Bibliography
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Notice:
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Found 431 entries in the Bibliography.
Showing entries from 301 through 350
| 2009 |
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Thermospheric response to periodic variation in solar wind and tidal force Published by: Published on: |
| 2008 |
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An empirical Kp-dependent global auroral model based on TIMED/GUVI FUV data Published by: Journal of Atmospheric and Solar-Terrestrial Physics Published on: Jan-06-2008 YEAR: 2008 DOI: 10.1016/j.jastp.2008.03.008 |
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Eriksson, S.; Hairston, M.; Rich, F.; Korth, H.; Zhang, Y.; Anderson, B.; Published by: Journal of Geophysical Research Published on: Jan-01-2008 YEAR: 2008 DOI: 10.1029/2008JA013139 |
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Interplanetary shock induced ring current auroras Zhang, Yongliang; Paxton, L.; Zheng, Yihua; Published by: Journal of Geophysical Research Published on: Jan-01-2008 YEAR: 2008 DOI: 10.1029/2007JA012554 |
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Periodic modulations in thermospheric composition by solar wind high speed streams Crowley, G.; Reynolds, A.; Thayer, J.; Lei, J.; Paxton, L.; Christensen, A.; Zhang, Y.; Meier, R.; Strickland, D.; Published by: Geophysical Research Letters Published on: Jan-01-2008 YEAR: 2008 DOI: 10.1029/2008GL035745 |
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GUVI observations of the ionosphere during the declining phase of the solar cycle Paxton, LJ; Comberiate, J; Zhang, Y; Kil, H; Christensen, A; Published by: Published on: |
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Tidal variability in the ionospheric dynamo region The seasonal and interannual variability of migrating (Sun-synchronous) and nonmigrating solar atmospheric tides at altitudes between 100 and 116 km are investigated using temperature measurements made with the SABER instrument on the TIMED spacecraft during 2002–2006. Quasi-biennial variations of order ±10–15\% in migrating diurnal and semidiurnal tidal amplitudes are found, presumably due to modulation by the quasi-biennial oscillation (QBO) as the tides propagate from their troposphere and stratospheric sources to the lower thermosphere. A number of nonmigrating tidal components are found that have the potential to produce significant longitudinal variability of the total tidal fields. The most prominent of these, i.e., those that appear at amplitudes of order 5–10 K in a 5-year mean climatology, include the zonally symmetric (s = 0) diurnal tide (D0); the eastward propagating diurnal and semidiurnal tides with zonal wave numbers s = −2 (DE2 and SE2) and s = −3 (DE3 and SE3); and the following westward propagating waves: diurnal s = 2 (DW2); semidiurnal s = 1 (SW1), s = 3 (SW3), and s = 4 (SW4); and terdiurnal s = 5 (TW5). These waves can be plausibly accounted for by nonlinear interaction between migrating tidal components and stationary planetary waves with s = 1 or s = 2 or by longitudinal variations of tropospheric thermal forcing. Additional waves that occur during some years or undergo phase cancellation within construction of a 5-year climatology include DW5, SE1, SE4, SW6, TE1, TW1, and TW7. It is anticipated that the winds that accompany all of these waves in the 100–170 km region will impose longitudinal variability in the electric fields produced through the ionospheric dynamo mechanism, thereby modulating vertical motion of the equatorial ionosphere and the concomitant plasma densities. In addition to the wave-4 modulation of the equatorial ionosphere that has recently been discovered and replicated in modeling studies, the waves revealed here will generate wave-1 (SW1, SW3, D0, DW2), wave-2 (SW4, TW1), wave-3 (DE2, SE1), wave-4 (DE3, SE2, DW5, SW6, TE1, TW7), wave-5 (SE3), and wave-6 (SE4) components of this ionospheric variability, depending on year and time of year. However, the absolute and relative efficiencies with which these waves produce electric fields remains to be determined. Forbes, J.; Zhang, X.; Palo, S.; Russell, J.; Mertens, C.; Mlynczak, M.; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2008 DOI: https://doi.org/10.1029/2007JA012737 |
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Prestorm enhancements in NmF2 and total electron content at low latitudes The enhancement of electron concentrations in the ionosphere before geomagnetic storms is one of the open questions. Using ionosonde observations and total electron content (TEC) from Global Positioning System (GPS) measurements along longitude 120°E, we analyzed three low latitude pre-storm enhancement events that occurred on 21 April (day 111) 2001, 29 May (day 149) 2003, and 22 September (day 265) 2001, respectively, in the Asia/Australia sector. All three events (and other two cases on 9 August 2000 and 10 May 2002) show quite similar features. The strong prestorm enhancements during these events are simultaneously presented in foF2 and TEC and enhancements have latitudinal dependence, tending to occur at low latitudes with maxima near the northern and southern equatorial ionization anomaly (EIA) crests and depletions in the equatorial region. This is quite different from what reported by Burešová and Laštovička (2007) for middle latitudes. They found no systemic latitudinal dependence in prestorm enhancements over Europe. It is argued that solar flares are not the main drivers for the enhancements, at least for low-latitude events. Main features of low-latitude prestorm enhancements do not coincide with the solar flare effects. We postulate that the vertical plasma drift or zonal electric field is a likely cause for the low-latitude prestorm enhancements. Its existence is supported by the facts of stronger EIA, the latitudinal coverage of the enhancements as well as the lift of the F layer peak height at an equatorward station during the prestorm enhancements. Moreover, the behaviors of hmF2 at low latitudes during the prestorm enhancements may possibly be explained in terms of the coupling nature of parallel and perpendicular dynamics at low latitudes (see, e.g., Behnke and Harper, 1973; Rishbeth et al., 1978). Liu, Libo; Wan, Weixing; Zhang, Man-Lian; Zhao, Biqiang; Ning, Baiqi; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2008 DOI: https://doi.org/10.1029/2007JA012832 |
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Modeling auroral E-region parameters for IRI: A new assimilative capability for IRI Zhang, Yongliang; Paxton, Larry; Bilitza, Dieter; Published by: 37th COSPAR Scientific Assembly Published on: |
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Wavenumber-4 patterns of the total electron content over the low latitude ionosphere Wan, W; Liu, L; Pi, X; Zhang, M-L; Ning, B; Xiong, J; Ding, F; Published by: Geophysical Research Letters Published on: |
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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: |
| 2007 |
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Tsugawa, T.; Zhang, S.-R.; Coster, A.; Otsuka, Y.; Sato, J.; Saito, A.; Zhang, Y.; Paxton, L.; Published by: Journal of Geophysical Research Published on: Jan-01-2007 YEAR: 2007 DOI: 10.1029/2007JA012415 |
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Tsugawa, T.; Zhang, S.-R.; Coster, A.; Otsuka, Y.; Sato, J.; Saito, A.; Zhang, Y.; Paxton, L.; Published by: Journal of Geophysical Research Published on: Jan-01-2007 YEAR: 2007 DOI: 10.1029/2007JA012415 |
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Zhang, M; Lin, W; Klein, S; Backmeister, J; Bony, S; Cederwall, R; Del Genio, A; Hack, J; Loeb, N; Lohmann, U; , others; Published by: Published on: |
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Paxton, LJ; Zhang, Y; Ridley, A; Christensen, A; DeMajistre, R; Schaefer, R; Morrison, D; Published by: Published on: |
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The seasonal dependence of cycle slip occurrence of GPS data over China low latitude region The relationship of daily accumulated cycle slip occurrence with the season is analyzed using the GPS data observed in six GPS stations located in China low latitude region in 2001. It is found that the seasonal dependence of cycle slip occurrence is evident. The cycle slip mainly occurs during the periods of two equinox months (March to May and September to October), and some correlative changes of the cycle slip occurrences over all six stations are exhibited in some special days. Considering the diurnal dependence of cycle slip, it can be inferred that the cycle slip occurrence with certain elevation limitation is related with the ionospheric irregularities over this region. Zhang, Donghe; Feng, Man; Xiao, Zuo; Hao, Yongqiang; Shi, LiQin; Yang, GuangLin; Suo, YuCheng; Published by: Science in China Series E: Technological Sciences Published on: YEAR: 2007 DOI: 10.1007/s11431-007-0059-4 |
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A 30-day incoherent scatter radar (ISR) experiment was conducted at Millstone Hill (288.5 E, 42.6 N) from 4 October to 4 November 2002. The altitude profiles of electron density N e Liu, L; Wan, W; Zhang, M-L; Ning, B; Zhang, S-R; Holt, JM; Published by: Published on: YEAR: 2007 DOI: 10.5194/angeo-25-2019-2007 |
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A 30-day incoherent scatter radar (ISR) experiment was conducted at Millstone Hill (288.5 E, 42.6 N) from 4 October to 4 November 2002. The altitude profiles of electron density N e Liu, L; Wan, W; Zhang, M-L; Ning, B; Zhang, S-R; Holt, JM; Published by: Published on: YEAR: 2007 DOI: 10.5194/angeo-25-2019-2007 |
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Kil, H; Oh, S-J; Paxton, LJ; Zhang, Y; Su, S-Y; Min, K-W; Published by: Geophysical research letters Published on: |
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Zhang, Yongliang; Paxton, Larry; Lui, Anthony; Published by: Geophysical research letters Published on: YEAR: 2007 DOI: 10.1029/2007GL031602 |
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Tsugawa, T; Zhang, S-R; Coster, AJ; Otsuka, Y; Sato, J; Saito, A; Zhang, Y; Paxton, LJ; Published by: Journal of Geophysical Research: Space Physics Published on: |
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Tsugawa, T; Zhang, S-R; Coster, AJ; Otsuka, Y; Sato, J; Saito, A; Zhang, Y; Paxton, LJ; Published by: Journal of Geophysical Research: Space Physics Published on: |
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Robust speaker identification in noisy environment using cross diagonal GTF-ICA feature Zhang, Yushi; Abdulla, Waleed; Published by: Published on: |
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Prelude to THEMIS tail conjunction study Lui, ATY; Zheng, Y; Zhang, Y; , Angelopoulos; Parks, GK; Mozer, FS; Reme, H; Kistler, LM; Dunlop, MW; Gustafsson, Georg; , others; Published by: Published on: |
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Synoptical Auroral Ovals: A Comparison study with TIMED/GUVI Observations Published by: Published on: |
| 2006 |
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Dayside convection aligned auroral arcs Published by: Geophysical Research Letters Published on: Jan-01-2006 YEAR: 2006 DOI: 10.1029/2006GL026388 |
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F-region Pedersen conductivity deduced using the TIMED/GUVI limb retrievals Kil, H.; DeMajistre, M.; Paxton, L.; Zhang, Y.; Published by: Annales Geophysicae Published on: Jan-01-2006 YEAR: 2006 DOI: 10.5194/angeo-24-1311-2006 |
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Zhang, Y.; Paxton, L.; Kozyra, J.; Kil, H.; Brandt, P.; Published by: Journal of Geophysical Research Published on: Jan-01-2006 YEAR: 2006 DOI: 10.1029/2005JA011152 |
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Bruinsma, Sean; Forbes, Jeffrey; Nerem, Steven; Zhang, Xiaoli; Published by: Journal of Geophysical Research Published on: Jan-01-2006 YEAR: 2006 DOI: 10.1029/2005JA011284 |
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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 companion paper by Kil and Paxton [2006] and corroborate that the SIBBs are associated with bubbles. We discuss the common characteristics of the SIBBs and the role of the E \texttimes B drift for the formation of the SIBBs. 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 |
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Nighttime F-region morphology in the low and middle latitudes seen from DMSP F15 and TIMED/GUVI We investigate the seasonal, longitudinal, and altitudinal variations of the FF-region morphology at 2100\textendash2300\ LT in the low- and middle-latitudes using the data collected in August, September, and November of 2003. The topside morphology is investigated using in situ measurements of the O+O+ fraction and total ion density by the Defense Meteorological Satellite Program (DMSP) F15 satellite. The morphology of the equatorial ionization anomaly (EIA) near the FF peak altitude is investigated using the OI 135.6-nm radiance maps provided by the Global Ultraviolet Imager (GUVI) on board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite. The hemispheric asymmetries of the topside ionosphere at 840\ km in the months near solstices can be characterized by the reduction of the O+O+ fraction and ion density in the winter hemisphere compared to those in the summer hemisphere. The minimum O+O+ fraction and ion density layers occur around 30o30o magnetic latitude in the winter hemisphere. During the fall equinox, the hemispheric asymmetries are reversed in the regions of opposite magnetic declinations. From the comparison of the topside morphology with the global wind circulation pattern at 2200\ LT predicted by the Horizontal Wind Model 93 (HWM93) we infer that hemispheric asymmetry of the topside ionosphere is created primarily by the retardation of the downward plasma diffusion in one hemisphere through the field-aligned equatorward winds. The global EIA morphology does not conform to the topside morphology. The complex seasonal-longitudinal variations of the EIA strength and asymmetry are not explained simply by considering the modulation of the FF-layer height by the winds. The magnetic declination is not a useful tool in understanding the global EIA morphology. Kil, Hyosub; DeMajistre, Robert; Paxton, L.; Zhang, Yongliang; Published by: Journal of Atmospheric and Solar-Terrestrial Physics Published on: 09/2006 YEAR: 2006 DOI: 10.1016/j.jastp.2006.05.024 Equatorial ionization anomaly; FF-region plasma distribution; low-latitude ionosphere; Neutral wind |
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We investigate the variations in the thermosphere and ionosphere using multi-instrument observations during the April 2002 period, with a particular focus on periods during small geomagnetic disturbances. Large and long-lasting reductions in the daytime electron density were observed at midlatitudes by incoherent scatter radars, ionosondes, and GPS receivers. These reductions reached 30\textendash50\% and were observed over an extended longitudinal area. They propagated to middle latitudes (35\textendash40\textdegreeN) in the case of a weak geomagnetic disturbance (Kp = 3-) and to low latitudes (0\textendash10\textdegreeN) in the case of a stronger disturbance (Kp = 5-). Data from the GUVI instrument aboard the TIMED satellite reveal a reduction in the daytime O/N2 ratio in the coincident area. Similar decreases are also predicted by the TIMEGCM/ASPEN model in both O/N2 ratio and electron density, though the magnitude of the decrease from the model is smaller than observed. We suggest that these ionospheric and thermospheric disturbances result from high-latitude energy input and efficient transport of regions with reduced O/N2 to lower latitudes. We discuss the possible role of a strong positive By component of the interplanetary magnetic field in the transport of regions with reduced O/N2. Goncharenko, L.; Salah, J.; Crowley, G.; Paxton, L.; Zhang, Y.; Coster, A.; Rideout, W.; Huang, C.; Zhang, S.; Reinisch, B.; Taran, V.; Published by: Journal of Geophysical Research Published on: 03/2006 YEAR: 2006 DOI: 10.1029/2004JA010683 Electron density; thermospheric composition; thermospheric wind |
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We investigate the variations in the thermosphere and ionosphere using multi-instrument observations during the April 2002 period, with a particular focus on periods during small geomagnetic disturbances. Large and long-lasting reductions in the daytime electron density were observed at midlatitudes by incoherent scatter radars, ionosondes, and GPS receivers. These reductions reached 30\textendash50\% and were observed over an extended longitudinal area. They propagated to middle latitudes (35\textendash40\textdegreeN) in the case of a weak geomagnetic disturbance (Kp = 3-) and to low latitudes (0\textendash10\textdegreeN) in the case of a stronger disturbance (Kp = 5-). Data from the GUVI instrument aboard the TIMED satellite reveal a reduction in the daytime O/N2 ratio in the coincident area. Similar decreases are also predicted by the TIMEGCM/ASPEN model in both O/N2 ratio and electron density, though the magnitude of the decrease from the model is smaller than observed. We suggest that these ionospheric and thermospheric disturbances result from high-latitude energy input and efficient transport of regions with reduced O/N2 to lower latitudes. We discuss the possible role of a strong positive By component of the interplanetary magnetic field in the transport of regions with reduced O/N2. Goncharenko, L.; Salah, J.; Crowley, G.; Paxton, L.; Zhang, Y.; Coster, A.; Rideout, W.; Huang, C.; Zhang, S.; Reinisch, B.; Taran, V.; Published by: Journal of Geophysical Research Published on: 03/2006 YEAR: 2006 DOI: 10.1029/2004JA010683 Electron density; thermospheric composition; thermospheric wind |
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TIMED/GUVI and DMSP/SSUSI-Data Products for Space Weather Hsieh, S; Paxton, L; Zhang, Y; DeMajistre, R; Wolven, B; Morrison, D; Schaefer, R; Published by: Published on: |
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An Empirical Model of Auroral Parameters Based on TIMED/GUVI Data Published by: Published on: |
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Sigwarth, JB; Paxton, LJ; Zhang, Y; Published by: Published on: |
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Observing the Coupled Ionosphere-Thermosphere System: From Solar Maximum to Solar Minimum and Beyond Paxton, L; Morrison, D; Zhang, Y; Kil, H; Wolven, B; Comberiate, J; Meng, C; Kozyra, J; Christensen, A; Published by: Published on: |
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GUVI Observations of Thermosphere/Ionosphere Coupling Paxton, L; Zhang, Y; Kil, H; Morrison, D; Wolven, B; Meng, C; Christensen, A; Published by: Published on: |
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The first long-duration incoherent scatter (IS) radar observations over Millstone Hill (42.6°N, 288.5°E) and EISCAT Svalbard radar (ESR, 78.15°N, 16.05°E) from October 4 to November 4, 2002 are compared with the newly updated version of the IRI model (IRI2001). The present study showed that: (1) For the peak parameters hmF2 and foF2, the IRI results are in good agreement with the observations over Millstone Hill, but there are large discrepancies over ESR. For the B parameters, the table option of IRI produces closer values to the observed ones with respect to the Gulyaeva’s option. (2) When the observed F2 peak parameters are used as input of IRI, the IRI model produces the reasonably results for the bottomside profiles during daytime over Millstone Hill, while it gives a lower bottomside density during nighttime over Millstone Hill and the whole day over ESR than what is observed experimentally. Moreover, IRI tends to overestimate the topside Ne profiles at both locations. (3) The Ti profiles of IRI can generally reproduce the observed values, whereas the IRI-produced Te profiles show large discrepancies with the observations. Overall comparative studies reveal that the agreement between the IRI predictions and experimental values is better over Millstone Hill than that over ESR. Lei, Jiuhou; Liu, Libo; Wan, Weixing; Zhang, Shun-Rong; Van Eyken, A.P.; Published by: Advances in Space Research Published on: YEAR: 2006 DOI: https://doi.org/10.1016/j.asr.2005.01.061 Ionosphere; incoherent scatter radar; Modelling and forecasting; International reference ionosphere |
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Summer-Winter Hemispheric Asymmetry of Sudden Increase in Ionospheric Total Electron Content Tsugawa, T; Zhang, S; Coster, A; Otsuka, Y; Sato, J; Saito, A; Zhang, Y; Paxton, L; Published by: Published on: |
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Summer-Winter Hemispheric Asymmetry of Sudden Increase in Ionospheric Total Electron Content Tsugawa, T; Zhang, S; Coster, A; Otsuka, Y; Sato, J; Saito, A; Zhang, Y; Paxton, L; Published by: Published on: |
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Kil, H; Oh, S; Paxton, LJ; Zhang, Y; Published by: Published on: |
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Bruinsma, Sean; Forbes, Jeffrey; Nerem, Steven; Zhang, Xiaoli; Published by: Journal of Geophysical Research: Space Physics Published on: |
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Goncharenko, L; Salah, J; Crowley, G; Paxton, LJ; Zhang, Y; Coster, A; Rideout, W; Huang, C; Zhang, S; Reinisch, B; , others; Published by: Journal of Geophysical Research: Space Physics Published on: |
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Goncharenko, L; Salah, J; Crowley, G; Paxton, LJ; Zhang, Y; Coster, A; Rideout, W; Huang, C; Zhang, S; Reinisch, B; , others; Published by: Journal of Geophysical Research: Space Physics Published on: |
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An unusual nightside distortion of the auroral oval: TIMED/GUVI and IMAGE/FUV observations Zhang, Y; Paxton, LJ; Lui, ATY; Published by: Journal of Geophysical Research: Space Physics (1978\textendash2012) Published on: |
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F-region Pedersen conductivity deduced using the TIMED/GUVI limb retrievals Kil, H; DeMajistre, M; Paxton, LJ; Zhang, Y; Published by: Published on: |
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Sigwarth, JB; Paxton, LJ; Zhang, Y; Published by: Published on: |
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Development of single and multi-parameter global auroral models Zhang, Y; Paxton, L; Morrison, D; Published by: Published on: |
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Cluster observation of plasma flow reversal in the magnetotail during a substorm Lui, ATY; Zheng, Y; Zhang, Y; Livi, S; Reme, H; Dunlop, MW; Gustafsson, Georg; Mende, SB; Mouikis, C; Kistler, LM; Published by: Published on: |