GUVI Biblio


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Found 41 entries in the Bibliography.

Showing entries from 1 through 41


On the impact of meridional wind circulation changes in the electron density distribution over the Indian equatorial and low latitude ionospheric region during a severe geomagnetic storm

Using a suite of instruments, which included a chain of ground-based dual-frequency GPS receivers, and magnetometers, we have studied the importance of thermospheric meridional wind circulation in controlling the distribution of plasma over the Indian low latitude ionospheric regions during the period of a severe geomagnetic storm. The storm on 15 May 2005, which had its onset coinciding with the local noon time sector for the Indian ionospheric zone, was a severe geomagnetic storm with symH ∼ - 305 nT. A steep increase i ...

Ambili, K.; Choudhary, R.;

Published by: Advances in Space Research      Published on: oct

YEAR: 2022     DOI: 10.1016/j.asr.2022.06.027

Compositional disturbances; Equatorial ionosphere; geomagnetic storm; total electron content

Solar and interplanetary events that drove two CIR-related geomagnetic storms of 1 June 2013 and 7 October 2015, and their ionospheric responses at the American and African equatorial ionization Anomaly regions

This study investigates the sequence of solar and interplanetary events that drove the 1 June 2013 and October 2015 geomagnetic storms and how the American (68°–78oE) and African (32°–42oE) Equatorial Ionization Anomaly (EIA) regions responded to them. We constructed the EIA structures by using Total Electron Content (TEC) and ionospheric irregularities derived from Global Navigation Satellite System (GNSS) receivers along with the study locations. We also analyzed disturbed time ionospheric electric field and model da ...

Oyedokun, Oluwole; Amaechi, P.; Akala, A.; Simi, K.; Ogwala, Aghogho; Oyeyemi, E.;

Published by: Advances in Space Research      Published on: mar

YEAR: 2022     DOI: 10.1016/j.asr.2021.12.027

geomagnetic storm; total electron content; Corotating Interacting Region; ionospheric irregularities

Local Persistent Ionospheric Positive Responses to the Geomagnetic Storm in August 2018 Using BDS-GEO Satellites over Low-Latitude Regions in Eastern Hemisphere

We present the ionospheric disturbance responses over low-latitude regions by using total electron content from Geostationary Earth Orbit (GEO) satellites of the BeiDou Navigation Satellite System (BDS), ionosonde data and Swarm satellite data, during the geomagnetic storm in August 2018. The results show that a prominent total electron content (TEC) enhancement over low-latitude regions is observed during the main phase of the storm. There is a persistent TEC increase lasting for about 1–2 days and a moderately positive d ...

Tang, Jun; Gao, Xin; Yang, Dengpan; Zhong, Zhengyu; Huo, Xingliang; Wu, Xuequn;

Published by: Remote Sensing      Published on: jan

YEAR: 2022     DOI: 10.3390/rs14092272

BDS-GEO; differential code biases; geomagnetic storm; Ionospheric disturbance; TEC

Ionospheric response to the 26 August 2018 geomagnetic storm along 280° E and 316° E in the South American sector

This paper studies the response of the ionospheric parameters critical frequency (foF2), their height (hmF2), and Total Electron Content (TEC) at mid, low, and near-equatorial latitudes of the South American sector during the intense geomagnetic storm of 26 August 2018. The ionospheric response at the beginning of the main phase was different depending on latitude (in general, there were decreases in foF2 at near-equatorial and low latitudes and small increases at mid-latitudes). During the recovery, positive storm effects i ...

Mansilla, Gustavo; Zossi, Marta;

Published by: Advances in Space Research      Published on: jan

YEAR: 2022     DOI: 10.1016/j.asr.2021.08.002

geomagnetic storm; Ionosphere; South America

Responses of Mesosphere and Lower Thermosphere Temperature to the Geomagnetic Storm on 7–8 September 2017

The variations of neutral temperature in the mesosphere and lower thermosphere (MLT) region, during the 7–8 September 2017 intense geomagnetic storm, are studied using observations by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument onboard the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite. They are also studied using simulations by the Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (TIMEGCM). The neutral temperature data cove ...

Sun, Meng; Li, Zheng; Li, Jingyuan; Lu, Jianyong; Gu, Chunli; Zhu, Mengbin; Tian, Yufeng;

Published by: Universe      Published on: feb

YEAR: 2022     DOI: 10.3390/universe8020096

geomagnetic storm; temperature; the mesosphere and lower thermosphere (MLT); TIMEGCM

FUV observations of variations in thermospheric composition and topside ionospheric density during the November 2004 magnetic superstorm

We revisited the November 2004 superstorm by analyzing TIMED/GUVI data. The 135.6 nm limb radiances at 520-km are mainly due to the O+ and electron radiative recombination and represent the daytime ionosphere density at the altitude. The 135.6 nm radiances clearly showed a signature of ionospheric equatorial arcs and their variations during the November 2004 magnetic superstorm. When an intense eastward Interplanetary Electric Field (IEF) occurred, the dayside equatorial arcs were enhanced and their latitude separation inc ...

Zhang, Yongliang; Paxton, LarryJ.; Huang, Chaosong; Wang, Wenbin;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: feb

YEAR: 2022     DOI: 10.1016/j.jastp.2022.105832

geomagnetic storm; penetration electric field; Thermosperic composition; topside ionosphere

Significant Variations of Thermospheric Nitric Oxide Cooling during the Minor Geomagnetic Storm on 6 May 2015

Using observations by the SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) instrument on board the TIMED (Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics) satellite and simulations by the TIEGCM (Thermosphere-Ionosphere-Electrodynamics General Circulation Model), we investigate the daytime variations of thermospheric nitric oxide (NO) cooling during the geomagnetic storm on 6 May 2015. The geomagnetic storm was minor, as the minimum Dst was −28 nT, the maximum Kp was 5+ and the maximum AE w ...

Li, Zheng; Sun, Meng; Li, Jingyuan; Zhang, Kedeng; Zhang, Hua; Xu, Xiaojun; Zhao, Xinhua;

Published by: Universe      Published on: apr

YEAR: 2022     DOI: 10.3390/universe8040236

geomagnetic storm; thermosphere; nitric oxide cooling

Response of the Ionospheric TEC to SSW and Associated Geomagnetic Storm Over the American Low Latitudinal Sector

During the sudden stratospheric warming (SSW) event in 2013, we investigated the American low latitude around 75°W. We used 12 Global Positioning System (GPS) receivers, a pair of magnetometers, and the NASA Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite airglow instrument to unveil the total electron content (TEC), inferred vertical drift, and the changes in the neutral composition, respectively. A major SSW characterized the 2013 SSW event with the main phase (7–27 January 2013) overlapped ...

Fashae, J.; Bolaji, O.; Rabiu, A.;

Published by: Space Weather      Published on:

YEAR: 2022     DOI: 10.1029/2021SW002999

equatorial ionization anomaly (EIA); geomagnetic storm; low-latitude ionosphere; sudden stratospheric wind (SSW)


Responses of the Indian Equatorial Ionization Anomaly to two CME-induced geomagnetic storms during the peak phase of solar cycle 24

This work analyzes the geo-effectiveness of Coronal Mass Ejection- (CME-) induced storms by investigating the responses of ionospheric Vertical Total Electron Content (VTEC) and the Equatorial Ionization Anomaly (EIA) over the Indian sector to two storms. One of the storms occurred on February 19, 2014 (SYM-H: −120 nT), while the other occurred on June 23, 2015 (SYM-H: −204 nT). Both storms were driven by full halo CMEs. Global TEC maps were used to characterize VTEC variations during the storms. June 23, 2015 storm was ...

Simi, K.; Akala, A.; Krishna, Siva; Amaechi, Paul; Ogwala, Aghogho; Ratnam, Venkata; Oyedokun, O.;

Published by: Advances in Space Research      Published on: oct

YEAR: 2021     DOI: 10.1016/j.asr.2021.06.013

Coronal mass ejection; Disturbance dynamo electric field; geomagnetic storm; prompt penetration electric field; total electron content

Assessment of the predictive capabilities of NIGTEC model over Nigeria during geomagnetic storms

The Nigerian Total Electron Content (NIGTEC) is a regional neural network-based model developed by the Nigerian Centre for Atmospheric Research to predict the Total Electron Content (TEC) at any location over Nigeria. The addition of the disturbance storm time (Dst) index as one of NIGTEC s input layer neurons raises a question of its accuracy during geomagnetic storms. In this paper, the capability of NIGTEC in predicting the variability of TEC during geomagnetic storms has been assessed. TEC data predicted by NIGTEC is com ...

Amaechi, Paul; Humphrey, Ibifubara; Adewoyin, David;

Published by: Geodesy and Geodynamics      Published on: nov

YEAR: 2021     DOI: 10.1016/j.geog.2021.09.003

geomagnetic storm; global navigation satellite system; Nigerian Total Electron Content (NIGTEC); total electron content

Features of the Ionospheric Storm on December 21–24, 2016

The purpose of this work is to investigate the response of the F region and topside ionosphere to the moderate geomagnetic storm on December 21, 2016 (Kp max = 6). The subject of the study is the height–time variations in the parameters of the ionospheric plasma over Kharkiv. Experimental data were obtained using vertical sounding and incoherent scatter methods by the ionosonde and incoherent scatter radar. The presented results are based on the correlation analysis of the incoherent scattered signal. The ion and elect ...

Katsko, S.; Emelyanov, Ya.; Chernogor, L.;

Published by: Kinematics and Physics of Celestial Bodies      Published on: mar

YEAR: 2021     DOI: 10.3103/S0884591321020045

geomagnetic storm; Electron density; Ionospheric storm; space weather; ionosonde; electron and ion temperatures; incoherent scatter radar; plasma velocity; positive and negative storm phases

Longitudinal variations of geomagnetic and ionospheric parameters in the Northern Hemisphere during magnetic storms according to multi-instrument observations

We present a joint analysis of longitude-temporal variations of ionospheric and geomagnetic parameters at middle and high latitudes in the Northern Hemisphere during the two severe magnetic storms in March and June 2015 by using data from the chains of magnetometers, ionosondes and GPS/GLONASS receivers. We identify the fixed longitudinal zones where the variability of the magnetic field is consistently high or low under quiet and disturbed geomagnetic conditions. The revealed longitudinal structure of the geomagnetic field ...

Chernigovskaya, M.; Shpynev, B.; Yasyukevich, A.; Khabituev, D.; Ratovsky, K.; Belinskaya, Yu.; Stepanov, A.; Bychkov, V.; Grigorieva, S.; Panchenko, V.; Kouba, D.; Mielich, J.;

Published by: Advances in Space Research      Published on: jan

YEAR: 2021     DOI: 10.1016/j.asr.2020.10.028

Chain of GPS/GLONASS receivers; Geomagnetic field variations; geomagnetic storm; Ionosonde chain; ionospheric disturbances

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

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, Millsto ...

Sergeeva, Maria; Maltseva, Olga; Caraballo, Ramon; Gonzalez-Esparza, Juan; Corona-Romero, Pedro;

Published by: Atmosphere      Published on: feb

YEAR: 2021     DOI: 10.3390/atmos12020164

foF2; geomagnetic storm; Ionospheric disturbance; ionospheric equivalent slab thickness; statistical analysis; TEC

Responses of the African equatorial ionization anomaly (EIA) to some selected intense geomagnetic storms during the maximum phase of solar cycle 24

This study investigates the morphology of the GPS TEC responses in the African Equatorial Ionization Anomaly (EIA) region to intense geomagnetic storms during the ascending and maximum phases of solar cycle 24 (2012–2014). Specifically, eight intense geomagnetic storms with Dst ≤ −100 nT were considered in this investigation using TEC data obtained from 13 GNSS receivers in the East African region within 36–42°E geographic longitude; 29°N–10°S geographic latitude; ± 20°N magnetic latitude. The storm-time beh ...

Oyedokun, O.; Akala, A.; Oyeyemi, E.;

Published by: Advances in Space Research      Published on: feb

YEAR: 2021     DOI: 10.1016/j.asr.2020.11.020

African equatorial ionization anomaly; geomagnetic storm; GNSS; Ionosphere

Assessing the performance of a Northeast Asia Japan-centered 3-D ionosphere specification technique during the 2015 St. Patrick’s day geomagnetic storm

This paper demonstrates and assesses the capability of the advanced three-dimensional (3-D) ionosphere tomography technique, during severe conditions. The study area is northeast Asia and quasi-Japan-centred. Reconstructions are based on total electron content data from a dense ground-based global navigation satellite system receiver network and parameters from operational ionosondes. We used observations from ionosondes, Swarm satellites and radio occultation (RO) to assess the 3-D picture. Specifically, we focus on St. Pat ...

Nicholas, Ssessanga; Mamoru, Yamamoto; Susumu, Saito;

Published by: Earth, Planets and Space (Online)      Published on: dec

YEAR: 2021     DOI: 10.1186/s40623-021-01447-8

geomagnetic storm; Ground-GNSS-STEC tomography; Ionosonde data assimilation

Effect of intense geomagnetic storms on low-latitude TEC during the ascending phase of the solar cycle 24

The results presented in this paper are obtained from low-latitude ionospheric total electron content (TEC) variation during the chosen geomagnetic storm events happening during the solar cycle 24. We include the four intense geomagnetic storms that occurred on 26 September 2011, 15 July 2012, 19 February 2014 and 20 December 2015, depending upon the availability of TEC data. For this, we have used the TEC data from low-latitude station Varanasi (geographic latitude 25°, 16′N, geographic longitude 82°, 59′E and geomagn ...

Singh, Abha; Rathore, Vishnu; Kumar, Sanjay; Rao, S.; Singh, Sudesh; Singh, A.;

Published by: Journal of Astrophysics and Astronomy      Published on: aug

YEAR: 2021     DOI: 10.1007/s12036-021-09774-8

geomagnetic storm; Global positioning system; low latitude; total electron contents

Solar flares and geomagnetic storms of September 2017: Their impacts on the TEC over 75°E longitude sector

This study investigates the ionospheric Total Electron Content (TEC) responses over 75°E longitude to the solar flares and geomagnetic storms of September 6–9, 2017. The results of this study provide the impacts of solely solar flares on the ionosphere and such impact when the effects of solar flares and geomagnetic storm are combined. On September 6, two X class solar flares, namely X2.2 at 0857 UT and X9.3 at 1153 UT, were recorded with quiet geomagnetic conditions. The EUV/X-ray intensity of X9.3 flare was significan ...

Chakraborty, Monti; Singh, A.; Rao, S.;

Published by: Advances in Space Research      Published on: aug

YEAR: 2021     DOI: 10.1016/j.asr.2021.04.012

TEC; geomagnetic storm; EUV; Solar flare; X-ray

A Statistical Analysis of Plasma Bubbles Observed by Swarm Constellation during Different Types of Geomagnetic Storms

Based on the observations of Ionospheric Bubble Index (IBI) data from the Swarm mission, the characteristics of plasma bubbles are investigated during different types of geomagnetic storms recorded from 2014 to 2020. The geometrical constellation of the Swarm mission enabled us to investigate the altitudinal profile of the IBIs during different activity levels in a statistical mean. Results show that the majority of IBIs associated with moderate storms are observed at low altitudes and the probability of observing IBIs at hi ...

Hussien, Fayrouz; Ghamry, Essam; Fathy, Adel;

Published by: Universe      Published on: apr

YEAR: 2021     DOI: 10.3390/universe7040090

geomagnetic storm; ionospheric irregularity; plasma bubble; Swarm mission

Periodic Variations in Solar Wind and Responses of the Magnetosphere and Thermosphere in March 2017

TIMED/GUVI observed thermospheric column ∑O/N2 depletion in both hemispheres between March 1 and 21, 2017 which was caused by large periodic variations in interplanetary magnetic field (IMF) and a high solar wind speed, likely in a solar wind. The dominant periods seen in the solar wind and magnetosphere coupling function (CF) were around 1.9, 3.0, 4.7, 7.6, 14.0 and 22.0 h on March 1 and 2. The major AE variations were around 3.0, 4.7, 7.6, 10.7, 14.0 and 22.0 h. Auroral hemispheric power (HP) also showed periodic variati ...

Zhang, Yongliang; Paxton, Larry; Wang, Wenbin; Huang, Chaosong;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2021JA029387

AE index; geomagnetic storm; hemispheric power; periodic variation; solar wind and magnetosphere coupling; thermospheric composition

An Unusually Large Electron Temperature Increase Over Arecibo Associated With an Intense Geomagnetic Storm

We present an investigation of the F-region electron temperature to an intense geomagnetic storm that occurred on 5 August 2011. The investigation is based on the incoherent scatter radar measurements at Arecibo Observatory, Puerto Rico (18.3°N, 66.7°W). The electron temperature exhibits a rapid and intensive enhancement after the commencement of the geomagnetic storm. The electron temperature increases by ∼800 K within an hour, which is seldomly reported at Arecibo. At the same time, a depletion of the electron density ...

Lv, Xiedong; Gong, Yun; Zhang, ShaoDong; Zhou, Qihou; Ma, Zheng;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2021JA029836

Arecibo; F-region electron temperature; geomagnetic storm; incoherent scatter radar


Dependence of the high-latitude plasma irregularities on the auroral activity indices: a case study of 17 March 2015 geomagnetic storm

The magnetosphere substorm plays a crucial role in the solar wind energy dissipation into the ionosphere. We report on the intensity of the high-latitude ionospheric irregularities during one of the largest storms of the current solar cycle\textemdashthe St. Patrick\textquoterights Day storm of 17 March 2015. The database of more than 2500 ground-based Global Positioning System (GPS) receivers was used to estimate the irregularities occurrence and dynamics over the auroral region of the Northern Hemisphere. We analyze the ...

Cherniak, Iurii; Zakharenkova, Irina;

Published by: Earth, Planets and Space      Published on: 12/2015

YEAR: 2015     DOI: 10.1186/s40623-015-0316-x

Auroral hemispheric power index Auroral precipitation; geomagnetic storm; GPS; Ionosphere irregularities; ROTI

The response of the ionosphere to intense geomagnetic storms in 2012 using GPS-TEC data from East Africa longitudinal sector

The response of the ionosphere to intense magnetic storms has been studied using total electron content (TEC). TEC data recorded by a series of GPS receivers at a longitude\~35\textdegreeE\ covering a wide range of latitudes (32\textdegreeS\ to\ 68\textdegreeN, geographic) is analyzed to study spatio-temporal modifications of the vertical TEC (vTEC) during storms on 07 and 09 March 2012 and on 14 July 2012. We have observed main phase positive response at equatorial ionization anomaly (EIA) crests and mid l ...

Tesema, F.; Damtie, B.; Nigussie, M.;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: 12/2015

YEAR: 2015     DOI: 10.1016/j.jastp.2015.10.021

Equatorial Electrojet; geomagnetic storm; Ionosphere

Ionospheric response to the 2015 St. Patrick\textquoterights Day storm: A global multi-instrumental overview

We present the first multi-instrumental results on the ionospheric response to the geomagnetic storm of 17\textendash18 March 2015 (the St. Patrick\textquoterights Day storm) that was up to now the strongest in the 24th solar cycle (minimum SYM-H value of -233 nT). The storm caused complex effects around the globe. The most dramatic positive ionospheric storm occurred at low latitudes in the morning (~100\textendash150\% enhancement) and postsunset (~80\textendash100\% enhancement) sectors. These significant vertical tota ...

Astafyeva, Elvira; Zakharenkova, Irina; Förster, Matthias;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2015

YEAR: 2015     DOI: 10.1002/2015JA021629

geomagnetic storm; hemispheric asymmetry; Ionosphere; negative storm; positive storm; Swarm mission

Dynamics of the high-latitude ionospheric irregularities during the 17 March 2015 St. Patrick\textquoterights Day storm: Ground-based GPS measurements

We report first results on the study of the high-latitude ionospheric irregularities observed in worldwide GPS data during the St. Patrick\textquoterights Day geomagnetic storm (17 March 2015). Multisite GPS observations from more than 2500 ground-based GPS stations were used to analyze the dynamics of the ionospheric irregularities in the Northern and Southern Hemispheres. The most intense ionospheric irregularities lasted for more than 24 h starting at 07 UT of 17 March. This period correlates well with an increase of t ...

Cherniak, Iurii; Zakharenkova, Irina; Redmon, Robert;

Published by: Space Weather      Published on: 09/2015

YEAR: 2015     DOI: 10.1002/swe.v13.910.1002/2015SW001237

auroral precipitation; geomagnetic storm; Ionosphere; irregularities; rate of TEC

Effects of geomagnetic storm on low latitude ionospheric total electron content: A case study from Indian sector

The effect of geomagnetic storms on low latitude ionosphere has been investigated with the help of Global Positioning System Total Electron Content (GPS-TEC) data. The investigation has been done with the aid of TEC data from the Indian equatorial region, Port Blair (PBR) and equatorial ionization anomaly region, Agartala (AGR). During the geomagnetic storms on 24th April and 15th July 2012, significant enhancement up to 150\% and depression up to 72\% in VTEC is observed in comparison to the normal day variation. The var ...

Chakraborty, Monti; Kumar, Sanjay; De, Barin; Guha, Anirban;

Published by: Journal of Earth System Science      Published on: 07/2015

YEAR: 2015     DOI: 10.1007/s12040-015-0588-3

geomagnetic storm; Ionospheric total electron content; low latitude ionosphere


E-region ionospheric storm on May 1\textendash3, 2010: GSM TIP model representation and suggestions for IRI improvement

his paper presents the model simulation results of ionospheric E-region parameters during geomagnetic storm on May 2\textendash3, 2010. For this investigation we used the Global Self-consistent Model of the Thermosphere, Ionosphere and Protonosphere (GSM TIP) developed in West Department of IZMIRAN. GSM TIP model simulations were performed using empirical model of high-energy electron precipitation. The temporal and spatial distributions of the lower ionosphere parameters and minor neutral species are presented. GSM TIP m ...

Bessarab, F.S.; Korenkov, Yu.N.; Klimenko, V.V.; Klimenko, M.V.; Zhang, Y.;

Published by: Advances in Space Research      Published on: 08/2014

YEAR: 2014     DOI: 10.1016/j.asr.2014.08.003

E-region; Electric field; geomagnetic storm; Ionospheric modeling; IRI-2012; Nitric oxide density

The responses of ionospheric topside diffusive fluxes to two geomagnetic storms in October 2002

O+ field-aligned ambipolar diffusive velocities Vd and fluxes Фd in the topside ionosphere have been calculated from the observed profiles of electron density, ion, and electron temperatures during a 30 day incoherent scatter radar experiment conducted at Millstone Hill (288.5\textdegreeE, 42.6\textdegreeN) from 4 October to 4 November 2002. Two geomagnetic storms took place during this period. During the negative phases (depleted electron densities) of these two storms, ...

Chen, Guang-Ming; Xu, JiYao; Wang, Wenbin; Lei, Jiuhou; Zhang, Shun-Rong;

Published by: Journal of Geophysical Research: Space Physics      Published on: 08/2014

YEAR: 2014     DOI: 10.1002/2014JA020013

diffusion; geomagnetic storm; scale height; topside ionosphere

Storm-time behaviors of O/N2 and NO variations

Algorithms have been developed to extract net nitric oxide (NO) radiances in the wavelength range of 172\textendash182\ nm from the dayside TIMED/GUVI spectrograph data and convert them to NO column density (100\textendash150\ km). The thermospheric O/N2 column density ratios (referenced from an altitude ~135\ km with a N2column density of 1017\ cm-2) are also obtained from the spectrograph data. The spatial resolution of the NO and O/N2 products a ...

Zhang, Y.; Paxton, L.J.; Morrison, D.; Marsh, D.; Kil, H.;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: 07/2014

YEAR: 2014     DOI: 10.1016/j.jastp.2014.04.003

geomagnetic storm; Thermospheric nitric oxide; Thermospheric O/N2 ratio

Traveling ionospheric disturbances observed at South African midlatitudes during the 29\textendash31 October 2003 geomagnetically disturbed period

This paper presents traveling ionospheric disturbances (TIDs) observations from GPS measurements over the South African region during the geomagnetically disturbed period of 29\textendash31 October 2003. Two receiver arrays, which were along two distinct longitudinal sectors of about 18\textdegree-20\textdegree and 27\textdegree-28\textdegree were used in order to investigate the amplitude, periods and virtual propagation characteristics of the storm induced ionospheric disturbances. The study revealed a large sudden TEC ...

Katamzi, Zama; Habarulema, John;

Published by: Advances in Space Research      Published on: 01/2014

YEAR: 2014     DOI: 10.1016/j.asr.2013.10.019

geomagnetic storm; Substorm; Total electron content (TEC); Traveling ionospheric disturbances (TIDs)


The effect of geomagnetic-storm-induced enhancements to ionospheric emissions on the interpretation of the TIMED/GUVI O/N 2 ratio

[1]\ We examine the consequence of enhanced atomic oxygen (OI) 135.6 nm emissions due to the recombination of O+ with electrons on the column number density ratio of atomic oxygen to molecular nitrogen (O/N2 ratio) provided by Global Ultraviolet Imager (GUVI) on board the Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics satellite. GUVI O/N2 ratio is derived from the measurements of OI 135.6 nm and N2 Lyman-Birge-Hopfield airglow emissions. The OI 135.6 nm emissi ...

Lee, Woo; Kil, Hyosub; Paxton, Larry; Zhang, Yongliang; Shim, Ja;

Published by: Journal of Geophysical Research: Space Physics      Published on: 12/2013

YEAR: 2013     DOI: 10.1002/2013JA019132

geomagnetic storm; GUVI O/N2 ratio; ionospheric effect

Storm time spatial variations in TEC during moderate geomagnetic storms in extremely low solar activity conditions (2007\textendash2009) over Indian region

The total electron content (TEC) measurements from a network of GPS receivers were analyzed to investigate the storm time spatial response of ionosphere over the Indian longitude sector. The GPS receivers from the GPS Aided Geo Augmented Navigation (GAGAN) network which are uniquely located around the \~77\textdegreeE longitude are used in the present study so as to get the complete latitudinal coverage from the magnetic equator to low mid-latitude region. We have selected the most intense storms but of moderate intensity ...

Sunda, Surendra; Vyas, B.M.; Khekale, P.V.;

Published by: Advances in Space Research      Published on: 07/2013

YEAR: 2013     DOI: 10.1016/j.asr.2013.03.006

Electrodynamics; Equatorial and low-latitude; geomagnetic storm; Total electron content (TEC)

Ionospheric response to a geomagnetic storm during November 8\textendash10, 2004

This paper investigates the response of the equatorial, and near equatorial, ionosphere to geomagnetic disturbances during the period November 8-10, 2004. Ionosonde data from Trivandrum (8.5\textdegreeN 77\textdegreeE and dip 0.5\textdegreeN) and SHAR (13.5\textdegreeN, 80.2\textdegreeE, dip \~5.5\textdegreeN), magnetic field data from Tirunelveli (8.7\textdegreeN, 76.9\textdegreeE, dip latitude 0.5\textdegreeS) and Alibag (18.64\textdegreeN, 72.87\textdegreeE), and GUVI O/N2 data in the Indian longitude sector ...

Simi, K.; Manju, G.; Haridas, M.; Nayar, S.; Pant, Tarun; Alex, S.;

Published by: Earth, Planets and Space      Published on: 05/2013

YEAR: 2013     DOI: 10.5047/eps.2012.09.005

Equatorial Electrojet; Equatorial ionization anomaly; geomagnetic storm; O/N2 ratio


Disturbance dynamo, prompt penetration electric field and overshielding in the Earth\textquoterights ionosphere during geomagnetic storm

This paper presents a result of model calculation of the disturbance dynamo electric field, prompt penetration, overshielding and their ionospheric effects during geomagnetic storm on December 14\textendash15, 2006. The calculations were carried out with use of the Global Self-Consistent Model of the Thermosphere, Ionosphere and Protonosphere (GSM TIP model) developed in WD IZMIRAN. Simulations were performed for quiet and disturbed conditions with took into account the magnetospheric convection electric field with and wi ...

Klimenko, M.V.; Klimenko, V.V.;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: 12/2012

YEAR: 2012     DOI: 10.1016/j.jastp.2012.02.018

Disturbance dynamo electric field; geomagnetic storm; Numerical modeling; Overshielding; prompt penetration electric field

Effects observed in the equatorial and low latitude ionospheric F-region in the Brazilian sector during low solar activity geomagnetic storms and comparison with the COSMIC measurements

The main objective of the present investigation has been to compare the ionospheric parameters (NmF2 and hmF2) observed by two ground-based ionospheric sounders (one at PALMAS- located near the magnetic equator and the other at Sao Jose dos Campos-located in the low-latitude region) in the Brazilian sector with that by the satellite FORMOSAT-3/COSMIC radio occultation (RO) measurements during two geomagnetic storms which occurred in December 2006 and July 2009. It should be pointed out that in spite of increasing the lati ...

Sahai, Y.; de Jesus, R.; Fagundes, P.R.; Selhorst, C.L.; de Abreu, A.J.; Ram, Tulasi; Aragon-Angel, A.; Pillat, V.G.; Abalde, J.R.; Lima, W.L.C.; Bittencourt, J.A.;

Published by: Advances in Space Research      Published on: 11/2012

YEAR: 2012     DOI: 10.1016/j.asr.2012.07.006

COSMIC satellite; F-region; geomagnetic storm; Ionosphere; Low solar activity

GPS-TEC variations during low solar activity period (2007\textendash2009) at Indian low latitude stations

The paper is based on the ionospheric variations in terms of vertical total electron content (VTEC) for the low solar activity period from May 2007 to April 2009 based on the analysis of dual frequency signals from the Global Positioning System (GPS) satellites recorded at ground stations Varanasi (Geographic latitude 25\textd ...

Kumar, Sanjay; Priyadarshi, S.; Krishna, Gopi; Singh, A.;

Published by: Astrophysics and Space Science      Published on: 05/2012

YEAR: 2012     DOI: 10.1007/s10509-011-0973-6

geomagnetic storm; GPS; Ionospheric total electron contents; IRI model

The source of the steep plasma density gradient in middle latitudes during the 11\textendash12 April 2001 storm

A steep plasma density gradient has been observed in the middle-latitude F region during large geomagnetic storms. This phenomenon can be understood as a special form of the middle-latitude ionization trough (hereafter trough), but its causal linkage has not yet been clarified. We investigate the association of the steep density gradient and the trough by comparing their morphologies and occurrence locations using the satellite and ground observation data during the 11\textendash12 April 2001 storm. Steep density ...

Park, S.; Kim, K.-H.; Kil, H.; Jee, G.; Lee, D.-H.; Goldstein, J.;

Published by: Journal of Geophysical Research      Published on: 05/2012

YEAR: 2012     DOI: 10.1029/2011JA017349

geomagnetic storm; plasma trough; steep density gradient


GPS observations of the ionospheric F2-layer behavior during the 20th November 2003 geomagnetic storm over South Korea

The ionospheric F2-layer peak density (NmF2) and its height (hmF2) are of great influence on the shape of the ionospheric electron density profile Ne (h) and may be indicative of other physical processes within the ionosphere, especially those due to geomagnetic storms. Such parameters are often estimated using models such as the semiempirical international reference ionosphere (IRI) models or are measured using moderately priced to expensive instrumentation, such as ionosondes or incoherent scatter radars. Global positio ...

Jin, Shuanggen; Luo, O.; Park, P.;

Published by: Journal of Geodesy      Published on: 03/2008

YEAR: 2008     DOI: 10.1007/s00190-008-0217-x

F2-layer; geomagnetic storm; GPS; Ionosphere; Tomography


Observations of a positive storm phase on September 10, 2005

In this study, we present multi-instrument observations of a strong positive phase of ionospheric storm, which occurred on September 10, 2005 during a moderate geomagnetic storm with minimum Dst=-60\ nT and maximum Kp=6\textendash. The daytime electron density measured by the Millstone Hill incoherent scatter radar (42.6\textdegreeN, 288.5\textdegreeE) increased after 13\ UT (\~8\ LT) compared with that before the storm. This increase is observed throughout the daytim ...

Goncharenko, L.P.; Foster, J.C.; Coster, A.J.; Huang, C.; Aponte, N.; Paxton, L.;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: 07/2007

YEAR: 2007     DOI: 10.1016/j.jastp.2006.09.011

F-region; geomagnetic storm; Ionosphere; positive phase


Ionospheric disturbances during the magnetic storm of 15 July 2000: Role of the fountain effect and plasma bubbles for the formation of large equatorial plasma density depletions

We investigate the role of the fountain effect and plasma bubbles for the formation of the large equatorial plasma depletions during the geomagnetic storm of 15 July 2000. The large equatorial plasma depletions are detected in the Atlantic sector on the night of the 15th by the Defense Meteorological Satellite Program (DMSP) F15 and the first Republic of China Satellite (ROCSAT-1). The observations show discontinuous drop of the plasma density at the walls of the depletions, flat plasma density inside the depletions, and ...

Kil, Hyosub; Paxton, Larry;

Published by: Journal of Geophysical Research      Published on: 12/2006

YEAR: 2006     DOI: 10.1029/2006JA011742

Equatorial ionosphere; geomagnetic storm; ionospheric disturbances

Characteristics of the storm-induced big bubbles (SIBBs)

Large equatorial plasma depletions, referred to as storm-induced big bubbles (SIBBs), are detected from the Defense Meteorological Satellite Program F15 and from the first Republic of China Satellite during the large magnetic storms of 31 March 2001, 29 October 2003, and 20 November 2003. They occur in the equatorial region at night, are elongated in the north-south direction, have steep walls, and always coexist with plasma bubbles. These observations are consistent with the SIBB characteristics described in the companio ...

Kil, Hyosub; Paxton, L.; Su, Shin-Yi; Zhang, Yongliang; Yeh, Hweyching;

Published by: Journal of Geophysical Research      Published on: 10/2006

YEAR: 2006     DOI: 10.1029/2006JA011743

Equatorial ionosphere; geomagnetic storm; irregularities


First look at the 20 November 2003 superstorm with TIMED/GUVI: Comparisons with a thermospheric global circulation model

The NASA TIMED/GUVI experiment obtained unprecedented far ultraviolet images of thermospheric composition and temperature during the intense geomagnetic storm on 20\textendash21 November 2003. Geographic maps of the atomic oxygen to molecular nitrogen column density ratio show severe depletions that extend to the equator near the peak of the storm. This ratio is a key indicator of how the thermospheric composition is disrupted at high latitudes and how the perturbed air moves globally as a result of dynamical forcing. For ...

Meier, R.; Crowley, G.; Strickland, D.; Christensen, A.; Paxton, L.; Morrison, D.; Hackert, C.;

Published by: Journal of Geophysical Research      Published on: 09/2005

YEAR: 2005     DOI: 10.1029/2004JA010990

dayglow; geomagnetic storm; GUVI; remote sensing; thermospheric composition; TIMED