Ionospheric Response along Meridian for the Certain Storm Using TEC and foF2

For a long time, the equivalent ionospheric slab thickness τ has remained in the shadow of ionospheric main parameters: the maximum density, NmF2 (or the critical frequency, foF2), and the total electron content. Empirical global models have been developed for these two parameters. Recently, several global models of τ have appeared concurrently. This paper compares τ of the Neustrelitz equivalent slab thickness model (NSTM), with τ(IRI-Plas) of the IRI-Plas model, and τ(Appr) of the approximation model, constructed along the 30° E meridian using data from several ionosondes. The choice of the model of the best conformity with observational data was made, which was used to study the effects of space weather during several magnetic storms in March 2012. The effects included: (1) a transition from negative disturbances at high latitudes to positive ones at low latitudes, (2) the super-fountain effect, which had been revealed and explained in previous papers, (3) a deepening of the main ionospheric trough. The efficiency of using τ(Appr) and τ(IRI-Plas) models for studying the effects of space weather has been confirmed. The advantage of the τ(Appr) model is its closeness to real data. The advantage of the τ(IRI-Plas) model is the ability to determine foF2 without ionosondes. The efficiency of the NSTM model is insufficient for a role of a global τ model due to the accuracy decreasing with the increasing latitude.

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New GGOS JWG3 on Improved understanding of space weather events and their monitoring

10.5194/egusphere-egu2020-20492 ◽

2020 ◽

Author(s):

Alberto Garcia-Rigo ◽

Benedikt Soja

Keyword(s):

Electron Density ◽

Space Weather ◽

International Association ◽

Real Data ◽

Weather Conditions ◽

Electron Content ◽

Vertical Total Electron Content ◽

Total Electron ◽

Weather Events ◽

Space Geodetic Techniques

Multiple space geodetic techniques are capable of measuring effects caused by space weather events. In particular, space weather events can cause ionospheric disturbances correlated with variations in the vertical total electron content (VTEC) or the electron density (Ne) of the ionosphere.In this regard and in the context of the new Focus Area on Geodetic Space Weather Research within IAG&#8217;s GGOS (International Association of Geodesy; Global Geodetic Observing System), the Joint Working Group 3 on Improved understanding of space weather events and their monitoring by satellite missions has been created as part of IAG Commission 4, Sub-Commission 4.3 to run for the next four years.Within JWG3, we expect investigating different approaches to monitor space weather events using the data from different space geodetic techniques and, in particular, combinations thereof. Simulations will be beneficial to identify the contribution of different techniques and prepare for the analysis of real data. Different strategies for the combination of data will also be investigated, in particular, the weighting of estimates from different techniques in order to increase the performance and reliability of the combined estimates. Furthermore, existing algorithms for the detection and prediction of space weather events will be explored and improved to the extent possible. Furthermore, the geodetic measurement of the ionospheric electron density will be complemented by direct observations from the Sun gathered from existing spacecraft, such as SOHO, ACE, SDO, Parker Solar Probe, among others. The combination and joint evaluation of multiple datasets with the measurements of space geodetic observation techniques (e.g. geodetic VLBI) is still a great challenge. In addition, other indications for solar activity - such as the F10.7 index on solar radio flux, SOLERA as EUV proxy or rate of Global Electron Content (dGEC)-, provide additional opportunities for comparisons and validation.Through these investigations, we will identify the key parameters useful to improve real-time/prediction of ionospheric/plasmaspheric VTEC, Ne estimates, as well as ionospheric perturbations, in case of extreme solar weather conditions. In general, we will gain a better understanding of space weather events and their effect on Earth&#8217;s atmosphere and near-Earth environment.

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The ionospheric response to perturbation electric fields during the onset phase of geomagnetic storms

Canadian Journal of Physics ◽

10.1139/p92-093 ◽

1992 ◽

Vol 70 (7) ◽

pp. 575-581 ◽

Cited By ~ 13

Author(s):

N. Jakowski ◽

A. Jungstand ◽

K. Schlegel ◽

H. Kohl ◽

K. Rinnert

Keyword(s):

Total Electron Content ◽

Electric Fields ◽

Geomagnetic Storms ◽

Slab Thickness ◽

Electron Content ◽

Total Electron ◽

Total Electron Content Data ◽

Critical Frequency Fof2 ◽

Eiscat Radar ◽

Onset Phase

The generation and propagation of ionospheric storms are studied by analyzing EISCAT radar, and vertical-sounding and total-electron-content data obtained under different geophysical conditions. Both, case studies as well as the average storm pattern of percentage deviations of different ionospheric parameters from their corresponding reference values such as total electron content, F2-layer critical frequency foF2, F2-layer height hmF2, and slab thickness τ indicate the action of a perturbation electric field during the first few hours during the onset phase of geomagnetic storms. Considering the onset phase of the storm on July 28–29, 1987 evidence has been found that high-latitude electric fields may penetrate to lower latitudes before the ring current has developed. In most cases this process is accompanied by a positive phase in the upper ionosphere and F2-layer ionization. Different mechanisms are assumed to be responsible for the daytime and nighttime behaviour, respectively. The negative phase propagates equatorward with velocities in the order of 70–350 m s−1 following a strong heating of the thermosphere and ionosphere due to the auroral electrojet.

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Obtaining Ionospheric Conditions according to Data of Navigation Satellites

International Journal of Antennas and Propagation ◽

10.1155/2015/804791 ◽

2015 ◽

Vol 2015 ◽

pp. 1-16 ◽

Cited By ~ 3

Author(s):

Olga Maltseva ◽

Natalia Mozhaeva

Keyword(s):

Critical Frequency ◽

Bench Mark ◽

Slab Thickness ◽

Electron Content ◽

Efficiency Coefficient ◽

Low Latitude ◽

Total Electron ◽

Average Value ◽

Middle Latitudes ◽

Critical Frequency Fof2

Defining ionospheric conditions, the deviation of the observational value of the total electron content TEC(obs), measured by means of navigation satellites, from a median is a bench mark. According to more than 40 ionospheric stations during April 2014 it is shown that synchronism of change of deviations of TEC and critical frequency foF2 of the ionosphere is kept under quiet and moderate disturbed conditions. This fact allows to use a median of the equivalent slab thicknessτ(med) as a reliable calibration factor to calculate foF2 from TEC(obs). The efficiency coefficient of joint use ofτ(med) and TEC(obs) changes from 1.5 to 4 with average value 2.2 across the globe. The highest coefficient corresponds to middle latitudes, however the estimations obtained for high- and low-latitude areas indicate possibility to useτ(med) and TEC(obs) in these areas.

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The Use of the Total Electron Content Measured by Navigation Satellites to Estimate Ionospheric Conditions

International Journal of Navigation and Observation ◽

10.1155/2016/7016208 ◽

2016 ◽

Vol 2016 ◽

pp. 1-15 ◽

Cited By ~ 2

Author(s):

Olga Maltseva ◽

Natalia Mozhaeva

Keyword(s):

Total Electron Content ◽

Critical Frequency ◽

Global Scale ◽

Maximum Density ◽

Slab Thickness ◽

Electron Content ◽

Total Electron ◽

Adequate Accuracy ◽

Critical Frequency Fof2 ◽

Experimental Values

Measurements of delays of the signals radiated by transmitters of navigational satellites allow us to obtain the total electron content (TEC). In addition, measurements of TEC allow solving problems such as development of local, regional, and global models of TEC and correction of ionospheric delay for increasing accuracy of positioning. Now, it is possible to set the task of calculation of critical frequency foF2 with the use of experimental values of TEC in a global scale. For this purpose it is necessary to know an equivalent slab thickness of the ionosphere τ which is a coefficient of proportionality between TEC and a maximum density of the ionosphere. The present paper is devoted to the analysis of investigation and utilization of this parameter. It is shown that (1) existing models of τ are not empirical and not always can provide an adequate accuracy of foF2 calculation, (2) experimental median τ(med) provides much larger accuracy of foF2 calculation than the empirical model and variations from day to day and allows filling gaps in the ionosonde data, and (3) it is possible to use a hyperbolic approximation and coefficient K(τ) for development of a global model of τ.

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Changes in the middle and upper atmosphere parameters during the January 2013 sudden stratospheric warming

Solnechno-Zemnaya Fizika ◽

10.12737/szf-44201807 ◽

2018 ◽

Vol 4 (4) ◽

pp. 62-75

Author(s):

Анна Ясюкевич ◽

Anna Yasyukevich ◽

Максим Клименко ◽

Maksim Klimenko ◽

Юрий Куликов ◽

...

Keyword(s):

Molecular Nitrogen ◽

Stratospheric Ozone ◽

Upper Atmosphere ◽

Electron Content ◽

Stratospheric Warming ◽

Sudden Stratospheric Warming ◽

Total Electron ◽

Model Calculations ◽

Long Time ◽

Critical Frequency Fof2

We present the results of complex obser-vations of various parameters of the middle and upper atmosphere over Siberia in December 2012 – January 2013, during a major sudden stratospheric warming (SSW) event. We analyze variations in ozone concentration from microwave measurements, in stratosphere and lower mesosphere temperatures from lidar and satellite measurements, in the F2-layer critical frequency (foF2), in the total electron content (TEC), as well as in the ratio of concentrations of atomic oxygen to molecular nitrogen (O/N2) in the thermosphere. To interpret the observed disturbances in the upper atmosphere, the experimental measurements are compared with the results of model calculations obtained with the Global Self-consistent Model of Thermosphere—Ionosphere—Protonosphere (GSM TIP). The response of the upper atmosphere to the SSW event is shown to be a decrease in foF2 and TEC during the evolution of the warming event and a prolonged increase in O/N2, foF2, and TEC after the SSW maximum. For the first time, we observe the relation between the increase in stratospheric ozone, thermospheric O/N2, and ionospheric electron density for a fairly long time (up to 20 days) after the SSW maximum at midlatitudes.

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Changes in the middle and upper atmosphere parameters during the January 2013 sudden stratospheric warming

Solar-Terrestrial Physics ◽

10.12737/stp-44201807 ◽

2018 ◽

Vol 4 (4) ◽

pp. 48-58 ◽

Cited By ~ 4

Author(s):

Анна Ясюкевич ◽

Anna Yasyukevich ◽

Максим Клименко ◽

Maksim Klimenko ◽

Юрий Куликов ◽

...

Keyword(s):

Molecular Nitrogen ◽

Stratospheric Ozone ◽

Upper Atmosphere ◽

Electron Content ◽

Stratospheric Warming ◽

Sudden Stratospheric Warming ◽

Total Electron ◽

Model Calculations ◽

Long Time ◽

Critical Frequency Fof2

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Latitudinal Dependence of the Ionospheric Slab Thickness for Estimation of Ionospheric Response to Geomagnetic Storms

Atmosphere ◽

10.3390/atmos12020164 ◽

2021 ◽

Vol 12 (2) ◽

pp. 164

Author(s):

Maria A. Sergeeva ◽

Olga A. Maltseva ◽

Ramon Caraballo ◽

Juan Americo Gonzalez-Esparza ◽

Pedro Corona-Romero

Keyword(s):

Space Weather ◽

Geomagnetic Storms ◽

Ionospheric Disturbance ◽

Slab Thickness ◽

Electron Content ◽

General Tendency ◽

Total Electron ◽

Ionospheric Response ◽

Latitudinal Dependence ◽

Longitudinal Sector

The changes in the ionosphere during geomagnetic disturbances is one of the prominent Space Weather effects on the near-Earth environment. The character of these changes can differ significantly at different regions on the Earth. We studied ionospheric response to five geomagnetic storms of March 2012, using data of Total Electron Content (TEC) and F2-layer critical frequency (foF2) along the meridian of 70° W in the Northern Hemisphere. There are few ionosondes along this longitudinal sector: in Thule, Sondrestrom, Millstone Hill and Puerto Rico. The lacking foF2 values between the ionosondes were determined by using the experimental latitudinal dependences of the equivalent ionospheric slab thickness and TEC values. During geomagnetic storms, the following features were characteristic: (a) two-hours (or longer in one case) delay of the ionospheric response to disturbances, (b) the more prominent mid-latitude trough and (c) the sharper border of the EIA northern crest. During four storms of 7–17 March, the general tendency was the transition from negative disturbances at high latitudes to intense positive disturbances at low latitudes. During the fifth storm, the negative ionospheric disturbance controlled by O/N2 change was masked by the overall prolonged electron density increase during 21–31 March. The multiple correlation analysis revealed the latitudinal dependence of dominant Space Weather parameters’ impacts on foF2.

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Could the Beirut Explosion perturb the Ionosphere? Pre-results Using TEC-GNSS observations.

10.5194/egusphere-egu21-8990 ◽

2021 ◽

Author(s):

Mohamed Freeshah ◽

Xiaohong Zhang ◽

Erman Şentürk ◽

Xiaodong Ren ◽

Muhammad Arqim Adil ◽

...

Keyword(s):

Ammonium Nitrate ◽

Space Weather ◽

Global Navigation Satellite Systems ◽

Electron Content ◽

Free Electrons ◽

Total Electron ◽

Satellite Systems ◽

Underground Nuclear Explosions ◽

Nuclear Explosions ◽

Global Navigation Satellite

Natural hazards such as shallow earthquakes and volcanic explosions are known to generate acoustic and gravity waves at infrasonic velocity to propagate in the atmosphere layers. These waves could induce the layers of the ionosphere by change the electron density based on the neutral particles and free electrons coupling. Recently, some studies have dealt with some manmade hazards such as buried explosions and underground nuclear explosions which could cause a trigger to the ionosphere. The Global Navigation Satellite Systems (GNSS) provide a good way to measure ionospheric total electron content (TEC) through the line of sight (LOS) from satellite to receiver. The carrier-to-code leveling (CCL) technique is carried out for each continuous arc where CCL eliminates potential ambiguity influence and it degrades the pseudo-range noise. Meanwhile, the CCL retains high precision in the carrier-phase. In this study, we focus on the Beirut Explosion on August 4, 2020, to check slant TEC (STEC) variations that may be associated with the blast of Beirut Port. The TECs were analyzed through the Morlet wavelet to check the possible ionospheric response to the blast. An acoustic&#8208;gravity wave could be generated by the event which could disturb the ionosphere through coupling between solid earth-atmosphere-ionosphere during the explosion. To verify TEC disturbances are not associated with space weather, disturbance storm-time (Dst), and Kp indices were investigated before, during, and after the explosion. The steady-state of space weather before and during the event indicated that the observed variations of TEC sequences were caused by the ammonium nitrate explosion. There was a large initial explosion, followed by a series of smaller blasts, about ~30 seconds, a colossal explosion has happened, a supersonic blast wave radiating through Beirut City. As a result of the chemistry behind ammonium nitrate&#8217;s explosive, a mushroom cloud was sent into the air. We suggest that these different explosions in strength and time could be the reason for different time arrival of the detected ionospheric disturbances over GNSS ground-based stations.

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Data Assimilation for Ionospheric Space-Weather Forecasting in the Presence of Model Bias

Frontiers in Applied Mathematics and Statistics ◽

10.3389/fams.2021.679477 ◽

2021 ◽

Vol 7 ◽

Author(s):

Juan Durazo ◽

Eric J. Kostelich ◽

Alex Mahalov

Keyword(s):

Data Assimilation ◽

Space Weather ◽

Bias Correction ◽

Geomagnetic Storms ◽

Circulation Model ◽

Storm Event ◽

Electron Content ◽

Systematic Bias ◽

Total Electron ◽

Mean Square Errors

The dynamics of many models of physical systems depend on the choices of key parameters. This paper describes the results of some observing system simulation experiments using a first-principles model of the Earth’s ionosphere, the Thermosphere Ionosphere Electrodynamics Global Circulation Model (TIEGCM), which is driven by parameters that describe solar activity, geomagnetic conditions, and the state of the thermosphere. Of particular interest is the response of the ionosphere (and predictions of space weather generally) during geomagnetic storms. Errors in the overall specification of driving parameters for the TIEGCM (and similar dynamical models) may be especially large during geomagnetic storms, because they represent significant perturbations away from more typical interactions of the earth-sun system. Such errors can induce systematic biases in model predictions of the ionospheric state and pose difficulties for data assimilation methods, which attempt to infer the model state vector from a collection of sparse and/or noisy measurements. Typical data assimilation schemes assume that the model produces an unbiased estimate of the truth. This paper tests one potential approach to handle the case where there is some systematic bias in the model outputs. Our focus is on the TIEGCM when it is driven with solar and magnetospheric inputs that are systematically misspecified. We report results from observing system experiments in which synthetic electron density vertical profiles are generated at locations representative of the operational FormoSat-3/COSMIC satellite observing platforms during a moderate (G2, Kp = 6) geomagnetic storm event on September 26–27, 2011. The synthetic data are assimilated into the TIEGCM using the Local Ensemble Transform Kalman Filter with a state-augmentation approach to estimate a small set of bias-correction factors. Two representative processes for the time evolution of the bias in the TIEGCM are tested: one in which the bias is constant and another in which the bias has an exponential growth and decay phase in response to strong geomagnetic forcing. We show that even simple approximations of the TIEGCM bias can reduce root-mean-square errors in 1-h forecasts of total electron content (a key ionospheric variable) by 20–45%, compared to no bias correction. These results suggest that our approach is computationally efficient and can be further refined to improve short-term predictions (∼1-h) of ionospheric dynamics during geomagnetic storms.

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Modeling of TEC over the Iberian Peninsula using PCA decomposition and multiple linear regression on space weather parameters

10.5194/egusphere-egu21-7393 ◽

2021 ◽

Author(s):

Anna Morozova ◽

Tatiana Barlyaeva ◽

Teresa Barata

Keyword(s):

Linear Regression ◽

Multiple Linear Regression ◽

Iberian Peninsula ◽

Space Weather ◽

Multiple Linear Regression Model ◽

Principal Component ◽

Electron Content ◽

Time Lags ◽

Total Electron ◽

Weather Parameters

The total electron content (TEC) over the Iberian Peninsula was modeled using a three-step procedure. At the 1st step the TEC series is decomposed using the principal component analysis (PCA) into several daily modes. Then, the amplitudes of those daily modes is fitted by a multiple linear regression model (MRM) using several types of space weather parameters as regressors. Finally, the TEC series is reconstructed using the PCA daily modes and MRM fitted amplitudes.The advantage of such approach is that seasonal variations of the TEC daily modes are automatically extracted by PCA. As space weather parameters we considered proxies for the solar UV and XR fluxes, number of the solar flares, parameters of the solar wind and the interplanetary magnetic field, and geomagnetic indices. Different time lags and combinations of the regressors are tested.The possibility to use such TEC models for forecasting was tested. Also, a possibility to use neural networks (NN) instead of MRM is studied.

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