GUVI Biblio





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Found 151 entries in the Bibliography.


Showing entries from 1 through 50


2020

Impacts of Binning Methods on High-Latitude Electrodynamic Forcing: Static Versus Boundary-Oriented Binning Methods

An outstanding issue in the general circulation model simulations for Earth\textquoterights upper atmosphere is the inaccurate estimation of Joule heating, which could be associated with the inaccuracy of empirical models for high-latitude electrodynamic forcing. The binning methods used to develop those empirical models may contribute to the inaccuracy. Traditionally, data are binned through a static binning approach by using fixed geomagnetic coordinates, in which the dynamic nature of the forcing is ...

Zhu, Qingyu; Deng, Yue; Richmond, Arthur; Maute, Astrid; Chen, Yun-Ju; Hairston, Marc; Kilcommons, Liam; Knipp, Delores; Redmon, Robert; Mitchell, Elizabeth;

YEAR: 2020     DOI: 10.1029/2019JA027270

Electric field; high latitude; Joule heating; particle precipitation

Real-Time Thermospheric Density Estimation via Two-Line Element Data Assimilation

Inaccurate estimates of the thermospheric density are a major source of error in low Earth orbit prediction. Therefore, real-time density estimation is required to improve orbit prediction. In this work, we develop a dynamic reduced-order model for the thermospheric density that enables real-time density estimation using two-line element (TLE) data. For this, the global thermospheric density is represented by the main spatial modes of the atmosphere and a time-varying low-dimensional state and a linear ...

Gondelach, David; Linares, Richard;

YEAR: 2020     DOI: 10.1029/2019SW002356

density estimation; reduced-order modeling; satellite drag; thermospheric density modeling; two-line element data

2019

Conjugate hemispheric response of earth\textquoterights ionosphere due to geomagnetic storms occurred during two equinox periods

The ionospheric response of two geomagnetic storms of 2016 occurred during spring equinox (5-8 March, 2016) and autumn equinox (12-15 October, 2016) is investigated using the total electron content (TEC) data derived from Global Positioning System (GPS) receivers located in the equatorial ionization anomaly (EIA) crest regions at northern hemisphere (Tripura University, Agartala, India) and southern hemisphere (Karratha, Australia). While in southern EIA station ionospheric responses for the two storms are found to be sym ...

Patari, Arup; De, Barin; Guha, Anirban; Paul, Bapan;

YEAR: 2019     DOI: 10.1088/1742-6596/1330/1/012004

Morphological study on the ionospheric variability at Bharati, a polar cusp station in the southern hemisphere

Morphological features of the quiet/disturbed time variations in the Total Electron Content (TEC) at the polar cusp station Bharati (76.69\textdegreeS MLAT) during a period of 5 years starting from February 2013 to December 2017 has been studied using GPS TEC measurements. The TEC at Bharati follows a diurnal pattern with its peak appearing close to local noon/magnetic noon during the summer/winter months. A nighttime enhancement in the TEC is seen around the magnetic midnight during winter. The plasma density at Bharati ...

Shreedevi, P.R.; Choudhary, R.K.; Yu, Yiqun; Thomas, Evan;

YEAR: 2019     DOI: 10.1016/j.jastp.2019.105058

Response of the Earth\textquoterights equatorial ionosphere during the severe G4-class geomagnetic storm of 8 th September 2017

Equatorial and low latitude ionospheric response of the 8th September 2017 severe G4-class geomagnetic storm is investigated using the total electron content (TEC) data from a longitudinal chain of global positioning system (GPS) receivers over Asian, African and American sectors. During the main phase, a positive storm effect is observed over Asian sector, a complete negative storm effect over African sector and both are observed over American sector. A sharp increase in peak TEC is observed over the complete ...

Paul, Bapan; Patari, Arup; De, Barin; Guha, Anirban;

YEAR: 2019     DOI: 10.1088/1742-6596/1330/1/012005

Global-Scale Observations of the Equatorial Ionization Anomaly

The National Aeronautics and Space Administration Global-scale Observations of the Limb and Disk ultraviolet spectrograph has been imaging the equatorial ionization anomaly (EIA), regions of the ionosphere with enhanced electron density north and south of the magnetic equator, since October 2018. The initial 3 months of observations was during solar minimum conditions, and they included observations in December solstice of unanticipated variability and depleted regions. Depletions are seen on most nights, in contrast to e ...

Eastes, R.; Solomon, S.; Daniell, R.; Anderson, D.; Burns, A.; England, S.; Martinis, C.; McClintock, W.;

YEAR: 2019     DOI: 10.1029/2019GL084199

Imaging of the Daytime Ionospheric Equatorial Arcs With Extreme and Far Ultraviolet Airglow

We present the first global images of the daytime ionosphere equatorial arcs as manifested in the 83.4-nm airglow. These images were collected by the Limb-Imaging Ionospheric and Thermospheric Extreme-Ultraviolet Spectrograph that commenced operations on the International Space Station in early 2017. We compare these to simultaneous images of the ionospheric radiative recombination airglow at 135.6 nm measured between 250- and 350-km tangent altitudes, where the emission is generated primarily by radiative recombination o ...

Stephan, A.; Finn, S.; Cook, T.; Geddes, G.; Chakrabarti, S.; Budzien, S.;

YEAR: 2019     DOI: 10.1029/2019JA026624

Evaluation of Space Traffic Effects in SBUV Polar Mesospheric Cloud Data

Water-rich rocket exhaust plumes, in particular those emitted by the National Aeronautics and Space Administration Space Shuttle, have been suggested to make a significant contribution to long-term trends in polar mesospheric cloud (PMC) ice water content. We investigate this claim using the combined Solar Backscatter Ultraviolet (SBUV) PMC data record from eight separate instruments, which includes 60 Shuttle launches during PMC seasons between 1985 and 2011. No statistically significant postlaunch signal in PMC total ic ...

DeLand, Matthew; Thomas, Gary;

YEAR: 2019     DOI: 10.1029/2018JD029756

An Observational Review on influence of Intense Geomagnetic Storm on Positional Accuracy of NavIC/IRNSS System

The positional accuracy of Navigation with the Indian Constellation (NavIC)/Indian Regional Navigation Satellite System (IRNSS) in the low latitudes of the Indian region during the intense geomagnetic storm of 8 September 2017 being reported first time. The existence of an intense geomagnetic storm is verified with several geomagnetic indices and interplanetary field parameters. The Total Electron Content (TEC) maps from the International GNSS Service (IGS) data and the thermosphere O/N2 ratio maps from the Global Ultra V ...

Desai, Mehul; Shah, Shweta;

YEAR: 2019     DOI: 10.1080/02564602.2019.1599739

Plasma transport process in the equatorial/low-latitude ionosphere

The behaviour of the equatorial/low-latitude ionosphere and the transport processes during magnetic disturbed and quiet periods of a high solar activity year, 2014, in the American sector are investigated. Parameters used include vertical drift (Vz), transport term (W), NmF2, hmF2 and scale-height (H). The F2 plasma variations followed the diurnal local solar pattern, being higher at daytime. The sunset maximum and sunrise minimum peaks of hmF2 were directly opposite to the scale height ...

Adebesin, Babatunde; Adekoya, Bolarinwa; David, Timothy;

YEAR: 2019     DOI: 10.1016/j.asr.2018.11.013

Plasma transport process in the equatorial/low-latitude ionosphere

The behaviour of the equatorial/low-latitude ionosphere and the transport processes during magnetic disturbed and quiet periods of a high solar activity year, 2014, in the American sector are investigated. Parameters used include vertical drift (Vz), transport term (W), NmF2, hmF2 and scale-height (H). The F2 plasma variations followed the diurnal local solar pattern, being higher at daytime. The sunset maximum and sunrise minimum peaks of hmF2 were directly opposite to the scale height ...

Adebesin, Babatunde; Adekoya, Bolarinwa; David, Timothy;

YEAR: 2019     DOI: 10.1016/j.asr.2018.11.013

2018

Latitudinal variation of F-region ionospheric response during three strongest geomagnetic storms of 2015

The latitudinal ionospheric response of the three strongest geomagnetic storms of 2015 of the current solar cycle 24 during 16\textendash19 March 2015, 21\textendash24 June 2015 and 19\textendash22 December 2015 is investigated using the total electron content data derived from a latitudinal chain of Global Positioning System (GPS) receivers extending from 70\textdegreeN to 70\textdegreeS. The storm time perturbations of the ionosphere during main and recovery phase is presented by the GPS derived vertical total electron ...

Paul, Bapan; De, Barin; Guha, Anirban;

YEAR: 2018     DOI: 10.1007/s40328-018-0221-4

Space Weather Events, Hurricanes, and Earthquakes in Mexico in September 2017

In the interval of 4\textendash10 September 2017, the Sun presented multiple solar flares from active region AR 2673. There were also coronal mass ejections that interacted with the Earth\textquoterights magnetosphere. This solar activity produced several space weather events. These events were observed with ground-based instruments of the Mexican Space Weather Service. The Mexican Array RadioTelescope detected highly perturbed solar transits associated with Type I radio emissions from active regions. The Compact Astronom ...

Gonzalez-Esparza, J.; Sergeeva, M.; Corona-Romero, P.; Mejia-Ambriz, J.; Gonzalez, L.; De la Luz, V.; Aguilar-Rodriguez, E.; Rodriguez, M.; andez, Romero-Hern\;

YEAR: 2018     DOI: 10.1029/2018SW001995

Space Weather Events, Hurricanes, and Earthquakes in Mexico in September 2017

In the interval of 4\textendash10 September 2017, the Sun presented multiple solar flares from active region AR 2673. There were also coronal mass ejections that interacted with the Earth\textquoterights magnetosphere. This solar activity produced several space weather events. These events were observed with ground-based instruments of the Mexican Space Weather Service. The Mexican Array RadioTelescope detected highly perturbed solar transits associated with Type I radio emissions from active regions. The Compact Astronom ...

Gonzalez-Esparza, J.; Sergeeva, M.; Corona-Romero, P.; Mejia-Ambriz, J.; Gonzalez, L.; De la Luz, V.; Aguilar-Rodriguez, E.; Rodriguez, M.; andez, Romero-Hern\;

YEAR: 2018     DOI: 10.1029/2018SW001995

Comparison of the Thermospheric Nitric Oxide Emission Observations and the GITM Simulations: Sensitivity to Solar and Geomagnetic Activities

An accurate estimate of the energy budget (heating and cooling) of the ionosphere and thermosphere, especially during space weather events, has been a challenge. The abundance of Nitric Oxide (NO), a minor species in the thermosphere, is an important component of energy balance here because its production comes from energy sources able to break the strong bond of molecular nitrogen, and infrared emissions from NO play an important role in thermospheric cooling. Recent studies have significantly improved our understanding ...

Lin, Cissi; Deng, Yue; Venkataramani, Karthik; Yonker, Justin; Bailey, Scott;

YEAR: 2018     DOI: 10.1029/2018JA025310

Ionospheric response to solar EUV variations: Preliminary results

We investigate the ionospheric response to solar Extreme Ultraviolet (EUV) variations using different proxies, based on solar EUV spectra observed from the Solar Extreme Ultraviolet Experiment (SEE) onboard the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite, the F10.7 index (solar irradiance at 10.7cm), and the Bremen composite Mg-II index during January 2003 to December 2016. The daily mean solar proxies are compared with global mean Total Electron Content (GTEC) values calculated from globa ...

Vaishnav, Rajesh; Jacobi, Christoph; Berdermann, Jens; Schmölter, Erik; Codrescu, Mihail;

YEAR: 2018     DOI: 10.5194/ars-16-157-2018

Investigation of the Causes of the Longitudinal and Solar Cycle Variation of the Electron Density in the Bering Sea and Weddell Sea Anomalies

This paper investigates and quantifies the longitudinal, solar cyclical, and diurnal variation of the ionosphere peak electron density observed by six ionosondes located between 18 and 151\textdegreeE near 60\textdegreeN. Embedded within this region is the Bering Sea anomaly (BSA) where the midnight peak electron density exceeds the midday peak electron density in summer. The BSA is a region West of Alaska extending from approximately 100\textdegree to 200\textdegree east geographic longitude and 55\textdegree to 70\textd ...

Richards, P.; Meier, R.; Chen, Shihping; Dandenault, P.;

YEAR: 2018     DOI: 10.1029/2018JA025413

Statistical Relations Between Field-Aligned Currents and Precipitating Electron Energy Flux

Measurements of field-aligned currents from the Active Magnetosphere and Planetary Electrodynamics Response Experiment are combined with measurements of far ultraviolet emissions from the Global Ultraviolet Imager on the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics satellite to examine the correlation between parallel currents and auroral electron energy flux. The energy flux is derived from the far ultraviolet emissions in the N2 Lyman-Birge-Hopfield bands. We find that energy flux correlates wit ...

Robinson, R.; Zhang, Y.; Anderson, B.; Zanetti, L.; Korth, H.; Fitzmaurice, A.;

YEAR: 2018     DOI: 10.1029/2018GL078718

Observations of Spatial Variations in O/N 2 During an Auroral Substorm Using the Multichannel Downlooking Camera on the VISIONS Rocket

At 0821 UT on 7 February 2013, during an auroral substorm, the NASA VISIONS rocket was launched northward from Poker Flat Research Range on a flight to approximately 750-km altitude that terminated in the Arctic Ocean. A subpayload jettisoned on the up leg carried a multichannel optical imager that looked downward and observed the auroral emission through four narrow passband filters. Three of the channels had sufficiently strong signal to allow a measure of the time evolution of the horizontal extent of the electron auro ...

Hecht, J.; Clemmons, J.; Conde, M.; Hampton, D.; Michell, R.; Rowland, D.; Pfaff, R.; Walterscheid, R.;

YEAR: 2018     DOI: 10.1029/2018JA025288

Daytime O/N2 Retrieval Algorithm for the Ionospheric Connection Explorer (ICON)

The NASA Ionospheric Connection Explorer Far-Ultraviolet spectrometer, ICON FUV, will measure altitude profiles of the daytime far-ultraviolet (FUV) OI 135.6 nm and N2 Lyman-Birge-Hopfield (LBH) band emissions that are used to determine thermospheric density profiles and state parameters related to thermospheric composition; specifically the thermospheric column O/N2 ratio (symbolized as ΣO/N2). This paper describes the algorithm concept that has been adapted and updated from one previous ...

Stephan, Andrew; Meier, R.; England, Scott; Mende, Stephen; Frey, Harald; Immel, Thomas;

YEAR: 2018     DOI: 10.1007/s11214-018-0477-6

Development and Validation of the Whole Atmosphere Community Climate Model With Thermosphere and Ionosphere Extension (WACCM-X 2.0)

Key developments have been made to the NCAR Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension (WACCM-X). Among them, the most important are the self-consistent solution of global electrodynamics, and transport of O+ in the F-region. Other ionosphere developments include time-dependent solution of electron/ion temperatures, metastable O+ chemistry, and high-cadence solar EUV capability. Additional developments of the thermospheric components are improvements to the mo ...

Liu, Han-Li; Bardeen, Charles; Foster, Benjamin; Lauritzen, Peter; Liu, Jing; Lu, Gang; Marsh, Daniel; Maute, Astrid; McInerney, Joseph; Pedatella, Nicholas; Qian, Liying; Richmond, Arthur; Roble, Raymond; Solomon, Stanley; Vitt, Francis; Wang, Wenbin;

YEAR: 2018     DOI: 10.1002/jame.v10.210.1002/2017MS001232

Impacts of Intense Geomagnetic Storms on NavIC / IRNSS System

The Total Electron Content (TEC) of Navigation with the Indian Constellation (NavIC)/ Indian Regional Navigation Satellite System (IRNSS) was examined under the influence of an intense geomagnetic storm occurred on 8 September, 2017, in the low latitudes of the Indian re- gion. One week (3 September, 2017 to 9 September, 2017) data from five stations located in the equatorial region and in the Equatorial Ionization Anomaly (EIA) area in India are collected from Accord NavIC/IRNSS dual-frequency (L5 and S-band) receivers f ...

Desai, Mehulkumar; Shah, Shweta;

YEAR: 2018     DOI: 10.4401/ag-7856

2017

The Far Ultra-Violet Imager on the Icon Mission

ICON Far UltraViolet (FUV) imager contributes to the ICON science objectives by providing remote sensing measurements of the daytime and nighttime atmosphere/ionosphere. During sunlit atmospheric conditions, ICON FUV images the limb altitude profile in the shortwave (SW) band at 135.6 nm and the longwave (LW) band at 157 nm perpendicular to the satellite motion to retrieve the atmospheric O/N2 ratio. In conditions of atmospheric darkness, ICON FUV measures the 135.6 nm recombination emission of O+ ions used to ...

Mende, S.; Frey, H.; Rider, K.; Chou, C.; Harris, S.; Siegmund, O.; England, S.; Wilkins, C.; Craig, W.; Immel, T.; Turin, P.; Darling, N.; Loicq, J.; Blain, P.; Syrstad, E.; Thompson, B.; Burt, R.; Champagne, J.; Sevilla, P.; Ellis, S.;

YEAR: 2017     DOI: 10.1007/s11214-017-0386-0

The Far Ultra-Violet Imager on the Icon Mission

ICON Far UltraViolet (FUV) imager contributes to the ICON science objectives by providing remote sensing measurements of the daytime and nighttime atmosphere/ionosphere. During sunlit atmospheric conditions, ICON FUV images the limb altitude profile in the shortwave (SW) band at 135.6 nm and the longwave (LW) band at 157 nm perpendicular to the satellite motion to retrieve the atmospheric O/N2 ratio. In conditions of atmospheric darkness, ICON FUV measures the 135.6 nm recombination emission of O+ ions used to ...

Mende, S.; Frey, H.; Rider, K.; Chou, C.; Harris, S.; Siegmund, O.; England, S.; Wilkins, C.; Craig, W.; Immel, T.; Turin, P.; Darling, N.; Loicq, J.; Blain, P.; Syrstad, E.; Thompson, B.; Burt, R.; Champagne, J.; Sevilla, P.; Ellis, S.;

YEAR: 2017     DOI: 10.1007/s11214-017-0386-0

The Global-Scale Observations of the Limb and Disk (GOLD) Mission

The Earth\textquoterights thermosphere and ionosphere constitute a dynamic system that varies daily in response to energy inputs from above and from below. This system can exhibit a significant response within an hour to changes in those inputs, as plasma and fluid processes compete to control its temperature, composition, and structure. Within this system, short wavelength solar radiation and charged particles from the magnetosphere deposit energy, and waves propagating from the lower atmosphere dissipate. Understand ...

Eastes, R.; McClintock, W.; Burns, A.; Anderson, D.; Andersson, L.; Codrescu, M.; Correira, J.; Daniell, R.; England, S.; Evans, J.; Harvey, J.; Krywonos, A.; Lumpe, J.; Richmond, A.; Rusch, D.; Siegmund, O.; Solomon, S.; Strickland, D.; Woods, T.; Aksnes, A.; Budzien, S.; Dymond, K.; Eparvier, F.; Martinis, C.; Oberheide, J.;

YEAR: 2017     DOI: 10.1007/s11214-017-0392-2

The Global-Scale Observations of the Limb and Disk (GOLD) Mission

The Earth\textquoterights thermosphere and ionosphere constitute a dynamic system that varies daily in response to energy inputs from above and from below. This system can exhibit a significant response within an hour to changes in those inputs, as plasma and fluid processes compete to control its temperature, composition, and structure. Within this system, short wavelength solar radiation and charged particles from the magnetosphere deposit energy, and waves propagating from the lower atmosphere dissipate. Understand ...

Eastes, R.; McClintock, W.; Burns, A.; Anderson, D.; Andersson, L.; Codrescu, M.; Correira, J.; Daniell, R.; England, S.; Evans, J.; Harvey, J.; Krywonos, A.; Lumpe, J.; Richmond, A.; Rusch, D.; Siegmund, O.; Solomon, S.; Strickland, D.; Woods, T.; Aksnes, A.; Budzien, S.; Dymond, K.; Eparvier, F.; Martinis, C.; Oberheide, J.;

YEAR: 2017     DOI: 10.1007/s11214-017-0392-2

The Global-Scale Observations of the Limb and Disk (GOLD) Mission

The Earth\textquoterights thermosphere and ionosphere constitute a dynamic system that varies daily in response to energy inputs from above and from below. This system can exhibit a significant response within an hour to changes in those inputs, as plasma and fluid processes compete to control its temperature, composition, and structure. Within this system, short wavelength solar radiation and charged particles from the magnetosphere deposit energy, and waves propagating from the lower atmosphere dissipate. Understand ...

Eastes, R.; McClintock, W.; Burns, A.; Anderson, D.; Andersson, L.; Codrescu, M.; Correira, J.; Daniell, R.; England, S.; Evans, J.; Harvey, J.; Krywonos, A.; Lumpe, J.; Richmond, A.; Rusch, D.; Siegmund, O.; Solomon, S.; Strickland, D.; Woods, T.; Aksnes, A.; Budzien, S.; Dymond, K.; Eparvier, F.; Martinis, C.; Oberheide, J.;

YEAR: 2017     DOI: 10.1007/s11214-017-0392-2

Impact of Oscillating IMF B z During 17 March 2013 Storm on the Distribution of Plasma Over Indian Low-Latitude and Mid-Latitude Ionospheric Regions

We show evidence of a positive ionospheric storm occurring simultaneously at the equatorial, low-latitude and mid-latitude ionospheric regions in the Indian sector in response to an intense geomagnetic storm on 17 March 2013. The storm had its onset time coinciding with the local noon. An on-site digisonde at Trivandrum (dip equator) recorded a sharp decrease in the height of F\ region peak in the afternoon, which is a signature of westward electric field associated with a counter electrojet (CEJ). Coupled w ...

Shreedevi, P.; Choudhary, R.;

YEAR: 2017     DOI: 10.1002/2017JA023980

Winter anomaly of the E-layer critical frequency in the nighttime auroral zone

Analysis of the annual variation of the E-layer critical frequency median foE in the nighttime (22-02 LT) auroral zone by the data of several stations of the Northern Hemisphere has shown the median maximum in winter and minimum in summer, even though the summer contribution of solar radiation to foE is greater. Thus, a new phenomenon was discovered\textemdashan foE median winter anomaly in the nighttime auroral zone. Its amplitude (ratio of winter to summer foE figures) can re ...

Deminov, M.; Deminova, G.;

YEAR: 2017     DOI: 10.1134/S0016793217050061

Winter anomaly of the E-layer critical frequency in the nighttime auroral zone

Analysis of the annual variation of the E-layer critical frequency median foE in the nighttime (22-02 LT) auroral zone by the data of several stations of the Northern Hemisphere has shown the median maximum in winter and minimum in summer, even though the summer contribution of solar radiation to foE is greater. Thus, a new phenomenon was discovered\textemdashan foE median winter anomaly in the nighttime auroral zone. Its amplitude (ratio of winter to summer foE figures) can re ...

Deminov, M.; Deminova, G.;

YEAR: 2017     DOI: 10.1134/S0016793217050061

Dual E~\texttimes~B flow responses in the dayside ionosphere to a sudden IMF By rotation

We report for the first time a dual transition state in the dayside ionosphere following a sudden rotation of the interplanetary magnetic field (IMF) in the upstream magnetosheath from IMF By\ \<\ 0 to By\ \>\ 0 during Bz\ \<\ 0. E\ \texttimes\ B drifts respond with different time delays in the dayside auroral zone and high-latitude polar cap with an init ...

Eriksson, S.; Maimaiti, M.; Baker, J.; Trattner, K.; Knipp, D.; Wilder, F.;

YEAR: 2017     DOI: 10.1002/2017GL073374

Total electron content responses to HILDCAAs and geomagnetic storms over South America

Total electron content (TEC) is extensively used to monitor the ionospheric behavior under geomagnetically quiet and disturbed conditions. This subject is of greatest importance for space weather applications. Under disturbed conditions the two main sources of electric fields, which are responsible for changes in the plasma drifts and for current perturbations, are the short-lived prompt penetration electric fields (PPEFs) and the longer-lasting ionospheric disturbance dynamo (DD) electric fields. Both mechanisms modulate ...

Negreti, Patricia; de Paula, Eurico; Candido, Claudia;

YEAR: 2017     DOI: 10.5194/angeo-35-1309-2017

Investigation of the causes of the longitudinal variation of the electron density in the Weddell Sea Anomaly

This paper investigates and quantifies the causes of the Weddell Sea Anomaly (WSA), a region near the tip of South America extending from approximately 30\textdegree to 120\textdegreeW geographic longitude and 50\textdegree to 75\textdegreeS geographic latitude at solar minimum between 2007 and 2010. This region is unusual because the midnight peak electron density exceeds the midday peak electron density in summer. This study is far more quantitative than previous studies because, unlike other models, it assimilates sele ...

Richards, P.; Meier, R.; Chen, Shih-Ping; Drob, D.; Dandenault, P.;

YEAR: 2017     DOI: 10.1002/2016JA023565

2016

Direct observational evidence for disturbance dynamo on the daytime low-latitude ionosphere: A case study based on the 28 June 2013 space weather event

A case of the westward disturbance dynamo (DD) electric field, influencing the daytime equatorial and low-latitude ionosphere, during a geomagnetic storm that occurred on 28\textendash29 June 2013 is presented. The GPS total electron content (TEC) observations from a network of stations in the Indian equatorial, low and middle latitude regions along with the radio beacon TEC, ionosonde, and magnetic field observations are used to study the storm time behavior of the ionosphere. Negative ionospheric storm effects were seen ...

Thampi, Smitha; Shreedevi, P.; Choudhary, R.; Pant, Tarun; Chakrabarty, D.; Sunda, S.; Mukherjee, S.; Bhardwaj, Anil;

YEAR: 2016     DOI: 10.1002/2016JA023037

Positive and negative GPS-TEC ionospheric storm effects during the extreme space weather event of March 2015 over the Brazilian sector

We studied the response of the ionosphere (F region) in the Brazilian sector during extreme space weather event of 17 March 2015 using a large network of 102 GPS- total electron content (TEC) stations. It is observed that the vertical total electron content (VTEC) was severely disturbed during the storm main and recovery phases. A wavelike oscillation with three peaks was observed in the TEC diurnal variation from equator to low latitudes during the storm main phase on 17\textendash18 March 2015. The latitudinal ...

Fagundes, P.; Cardoso, F.; Fejer, B.; Venkatesh, K.; Ribeiro, B.; Pillat, V.;

YEAR: 2016     DOI: 10.1002/2015JA022214

Ionospheric F2 layer responses to total solar eclipses at low and mid-latitude

In this article, we presented ionospheric F2 responses to total solar eclipses on the basis of the data obtained from five (5) equatorial/low-latitude and twenty-seven (27) mid-latitude ionosonde stations, which are within the obscuration percentage of 50\textendash100\% of the path of the total solar eclipses progression. Statistically, the diurnal changes in the F2 layer peak height hmF2 and electron density NmF2, as well as the latitudinal and hemispheric dependence and the contribution of both magnetic and solar activ ...

Adekoya, B.J.; Chukwuma, V.U.;

YEAR: 2016     DOI: 10.1016/j.jastp.2016.01.006

Equatorial/low-latitude; Hemisphere; mid-latitude; NmF2 and hmF2; Solar ionizing radiation

On the latitudinal changes in ionospheric electrodynamics and composition based on observations over the 76-77\textdegreeE meridian from both hemispheres during a geomagnetic storm

The relative contributions of the composition disturbances and the disturbance electric fields in the redistribution of ionospheric plasma is investigated in detail by taking the case of a long-duration positive ionospheric storm that occurred during 18\textendash21 February 2014. GPS total electron content (TEC) data from the Indian Antarctic station, Bharti (69.4\textdegreeS, 76.2\textdegreeE geographic), the northern midlatitude station Hanle (32.8\textdegreeN, 78.9\textdegreeE geographic), northern low-latitude statio ...

Shreedevi, P.; Thampi, Smitha; Chakrabarty, D.; Choudhary, R.; Pant, Tarun; Bhardwaj, Anil; Mukherjee, S.;

YEAR: 2016     DOI: 10.1002/2015JA021841

Geomagnetic storms; High latitude low latitude coupling; Ionosphere; positive ionospheric storm

Average field-aligned current configuration parameterised by solar wind conditions

We present the first large-scale comparison of the spatial distribution of field-aligned currents as measured by the Active Magnetosphere and Planetary Electrodynamics Response Experiment, with the location and brightness of the average auroral oval, determined from the Imager for Magnetopause-to-Aurora Global Exploration far ultraviolet instrument. These distributions are compared under the same interplanetary magnetic field magnitude and clock angle conditions. The field-aligned currents and auroral oval drop to lower l ...

Carter, J.; Milan, S.; Coxon, J.; Walach, M.-T.; Anderson, B.;

YEAR: 2016     DOI: 10.1002/2015JA021567

auroral oval; field-aligned currents

2015

The August 2011 URSI World Day campaign: Initial results

During a 10-day URSI World Day observational campaign beginning on August 1, 2011, an isolated, major geomagnetic storm occurred. On August 5,\ Kp\ reached values of 8-and\ Dst\ dropped to -113\ nT. The occurrence of this isolated storm in the middle of a 10-day URSI World Day campaign provides and unprecedented opportunity to observe the coupling of solar wind energy into the magnetosphere and to evaluate the varied effects that occur in the coupled magnetosphere\text ...

Immel, Thomas; Liu, Guiping; England, Scott; Goncharenko, Larisa; Erickson, Philip; Lyashenko, Mykhaylo; Milla, Marco; Chau, Jorge; Frey, Harald; Mende, Stephen; Zhou, Qihou; Stromme, Anja; Paxton, Larry;

YEAR: 2015     DOI: 10.1016/j.jastp.2015.09.005

Aeronomy; Ionosphere; Radar; thermosphere

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;

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

geomagnetic storm; Ionospheric total electron content; low latitude ionosphere

Solar illumination control of ionospheric outflow above polar cap arcs

We measure the flux density, composition, and energy of outflowing ions above the polar cap, accelerated by quasi-static electric fields parallel to the magnetic field and associated with polar cap arcs, using Cluster. Mapping the spacecraft position to its ionospheric foot point, we analyze the dependence of these parameters on the solar zenith angle (SZA). We find a clear transition at SZA between \~94\textdegree and \~107\textdegree, with the O+ flux higher above the sunlit ionosphere. This dependence on the ...

Maes, L.; Maggiolo, R.; De Keyser, J.; Dandouras, I.; Fear, R.; Fontaine, D.; Haaland, S.;

YEAR: 2015     DOI: 10.1002/2014GL062972

cold ion outflow; ion upflow; polar cap arc; polar ionosphere; polar wind; solar illumination

2014

GPS derived TEC and foF2 variability at an equatorial station and the performance of IRI-model

The ionosphere induces a time delay in transionospheric radio signals such as the Global Positioning System (GPS) signal. The Total Electron Content (TEC) is a key parameter in the mitigation of ionospheric effects on transionospheric signals. The delay in GPS signal induced by the ionosphere is proportional to TEC along the path from the GPS satellite to a receiver. The diurnal monthly and seasonal variations of ionospheric electron content were studied during the year 2010, a year of extreme solar minimum (F10.7\ = ...

Adebiyi, S.J.; Odeyemi, O.O.; Adimula, I.A.; Oladipo, O.A.; Ikubanni, S.O.; Adebesin, B.O.; Joshua, B.W.;

YEAR: 2014     DOI: 10.1016/j.asr.2014.03.026

Equator; IRI-model; NmF2; Prediction; TEC

GPS derived TEC and foF2 variability at an equatorial station and the performance of IRI-model

The ionosphere induces a time delay in transionospheric radio signals such as the Global Positioning System (GPS) signal. The Total Electron Content (TEC) is a key parameter in the mitigation of ionospheric effects on transionospheric signals. The delay in GPS signal induced by the ionosphere is proportional to TEC along the path from the GPS satellite to a receiver. The diurnal monthly and seasonal variations of ionospheric electron content were studied during the year 2010, a year of extreme solar minimum (F10.7\ = ...

Adebiyi, S.J.; Odeyemi, O.O.; Adimula, I.A.; Oladipo, O.A.; Ikubanni, S.O.; Adebesin, B.O.; Joshua, B.W.;

YEAR: 2014     DOI: 10.1016/j.asr.2014.03.026

Equator; IRI-model; NmF2; Prediction; TEC

GPS derived TEC and foF2 variability at an equatorial station and the performance of IRI-model

The ionosphere induces a time delay in transionospheric radio signals such as the Global Positioning System (GPS) signal. The Total Electron Content (TEC) is a key parameter in the mitigation of ionospheric effects on transionospheric signals. The delay in GPS signal induced by the ionosphere is proportional to TEC along the path from the GPS satellite to a receiver. The diurnal monthly and seasonal variations of ionospheric electron content were studied during the year 2010, a year of extreme solar minimum (F10.7\ = ...

Adebiyi, S.J.; Odeyemi, O.O.; Adimula, I.A.; Oladipo, O.A.; Ikubanni, S.O.; Adebesin, B.O.; Joshua, B.W.;

YEAR: 2014     DOI: 10.1016/j.asr.2014.03.026

Equator; IRI-model; NmF2; Prediction; TEC

GPS L1-Frequency Observations of Equatorial Scintillations and Irregularity Zonal Velocities

In this work, the climatology of ionospheric scintillations at global positioning system (GPS) L-band frequency and the zonal drift velocities of scintillation-producing irregularities were depicted for the equatorial observatory of S\~ao Luis (2.33\textdegreeS; 44.21\textdegreeW; dip latitude 1.3\textdegreeS), Brazil. This is the first time that the hourly, monthly, and seasonal variations of scintillations and irregularity zonal drifts at S\~ao Luis were characterized during periods of different solar activity levels (f ...

Muella, Marcio; de Paula, Eurico; Jonah, Olusegun;

YEAR: 2014     DOI: 10.1007/s10712-013-9252-0

GPS; Ionospheric drifts; ionospheric irregularities; Ionospheric scintillation

Height-integrated Pedersen conductivity in both E and F regions from COSMIC observations

Altitudinal distribution of Joule heating is very important to the thermosphere and ionosphere, which is roughly proportional to the Pedersen conductance at high latitudes. Based on the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites observations from 2008 to 2011, the height-integrated Pedersen conductivities in both E (100\textendash150\ km) and F (150\textendash600\ km) regions and their ratio γPγP (PE/< ...

Sheng, Cheng; Deng, Yue; Yue, Xinan; Huang, Yanshi;

YEAR: 2014     DOI: 10.1016/j.jastp.2013.12.013

COSMIC; Interhemispheric asymmetry; Joule heating; Pedersen conductivity

Ionospheric response to magnetic activity at low and mid-latitude stations

The F2-layer response to the moderate storm of 5\textendash7 April 2010 was investigated using data from two equatorial stations (Ilorin: lat. 8.5\textdegreeN, 4.5\textdegreeE; Kwajalein: lat. 9\textdegreeN, long. 167.2\textdegreeE) and mid-latitude (San Vito: lat. 40.6\textdegreeN, long. 17.8\textdegreeE; Pruhonice: lat. 50\textdegreeN, long. 14.6\textdegreeE). Before storm commencement, enhancement, and depletion of NmF2 values were observed in the equatorial and mid-latitude stations, respectively, in ...

Adebiyi, Shola; Adimula, Isaac; Oladipo, Olusola; Joshua, Benjamin; Adebesin, Babatunde; Ikubanni, Stephen;

YEAR: 2014     DOI: 10.2478/s11600-014-0205-x

Electric field; equatorial station; Ionosphere; mid-latitude; moderate storm; positive phase

Ionospheric response to magnetic activity at low and mid-latitude stations

The F2-layer response to the moderate storm of 5\textendash7 April 2010 was investigated using data from two equatorial stations (Ilorin: lat. 8.5\textdegreeN, 4.5\textdegreeE; Kwajalein: lat. 9\textdegreeN, long. 167.2\textdegreeE) and mid-latitude (San Vito: lat. 40.6\textdegreeN, long. 17.8\textdegreeE; Pruhonice: lat. 50\textdegreeN, long. 14.6\textdegreeE). Before storm commencement, enhancement, and depletion of NmF2 values were observed in the equatorial and mid-latitude stations, respectively, in ...

Adebiyi, Shola; Adimula, Isaac; Oladipo, Olusola; Joshua, Benjamin; Adebesin, Babatunde; Ikubanni, Stephen;

YEAR: 2014     DOI: 10.2478/s11600-014-0205-x

Electric field; equatorial station; Ionosphere; mid-latitude; moderate storm; positive phase

Solar filament impact on 21 January 2005: Geospace consequences

On 21 January 2005, a moderate magnetic storm produced a number of anomalous features, some seen more typically during superstorms. The aim of this study is to establish the differences in the space environment from what we expect (and normally observe) for a storm of this intensity, which make it behave in some ways like a superstorm. The storm was driven by one of the fastest interplanetary coronal mass ejections in solar cycle 23, containing a piece of the dense erupting solar filament material. The momentum of the mas ...

Kozyra, J.; Liemohn, M.; Cattell, C.; De Zeeuw, D.; Escoubet, C.; Evans, D.; Fang, X.; Fok, M.-C.; Frey, H.; Gonzalez, W.; Hairston, M.; Heelis, R.; Lu, G.; Manchester, W.; Mende, S.; Paxton, L.; Rastaetter, L.; Ridley, A.; Sandanger, M.; Soraas, F.; Sotirelis, T.; Thomsen, M.; Tsurutani, B.; Verkhoglyadova, O.;

YEAR: 2014     DOI: 10.1002/2013JA019748

cold dense plasma sheet; Equatorial anomaly; magnetotail; precipitation; prompt penetration electric field; solar filament

Solar filament impact on 21 January 2005: Geospace consequences

On 21 January 2005, a moderate magnetic storm produced a number of anomalous features, some seen more typically during superstorms. The aim of this study is to establish the differences in the space environment from what we expect (and normally observe) for a storm of this intensity, which make it behave in some ways like a superstorm. The storm was driven by one of the fastest interplanetary coronal mass ejections in solar cycle 23, containing a piece of the dense erupting solar filament material. The momentum of the mas ...

Kozyra, J.; Liemohn, M.; Cattell, C.; De Zeeuw, D.; Escoubet, C.; Evans, D.; Fang, X.; Fok, M.-C.; Frey, H.; Gonzalez, W.; Hairston, M.; Heelis, R.; Lu, G.; Manchester, W.; Mende, S.; Paxton, L.; Rastaetter, L.; Ridley, A.; Sandanger, M.; Soraas, F.; Sotirelis, T.; Thomsen, M.; Tsurutani, B.; Verkhoglyadova, O.;

YEAR: 2014     DOI: 10.1002/2013JA019748

cold dense plasma sheet; Equatorial anomaly; magnetotail; precipitation; prompt penetration electric field; solar filament



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