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Found 644 entries in the Bibliography.
Showing entries from 1 through 50
| 2022 |
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A paper A new method to subtract dayglow for auroral observation of SSUSI in LBH ranges based on the improved AURIC reports a new method to estimate the dayglow intensities in DMSP/SSUSI LBH bands using an improved AURIC model. It is claimed that the new method offers a better alternative than the SSUSI operational algorithm which uses a data based table. The paper showed a few examples and compared them with SSSUI operational results. The comparison indicated that the new method didn t offer any improvement and provided net ... Zhang, Yongliang; Paxton, Larry; Schaefer, Robert; Published by: Journal of Atmospheric and Solar-Terrestrial Physics Published on: mar YEAR: 2022 DOI: 10.1016/j.jastp.2022.105833 |
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Thermospheric density enhancement and limb O 130.4 nm radiance increase during geomagnetic storms We explore a connection between thermospheric density enhancement and increase in thermospheric O 130.4 nm radiance. We observe TIMED/GUVI enhancements in the limb 130.4 nm radiances at ∼400 and ∼520 km on the dayside during four intense geomagnetic storms in 2003 and 2004. The enhancements were well correlated with Dst and CHAMP total neutral density at 400 km which represents O density as O is the dominant species at those altitudes. At the 400 and 520 km altitudes, O 130.4 nm emissions are mostly created by two ... Zhang, Yongliang; Paxton, Larry; Schaefer, R.; Published by: Journal of Atmospheric and Solar-Terrestrial Physics Published on: mar YEAR: 2022 DOI: 10.1016/j.jastp.2022.105830 FUV emission; Geomagentic storms; neutral density; thermosphere |
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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 |
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Simultaneous Detection of Signatures of Conjugate Photoelectrons in the Ionosphere and Thermosphere We investigate the impact of conjugate photoelectrons (CPEs) on the topside (∼600 km altitude) ionosphere at low and midlatitudes using measurements of the ion temperature, density, and composition from the first Republic of China satellite during a period of the high to moderate solar activity (March 1999 to June 2004). Elevated ion temperatures and densities are observed in the dark Northern American-Atlantic sector during the December solstice and in the Australian sector during the June solstice. The oxygen ion fractio ... Kil, Hyosub; Paxton, Larry; Schaefer, Robert; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2022 DOI: 10.1029/2021JA030121 airglow; conjugate photoelectron; ion density; ion temperature |
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Transpolar Arcs: Seasonal Dependence Identified by an Automated Detection Algorithm Transpolar arcs (TPAs) are auroral features that occur polewards of the main auroral oval suggesting that the magnetosphere has acquired a complicated magnetic topology. They are primarily a northward interplanetary magnetic field (IMF) auroral phenomenon, and their formation and evolution have no single explanation that is unanimously agreed upon. An automated detection algorithm has been developed to detect the occurrence of TPAs in UV images captured from the Special Sensor Ultraviolet Spectrographic Imager (SSUSI) instru ... Bower, G.; Milan, S.; Paxton, L.; Imber, S.; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2022 DOI: 10.1029/2021JA029743 |
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Thermospheric density enhancement and limb O 130.4 nm radiance increase during geomagnetic storms
Zhang, Yongliang; Paxton, Larry; Schaefer, R; Published by: Journal of Atmospheric and Solar-Terrestrial Physics Published on: |
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Zhang, Yongliang; Paxton, Larry; Schaefer, Robert; Published by: Journal of Atmospheric and Solar-Terrestrial Physics Published on: |
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Occurrence statistics of horse collar aurora
Bower, Gemma; Milan, Stephen; Paxton, Larry; Anderson, Brian; Published by: Journal of Geophysical Research: Space Physics Published on: |
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Empirical modelling of SSUSI derived auroral ionization rates
Bender, Stefan; Espy, Patrick; Paxton, Larry; Published by: Published on: |
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Kil, Hyosub; Chang, Hyeyeon; Lee, Woo; Paxton, Larry; Sun, Andrew; Lee, Jiyun; Published by: Journal of Geophysical Research: Space Physics Published on: |
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Hong, Junseok; Kil, Hyosub; Lee, Woo; Kwak, Young-Sil; Choi, Byung-Kyu; Paxton, Larry; Published by: Published on: |
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Novel Observations of the Aurora (NOA) from New Platforms
Paxton, LJ; Hibbitts, CA; Swartz, WH; Published by: Published on: |
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Increased Sensitivity FUV Spectrographic Imager
Schaefer, RK; Paxton, LJ; Zhang, Y; Kil, H; Liou, K; Published by: Published on: |
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Statistics of transpolar arcs identified by an automated detection algorithm
Bower, Gemma; Milan, Steve; Paxton, Larry; Imber, Suzie; Published by: Published on: |
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Height-integrated polar cap conductances during an average substorm
Carter, Jennifer; Milan, Steven; Lester, Mark; Forsyth, Colin; Paxton, Larry; Gjerloev, Jesper; Anderson, Brian; Published by: Published on: |
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Lobe Reconnection and Cusp-Aligned Auroral Arcs Abstract Following the St. Patrick s Day (17 March) geomagnetic storm of 2013, the interplanetary magnetic field had near-zero clock angle for almost two days. Throughout this period multiple cusp-aligned auroral arcs formed in the polar regions; we present observations of, and provide a new explanation for, this poorly understood phenomenon. The arcs were observed by auroral imagers onboard satellites of the Defense Meteorological Satellite Program. Ionospheric flow measurements and observations of energetic particles from ... Milan, S.; Bower, G.; Carter, J.; Paxton, L.; Anderson, B.; Hairston, M.; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2022 DOI: https://doi.org/10.1029/2021JA030089 |
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Hemispheric Asymmetry in the Auroral Ionosphere-Thermosphere System
Liou, K; Zhang, Y-L; Paxton, LJ; Kil, H; Schaefer, R; Published by: Published on: |
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This study presents multi-instrument observations of persistent large-scale traveling ionosphere/atmospheric disturbances (LSTIDs/LSTADs) observed during moderately increased auroral electrojet activity and a sudden stratospheric warming in the polar winter hemisphere. The Global Ultraviolet Imager (GUVI), Gravity field and steady-state Ocean Circulation Explorer, Scanning Doppler Imaging Fabry–Perot Interferometers, and the Poker Flat Incoherent Scatter Radar are used to demonstrate the presence of LSTIDs/LSTADs between 1 ... Bossert, Katrina; Paxton, Larry; Matsuo, Tomoko; Goncharenko, Larisa; Kumari, Komal; Conde, Mark; Published by: Geophysical Research Letters Published on: YEAR: 2022 DOI: 10.1029/2022GL099901 |
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Revisiting the November 2004 Superstorm: Lessons from the TIMED/GUVI Limb Observation We revisited the November 2004 superstorm by analyzing data from TIMED/GUVI, a FUV spectrograph imager. The GUVI 135.6 nm limb radiances at 520-km tangent altitude 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 ... Zhang, Yongliang; Wang, Wenbin; Paxton, Larry; Schaefer, Robert; Huang, Chaosong; Published by: 44th COSPAR Scientific Assembly. Held 16-24 July Published on: |
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Thermospheric conditions associated with the loss of 40 Starlink satellites We analyzed far ultraviolet data from Defense Meteorological Satellite Program (DMSP)/Special Sensor Ultraviolet Spectrographic Imager (SSUSI) and Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED)/Global Ultraviolet Imager (GUVI) and found significant changes in the thermospheric density and composition during the 3–5 February 2022 storm when 40 Starlink satellites started to re-enter the atmosphere associated with increased neutral drag at an altitude around 210 km. The standard NRLMSISE-00 model predicts ... Zhang, Yongliang; Paxton, Larry; Schaefer, Robert; Swartz, William; Published by: Space Weather Published on: YEAR: 2022 DOI: 10.1029/2022SW003168 |
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Solar cycle, seasonal, and dawn-to-dusk variations of the hydrogen in the upper thermosphere Atomic hydrogen is one of the least-understood atmospheric constituents whose distribution is important for the studies of aeronomy and magnetospheric physics. Using 6 years of space-based daytime Lyman-α observations from 2002 to 2007, we quantify the solar cycle, seasonal, and dawn-to-dusk variations of the H density in the upper thermosphere. Our results show evident dawn-dusk asymmetry of the exobase H density that decreases nearly linearly from dawn to dusk. The observed asymmetry in terms of the dawn-dusk density rati ... Wan, Changan; Qin, Jianqi; Paxton, Larry; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2022 DOI: 10.1029/2022JA030504 |
| 2021 |
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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 |
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Storm-Time Neutral Composition Changes in the Upper Atmosphere During geomagnetic storms, energy inputs, such as particle precipitation and Joule heating from the magnetosphere and solar wind, create significant disturbances in the upper atmosphere in the form of changes in the thermospheric density and temperature and, more important, composition, such as O/N 2 column density ratio, nitric oxide (NO) density, and atomic nitrogen (N) density. The composition changes control the ionosphere and have a feedback effect on thermospheric temperature and density due to a cooling effect of enha ... Zhang, Yongliang; Paxton, Larry; Published by: Published on: YEAR: 2021 DOI: 10.1002/9781119815631.ch7 far ultraviolet observations; storm-time neutral composition changes; thermospheric nitric oxide variations; traveling atmospheric disturbance; traveling ionosphere disturbance; upper atmosphere |
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FTA: A Feature Tracking Empirical Model of Auroral Precipitation The Feature Tracking of Aurora (FTA) model was constructed using 1.5 years of Polar Ultraviolet Imager data and is based on tracking a cumulative energy grid in 96 magnetic local time (MLT) sectors. The equatorward boundary, poleward boundary, and 19 cumulative energy bins are tracked with the energy flux and the latitudinal position. With AE increasing, the equatorward boundary moves to lower latitudes everywhere, while the poleward boundary moves poleward in the 2300–0300 MLT region and equatorward in other MLT sectors. ... Wu, Chen; Ridley, Aaron; DeJong, Anna; Paxton, Larry; Published by: Space Weather Published on: YEAR: 2021 DOI: 10.1029/2020SW002629 Auroral Precipitation Model; cumulative energy bins; data-model comparisons; M-I coupling; statistical analyses |
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Exploring the Upper Atmosphere In this chapter, we describe how we can understand the state of the upper atmosphere (the ionosphere, thermosphere, and aurora) using optical observations and how one produces a global view of the Earth s upper atmosphere from optical remote sensing, especially using far ultraviolet (FUV) wavelengths, to advance our understanding of the near Earth space environment. We examine the choice of optical signatures, the basic science behind the signatures, and the techniques for observations. Examples of the technique as applied t ... Paxton, Larry; Zhang, Yongliang; Kil, Hyosub; Schaefer, Robert; Published by: Published on: YEAR: 2021 DOI: 10.1002/9781119815631.ch23 Earth space environment; far ultraviolet wavelengths; high-latitude regions; optical remote sensing; solar wind; upper atmosphere |
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Lee, Woo; Kil, Hyosub; Paxton, Larry; Published by: Journal of Geophysical Research: Space Physics Published on: |
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Space Physics and Aeronomy, Upper Atmosphere Dynamics and Energetics
Published by: Published on: |
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Mlynczak, Martin; Yee, Jeng-Hwa; Paxton, Larry; Ridley, Aaron; Published by: Published on: |
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Carter, Jennifer; Samsonov, AA; Milan, Stephen; Branduardi-Raymont, Graziella; Ridley, Aaron; Paxton, Larry; Anderson, Brian; Waters, Colin; Edwards, Thomas; Published by: Journal of Geophysical Research: Space Physics Published on: |
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Far Ultraviolet Hyperspectral Imager: NASA's TIMED/GUVI and DMSP SSUSI
Paxton, Larry; Zhang, Yongliang; Schaefer, Robert; Kil, Hyosub; Wolven, Brian; Romeo, Giuseppe; Yonker, Justin; Published by: Published on: |
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Non-storm time thermospheric O/N 2 depletion and NO enhancement
Zhang, Yongliang; Paxton, Larry; Wang, Wenbin; Huang, Chaosong; Published by: Published on: |
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Investigating Geocoronal Absorption for Wavelength Calibration of Sounding Rockets
Donders, Nicolas; Winebarger, Amy; Kankelborg, Charles; Vigil, Genevieve; Paxton, Larry; Zank, Gary; Published by: Published on: |
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Progresses and Challenges to specifying the IT system during weak storms
Deng, Yue; Heelis, Roderick; Paxton, Larry; Lyons, Larry; Nishimura, Toshi; Zhang, Shunrong; Bristow, Bill; Maute, Astrid; Sheng, Cheng; Zhu, Qingyu; , others; Published by: Published on: |
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Space Physics and Aeronomy: Space Physics and Aeronomy, Solar Physics and Solar Wind
Raouafi, Nour; Vourlidas, Angelos; Zhang, Yongliang; Paxton, Larry; Published by: Published on: |
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Signatures of conjugate photoelectrons in the ionosphere and thermosphere
Kil, Hyosub; Paxton, Larry; Schaefer, Robert; Huba, Joseph; Published by: Published on: |
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Solar, auroral, and radiation belt electrons enter the atmosphere at polar regions leading to ionization and affecting its chemistry. Climate models usually parametrize this ionization and the related changes in chemistry based on satellite particle measurements. Precise measurements of the particle and energy influx into the upper atmosphere are difficult because they vary substantially in location and time. Widely used particle data are derived from the POES and GOES satellite measurements which provide electron and proton ... Bender, Stefan; Espy, Patrick; Paxton, Larry; Published by: Earth and Space Science Open Archive ESSOAr Published on: YEAR: 2021 DOI: 10.1002/essoar.10506056.1 |
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Validation of SSUSI-derived auroral electron densities: comparisons to EISCAT data
Bender, Stefan; Espy, Patrick; Paxton, Larry; Published by: Published on: |
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Recently, citizen scientist photographs led to the discovery of a new auroral form called “the dune aurora” which exhibits parallel stripes of brighter emission in the green diffuse aurora at about 100 km altitude. This discovery raised several questions, such as (i) whether the dunes are associated with particle precipitation, (ii) whether their structure arises from spatial inhomogeneities in the precipitating fluxes or in the underlying neutral atmosphere, and (iii) whether they are the auroral manifestation of an atm ... Grandin, Maxime; Palmroth, Minna; Whipps, Graeme; Kalliokoski, Milla; Ferrier, Mark; Paxton, Larry; Mlynczak, Martin; Hilska, Jukka; Holmseth, Knut; Vinorum, Kjetil; , others; Published by: AGU Advances Published on: YEAR: 2021 DOI: https://doi.org/10.1029/2020AV000338 |
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Space Physics and Aeronomy, Ionosphere Dynamics and Applications
Zhang, Yongliang; Paxton, Larry; Published by: Published on: |
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Exploring the Upper Atmosphere: Using Optical Remote Sensing
Paxton, Larry; Zhang, Yongliang; Kil, Hyosub; Schaefer, Robert; Published by: Upper Atmosphere Dynamics and Energetics Published on: |
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Space Physics and Aeronomy, Upper Atmosphere Dynamics and Energetics
Zhang, Yongliang; Paxton, Larry; Published by: Published on: |
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Space Physics and Aeronomy, Magnetospheres in the Solar System
Zhang, Yongliang; Paxton, Larry; Published by: Published on: |
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Space Physics and Aeronomy, Solar Physics and Solar Wind
Zhang, Yongliang; Paxton, Larry; Published by: Published on: |
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Carter, Jennifer; Samsonov, Andrey; Milan, Stephen; Branduardi-Raymont, Graziella; Ridley, Aaron; Paxton, Larry; Anderson, Brian; Waters, Colin; Edwards, Thomas; Published by: Earth and Space Science Open Archive ESSOAr Published on: |
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Goncharenko, Larisa; Harvey, Lynn; Greer, Katelynn; Zhang, Shun-Rong; Coster, Anthea; Paxton, Larry; Published by: Geophysical Research Letters Published on: |
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Smith, Todd; Hacala, Ryan; Hohlfeld, Erik; Edens, Weston; Hibbitts, Charles; Paxton, Larry; Arnold, Steven; Westlake, Joseph; Rymer, Abigail; Chacos, Al; , others; Published by: Gravitational and Space Research Published on: |
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Transpolar arcs: Seasonal dependence identified by an automated detection algorithm
Bower, Gemma; Milan, Stephen; Paxton, Larry; Published by: Earth and Space Science Open Archive ESSOAr Published on: |
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Ionospheric and thermospheric contributions in TIMED/GUVI O 135.6 nm radiances
Zhang, Yongliang; Paxton, Larry; Schaefer, Robert; Published by: Journal of Geophysical Research: Space Physics Published on: |
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Schaefer, Robert; Paxton, Larry; Zhang, Yongliang; Kil, Hyosub; Romeo, Giuseppe; Wolven, Brian; Yonker, Justin; Published by: Published on: |
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Dual-lobe reconnection and cusp-aligned auroral arcs
Milan, Stephen; Bower, Gemma; Carter, Jennifer; Paxton, Larry; Anderson, Brian; Hairston, Marc; Published by: Published on: |