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Found 25 entries in the Bibliography.
Showing entries from 1 through 25
| 2022 |
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A Simulation Study on the Variation of Thermospheric O/N2 With Solar Activity The ratio of number density of atomic oxygen (O) to that of molecular nitrogen (N2) in the thermosphere (O/N2) on the constant pressure surface, which has complex temporal and spatial characteristics, is widely regarded as an important parameter connecting the terrestrial thermosphere and daytime ionosphere. Previous studies demonstrated that the thermospheric O/N2 increases with increasing solar activity, and the changes in O/N2 with solar activity show significant difference between winter and summer hemispheres. However, ... Li, Zhongli; Luan, Xiaoli; Lei, Jiuhou; Ren, Dexin; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2022 DOI: 10.1029/2022JA030305 circulation; O/N2; photochemistry; solar cycle; thermosphere |
| 2021 |
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The Universal Time Variations of the Intensity of Afternoon Aurora in Equinoctial Seasons The afternoon auroral emissions are investigated in the equinoxes for geomagnetically quiet conditions (Kp = 1) using auroral images from ultraviolet imager (UVI) aboard the Polar satellite. They are compared with solar illumination effects (the solar zenith angle [SZA] and the consequent ionospheric conductivity) and the dipole tilt angle, as well as the observational region 1 upward field-aligned currents (FACs) from AMPERE data. The averaged afternoon auroral emissions have pronounced universal time (UT) variations with v ... Wang, Lingmin; Luan, Xiaoli; Lei, Jiuhou; Lynch, Kristina; Zhang, Binzheng; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2021 DOI: 10.1029/2020JA028504 afternoon auroral emissions; auroral hot spots; dipole tilt angle; region 1 upward FACs; solar zenith angle; UT variations |
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Equatorial Ionization Anomaly Variations During Geomagnetic Storms The equatorial ionization anomaly (EIA) was discovered in the 1940s. Since then, the research on ionospheric storm effects at the equatorial and low latitudes has become one of the hottest topics in the ionospheric community. During the past 2 decades, large amounts of ionospheric and thermospheric data from the ground-based and satellite-borne observations and also from the novel capability of three-dimensional numerical models stimulated the ionospheric weather studies. Recent scientific progresses on the EIA response to g ... Published by: Published on: YEAR: 2021 DOI: 10.1002/9781119815617.ch13 Geomagnetic storms; Equatorial ionization anomaly; equatorial ionospheric response; equatorial regions; low latitude regions; physical mechanisms |
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Global Effects of a Polar Solar Eclipse on the Coupled Magnetosphere-Ionosphere System It is well-known that solar eclipses can significantly impact the ionosphere and thermosphere, but how an eclipse influences the magnetosphere-ionosphere system is still unknown. Using a coupled magnetosphere-ionosphere-thermosphere model, we examined the impact on geospace of the northern polar-region eclipse that occurred on June 10, 2021. The simulations reveal that the eclipse-induced reduction in polar ionospheric conductivity causes large changes in field-aligned current, cross-polar cap potential and auroral activity. ... Chen, Xuetao; Dang, Tong; Zhang, Binzheng; Lotko, William; Pham, Kevin; Wang, Wenbin; Lin, Dong; Sorathia, Kareem; Merkin, Viacheslav; Luan, Xiaoli; Dou, Xiankang; Luo, Bingxian; Lei, Jiuhou; Published by: Geophysical Research Letters Published on: YEAR: 2021 DOI: 10.1029/2021GL096471 auroral activity; magnetosphere-ionosphere coupling; polar solar eclipse |
| 2019 |
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Isolated Auroral Spots Observed by DMSP/SSUSI This work reports auroral spots event observed by the SSUSI instruments on board the DMSP spacecraft between 22 and 23 July 2009 during the recovery phase of a moderate magnetic storm. The spots were observed between 18:00 and 02:00 magnetic local time and stayed at ~60\textdegree magnetic latitude. They lasted for ~10 hr and corotated with ~64\% of the Earth\textquoterights rotational speed. In situ observations indicate that the isolated auroral spots were produced by energetic ions at energies between 10 and 240 keV, w ... Zhou, Su; Luan, Xiaoli; Pierrard, Viviane; Han, Desheng; Published by: Journal of Geophysical Research: Space Physics Published on: 10/2019 YEAR: 2019 DOI: 10.1029/2019JA026853 |
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Li, Zhenxing; Luan, Xiaoli; Ren, Dexin; Published by: Journal of Geophysical Research: Space Physics Published on: |
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Topside ionospheric conditions during the 7—8 September 2017 geomagnetic storm The uplooking total electron contents (TECs) from the GRACE, SWARM-A, TerraSAR-X, and MetOp-A satellites and in situ electron density (Ne) from SWARM-A were utilized to investigate the topside ionospheric conditions during the 7–8 September 2017 geomagnetic storm. The rate of TEC index (ROTI) and rate of density index (RODI), which are derivative indices of TEC and Ne, respectively, were also used to characterize the topside ionospheric irregularities. The main results of this study are as follows: (1) There were significa ... Jimoh, Oluwaseyi; Lei, Jiuhou; Zhong, Jiahao; Owolabi, Charles; Luan, Xiaoli; Dou, Xiankang; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2019 DOI: 10.1029/2019JA026590 |
| 2018 |
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The Lyman-Birge-Hopfield-long band dayglow emissions near 1,700\ \r A, which were observed by the ultraviolet imager on board Polar satellite, are characterized as a cosine-like function of the solar zenith angle. These emissions are mainly excited by the solar extreme ultraviolet produced photoelectrons acting on the nitrogen molecules. The amplitude and phase factors are used to quantify the cosine-like function and subsequently develop a dayglow model. In this study, a model is developed by considering broader day ... Wang, Lingmin; Luan, Xiaoli; Lei, Jiuhou; Dou, Xiankang; Published by: Space Weather Published on: 07/2018 YEAR: 2018 DOI: 10.1029/2018SW001954 |
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In this study, multiple data sets from Beidou geostationary orbit satellites total electron contents (TECs), ionosonde, meteor radar, magnetometer, and model simulations have been used to investigate the ionospheric responses in the Asian-Australian sector during the September 2017 geomagnetic storm. It was found that long-duration daytime TEC enhancements that lasted from 7 to 12 September 2017 were observed by the Beidou geostationary orbit satellite constellation. This is a unique event as the prominent TEC enhancement ... Lei, Jiuhou; Huang, Fuqing; Chen, Xuetao; Zhong, Jiahao; Ren, Dexin; Wang, Wenbin; Yue, Xinan; Luan, Xiaoli; Jia, Mingjiao; Dou, Xiankang; Hu, Lianhuan; Ning, Baiqi; Owolabi, Charles; Chen, Jinsong; Li, Guozhu; Xue, Xianghui; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2018 YEAR: 2018 DOI: 10.1029/2017JA025166 |
| 2017 |
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Solar cycle variations of thermospheric O/N 2 longitudinal pattern from TIMED/GUVI Thermospheric composition (O/N2 ratio) is well known to have a great impact on the variation of daytime ionospheric electron density. This study aims to investigate the local time, seasonal, and solar cycle variations of the O/N2 longitudinal pattern in both hemispheres during daytime in solstices. The O/N2 data used are from TIMED/Global Ultraviolet Imager observations made over a solar cycle for geomagnetically quiet conditions. The main findings are as follows: (1) The O/N2 l ... Luan, Xiaoli; Wang, Wenbin; Burns, Alan; Dou, Xiankang; Published by: Journal of Geophysical Research: Space Physics Published on: 03/2018 YEAR: 2017 DOI: 10.1002/jgra.v122.210.1002/2016JA023696 |
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Solar cycle variations of thermospheric O/N2 longitudinal pattern from TIMED/GUVI
Luan, Xiaoli; Wang, Wenbin; Burns, Alan; Dou, Xiankang; Published by: Journal of Geophysical Research: Space Physics Published on: |
| 2016 |
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Solar activity dependence of nightside aurora in winter conditions The dependence of the nightside (21:00\textendash03:00 MLT; magnetic local time) auroral energy flux on solar activity was quantitatively studied for winter/dark and geomagnetically quiet conditions. Using data combined from Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics/Global Ultraviolet Imager and Defense Meteorological Satellite Program/Special Sensor Ultraviolet Spectrographic Imager observations, we separated the effects of geomagnetic activity from those of solar flux on the nightside auroral precipit ... Zhou, Su; Luan, Xiaoli; Dou, Xiankang; Published by: Journal of Geophysical Research: Space Physics Published on: 02/2016 YEAR: 2016 DOI: 10.1002/2015JA021865 auroral conjugate effects; auroral geomagnetic activity variation; auroral imaging scaling; auroral solar cycle variation |
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This paper quantitatively analyzes the auroral hemispheric power (HP) and its interhemispheric asymmetry as a function of universal time (UT) for geomagnetically quiet conditions (Kp 1\textendash3) from Thermosphere Ionosphere Mesosphere Energetics and Dynamics/Global Ultraviolet Imager (TIMED/GUVI) imaging observations. The HP variation with UT can be approximately characterized as two cases: One is for similar HP variations in the equinoxes in the Northern Hemisphere and for the June solstices of both hemispher ... Luan, Xiaoli; Wang, Wenbin; Burns, Alan; Dou, Xiankang; Published by: Journal of Geophysical Research: Space Physics Published on: 01/2016 YEAR: 2016 DOI: 10.1002/2016JA022730 |
| 2015 |
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Longitudinal variations of the nighttime E layer electron density in the auroral zone Longitudinal variations of the nighttime E layer electron density (21:00\textendash03:00 magnetic local time) in the auroral zone are investigated, and their sources are discussed in terms of auroral precipitation and solar radiation. The electron density data used in this study are retrieved from Constellation Observing System for Meteorology, Ionosphere, and Climate radio occultation observations during 2006\textendash2009 under quiet geomagnetic activity (Kp <= 3) and solar minimum conditions. The mai ... Luan, Xiaoli; Wang, Wenbin; Dou, Xiankang; Burns, Alan; Yue, Xinan; Published by: Journal of Geophysical Research: Space Physics Published on: 01/2015 YEAR: 2015 DOI: 10.1002/2014JA020610 auroral E layer; hemispheric asymmetry; longitudinal variations; Seasonal variations |
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Longitudinal variations of the nighttime E layer electron density in the auroral zone
Luan, Xiaoli; Wang, Wenbin; Dou, Xiankang; Burns, Alan; Yue, Xinan; Published by: Journal of Geophysical Research: Space Physics Published on: |
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Solar Activity Dependence of Night Side Aurora in Winter/Dark Conditions
Luan, Xiaoli; Zhou, Su; Dou, Xiankang; Published by: Published on: |
| 2014 |
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Simulations of the equatorial thermosphere anomaly: Geomagnetic activity modulation The modulation of geomagnetic activity on the equatorial thermosphere anomaly (ETA) in thermospheric temperature under the high solar activity condition is investigated using the Thermosphere Ionosphere Electrodynamics General Circulation Model simulations. The model simulations during the geomagnetically disturbed interval, when the north-south component of the interplanetary magnetic field (Bz) oscillates between southward and northward directions, are analyzed and also compared with those under the ... Lei, Jiuhou; Wang, Wenbin; Thayer, Jeffrey; Luan, Xiaoli; Dou, Xiankang; Burns, Alan; Solomon, Stanley; Published by: Journal of Geophysical Research: Space Physics Published on: 08/2014 YEAR: 2014 DOI: 10.1002/2014JA020152 equatorial thermosphere anomaly; geomagnetic activity; ion-neutral coupling; positive ionospheric storm |
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Longitudinal and Hemispheric Variations of Nighttime E-Layer Electron Density in the Auroral Zone
Luan, Xiaoli; Wang, Wenbin; Dou, Xiankang; Burns, Alan; Yue, Xinan; Published by: Published on: |
| 2013 |
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Annual asymmetry in thermospheric density: Observations and simulations [1]\ In this paper, the Challenging Minisatellite Payload (CHAMP) and Gravity Recovery and Climate Experiment (GRACE) observations during 2002\textendash2010 are utilized to study the variation of the annual asymmetry in thermospheric density at 400 km under low solar activity condition (F10.7 = 80) based on the method of empirical orthogonal functions (EOFs). The derived asymmetry index (AI) in thermospheric density from the EOF analysis shows a strong latitudinal variation at night but varies a little with ... Lei, Jiuhou; Dou, Xiankang; Burns, Alan; Wang, Wenbin; Luan, Xiaoli; Zeng, Zhen; Xu, JiYao; Published by: Journal of Geophysical Research: Space Physics Published on: 05/2013 YEAR: 2013 DOI: 10.1002/jgra.50253 Annual asymmetry; Empirical orthogonal functions; Sun-Earth distance; Upper thermosphere |
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A superposed epoch analysis is performed to investigate the relative impact of the solar wind/interplanetary magnetic field (IMF) on geomagnetic activity, auroral hemispheric power, and auroral morphology during corotating interaction regions (CIRs) events between 2002 and 2007, when auroral images from Thermosphere Ionosphere Mesosphere Energetics and Dynamics/Global Ultraviolet Imager were available. Four categories of CIRs have been compared. These were classified by the averaged IMF Bz and the time of maximum solar wi ... Luan, Xiaoli; Wang, Wenbin; Lei, Jiuhou; Burns, Alan; Dou, Xiankang; Xu, JiYao; Published by: Journal of Geophysical Research: Space Physics Published on: 03/2013 YEAR: 2013 DOI: 10.1002/jgra.50195 auroral morphology; corotating interaction regions; solar wind/IMF forcing |
| 2012 |
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Annual and semiannual variations of thermospheric density: EOF analysis of CHAMP and GRACE data
Lei, Jiuhou; Matsuo, Tomoko; Dou, Xiankang; Sutton, Eric; Luan, Xiaoli; Published by: Journal of Geophysical Research: Space Physics Published on: |
| 2011 |
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Luan, Xiaoli; Wang, Wenbin; Burns, Alan; Solomon, Stanley; Zhang, Yongliang; Paxton, L.; Xu, JiYao; Published by: Journal of Geophysical Research Published on: Jan-01-2011 YEAR: 2011 DOI: 10.1029/2010JA016051 |
| 2010 |
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Seasonal and hemispheric variations of the total auroral precipitation energy flux from TIMED/GUVI
Luan, Xiaoli; Wang, Wenbin; Burns, Alan; Solomon, Stanley; Zhang, Yongliang; Paxton, L.; Published by: Journal of Geophysical Research Published on: Jan-01-2010 YEAR: 2010 DOI: 10.1029/2009JA015063 |
| 2009 |
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Luan, Xiaoli; Wang, Wenbin; Burns, Alan; Solomon, Stanley; Zhang, Yongliang; Paxton, L.; Published by: Geophysical Research Letters Published on: Jan-01-2009 YEAR: 2009 DOI: 10.1029/2009GL040825 |
| 2008 |
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Variations of Auroral Electron Precipitation Measured by TIMED/GUVI
Luan, X; Wang, W; Burns, A; Zhang, Y; Solomon, S; Published by: Published on: |
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