Articles | Volume 37, issue 5
https://doi.org/10.5194/angeo-37-843-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Special issue:
https://doi.org/10.5194/angeo-37-843-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Regular paper
| 
23 Sep 2019
Regular paper |
| 23 Sep 2019
| 23 Sep 2019
Strong influence of solar X-ray flares on low-frequency electromagnetic signals in middle latitudes
Alexander Rozhnoi
Schmidt Institute of Physics of the Earth of RAS, 10-1 B. Gruzinskaya St., 123242 Moscow, Russia
Maria Solovieva
Schmidt Institute of Physics of the Earth of RAS, 10-1 B. Gruzinskaya St., 123242 Moscow, Russia
Viktor Fedun
CORRESPONDING AUTHOR
Plasma Dynamics Group, Department of Automatic Control and Systems Engineering, University of Sheffield, Mappin 6 St., Sheffield, S1 3JD, UK
Peter Gallagher
Trinity College Dublin, the University of Dublin, Dublin 2, Ireland
Joseph McCauley
Trinity College Dublin, the University of Dublin, Dublin 2, Ireland
Mohammed Y. Boudjada
Space Research Institute of AAS, Schmiedlstraße 6, 8042 Graz, Austria
Sergiy Shelyag
School of Information Technology, Deakin University, Geelong, Australia
Hans U. Eichelberger
Space Research Institute of AAS, Schmiedlstraße 6, 8042 Graz, Austria
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Yuriy Rapoport, Vladimir Grimalsky, Viktor Fedun, Oleksiy Agapitov, John Bonnell, Asen Grytsai, Gennadi Milinevsky, Alex Liashchuk, Alexander Rozhnoi, Maria Solovieva, and Andrey Gulin
Ann. Geophys., 38, 207–230, https://doi.org/10.5194/angeo-38-207-2020, https://doi.org/10.5194/angeo-38-207-2020, 2020
Short summary
Short summary
The paper analytically and numerically treats the new theoretical basis for ground-based and satellite monitoring of the most powerful processes in the lower atmosphere and Earth (hurricanes, earthquakes, etc.), solar-wind magnetosphere (magnetic storms) and ionosphere (lightning discharges, thunderstorms, etc.). This can be provided by the determination of phases and amplitudes of radio waves in the Earth and ionosphere. In perspective, damage from the natural disasters can be decreased.
A. Rozhnoi, M. Solovieva, V. Fedun, M. Hayakawa, K. Schwingenschuh, and B. Levin
Ann. Geophys., 32, 1455–1462, https://doi.org/10.5194/angeo-32-1455-2014, https://doi.org/10.5194/angeo-32-1455-2014, 2014
A. Rozhnoi, M. Solovieva, B. Levin, M. Hayakawa, and V. Fedun
Nat. Hazards Earth Syst. Sci., 14, 2671–2679, https://doi.org/10.5194/nhess-14-2671-2014, https://doi.org/10.5194/nhess-14-2671-2014, 2014
Patrick H. M. Galopeau, Ashanthi S. Maxworth, Mohammed Y. Boudjada, Hans U. Eichelberger, Mustapha Meftah, Pier F. Biagi, and Konrad Schwingenschuh
Geosci. Instrum. Method. Data Syst., 12, 231–237, https://doi.org/10.5194/gi-12-231-2023, https://doi.org/10.5194/gi-12-231-2023, 2023
Short summary
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We present the implementation of a VLF/LF network to search for earthquake electromagnetic precursors. The proposed system will deliver a steady stream of real-time amplitude and phase measurements as well as a daily recording VLF/LF data set. The first implementation of the system was done in Graz, Austria. The second one will be in Guyancourt (France), with a third one in Réunion (France) and a fourth one in Moratuwa (Sri Lanka).
Mohammed Y. Boudjada, Hans U. Eichelberger, Emad Al-Haddad, Werner Magnes, Patrick H. M. Galopeau, Xuemin Zhang, Andreas Pollinger, and Helmut Lammer
Adv. Radio Sci., 20, 77–84, https://doi.org/10.5194/ars-20-77-2023, https://doi.org/10.5194/ars-20-77-2023, 2023
Short summary
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We investigate the variation of the electric power density linked to VLF signals emitted by NWC transmitter. The power density measurements were detected by the Electric Field Detector (EFD) instrument onboard CSES satellite above NWC station and its conjugate region (CR). The beam is subject to disturbances and modulations in CR. Above the NWC station, the beam can be considered as a hollow cone with inconsistency dependence of the half-opening angle on the electric power density.
Anatoliy Lozbin, Viktor Fedun, and Olga Kryakunova
Ann. Geophys., 40, 55–65, https://doi.org/10.5194/angeo-40-55-2022, https://doi.org/10.5194/angeo-40-55-2022, 2022
Short summary
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Detection of Ionosphere Anomalies (DIA) for detection, identification, and analysis of ionosphere anomalies from satellite spectrograms and time series row data from instruments onboard the DEMETER satellite was designed. Using this software, the analyses of ionosphere parameter variations caused by various factors are provided. The scientific data processing and visualization technologies used in the development of DIA can be used in the creation of software for other scientific space missions.
Mohammed Y. Boudjada, Ahmed Abou el-Fadl, Patrick H. M. Galopeau, Eimad Al-Haddad, and Helmut Lammer
Adv. Radio Sci., 18, 83–87, https://doi.org/10.5194/ars-18-83-2020, https://doi.org/10.5194/ars-18-83-2020, 2020
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We investigate the solar Type III radio bursts recorded at about 10 AU by Cassini spacecraft. More than 300 bursts have been recorded by the RPWS experiment in the time interval from 01 Jan. 2008 to 31 Dec. 2014. We show that the solar Type III occurrence is mainly depending on the solar activity and also exhibits maxima and minima of detection. The source location of such solar bursts is the interplanetary medium because the dominant emission appears at frequency lower than 2.3 MHz.
Mohammed Y. Boudjada, Patrick H. M. Galopeau, Sami Sawas, Valery Denisenko, Konrad Schwingenschuh, Helmut Lammer, Hans U. Eichelberger, Werner Magnes, and Bruno Besser
Ann. Geophys., 38, 765–774, https://doi.org/10.5194/angeo-38-765-2020, https://doi.org/10.5194/angeo-38-765-2020, 2020
Short summary
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In this paper, we report on observations of frequency-banded wave emissions by ICE (Instrument Champ Électrique) on board DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions). We distinguish two components: positive and negative frequency drift rates and multiple spaced frequency bands near the magnetic equatorial plane. We show and discuss the non-free-space DEMETER frequency-banded emissions and the free-space terrestrial kilometric radiation.
Yuriy Rapoport, Vladimir Grimalsky, Viktor Fedun, Oleksiy Agapitov, John Bonnell, Asen Grytsai, Gennadi Milinevsky, Alex Liashchuk, Alexander Rozhnoi, Maria Solovieva, and Andrey Gulin
Ann. Geophys., 38, 207–230, https://doi.org/10.5194/angeo-38-207-2020, https://doi.org/10.5194/angeo-38-207-2020, 2020
Short summary
Short summary
The paper analytically and numerically treats the new theoretical basis for ground-based and satellite monitoring of the most powerful processes in the lower atmosphere and Earth (hurricanes, earthquakes, etc.), solar-wind magnetosphere (magnetic storms) and ionosphere (lightning discharges, thunderstorms, etc.). This can be provided by the determination of phases and amplitudes of radio waves in the Earth and ionosphere. In perspective, damage from the natural disasters can be decreased.
Yuriy G. Rapoport, Oleg K. Cheremnykh, Volodymyr V. Koshovy, Mykola O. Melnik, Oleh L. Ivantyshyn, Roman T. Nogach, Yuriy A. Selivanov, Vladimir V. Grimalsky, Valentyn P. Mezentsev, Larysa M. Karataeva, Vasyl. M. Ivchenko, Gennadi P. Milinevsky, Viktor N. Fedun, and Eugen N. Tkachenko
Ann. Geophys., 35, 53–70, https://doi.org/10.5194/angeo-35-53-2017, https://doi.org/10.5194/angeo-35-53-2017, 2017
Short summary
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Before many catastrophic phenomena such as earthquakes, sound is generated at a very low frequency. It is already established that it can disturb the upper layer of the atmosphere – the ionosphere. Control of disasters' precursors is important. Using the unique, powerful sound generator, whose loudness is comparable to an ascending jet, we have constructed the theory and conducted a series of experiments trying to model acoustic action of disasters on the ionosphere.
O. Onishchenko, O. Pokhotelov, W. Horton, and V. Fedun
Ann. Geophys., 33, 1343–1347, https://doi.org/10.5194/angeo-33-1343-2015, https://doi.org/10.5194/angeo-33-1343-2015, 2015
A. Rozhnoi, M. Solovieva, V. Fedun, M. Hayakawa, K. Schwingenschuh, and B. Levin
Ann. Geophys., 32, 1455–1462, https://doi.org/10.5194/angeo-32-1455-2014, https://doi.org/10.5194/angeo-32-1455-2014, 2014
M. Y. Boudjada, P. H. M. Galopeau, M. Maksimovic, and H. O. Rucker
Adv. Radio Sci., 12, 167–170, https://doi.org/10.5194/ars-12-167-2014, https://doi.org/10.5194/ars-12-167-2014, 2014
A. Rozhnoi, M. Solovieva, B. Levin, M. Hayakawa, and V. Fedun
Nat. Hazards Earth Syst. Sci., 14, 2671–2679, https://doi.org/10.5194/nhess-14-2671-2014, https://doi.org/10.5194/nhess-14-2671-2014, 2014
M. Y. Boudjada, P. H. M. Galopeau, S. Sawas, and H. Lammer
Ann. Geophys., 32, 1119–1128, https://doi.org/10.5194/angeo-32-1119-2014, https://doi.org/10.5194/angeo-32-1119-2014, 2014
Yu. Rapoport, Yu. Selivanov, V. Ivchenko, V. Grimalsky, E. Tkachenko, A. Rozhnoi, and V. Fedun
Ann. Geophys., 32, 449–463, https://doi.org/10.5194/angeo-32-449-2014, https://doi.org/10.5194/angeo-32-449-2014, 2014
O. Onishchenko, O. Pokhotelov, W. Horton, A. Smolyakov, T. Kaladze, and V. Fedun
Ann. Geophys., 32, 181–186, https://doi.org/10.5194/angeo-32-181-2014, https://doi.org/10.5194/angeo-32-181-2014, 2014
A. Kryshtal, S. Gerasimenko, A. Voitsekhovska, and V. Fedun
Ann. Geophys., 31, 2193–2200, https://doi.org/10.5194/angeo-31-2193-2013, https://doi.org/10.5194/angeo-31-2193-2013, 2013
S. Zharkov, S. Shelyag, V. Fedun, R. Erdélyi, and M. J. Thompson
Ann. Geophys., 31, 1357–1364, https://doi.org/10.5194/angeo-31-1357-2013, https://doi.org/10.5194/angeo-31-1357-2013, 2013
O. Onishchenko, O. Pokhotelov, and V. Fedun
Ann. Geophys., 31, 459–462, https://doi.org/10.5194/angeo-31-459-2013, https://doi.org/10.5194/angeo-31-459-2013, 2013
Related subject area
Subject: Earth's ionosphere & aeronomy | Keywords: Ionospheric disturbances
Effects of the super-powerful tropospheric western Pacific phenomenon of September–October 2018 on the ionosphere over China: results from oblique sounding
Ionospheric effects of the 5–6 January 2019 eclipse over the People's Republic of China: results from oblique sounding
Study of the equatorial and low-latitude total electron content response to plasma bubbles during solar cycle 24–25 over the Brazilian region using a Disturbance Ionosphere indeX
Diagnostic study of geomagnetic storm-induced ionospheric changes over very low-frequency signal propagation paths in the mid-latitude D region
Complex analysis of the ionosphere variations during the geomagnetic storm at 20 January 2010 performed by Detection of Ionosphere Anomalies (DIA) software and DEMETER satellite data
Dynamic processes in the magnetic field and in the ionosphere during the 30 August–2 September 2019 geospace storm: influence on high frequency radio wave characteristics
Tomographic imaging of a large-scale travelling ionospheric disturbance during the Halloween storm of 2003
Ionospheric anomalies associated with the Mw 7.3 Iran–Iraq border earthquake and a moderate magnetic storm
Model of the propagation of very low-frequency beams in the Earth–ionosphere waveguide: principles of the tensor impedance method in multi-layered gyrotropic waveguides
A case study of the large-scale traveling ionospheric disturbances in the eastern Asian sector during the 2015 St. Patrick's Day geomagnetic storm
Geomagnetic conjugate observations of ionospheric disturbances in response to a North Korean underground nuclear explosion on 3 September 2017
Emergence of a localized total electron content enhancement during the severe geomagnetic storm of 8 September 2017
Mitigation of ionospheric signatures in Swarm GPS gravity field estimation using weighting strategies
PPP-based Swarm kinematic orbit determination
Impact of magnetic storms on the global TEC distribution
Leonid F. Chernogor, Kostiantyn P. Garmash, Qiang Guo, Victor T. Rozumenko, and Yu Zheng
Ann. Geophys., 41, 173–195, https://doi.org/10.5194/angeo-41-173-2023, https://doi.org/10.5194/angeo-41-173-2023, 2023
Short summary
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The receiver at the Harbin Engineering University and eight surrounding HF broadcast stations ~1000 km observed the response in the ionospheric electron density to the activity of Typhoon Kong-rey (30 September–6 October 2018). On 1–2 and 5–6 October 2018, the 20 min to 60 min period quasi-sinusoidal variations in the electron density with an amplitude of 0.4 % to 6 % resulted in 0.1 Hz to 0.5 Hz amplitude Doppler shift variations, a factor of 2–3 increase as compared to a quiet time reference.
Leonid F. Chernogor, Kostyantyn P. Garmash, Qiang Guo, Victor T. Rozumenko, and Yu Zheng
Ann. Geophys., 40, 585–603, https://doi.org/10.5194/angeo-40-585-2022, https://doi.org/10.5194/angeo-40-585-2022, 2022
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The solar eclipse of 5–6 January 2019 perturbed the ionospheric electron density, N, observed with the receiver at the Harbin Engineering University and 14 HF broadcasting stations ~1 000 km around. It was accompanied by ±1.5 Hz Doppler-spectrum broadening, ±0.5 Hz Doppler shift, fD, variations, 15 min period variations in fD caused by 1.6–2.4 % perturbations in N, and period changes of 4–5 min in fD caused by 0.2–0.3 % disturbances in N. The decrease in N attained ~15 % (vs. modeled 16 %).
Giorgio Arlan Silva Picanço, Clezio Marcos Denardini, Paulo Alexandre Bronzato Nogueira, Laysa Cristina Araujo Resende, Carolina Sousa Carmo, Sony Su Chen, Paulo França Barbosa-Neto, and Esmeralda Romero-Hernandez
Ann. Geophys., 40, 503–517, https://doi.org/10.5194/angeo-40-503-2022, https://doi.org/10.5194/angeo-40-503-2022, 2022
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In this work, we use the Disturbance Ionosphere indeX (DIX) to study equatorial plasma bubble (EPB) events over the Brazilian equatorial and low latitudes. Our results showed that the DIX detected EPB disturbances in terms of their intensity and occurrence times. Therefore, these responses agreed with the ionosphere behavior before, during, and after the studied EPBs. Finally, these disturbances tended to be higher (lower) in high (low) solar activity.
Victor U. J. Nwankwo, William Denig, Sandip K. Chakrabarti, Olugbenga Ogunmodimu, Muyiwa P. Ajakaiye, Johnson O. Fatokun, Paul I. Anekwe, Omodara E. Obisesan, Olufemi E. Oyanameh, and Oluwaseun V. Fatoye
Ann. Geophys., 40, 433–461, https://doi.org/10.5194/angeo-40-433-2022, https://doi.org/10.5194/angeo-40-433-2022, 2022
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We combined the observed diurnal VLF amplitude variation in the D region with standard measurements of the E and F regions to perform a diagnostic investigation of coupled geomagnetic storm effects in order to understand the observed storm-induced variations in VLF narrowband based on state and responses of the ionosphere. The dayside VLF amplitude showed a tendency for attenuation following geomagnetic storms, and the h’E and h’F variations confirmed strong storm response over the signal paths.
Anatoliy Lozbin, Viktor Fedun, and Olga Kryakunova
Ann. Geophys., 40, 55–65, https://doi.org/10.5194/angeo-40-55-2022, https://doi.org/10.5194/angeo-40-55-2022, 2022
Short summary
Short summary
Detection of Ionosphere Anomalies (DIA) for detection, identification, and analysis of ionosphere anomalies from satellite spectrograms and time series row data from instruments onboard the DEMETER satellite was designed. Using this software, the analyses of ionosphere parameter variations caused by various factors are provided. The scientific data processing and visualization technologies used in the development of DIA can be used in the creation of software for other scientific space missions.
Yiyang Luo, Leonid Chernogor, Kostiantyn Garmash, Qiang Guo, Victor Rozumenko, and Yu Zheng
Ann. Geophys., 39, 657–685, https://doi.org/10.5194/angeo-39-657-2021, https://doi.org/10.5194/angeo-39-657-2021, 2021
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The 30 August–2 September 2019 geospace storm and its influence on the characteristics of high frequency radio waves over the People's Republic of China have been analyzed. The geospace storm was weak, the magnetic storm was moderate, and the ionospheric storm was moderate to strongly negative, which manifested itself by the reduction in the ionospheric F-region electron density. Appreciable disturbances were also observed to occur in the ionospheric E-region and possibly in the Es layer.
Karl Bolmgren, Cathryn Mitchell, Talini Pinto Jayawardena, Gary Bust, Jon Bruno, and Elizabeth Mitchell
Ann. Geophys., 38, 1149–1157, https://doi.org/10.5194/angeo-38-1149-2020, https://doi.org/10.5194/angeo-38-1149-2020, 2020
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Travelling ionospheric disturbances behave like waves in the ionosphere, the ionised upper part of the atmosphere. In this study, we use an ionospheric tomography technique to map the electron content as affected by the passage of a large-scale travelling ionospheric disturbance launched during the largest geomagnetic storm observed by modern instruments. This is the first such imaging using this software and to the authors' knowledge the first study of this travelling ionospheric disturbance.
Erman Şentürk, Samed Inyurt, and İbrahim Sertçelik
Ann. Geophys., 38, 1031–1043, https://doi.org/10.5194/angeo-38-1031-2020, https://doi.org/10.5194/angeo-38-1031-2020, 2020
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The analysis of unexpected ionospheric phases before large earthquakes is one of the cutting-edge issues in earthquake prediction studies. Ionospheric TEC data were analyzed by short-time Fourier transform and a classic running median to detect abnormalities before the Mw 7.3 Iran–Iraq earthquake on November 12, 2017. The results showed clear positive anomalies 8–9 d before the earthquake as an earthquake precursor due to quiet space weather, local dispersion, and proximity to the epicenter.
Yuriy Rapoport, Vladimir Grimalsky, Viktor Fedun, Oleksiy Agapitov, John Bonnell, Asen Grytsai, Gennadi Milinevsky, Alex Liashchuk, Alexander Rozhnoi, Maria Solovieva, and Andrey Gulin
Ann. Geophys., 38, 207–230, https://doi.org/10.5194/angeo-38-207-2020, https://doi.org/10.5194/angeo-38-207-2020, 2020
Short summary
Short summary
The paper analytically and numerically treats the new theoretical basis for ground-based and satellite monitoring of the most powerful processes in the lower atmosphere and Earth (hurricanes, earthquakes, etc.), solar-wind magnetosphere (magnetic storms) and ionosphere (lightning discharges, thunderstorms, etc.). This can be provided by the determination of phases and amplitudes of radio waves in the Earth and ionosphere. In perspective, damage from the natural disasters can be decreased.
Jing Liu, Dong-He Zhang, Anthea J. Coster, Shun-Rong Zhang, Guan-Yi Ma, Yong-Qiang Hao, and Zuo Xiao
Ann. Geophys., 37, 673–687, https://doi.org/10.5194/angeo-37-673-2019, https://doi.org/10.5194/angeo-37-673-2019, 2019
Yi Liu, Chen Zhou, Qiong Tang, Guanyi Chen, and Zhengyu Zhao
Ann. Geophys., 37, 337–345, https://doi.org/10.5194/angeo-37-337-2019, https://doi.org/10.5194/angeo-37-337-2019, 2019
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Underground nuclear explosion (UNE) can produce ionospheric disturbances through a lithosphere–atmosphere–ionosphere coupling mechanism, which is very similar with earthquakes. By using the total electron content observations and Swarm ionospheric current data, we have investigated the geomagnetic conjugate ionospheric disturbances. We proposed that the electric field generated during the UNE test can be an important mechanism for ionospheric disturbance.
Carlos Sotomayor-Beltran and Laberiano Andrade-Arenas
Ann. Geophys., 37, 153–161, https://doi.org/10.5194/angeo-37-153-2019, https://doi.org/10.5194/angeo-37-153-2019, 2019
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A localized total electron content enhancement (LTE) was observed as a product of the geomagnetic storm that happened on 8 September 2017. This result was unexpected because it was located south of the equatorial ionization anomaly (EIA). The origin of the enhancement of the TEC in the EIA is very likely due to the super-fountain effect. On the other hand, the LTE is suggested to be produced by the contribution of the super-fountain effect along with traveling ionospheric disturbances.
Lucas Schreiter, Daniel Arnold, Veerle Sterken, and Adrian Jäggi
Ann. Geophys., 37, 111–127, https://doi.org/10.5194/angeo-37-111-2019, https://doi.org/10.5194/angeo-37-111-2019, 2019
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Comparing Swarm GPS-only gravity fields to the ultra-precise GRACE K-Band gravity field schematic errors occurs around the geomagnetic equator. Due to the end of the GRACE mission, and the gap to the GRACE-FO mission, only Swarm can provide a continuous time series of gravity fields. We present different and assess different approaches to remove the schematic errors and thus improve the quality of the Swarm gravity fields.
Le Ren and Steffen Schön
Ann. Geophys., 36, 1227–1241, https://doi.org/10.5194/angeo-36-1227-2018, https://doi.org/10.5194/angeo-36-1227-2018, 2018
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In this contribution, we analyse the performance of the Swarm onboard GPS receiver and present the approach for determination of the IfE Swarm kinematic orbit with PPP. The differences between our kinematic orbits and ESA reduced-dynamic orbits are at 1.5 cm, 1.5 cm and 2.5 cm level in along-track, cross-track and radial directions, respectively. A comparison with SLR underlines an accuracy of the kinematic orbits of 3–4 cm.
Donat V. Blagoveshchensky, Olga A. Maltseva, and Maria A. Sergeeva
Ann. Geophys., 36, 1057–1071, https://doi.org/10.5194/angeo-36-1057-2018, https://doi.org/10.5194/angeo-36-1057-2018, 2018
Cited articles
Chilton, C. J., Steele, F. K., and Norton, R. B.: Very-Low-Frequency
Phase Observations of Solar Flare Ionization in the D Region of the
Ionosphere, J. Geophys. Res., 68, 5421,
https://doi.org/10.1029/JZ068i019p05421, 1963. a
Deshpande, S. D., Subrahmanyam, C. V., and Mitra, A. P.: Ionospheric
effects of solar flares – I. The statistical relationship between X-ray
flares and SID's, J. Atmos. Terr. Phys., 34,
211–227, https://doi.org/10.1016/0021-9169(72)90165-1, 1972. a
Druzhin, G. I., Mel'nikov, A. N., and Cherneva, N. V.: Manifestation of
Earth's diurnal periods in VLF radiation, Doklady Earth Sciences, 457,
842–844, https://doi.org/10.1134/S1028334X14070046, 2014. a
Grubor, D. P., Šulić, D. M., and Žigman, V.: Classification of X-ray solar flares regarding their effects on the lower ionosphere electron density profile, Ann. Geophys., 26, 1731–1740, https://doi.org/10.5194/angeo-26-1731-2008, 2008. a, b
Hayes, L. A., Gallagher, P. T., McCauley, J., Dennis, B. R., Ireland,
J., and Inglis, A.: Pulsations in the Earth's Lower Ionosphere
Synchronized With Solar Flare Emission, J. Geophys. Res.-Space Phys., 122, 9841–9847, https://doi.org/10.1002/2017JA024647, 2017. a, b
Kamada, T.: Synoptic report of VLF sudden phase anomalies observed at
Toyokawa, Japan, J. Geomagn. Geoelectr., 37, 667–699,
https://doi.org/10.5636/jgg.37.667, 1985. a, b
Khan, I., Devi, M. I., Arunamani, T., and Madhusudhana Rao, D. N.: A
synoptic study of VLF sudden phase anomalies recorded at Visakhapatnam,
Earth Planets Space, 57, 1073–1081, 2005. a
Kreplin, R. W., Chubb, T. A., and Friedmann, H.: X-Ray and Lyman-Alpha
Emission from the Sun as Measured from the NRL SR-1 Satellite, J. Geophys. Res., 67, 2231–2253, https://doi.org/10.1029/JZ067i006p02231, 1962. a
Li, N., Lei, J., Luan, X., Chen, J., Zhong, J., Wu, Q., Xu, Z.,
and Lin, L.: Responses of the D region ionosphere to solar flares revealed
by MF radar measurements, J. Atmos. Solar-Terr.
Phy., 182, 211–216, https://doi.org/10.1016/j.jastp.2018.11.014, 2019. a
Liu, F., Qin, Z., Zhu, B., Ma, M., Chen, M., and Shen, P.:
Observations of ionospheric D layer fluctuations during sunrise and sunset
by using time domain waveforms of lightning narrow bipolar events, Chinese
J. Geophys., 61, 484–493, https://doi.org/10.6038/cjg2018K0658, 2018. a
Mitra, A. P. (Ed.): Ionospheric effects of solar flares, Astrophys. Space Sc. L., 46, 307 pp.,
https://doi.org/10.1007/978-94-010-2231-6,
1974. a
Muraoka, Y., Murata, H., and Sato, T.: The quantitative relationship
between VLF phase deviations and 1–8 A solar X-ray fluxes during solar
flares, J. Atmos. Terr. Phys., 39, 787–792,
https://doi.org/10.1016/0021-9169(77)90140-4, 1977. a
Raulin, J.-P., Bertoni, F. C. P., Gavilán, H. R., Guevara-Day, W.,
Rodriguez, R., Fernandez, G., Correia, E., Kaufmann, P., Pacini,
A., Stekel, T. R. C., Lima, W. L. C., Schuch, N. J., Fagundes, P. R.,
and Hadano, R.: Solar flare detection sensitivity using the South America
VLF Network (SAVNET), J. Geophys. Res.-Space Phys., 115,
A07301, https://doi.org/10.1029/2009JA015154, 2010. a
Raulin, J.-P., Trottet, G., Kretzschmar, M., Macotela, E. L., Pacini,
A., Bertoni, F. C. P., and Dammasch, I. E.: Response of the low
ionosphere to X-ray and Lyman-α solar flare emissions, J. Geophys. Res.-Space Phys., 118, 570–575,
https://doi.org/10.1029/2012JA017916, 2013.
a
Thomson, N. R., Rodger, C. J., and Clilverd, M. A.: Large solar flares
and their ionospheric D region enhancements, J. Geophys. Res.-Space Phys., 110, A06306, https://doi.org/10.1029/2005JA011008, 2005. a
Wait, J. R. and Spices, K. P.: Characteristics of the Earth ionosphere
waveguide for VLF radio waves, NBS Tech. Note, p. 300, 1964. a
Westfall, W. D.: Prediction of VLF Diurnal Phase Changes and Solar Flare
Effects, J. Geophys. Res., 66, 2733–2736,
https://doi.org/10.1029/JZ066i009p02733, 1961. a
Whitten, R. C. and Poppoff, I. G.: Physics of the Lower Ionosphere, Prentice-Hall, New York, 232 pp., 1965. a
Žigman, V., Grubor, D., and Šulić, D.: D-region electron
density evaluated from VLF amplitude time delay during X-ray solar flares,
J. Atmos. Solar-Terr. Phy., 69, 775–792,
https://doi.org/10.1016/j.jastp.2007.01.012, 2007. a
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