disturbance levels (WTEC < 0.1TECU) WTEC index looks more sensitive than AATR; at high disturbance levels, the AATR is nearly proportional to WTEC with a factor of 1.5min−1.

Comparison of adaptive neuro-fuzzy inference system and recurrent neural network in vertical total electron content forecasting

Accurate prediction of total electron content (TEC) is important for monitoring the behavior of the ionosphere and indeed a magnitude of interest to understand the properties and behavior of the Sun–Earth System. The conditions of this medium have a direct impact on a growing variety of critical technological infrastructure. This work presents a comparison between two different artificial neural networks (ANNs): an adaptive neuro-fuzzy inference system and nonlinear autoregressive neural network (NAR-NN) applied to TEC. Both ANNs where tested on four different geomagnetic locations on 4 1-week periods having a variety of geomagnetic disturbance levels. The effect of using different training period lengths and the system response for 60 and 30 min sampling rate TEC time series was investigated. NAR-NN shows a slightly better performance, being the higher difference during the greater perturbations. There is also a better response when sampling rates of 30 min are used.

ANALISIS INDEKS AKTIVITAS GEOMAGNET PADA SAAT BADAI GEOMAGNET 13 OKTOBER 2016

Badai geomagnet terjadi akibat aktivitas abnormal di matahari yang mempengaruhi intensitas angin matahari. Badai ini ditandai dengan perubahan nilai variasi harian medan magnet bumi yang besar, cepat dan tidak beraturan. Efek badai geomagnet di sekitar bumi dapat berdampak pada aktivitas manusia di luar angkasa dan di permukaan bumi. Salah satu kejadian badai geomagnet yang pernah tercatat adalah pada tanggal 13 Oktober 2016. Dalam penentuan tingkat gangguan geomagnet digunakan indeks geomagnet. Indeks geomagnet merupakan ukuran sederhana yang menggambarkan aktivitas magnetis yang berasal dari ionosfer dan magnetosfer bumi. Penelitian ini bertujuan untuk menganalisis indeks geomagnet ketika terjadi badai tanggal 13 Oktober 2016. Indeks geomagnet yang dianalisis antara lain indeks K, indeks A dan indeks Dst khususnya di wilayah Sumatera. Data yang digunakan adalah data variasi harian komponen H medan magnet bumi dari rekaman sensor magnetometer BMKG di Stasiun Gunungsitoli, Tuntungan, Sicincin, Liwa dan Tangerang. Berdasarkan hasil analisis dapat diidentifikasi jika badai geomagnet pada tanggal 13 Oktober 2016 tersebut termasuk kriteria badai geomagnet kuat jika ditinjau dari nilai Dst indeks yang menyentuh angka dibawah -100 nT.

Evaluation of a global model of ionospheric slab thickness for foF2 estimation during geomagnetic storm

&lt;p class="p0"&gt;This study aims to evaluate the performance of the global model of ionospheric slab thickness (GMIST) in terms of F2 layer critical frequency (foF2) estimation during geomagnetic disturbed conditions. Hourly values of foF2 as obtained from ionosonde stations located at equatorial, low- and mid-latitude regions are compared with the corresponding GMIST and IRI-STORM modeled values. For this purpose, the correlation coefficient, daily mean, root mean square error and improvement percentage are calculated at different regions and geomagnetic disturbance levels. The results show that GMIST is more accurate than IRI-STORM model in terms of foF2 estimation at low- and mid-latitude regions, while at equatorial areas GMIST is less accurate during geomagnetically disturbed and quiet conditions.&lt;/p&gt;

Strong E region ionization caused by the 1767 trail during the 2002 Leonids

AbstractIntensive E region ionization extending up to 140 km altitude and lasting for several hours was observed with the European Incoherent Scatter (EISCAT) UHF radar during the 2002 Leonids meteor shower maximum. The level of global geomagnetic disturbance as well as the local geomagnetic and auroral activity in northern Scandinavia were low during the event. Thus, the ionization cannot be explained by intensive precipitation. The layer was 30–40 km thick, so it cannot be classified as a sporadic E layer which are typically just a few kilometers wide. Incoherent scatter radars have not to date reported any notable meteor shower‐related increases in the average background ionization. The 2002 Leonids storm flux, however, was so high that it might have been able to induce such an event. The Chemical Ablation Model is used to estimate deposition rates of individual meteors. The resulting electron production, arising from hyperthermal collisions of ablated atoms with atmospheric molecules, is related to the predicted Leonid flux values and observed ionization on 19 November 2002. The EISCAT Svalbard Radar (ESR) located at some 1000 km north of the UHF site did not observe any excess ionization during the same period. The high‐latitude electrodynamic conditions recorded by the SuperDARN radar network show that the ESR was within a strongly drifting convection cell continuously fed by fresh plasma while the UHF radar was outside the polar convection region maintaining the ionization.

Response of polar mesosphere summer echoes to geomagnetic disturbances in the Southern and Northern Hemispheres: the importance of nitric oxide

Abstract. The relationship between polar mesosphere summer echoes (PMSE) and geomagnetic disturbances (represented by magnetic K indices) is examined. Calibrated PMSE reflectivities for the period May 2006–February 2012 are used from two 52.0/54.5 MHz radars located in Arctic Sweden (68° N, geomagnetic latitude 65°) and at two different sites in Queen Maud Land, Antarctica (73°/72° S, geomagnetic latitudes 62°/63°). In both the Northern Hemisphere (NH) and the Southern Hemisphere (SH) there is a strong increase in mean PMSE reflectivity between quiet and disturbed geomagnetic conditions. Mean volume reflectivities are slightly lower at the SH locations compared to the NH, but the position of the peak in the lognormal distribution of PMSE reflectivities is close to the same at both NH and SH locations, and varies only slightly with magnetic disturbance level. Differences between the sites, and between geomagnetic disturbance levels, are primarily due to differences in the high-reflectivity tail of the distribution. PMSE occurrence rates are essentially the same at both NH and SH locations during most of the PMSE season when a sufficiently low detection threshold is used so that the peak in the lognormal distribution is included. When the local-time dependence of the PMSE response to geomagnetic disturbance level is considered, the response in the NH is found to be immediate at most local times, but delayed by several hours in the afternoon sector and absent in the early evening. At the SH sites, at lower magnetic latitude, there is a delayed response (by several hours) at almost all local times. At the NH (auroral zone) site, the dependence on magnetic disturbance is highest during evening-to-morning hours. At the SH (sub-auroral) sites the response to magnetic disturbance is weaker but persists throughout the day. While the immediate response to magnetic activity can be qualitatively explained by changes in electron density resulting from energetic particle precipitation, the delayed response can largely be explained by changes in nitric oxide concentrations. Observations of nitric oxide concentration at PMSE heights by the Odin satellite support this hypothesis. Sensitivity to geomagnetic disturbances, including nitric oxide produced during these disturbances, can explain previously reported differences between sites in the auroral zone and those at higher or lower magnetic latitudes. The several-day lifetime of nitric oxide can also explain earlier reported discrepancies between high correlations for average conditions (year-by-year PMSE reflectivities and K indices) and low correlations for minute-to-day timescales.

Effects in cosmic rays in March 1991

Using the spectrographic global survey method, variations in the rigidity spectrum and anisotropy of galactic cosmic rays (March 1991) have been studied using data from ground-based observations of cosmic rays (CR) at the worldwide network of stations. Variations in geomagnetic cutoff rigidity (GCR) have been calculated. The paper also presents latitudinal GCR variations at certain moments of the considered period for different geomagnetic field disturbance levels. Calculation results of GCR variations have been compared with those of effect of the westward current flowing with a strength proportional to the latitude cosine along parallels on the sphere, for different radii of the current ring in the dipole field.

Determination of solar cycle variations of midlatitude ELF/VLF chorus and hiss via automated signal detection

[1] An automated algorithm for detecting chorus and hiss emissions in ground-based extremely low frequency/very low frequency (ELF/VLF) wave receiver data is developed and applied to 10 years of data collected at Palmer Station, Antarctica (L = 2.4, 50°S invariant latitude). The algorithm consists of three major processing steps. First, sferics and power line hum are removed from the broadband data. Second, individual events are detected and a set of 19 scalar event parameters are determined. Finally, on the basis of the parameters, detected events are categorized by a sequential pair of neural networks as either chorus, hiss, or noise. The detector runs on a modern 8-core computer at a speed of 350x real time. Results of training indicate that the neural networks are capable of differentiating between noise and emissions with a 92% success rate and between chorus and hiss with an 84% success rate. Data collected at Palmer from May 2000 to May 2010 were processed, and yearly and seasonal trends of chorus and hiss are analyzed. Yearly occurrence rates of chorus and hiss are strongly dependent on the geomagnetic disturbance level, as measured by Kp and AE, whereas seasonal occurrence rates are more strongly dependent on variations of the day/night terminator and associated variations in ionospheric absorption.

Geomagnetic activity effects on plasma sheet energy conversion

Abstract. In this article we use three years (2001, 2002, and 2004) of Cluster plasma sheet data to investigate what happens to localized energy conversion regions (ECRs) in the plasma sheet during times of high magnetospheric activity. By examining variations in the power density, E·J, where E is the electric field and J is the current density obtained by Cluster, we have studied the influence on Concentrated Load Regions (CLRs) and Concentrated Generator Regions (CGRs) from variations in the geomagnetic disturbance level as expressed by the Kp, the AE, and the Dst indices. We find that the ECR occurrence frequency increases during higher magnetospheric activities, and that the ECRs become stronger. This is true both for CLRs and for CGRs, and the localized energy conversion therefore concerns energy conversion in both directions between the particles and the fields in the plasma sheet. A higher geomagnetic activity hence increases the general level of energy conversion in the plasma sheet. Moreover, we have shown that CLRs live longer during magnetically disturbed times, hence converting more electromagnetic energy. The CGR lifetime, on the other hand, seems to be unaffected by the geomagnetic activity level. The evidence for increased energy conversion during geomagnetically disturbed times is most clear for Kp and for AE, but there are also some indications that energy conversion increases during large negative Dst. This is consistent with the plasma sheet magnetically mapping to the auroral zone, and therefore being more tightly coupled to auroral activities and variations in the AE and Kp indices, than to variations in the ring current region as described by the Dst index.

Spectral characteristics of protons in the Earth's plasmasheet: statistical results from Cluster CIS and RAPID

Abstract. We present a study of the spectral characteristics of protons in the Earth's plasma sheet for various geomagnetic disturbance levels. The study is based on about 5400 h of data combined from the Cluster RAPID and CIS instruments obtained during the tail season (July–October). The overall proton spectral shape is generally that of a κ distribution, that is, resembling a Maxwellian at lower energies which smoothly merges into a power-law tail at higher energies. The actual spectral long-term slope depends on various magnetospheric driver parameters, but is on average around 3.5–4. During disturbed conditions, such as geomagnetic storm or substorm periods, a shift in the characteristic energy is observed. For two individual storms, we also found a hardening of the spectra. Unlike the electron spectra, we do not see any significant local time dependence in the spectral slope, but we find higher average ion fluxes in the dusk side. We also do not find any direct response in the energy spectra to changes in the interplanetary magnetic field or solar wind dynamic pressure. This suggests that energization of the ions are mainly due to internal processes in the plasma sheet.

Geomagnetic storms and the occurrence of phase slips in the reception of GPS signals

We have investigated a dependence of the relative density of GPS phase slips on the geomagnetic disturbance level. The study is based on using Internet-available selected data from the global GPS network, with the simultaneously handled number of receiving stations ranging from 160 to 323. The analysis used four days from the period 1999-2000, with the values of the geomagnetic field disturbance index Dst from 5 to – 300 nT. During strong magnetic storms, the relative density of phase slips on mid-latitudes exceeds that for magnetically quiet days by one-two orders of magnitude as a minimum, and reaches a few percent of the total density of observations. Furthermore, the level of phase slips for the GPS satellites located on the sunward side of the Earth was by a factor of 5-10 larger compared with the opposite side of the Earth. The level of slips of L1 phase measurements at the fundamental GPS frequency is at least one order of magnitude lower than that in L1 – L2 measurements. The slips of L1 – L2 measurements are most likely to be caused by the high level of slips of L2 phase measurements at the auxiliary frequency. As an alternative, we developed and tested a new method for determining TEC variations using only data on the pseudo-range and phase measurements at fundamental frequency L1. The standard deviation of the TEC variations which were obtained in phase measurements at two frequencies, L 1 – L 2 , and at fundamental frequency L 1 , does not exceed 0.1 TECU, which permits this method to be used in strong disturbance conditions when phase slips at auxiliary frequency L2 are observed.

Geoefficiency of solar eruptive events

The sources of geomagnetic disturbances during 1999–2003 are discussed. The relation between geomagnetic activity and the rate of coronal mass ejections (CMEs), their parameters, and the dynamics of solar photospheric magnetic fields is considered. It is shown that during the reorganization of unipolar regions of the photospheric magnetic field, the number of CMEs increases and their parameters change. The geomagnetic disturbance level also increases in these periods.

Statistical properties of the most powerful solar and heliospheric disturbances

We present and discuss here the first version of a data base of extreme solar and heliospheric events. The data base contains now 87 extreme events mostly since 1940. An event is classified as extreme if one of the three critical parameters passed a lower limit. The critical parameters were the X-ray flux (parameter R), solar proton flux (parameter S) and geomagnetic disturbance level (parameter G). We find that the five strongest extreme events based on four variables (X-rays SEP, Dst, Ap) are completely separate except for the October 2003 event which is one the five most extreme events according to SEP, Dst and Ap. This underlines the special character of the October 2003 event, making it unique within 35 years. We also find that the events based on R and G are rather separate, indicating that the location of even extreme flares on the solar disk is important for geomagnetic effects. We also find that S = 3 events are not extreme in the same sense as R > 3 and G > 3 events, while S = 5 events are missing so far. This suggests that it might be useful to rescale the classification of SEP fluxes.

Plasma convection in the magnetotail lobes: statistical results from Cluster EDI measurements

Abstract. A major part of the plasma in the Earth's magnetotail is populated through transport of plasma from the solar wind via the magnetotail lobes. In this paper, we present a statistical study of plasma convection in the lobes for different directions of the interplanetary magnetic field and for different geomagnetic disturbance levels. The data set used in this study consists of roughly 340 000 one-minute vector measurements of the plasma convection from the Cluster Electron Drift Instrument (EDI) obtained during the period February 2001 to June 2007. The results show that both convection magnitude and direction are largely controlled by the interplanetary magnetic field (IMF). For a southward IMF, there is a strong convection towards the central plasma sheet with convection velocities around 10 km s−1. During periods of northward IMF, the lobe convection is almost stagnant. A By dominated IMF causes a rotation of the convection patterns in the tail with an oppositely directed dawn-dusk component of the convection for the northern and southern lobe. Our results also show that there is an overall persistent duskward component, which is most likely a result of conductivity gradients in the footpoints of the magnetic field lines in the ionosphere.