GPS normalization and preliminary modeling results of total electron content during a midlatitude space weather event

Objective: The diurnal variations of several ionospheric characteristics during the Space Weather Events of 4-10 September 2017, for Chilean latitudes, will be reported. Materials and Methods: Observations were made using a recently installed ionosonde at the Universidad de La Serena field station (29°52'S; 71°15’W). Also, reported is the total electron content determined using the upgraded Chilean network of dual-frequency Global Navigation Satellite Systems (GNSS) receivers. Results: Sudden ionospheric disturbances are described in terms of the minimum reflection frequency determined from ionosonde records. An attempt to derive the extent of the effect on high frequency propagation paths in the region is made using simultaneous ionosonde observations at other locations. The geomagnetic storm ionospheric effects are discussed in detail using the observed diurnal variation of maximum electron concentration (NmF2), virtual height of the F-region (h’F/F2) and Total Electron Content (TEC). These are complemented with the time-latitude variation of TEC for the 70°W meridian. Conclusion: It is found that large increases of NmF2, h’F/F2 and TEC observed during 8 September 2017 storm are well described in terms of the evolution of the Equatorial Ionospheric Anomaly (EIA) over the same time interval. Known physical mechanisms are suggested to explain most of the observations.

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INVESTIGATION OF THE RELATIONSHIP BETWEEN IONOSPHERIC TEC ANOMALY VARIATIONS AND FAULT TYPES BEFORE THE EARTHQUAKES

ISPRS Annals of Photogrammetry Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-annals-iv-4-w4-383-2017 ◽

2017 ◽

Vol IV-4/W4 ◽

pp. 383-388 ◽

Cited By ~ 1

Author(s):

M. Ulukavak ◽

M. Yalçınkaya

Keyword(s):

Total Electron Content ◽

Space Weather ◽

Environmental Changes ◽

Weather Conditions ◽

Earthquake Precursor ◽

Strike Slip ◽

Time Of Arrival ◽

Electron Content ◽

Total Electron ◽

Fault Type

Earthquakes are natural phenomena that shake the earth and cause many damage. Since the time of arrival of the earthquakes cannot be determined directly, some signs before the earthquake should be examined and interpreted by examining the environmental changes. One of the methods used for this is monitoring the ionospheric total electron content (TEC) changes in total electron content unit (TECU). GPS satellites have begun to be used as a means of monitoring ionospheric TEC anomalies before earthquakes since they began to be used as sensors around the world. In this study, three fault type (normal, thrust and strike-slip faulting) of 28 earthquakes with a magnitude greater than 7 (Mw) and the percentage changes of TEC anomalies before the earthquakes were investigated. The ionospheric TEC anomalies before the earthquake were calculated according to the 15-day running median statistical analysis method. Different solar and geomagnetic indices have been investigated to determine the active space weather conditions and quiet days before and after the earthquake. The TEC anomalies were determined during the quiet days before the earthquake by comparing the ionospheric anomalies that occurred before the earthquake after the determination of quiet days with the indices of the space weather conditions. The results show that there is a relationship between fault type and the earthquake precursor percentage changes and were determined as 47.6&thinsp;% TECU for regions where normal faulting, 50.4&thinsp;% TECU for regions where thrust faulting, and 44.2&thinsp;% TECU for regions where strike-slip faulting occurred, respectively.

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Forecasting the total electron content TEC of the ionosphere using space weather parameters

10.1109/wisee50203.2021.9613829 ◽

2021 ◽

Author(s):

Artem Kharakhashyan ◽

Olga Maltseva ◽

Galina Glebova

Keyword(s):

Total Electron Content ◽

Space Weather ◽

Electron Content ◽

Total Electron ◽

Weather Parameters

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Contribution to the Research of the Effects of Etna Volcano Activity on the Features of the Ionospheric Total Electron Content Behaviour

Remote Sensing ◽

10.3390/rs13051006 ◽

2021 ◽

Vol 13 (5) ◽

pp. 1006

Author(s):

Ivan Toman ◽

David Brčić ◽

Serdjo Kos

Keyword(s):

Total Electron Content ◽

Space Weather ◽

Volcanic Activity ◽

Reference Station ◽

Electron Content ◽

Etna Volcano ◽

Short Term ◽

Activity Increase ◽

Total Electron ◽

Ionospheric Dynamics

This research represents a contribution to the theory on the coupling of the volcanic activity and the ionospheric dynamics, represented by total electron content (TEC) patterns and their behaviour. The ionospheric response to the activity of the Etna volcano has been analysed using global navigation satellite system (GNSS)-derived TEC values, employing data from International GNSS Service (IGS) reference station near the volcano and on two distant IGS locations. Volcanic activity has been modelled using volcanic radiative power (VRP) data obtained by the Middle InfraRed Observation of Volcanic Activity (MIROVA) system. The estimated minimal night TEC values have been averaged over defined index days of the VRP increase. During the analysed period of 19 years, the volcano activity was categorised according to pre-defined criteria. The influence of current space weather and short-term solar activity on TEC near the volcano was systematically minimised. The results showed mean/median TEC increases of approximately +3 standard deviations from the overall mean values, with peak values placed approximately 5 days before the VRP increase and followed by general TEC depletion around the time of the actual volcanic activity increase. Additionally, TEC oscillation pattern was found over the volcano site with a half-period of 6.25 days. The main interpretation of results indicates that the volcanic activity has modified the ionospheric dynamics within the nearby ionospheric region before the actual VRP increase, and that the residual impact in the volcano’s surrounding area refers to terrestrial endogenous processes and air–earth currents. Those changes can be detected during criteria predefined in the research: during quiet space weather conditions, observing night-time TEC values and within the limits of low short-term solar influence.

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The influence of space weather on ionospheric total electron content during the 23rd solar cycle

Journal of Space Weather and Space Climate ◽

10.1051/swsc/2013047 ◽

2013 ◽

Vol 3 ◽

pp. A25 ◽

Cited By ~ 22

Author(s):

Nicolas Bergeot ◽

Ioanna Tsagouri ◽

Carine Bruyninx ◽

Juliette Legrand ◽

Jean-Marie Chevalier ◽

...

Keyword(s):

Solar Cycle ◽

Total Electron Content ◽

Space Weather ◽

Electron Content ◽

Total Electron ◽

23Rd Solar Cycle ◽

Ionospheric Total Electron Content

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An ionospheric index suitable for estimating the degree of ionospheric perturbations

Journal of Space Weather and Space Climate ◽

10.1051/swsc/2018008 ◽

2018 ◽

Vol 8 ◽

pp. A19 ◽

Cited By ~ 10

Author(s):

Volker Wilken ◽

Martin Kriegel ◽

Norbert Jakowski ◽

Jens Berdermann

Keyword(s):

Situation Awareness ◽

Space Weather ◽

Ionospheric Disturbance ◽

Solar Wind Speed ◽

Wolf Number ◽

Proton Density ◽

Electron Content ◽

Total Electron ◽

Radio Signals ◽

Space Weather Event

Space weather can strongly affect trans-ionospheric radio signals depending on the used frequency. In order to assess the strength of a space weather event from its origin at the sun towards its impact on the ionosphere a number of physical quantities need to be derived from scientific measurements. These are for example the Wolf number sunspot index, the solar flux density F10.7, measurements of the interplanetary magnetic field, the proton density, the solar wind speed, the dynamical pressure, the geomagnetic indices Auroral Electrojet, Kp, Ap and Dst as well as the Total Electron Content (TEC), the Rate of TEC, the scintillation indices S4 and σ(ϕ) and the Along-Arc TEC Rate index index. All these quantities provide in combination with an additional classification an orientation in a physical complex environment. Hence, they are used for brief communication of a simplified but appropriate space situation awareness. However, space weather driven ionospheric phenomena can affect many customers in the communication and navigation domain, which are still served inadequately by the existing indices. We present a new robust index, that is able to properly characterize temporal and spatial ionospheric variations of small to medium scales. The proposed ionospheric disturbance index can overcome several drawbacks of other ionospheric measures and might be suitable as potential driver for an ionospheric space weather scale.

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Determination of a non-perturbed reference for a new version of the disturbance ionosphere index

10.21203/rs.3.rs-51725/v1 ◽

2020 ◽

Author(s):

Giorgio Arlan da Silva Picanço ◽

Clezio Marcos Denardini ◽

Paulo Alexandre Bronzato Nogueira ◽

Paulo França Barbosa-Neto ◽

Láysa Cristina Araújo Resende ◽

...

Keyword(s):

Dispersion Coefficient ◽

Moving Average ◽

Electron Content ◽

Iri Model ◽

Weather Event ◽

Total Electron ◽

Reference Determination ◽

Space Weather Event

Abstract In the present work, we propose and evaluate a new method for the determination of a non-perturbed Total Electron Content (TEC) reference to apply it on a new version of the disturbance ionosphere index (DIX). This method is based on the calculation of a 3-hour moving average over the TEC obtained during a given reference day (named 3hMAQd method). In this context, the reference day is supposed to represent a quiet pattern considering geomagnetic and ionospheric features. To evaluate its performance, we compared the proposed method with TEC values obtained from monthly medians and the International Reference Ionosphere (IRI) model. The results are presented and discussed in terms of a dispersion coefficient between each method and the averaged TEC from the five quietest days of each month of 2015, over three Brazilian sites. Finally, we calculated the new DIX based on our proposed method and compared it with the original DIX values obtained during the extreme space weather event of St. Patrick’s Day magnetic storm (17–18 March 2015). Differences between the two DIX approaches are discussed to show the improvements in new DIX due to the application of the proposed non-perturbed reference. Moreover, results showed that the quality of the DIX calculation can be highly influenced by the non-perturbed reference determination. In this regard, the 3-hour moving average (3hMAQd) method showed to be a quite appropriate technique for the new DIX calculation, besides the 3-hour window matches with ordinary magnetic indices resolution (e.g. Kp and Ksa).

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Producing solar flare predictions using support vector machine (SVM) applied with ionospheric total electron content (TEC) global maps

10.5194/egusphere-egu2020-17319 ◽

2020 ◽

Author(s):

Saed Asaly ◽

Lee-Ad Gottlieb ◽

Yuval Reuveni

Keyword(s):

Solar Flare ◽

Total Electron Content ◽

Space Weather ◽

Support Vector ◽

Electron Content ◽

X Rays ◽

Total Electron ◽

Ionospheric Total Electron Content ◽

Weather Events ◽

Weather Research

<p>Ground and space-based remote sensing technology is one of the most useful tools for near-space environment studies and space weather research.&#160;During the last decade, a considerable amount of efforts in space weather research is being devoted for developing the ability to predict the exact time and location of space weather events such as solar flares and X-rays bursts.&#160;Despite the fact that most of the natural factors of&#160;such events can be modeled numerically, it is still a challenging task to produce accurate predications due to insufficient detailed and real&#8208;time data. Hence, space weather scientists are&#160;trying to learn patterns of previous&#160;data&#160;distribution using data mining and machine learning (ML) tools in order to accurately predict future space weather events.&#160;Here, we present a new methodology based on support vector machines (SVM) approach applied&#160;with ionospheric Total Electron Content (TEC) data, derived from worldwide GPS geodetic receiver network&#160;that predict&#160;B, C, M and X-class solar flare events.&#160;Experimental results indicate that the proposed method&#160;has the ability to predict solar flare events of X and M-class with 80-94% and 78-93% accuracy, respectively. However, it&#160;does not succeed in producing similar promising results&#160;for the small-size C and B-class flares.</p>

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