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Found 11 entries in the Bibliography.
Showing entries from 1 through 11
The Thermospheric Column O/N2 Ratio
More than 2 decades ago, D. J. Strickland and colleagues proposed use of the O/N2 column number density ratio as a new geophysical quantity to interpret thermospheric processes recorded in far ultraviolet (FUV) images of the Earth. This concept has enabled multiple advances in understanding the global behavior of Earth s thermosphere. Nevertheless, confusion remains about the conceptual meaning of the column density ratio, and in the application of this integral quantity. This is so even though it is now a key thermospheric ...
Published by: Journal of Geophysical Research: Space Physics Published on:
YEAR: 2021   DOI: 10.1029/2020JA029059
disk algorithm; far UV remote sensing; GUVI; ICON; N2 LBH bands; Oxygen 135.6 nm
Auroral Structure and Dynamics From GOLD
The Global-scale Observations of the Limb and Disk (GOLD) mission data contain significant quantitative information about the aurora on a global scale. Here we present techniques for quantifying such information, including the temporal development of the structure within the auroral oval using the GOLD images. These techniques are applied to auroral observations in the GOLD data, in particular showing an example of how the longitudinal structure within the aurora varies over the course of six consecutive days with differi ...
Published by: Journal of Geophysical Research: Space Physics Published on: 02/2020
YEAR: 2020   DOI: 10.1029/2019JA027650
Effects of transionospheric signal decorrelation on Global Navigation Satellite Systems (GNSS) performance studied from irregularity dynamics around the northern crest of the EIA
Transionospheric satellite navigation links operate primarily at L band and are frequently subject to severe degradation of performances arising out of ionospheric irregularities. Various characteristic features of equatorial ionospheric irregularity bubbles like the drift velocity, characteristic velocity, decorrelation time, and decorrelation distance can be determined using spaced aerial measurements at VHF. These parameters measured at VHF from a station Calcutta situated near the northern crest of the Equatorial Ioni ...
Published by: Radio Science Published on: 10/2014
YEAR: 2014   DOI: 10.1002/rds.v49.1010.1002/2014RS005406
GNSS position determination accuracy under adverse ionospheric conditions; GUVI; irregularity dynamics at VHF
A case study of ionospheric storm effects during long-lasting southward IMF B z -driven geomagnetic storm
Multiple instrumental observations including GPS total electron content (TEC), foF2 and hmF2 from ionosondes, vertical ion drift measurements from Communication/Navigation Outage Forecasting System, magnetometer data, and far ultraviolet airglow measured by Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics/Global Ultraviolet Imager (TIMED/GUVI) are used to investigate the profound ionospheric disturbances at midlatitude and low latitude during the 14 ...
Liu, Jing; Liu, Libo; Nakamura, Takuji; Zhao, Biqiang; Ning, Baiqi; Yoshikawa, A.;
Published by: Journal of Geophysical Research: Space Physics Published on: 09/2014
YEAR: 2014   DOI: 10.1002/jgra.v119.910.1002/2014JA020273
GUVI; Ionospheric storm; prompt penetration electric fields; TIMED
Polar cap arcs correlated with solar wind entry at the high latitude magnetosphere
Polar cap arcs are sun-aligned aurora structures occurring during northward turnings of the Interplanetary Magnetic Field (IMF) Bz component. At the same time, a new region of solar wind entry at the high latitude magnetosphere, tailward of the cusp region, was found recently at the periods of northward IMF Bz. We propose a study to see the relationship of these entry events with the transpolar arc formation. Data of Global Ultraviolet Imager (GUVI) onboard TIMED mission is examined to see the transp ...
Mailyan, B.; Shi, Q.; Gou, X.;
Published by: Published on:
YEAR: 2014   DOI: 10.1109/URSIGASS.2014.6929926
aurora interplanetary; GUVI; magnetic fields; magnetosphere; solar wind; TIMED
Nightside midlatitude ionospheric arcs: TIMED/GUVI observations
\ Midlatitude arcs (MLA) are the phenomenon of the nightside enhancements of ionospheric electron density at 20\textdegree-45\textdegree magnetic latitudes in both hemispheres. We investigate the occurrence of MLA and its dependence on season using the Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics/Global Ultraviolet Imager (TIMED/GUVI) O I 135.6 nm intensity data between March 2008 and March 2012. The 135.6 nm emission is mainly caused by radiant recombination between O+ ions and electron ...
Zhang, Yongliang; Paxton, Larry; Kil, Hyosub;
Published by: Journal of Geophysical Research: Space Physics Published on: 06/2013
YEAR: 2013   DOI: 10.1002/jgra.50327
Statistical comparison of isolated and non-isolated auroral substorms
The present study compares isolated and non-isolated substorms in terms of their global morphology and energy deposition. The analysis is based on a list of geomagnetic substorm onsets identified with magnetometer data from SuperMAG and published previously by Newell and Gjerlove (2011a). Isolated substorms are defined as those with separation of two consecutive onsets no less than 3 h. The auroral data are obtained from the global ultraviolet imager (GUVI) on board the TIMED satellite and are rebinned into typical magnet ...
Liou, Kan; Newell, Patrick; Zhang, Yong-Liang; Paxton, Larry;
Published by: Journal of Geophysical Research: Space Physics Published on: 05/2013
YEAR: 2013   DOI: 10.1002/jgra.50218
Determination of the Ionospheric Electron Density Profile from FUV Remote Sensing Measurements
A limb viewing model is established in this paper based on GUVI measurements of OI 135.6 nm nightglow and a method with Chapman function describing the distribution of ionospheric electron density is presented to obtain the ionospheric electron density profile. We apply the regularization and Newton iteration method to calculate ionospheric peak electron density and peak height with GUVI measurements, eliminating the ill condition of the weighted matrix. The ionospheric electron density profile is obtained using the calcu ...
Jing, Wang; Yi, TANG; Zhi-Ge, ZHANG; Xu-Li, ZHENG; Guo-Qiang, NI;
Published by: Chinese Journal of Geophysics Published on: 03/2013
YEAR: 2013   DOI: 10.1002/cjg2.20011
Electron density profile; Far ultraviolet spectrum remote sensing; GUVI; Ionosphere
The quiet nighttime low-latitude ionosphere as observed by TIMED/GUVI
In this paper, we examine the nighttime ionosphere climatology structure in the low latitude region and discrepancies between Global Ultraviolet Imager (GUVI) observations and the IRI model predictions using (1) the magnetic zonal mean of electron number density as a function of altitude and magnetic latitude, (2) vertical electron density profiles at various levels of F10.7 index, (3) nighttime descent and magnitude decrease of the ionosphere, (4) point-to-point comparisons of F-peak height (hmF2) and density (NmF2), and ...
Talaat, E.R.; Yee, J.-H.; Hsieh, S.-Y.; Paxton, L.J.; DeMajistre, R.; Christensen, A.B.; Bilitza, D.;
Published by: Advances in Space Research Published on: 02/2013
YEAR: 2013   DOI: 10.1016/j.asr.2012.11.012
Research on Retrieving Thermospheric O/N2 from FUV Remote Sensing
Magnetic storms usually cause significant departures of thermospheric O and N2\ from their normal values. To study the effects on thermospheric neutral species caused by magnetic storms, a method to retrieve thermospheric O/N2\ based on the data obtained from global ultraviolet imager on board TIMED is presented. With the help of AURIC, the normalizations of observing angles and SZAs were preformed to the measurements and a relationship between 135.6/LBHs and O/N2\ was estab ...
Peng, S.; Tang, Y.; Wang, J.; Zheng, X.;
Published by: Spectroscopy and Spectral Analysis Published on: 05/2012
YEAR: 2012   DOI: 10.3964/j.issn.1000-0593(2012)05-1296-05
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