GUVI Biblio





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Found 748 entries in the Bibliography.


Showing entries from 251 through 300


2016

High-latitude ionospheric irregularities: differences between ground- and space-based GPS measurements during the 2015 St. Patrick\textquoterights Day storm

We present an analysis of ionospheric irregularities at high latitudes during the 2015 St. Patrick\textquoterights Day storm. Our study used measurements from\ ~2700 ground-based GPS stations and GPS receivers onboard five low earth orbit (LEO) satellites\textemdashSwarm A, B and C, GRACE and TerraSAR-X\textemdashthat had close orbit altitudes of\ ~500\ km, and the Swarm in situ plasma densities. An analysis of the rate of TEC index (ROTI) derived from LEO\textendashGPS data, together with Swarm in situ pla ...

Cherniak, Iurii; Zakharenkova, Irina;

Published by: Earth, Planets and Space      Published on: 07/2016

YEAR: 2016     DOI: 10.1186/s40623-016-0506-1

Peculiar features of the low-latitude and midlatitude ionospheric response to the St. Patrick\textquoterights Day geomagnetic storm of 17 March 2015

The current study aims at investigating and identifying the ionospheric effects of the geomagnetic storm that occurred during 17\textendash19 March 2015. Incidentally, with SYM-H hitting a minimum of -232\ nT, this was the strongest storm of the current solar cycle 24. The study investigates how the storm has affected the equatorial, low-latitude, and midlatitude ionosphere in the American and the European sectors using available ground-based ionosonde and GPS TEC (total electron content) data. The possible ...

Nayak, Chinmaya; Tsai, L.-C.; Su, S.-Y.; Galkin, I.; Tan, Adrian; Nofri, Ed; Jamjareegulgarn, Punyawi;

Published by: Journal of Geophysical Research: Space Physics      Published on: 07/2016

YEAR: 2016     DOI: 10.1002/2016JA022489

Solar wind driving of ionosphere-thermosphere responses in three storms near St. Patrick\textquoterights Day in 2012, 2013, and 2015

We identify interplanetary plasma regions associated with three intense interplanetary coronal mass ejections (ICMEs)-driven geomagnetic storm intervals which occurred around the same time of the year: day of year 74\textendash79 (March) of 2012, 2013, and 2015. We show that differences in solar wind drivers lead to different dynamical ionosphere-thermosphere (IT) responses and to different preconditioning of the IT system. We introduce a new hourly based global metric for average low-latitude and northern middle-latitude ...

Verkhoglyadova, O.; Tsurutani, B.; Mannucci, A.; Mlynczak, M.; Hunt, L.; Paxton, L.; Komjathy, A.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 07/2016

YEAR: 2016     DOI: 10.1002/jgra.v121.910.1002/2016JA022883

Equatorial ionospheric plasma drifts and O + concentration enhancements associated with disturbance dynamo during the 2015 St. Patrick\textquoterights Day magnetic storm

Disturbance dynamo is an important dynamic process during magnetic storms. However, very few direct observations of dynamo-induced plasma drifts and ion composition changes in the equatorial ionosphere are available. In this study, we use measurements of the Defense Meteorological Satellite Program (DMSP) satellites to identify the characteristics of the disturbance dynamo process in the topside equatorial ionosphere near dawn during the magnetic storm with a minimum Dst of -223 nT on 17 March 2015. Data from fou ...

Huang, Chao-Song; Wilson, Gordon; Hairston, Marc; Zhang, Yongliang; Wang, Wenbin; Liu, Jing;

Published by: Journal of Geophysical Research: Space Physics      Published on: 06/2016

YEAR: 2016     DOI: 10.1002/2016JA023072

Longitudinal variations of thermospheric composition at the solstices

O/N2, measured by the Global Ultraviolet Imager on board the Thermosphere Ionosphere Mesosphere Energetics Dynamics satellite, has large longitudinal variations at the solstices, which are simulated well in upper atmosphere general circulation models. These longitudinal variations are caused by the displacement of the Earth\textquoterights magnetic poles from the geographic ones. The location of a magnetic pole affects the latitude at which the winds, driven by heating in summer, converge in the subauroral regi ...

Qian, Liying; Burns, Alan; Wang, Wenbin; Solomon, Stanley; Zhang, Yongliang;

Published by: Journal of Geophysical Research: Space Physics      Published on: 06/2016

YEAR: 2016     DOI: 10.1002/2016JA022898

Modeling the problem of low-orbital satellite UV-tomography of the ionosphere

The results of modeling the direct and inverse problems of low-orbital satellite ultraviolet (UV) tomography of the ionospheric 135.6 OI volume emission rate are presented. The direct problem was solved with the orbital geometry of DMSP block 5D3 satellites with SSUSI and SSULI UV spectrographs among the other payloads, the real operating parameters of these instruments (the scan rate and the interval of scan angles), and the set of the model distributions of the volume emission rate that contain irregularities on various ...

Nesterov, I.; Padokhin, A.; Andreeva, E.; Kalashnikova, S.;

Published by: Moscow University Physics Bulletin      Published on: 06/2016

YEAR: 2016     DOI: 10.3103/S0027134916030103

Ionospheric data assimilation with thermosphere-ionosphere-electrodynamics general circulation model and GPS-TEC during geomagnetic storm conditions

The main purpose of this paper is to investigate the effects of rapid assimilation-forecast cycling on the performance of ionospheric data assimilation during geomagnetic storm conditions. An ensemble Kalman filter software developed by the National Center for Atmospheric Research (NCAR), called Data Assimilation Research Testbed, is applied to assimilate ground-based GPS total electron content (TEC) observations into a theoretical numerical model of the thermosphere and ionosphere (NCAR thermosphere-ionosphere-electrodyn ...

Chen, C.; Lin, C.; Matsuo, T.; Chen, W.; Lee, I.; Liu, J; Lin, J.; Hsu, C.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 05/2016

YEAR: 2016     DOI: 10.1002/2015JA021787

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.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 05/2016

YEAR: 2016     DOI: 10.1002/2015JA022214

Long-duration depletion in the topside ionospheric total electron content during the recovery phase of the March 2015 strong storm

Topside ionospheric total electron content (TEC) observations from multiple low-Earth orbit (LEO) satellites have been used to investigate the local time, altitudinal, and longitudinal dependence of the topside ionospheric storm effect during both the main and recovery phases of the March 2015 geomagnetic storm. The results of this study show, for the first time, that there was a persistent topside TEC depletion that lasted for more than 3 days after the storm main phase at most longitudes, except in the Pacific Ocean reg ...

Zhong, Jiahao; Wang, Wenbin; Yue, Xinan; Burns, Alan; Dou, Xiankang; Lei, Jiuhou;

Published by: Journal of Geophysical Research: Space Physics      Published on: 04/2016

YEAR: 2016     DOI: 10.1002/2016JA022469

Solar cycle variations of thermospheric composition at the solstices

We examine the solar cycle variability of thermospheric composition (O/N2) at the solstices. Our observational and modeling studies show that the summer-to-winter latitudinal gradient of O/N2 is small at solar minimum but large at solar maximum; O/N2 is larger at solar maximum than at solar minimum on a global-mean basis; there is a seasonal asymmetry in the solar cycle variability of O/N2, with large solar cycle variations in the winter hemisphere and small solar cycle variatio ...

Qian, Liying; Burns, Alan; Solomon, Stanley; Wang, Wenbin; Zhang, Yongliang;

Published by: Journal of Geophysical Research: Space Physics      Published on: 04/2016

YEAR: 2016     DOI: 10.1002/2016JA022390

Middle- and low-latitude ionosphere response to 2015 St. Patrick\textquoterights Day geomagnetic storm

This paper presents a study of the St Patrick\textquoterights Day storm of 2015, with its ionospheric response at middle and low latitudes. The effects of the storm in each longitudinal sector (Asian, African, American, and Pacific) are characterized using global and regional electron content. At the beginning of the storm, one or two ionospheric positive storm effects are observed depending on the longitudinal zones. After the main phase of the storm, a strong decrease in ionization is observed at all longitudes, lasting ...

Nava, B.; iguez-Zuluaga, Rodr\; Alazo-Cuartas, K.; Kashcheyev, A.; e, Migoya-Oru\; Radicella, S.M.; Amory-Mazaudier, C.; Fleury, R.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 03/2016

YEAR: 2016     DOI: 10.1002/2015JA022299

Thermospheric hydrogen response to increases in greenhouse gases

We investigated thermospheric hydrogen response to increase in greenhouse gases and the dependence of this response to solar activity, using a global mean version of the National Center for Atmospheric Research Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model. We separately doubled carbon dioxide (CO2) and methane (CH4) to study the influence of temperature and changes to source species for hydrogen. Our results indicate that both CO2 cooling and CH4 ...

Nossal, S.; Qian, L.; Solomon, S.; Burns, A.; Wang, W.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 03/2016

YEAR: 2016     DOI: 10.1002/2015JA022008

Effects of the Equatorial Ionosphere Anomaly on the Inter-Hemispheric Circulation in the Thermosphere

We investigate the interhemispheric circulation at the solstices, in order to understand why O/N2\ is larger in the northern hemisphere winter than in the southern hemisphere winter. Our studies reveal that the equatorial ionosphere anomaly (EIA) significantly impacts the summer-to-winter wind through plasma-neutral collisional heating, which changes the summer-to-winter pressure gradient, and ion drag. Consequently, the wind is suppressed in the summer hemisphere as it encounters the EIA but accelerates a ...

Qian, Liying; Burns, Alan; Wang, Wenbin; Solomon, Stanley; Zhang, Yongliang; Hsu, V.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 02/2016

YEAR: 2016     DOI: 10.1002/2015JA022169

Equatorial ionization anomaly; interhemispheric circulation; ionosphere winter anomaly; plasma-neutral collisional heating; thermosphere composition; vertical advection

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.;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: 02/2016

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.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 02/2016

YEAR: 2016     DOI: 10.1002/2015JA021841

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

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

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.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 01/2016

YEAR: 2016     DOI: 10.1002/2015JA021567

auroral oval; field-aligned currents

Ionosphere-thermosphere (IT) response to solar wind forcing during magnetic storms

During magnetic storms, there is a strong response in the ionosphere and thermosphere which occurs at polar latitudes. Energy input in the form of Poynting flux and energetic particle precipitation, and energy output in the form of heated ions and neutrals have been detected at different altitudes and all local times. We have analyzed a number of storms, using satellite data from the Defense Meteorological Satellite Program (DMSP), the Gravity Recovery and Climate Experiment (GRACE), Gravity field and steady-state Ocean C ...

Huang, Cheryl; Huang, Yanshi; Su, Yi-Jiun; Sutton, Eric; Hairston, Marc; Coley, William;

Published by: Journal of Space Weather and Space Climate      Published on: 01/2016

YEAR: 2016     DOI: 10.1051/swsc/2015041

Energy distribution; Ionosphere; polar cap; solar wind; thermosphere

Universal time variations of the auroral hemispheric power and their interhemispheric asymmetry from TIMED/GUVI observations

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

Sparse Hierarchical Nonparametric Bayesian learning for light field representation and denoising

In this paper, we present a sparse hierarchical non-parametric Bayesian (SHNB) model, which is used to represent the data captured by the light field cameras. Specifically, a light field can be represented as a set of sub-aperture views. In order to capture the visual variations of these viewpoints, we propose the so-called \textquotedblleftdepth flow\textquotedblright features. Then based on the depth flow features, we model these views statistically with a sparse representation in a fully unsupervised manner. While loca ...

Sun, Xing; Meng, Nan; Xu, Zhimin; Lam, Edmund; So, Hayden;

Published by:       Published on:

YEAR: 2016     DOI: 10.1109/IJCNN.2016.7727617

SPIE ProceedingsThe reconnaissance and early-warning optical system design for dual field of space-based "solar blind ultraviolet"

With the development of modern technology, especially the development of information technology at high speed, the ultraviolet early warning system plays an increasingly important role. In the modern warfare, how to detect the threats earlier, prevent and reduce the attack of precision-guided missile has become a new challenge. Because the ultraviolet warning technology has high environmental adaptability, the low false alarm rate, small volume and other advantages, in the military field applications it has been developed ...

Wang, Wen-cong; Jin, Dong-dong; Shao, Fei; Hu, Hui-jun; Shi, Yu-feng; Song, Juan; Zhang, Yu-tu; Yong, Liu;

Published by:       Published on:

YEAR: 2016     DOI: 10.1117/12.2236440

2015

Airglow simulation based on the Atmospheric Ultraviolet Radiance Integrated Code of 2012

The Atmospheric Ultraviolet Radiance Integrated Code (AURIC) is a software package developed by Computational Physics, Inc. (CPI) under the sponsorship of the Air Force Phillips Laboratory/Geophysics Directorate (PL/GP) (currently the Air Force Research Laboratory) for middle and upper atmospheric radiance modeling from the far ultraviolet to the near infrared. The AURIC has been considered as a general model for the radiative transfer simulation of airglow. Based on the theory of MODerate resolution atmospheric TRANsmiss ...

Wang, HouMao; Wang, YongMei;

Published by: Science China Earth Sciences      Published on: Oct-09-2016

YEAR: 2015     DOI: 10.1007/s11430-015-5166-7

airglow simulation; AURIC-2012; Limb Column Emission Intensity (L-CEI); Volume Emission Rate

NmF2 and hmF2 measurements at 95\textdegree E and 127\textdegree E around the EIA northern crest during 2010\textendash2014

The characteristics of the F2 layer parameters NmF2 and hmF2 over Dibrugarh (27.5\textdegree N, 95\textdegree E, 17\textdegree N geomagnetic, 43\textdegree dip) measured by a Canadian Advanced Digital Ionosonde (CADI) for the period of August 2010 to July 2014 are reported for the first time from this low mid-latitude station lying within the daytime peak of the longitudinal wave number 4 structure of equatorial anomaly (EIA) around the northern edge of anomaly crest. Equinoctial asymmetry is clearly observed at all solar ...

Kalita, Bitap; Bhuyan, Pradip; Yoshikawa, Akimasa;

Published by: Earth, Planets and Space      Published on: Jan-12-2015

YEAR: 2015     DOI: 10.1186/s40623-015-0355-3

Characteristics of post-midnight L-band scintillation in the transition region from the equatorial to mid-latitudes over the Indian longitude sector using COSMIC, C/NOFS and GPS measurements

Occurrence of L band scintillations around midnight and postmidnight hours have not been well studied and reported from the higher equatorial latitudes in the transition region from the equatorial to midlatitudes over the Indian longitude sector. The present paper reports cases of postmidnight L band scintillation observations by COSMIC during March 2014 over the Indian longitude sector. GPS\ S4measurements from the International Global Navigation Satellite Systems Service station at Lucknow (26.9 ...

Paul, A.; Haralambous, H.; Oikonomou, C.;

Published by: Radio Science      Published on: 12/2015

YEAR: 2015     DOI: 10.1002/2015RS005807

postmidnight L band scintillation over Indian longitude sector

Dependence of the high-latitude plasma irregularities on the auroral activity indices: a case study of 17 March 2015 geomagnetic storm

The magnetosphere substorm plays a crucial role in the solar wind energy dissipation into the ionosphere. We report on the intensity of the high-latitude ionospheric irregularities during one of the largest storms of the current solar cycle\textemdashthe St. Patrick\textquoterights Day storm of 17 March 2015. The database of more than 2500 ground-based Global Positioning System (GPS) receivers was used to estimate the irregularities occurrence and dynamics over the auroral region of the Northern Hemisphere. We analyze the ...

Cherniak, Iurii; Zakharenkova, Irina;

Published by: Earth, Planets and Space      Published on: 12/2015

YEAR: 2015     DOI: 10.1186/s40623-015-0316-x

Auroral hemispheric power index Auroral precipitation; geomagnetic storm; GPS; Ionosphere irregularities; ROTI

The response of the ionosphere to intense geomagnetic storms in 2012 using GPS-TEC data from East Africa longitudinal sector

The response of the ionosphere to intense magnetic storms has been studied using total electron content (TEC). TEC data recorded by a series of GPS receivers at a longitude\~35\textdegreeE\ covering a wide range of latitudes (32\textdegreeS\ to\ 68\textdegreeN, geographic) is analyzed to study spatio-temporal modifications of the vertical TEC (vTEC) during storms on 07 and 09 March 2012 and on 14 July 2012. We have observed main phase positive response at equatorial ionization anomaly (EIA) crests and mid l ...

Tesema, F.; Damtie, B.; Nigussie, M.;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: 12/2015

YEAR: 2015     DOI: 10.1016/j.jastp.2015.10.021

Equatorial Electrojet; geomagnetic storm; Ionosphere

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;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: 11/2015

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

Aeronomy; Ionosphere; Radar; thermosphere

Radiative transfer modeling of the OI 135.6~nm emission in the nighttime ionosphere

Remote sensing of the nighttime OI 135.6\ nm emissions has been a widely used method for measuring the\ F\ region ionospheric plasma densities. In this work, we first develop a comprehensive radiative transfer model from first principles to investigate the effects of different physical processes on the production and transport of the 135.6\ nm photons in the ionosphere and then propose a new approach for estimating electron densities from the nightglow. The forward modeling investigation indic ...

Qin, Jianqi; Makela, Jonathan; Kamalabadi, Farzad; Meier, R.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2015

YEAR: 2015     DOI: 10.1002/jgra.v120.1110.1002/2015JA021687

OI 135.6-nm Emission; onosphere; Radiative transfer; remote sensing

Towards estimation of atmospheric tidal effects on the ionosphere via data assimilation

The impact of atmospheric tides on the night time ionosphere is now being a subject of the extensive research within the scientific community. The plausible effect has been observed using the multiple space-borne instruments (e.g. COSMIC/FORMOSAT-3 constellation, TIMED GUVI and NASA IMAGE). Along with the observations, several modelling attempts has been undertaken to prove or refute the interrelation between the atmospheric tides and the wave-four longitudinal night time ionosphere structure. The scope of the current art ...

Solomentsev, Dmitry; Cherniak, Yakov; Titov, Anton; Khattatov, Boris; Khattatov, Vyacheslav;

Published by: Advances in Space Research      Published on: 11/2015

YEAR: 2015     DOI: 10.1016/j.asr.2015.07.014

Atmosphere tides; data assimilation; Ionosphere longitudinal structure

Ionospheric response to the 2015 St. Patrick\textquoterights Day storm: A global multi-instrumental overview

We present the first multi-instrumental results on the ionospheric response to the geomagnetic storm of 17\textendash18 March 2015 (the St. Patrick\textquoterights Day storm) that was up to now the strongest in the 24th solar cycle (minimum SYM-H value of -233 nT). The storm caused complex effects around the globe. The most dramatic positive ionospheric storm occurred at low latitudes in the morning (~100\textendash150\% enhancement) and postsunset (~80\textendash100\% enhancement) sectors. These significant vertical tota ...

Astafyeva, Elvira; Zakharenkova, Irina; Förster, Matthias;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2015

YEAR: 2015     DOI: 10.1002/2015JA021629

geomagnetic storm; hemispheric asymmetry; Ionosphere; negative storm; positive storm; Swarm mission

SPIE ProceedingsSpace-borne imager of mesospheric gravity waves

Mesospheric gravity waves play important roles in atmospheric circulation and variability. It is meaningful to obtain the features of the mesospheric gravity waves on a global scale, such as the distribution and the sources. However, limited by the field of view, the ground-based instrument can only access some local information. We developed a space-borne imager to observe the global gravity waves by collecting the O2 airglow with TDI (Time Delayed and Integration) method. The function of the imager was testified in our ...

Tu, Cui; Hu, Xiong; Xu, Qingchen; Song, Liang; Li, Hui;

Published by:       Published on: 10/2015

YEAR: 2015     DOI: 10.1117/12.2197894

airglow imaging; gravity wave; mesosphere; space borne; TDI

Dynamics of the high-latitude ionospheric irregularities during the 17 March 2015 St. Patrick\textquoterights Day storm: Ground-based GPS measurements

We report first results on the study of the high-latitude ionospheric irregularities observed in worldwide GPS data during the St. Patrick\textquoterights Day geomagnetic storm (17 March 2015). Multisite GPS observations from more than 2500 ground-based GPS stations were used to analyze the dynamics of the ionospheric irregularities in the Northern and Southern Hemispheres. The most intense ionospheric irregularities lasted for more than 24 h starting at 07 UT of 17 March. This period correlates well with an increase of t ...

Cherniak, Iurii; Zakharenkova, Irina; Redmon, Robert;

Published by: Space Weather      Published on: 09/2015

YEAR: 2015     DOI: 10.1002/swe.v13.910.1002/2015SW001237

auroral precipitation; geomagnetic storm; Ionosphere; irregularities; rate of TEC

Impacts of CME-induced geomagnetic storms on the midlatitude mesosphere and lower thermosphere observed by a sodium lidar and TIMED/GUVI

In this paper, we report our findings on the correlation between the neutral temperature (around the mesopause) and thermospheric column density O/N2\ ratio, along with their response to geomagnetic storms above midlatitude of North America. A temperature/wind Doppler Na lidar, operating at Fort Collins, CO (41\textdegreeN, 105\textdegreeW), and later at Logan, UT (42\textdegreeN and 112\textdegreeW), observed significant temperature increases (temperature anomaly) above 95 km (as much as 55 K at 105 km al ...

Yuan, T.; Zhang, Y.; Cai, X.; She, C.-Y.; Paxton, L.;

Published by: Geophysical Research Letters      Published on: 09/2015

YEAR: 2015     DOI: 10.1002/2015GL064860

Positive and negative ionospheric storms occurring during the 15 May 2005 geomagnetic superstorm

This study focuses on the 15 May 2005 geomagnetic superstorm and aims to investigate the global variation of positive and negative storm phases and their development. Observations are provided by a series of global total electron content maps and multi-instrument line plots. Coupled Thermosphere-Ionosphere-Plasmasphere electrodynamics (CTIPe) simulations are also employed. Results reveal some sunward streaming plumes of storm-enhanced density (SED) over Asia and a well-developed midlatitude trough over North America formi ...

Horvath, Ildiko; Lovell, Brian;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2015

YEAR: 2015     DOI: 10.1002/2015JA021206

CTIP/CTIPe simulations; Ionospheric storms; midlatitude trough; polar TOI; SED plume; thermospheric composition

Statistical analysis of the ionospheric response during geomagnetic storm conditions over South Africa using ionosonde and GPS data

This paper presents a statistical analysis of ionospheric response over ionosonde stations Grahamstown (33.3\textdegreeS, 26.5\textdegreeE, geographic) and Madimbo (22.4\textdegreeS, 30.9\textdegreeE, geographic), South Africa, during geomagnetic storm conditions which occurred during the period 1996\textendash2011. Such a climatological study is important in establishing local ionospheric behavior trend which later forms a basis for accurate modeling and forecasting electron density and critical frequency of the\ 

Matamba, Tshimangadzo; Habarulema, John; McKinnell, Lee-Anne;

Published by: Space Weather      Published on: 09/2015

YEAR: 2015     DOI: 10.1002/swe.v13.910.1002/2015SW001218

Geomagnetic storms; ionospheric storm effects; midlatitude ionosphere

Thermospheric mass density: A review

The mass density of Earth\textquoterights thermosphere (\~90\textendash600\ km altitude) is a critical parameter for low Earth orbit prediction because of the atmospheric drag on satellites in this region. In this review, we first survey techniques for measuring thermospheric density, empirical models that provide a synthesis of historical data, and physical models that simulate the environment by solving fluid equations. We then review the climate and weather features that are observed in thermospheric density (incl ...

Emmert, J.T.;

Published by: Advances in Space Research      Published on: 09/2015

YEAR: 2015     DOI: 10.1016/j.asr.2015.05.038

thermosphere; ~Mass density

Climatology of equatorial plasma bubble observed by MyRTKnet over the years 2008\textendash2013

Malaysia Real-Time Kinematics GNSS Network (MyRTKnet) which consists of 78 GPS receivers was used to investigate the occurrence of equatorial plasma bubble (EPB) along 96\textdegreeE-120\textdegreeE longitude. In this study, we present the monthly occurrence rate of EPB along the geographical longitudes of 96\textdegreeE-120\textdegreeE for a half of solar cycle period (2008-2013). A 2D map of rate of TEC change index (ROTI) projected at 300 km altitude was derived from the signal paths between GPS satellites and the rece ...

Buhari, S.; Abdullah, M.; Yokoyama, T.; Hasbi, A.; Otsuka, Y.; Nishioka, M.; Bahari, S.A.; Tsugawa, T.;

Published by:       Published on: 08/2015

YEAR: 2015     DOI: 10.1109/IconSpace.2015.7283752

Studying the G condition occurrence in different latitudes under solar minimum: Observation and modeling

We analyzed the G condition occurrence, using data of ionospheric vertical sounding from stations Norilsk (69.4\textdegreeN, 88.1\textdegreeЕ), Irkutsk (52.5\textdegreeN, 104\textdegreeЕ) and Hainan (18.3\textdegreeN, 109.3\textdegreeЕ) during the last extreme low solar activity period (2006\textendash2009). In most cases, the three stations registered the G condition in May\textendashAugust; in Norilsk, however, it was registered in March\textendashApril 2008. Under quiet geomagnetic conditions, the longest intervals ...

N.M., Polekh; E.B., Romanova; K.G., Ratovsky; J.K., Shi; X., Wang; G.J., Wang;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: 08/2015

YEAR: 2015     DOI: 10.1016/j.jastp.2015.06.001

Vertical sounding; Ionogram; Critical frequency; G condition; Ionosphere\textendashatmosphere interaction

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;

Published by: Journal of Earth System Science      Published on: 07/2015

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

geomagnetic storm; Ionospheric total electron content; low latitude ionosphere

Explaining solar cycle effects on composition as it relates to the winter anomaly

The solar cycle variation of\ F2\ region winter anomaly is related to solar cycle changes in the latitudinal winter-to-summer difference of O/N2. Here we use the National Center for Atmospheric Research\textendashGlobal Mean Model to develop a concept of why the latitudinal winter-to-summer difference of O/N2\ varies with solar cycle. The main driver for these seasonal changes in composition is vertical advection, which is expressed most simply in pressure coordinat ...

Burns, A.; Solomon, S.; Wang, W.; Qian, L.; Zhang, Y.; Paxton, L.; Yue, X.; Thayer, J.; Liu, H.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 07/2015

YEAR: 2015     DOI: 10.1002/2015JA021220

composition; solar cycle; upper atmosphere

Ionosphere equatorial ionization anomaly observed by GPS radio occultations during 2006\textendash2014

A large number of Global Position System (GPS) radio occultation (RO) observations have been accumulated in the University Corporation for Atmospheric Research (UCAR) Constellation Observation System for Meteorology, Ionosphere and Climate (COSMIC) Data Analysis and Archive Center (CDAAC) especially since the launch of COSMIC mission. This study made use of these RO data to study the morphology of ionosphere equatorial ionization anomaly (EIA) statistically during 2006\textendash2014. The ionospheric peak density (NmF2) a ...

Yue, Xinan; Schreiner, William; Kuo, Ying-Hwa; Lei, Jiuhou;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: 07/2015

YEAR: 2015     DOI: 10.1016/j.jastp.2015.04.004

Use of radio occultation to probe the high-latitude ionosphere

We have explored the use of COSMIC data to provide valuable scientific information on the ionospheric impacts of energetic particle precipitation during geomagnetic storms. Ionospheric electron density in the E region, and hence ionospheric conductivity, is significantly altered by precipitating particles from the magnetosphere. This has global impacts on the thermosphere\textendashionosphere because of the important role of conductivity on high-latitude Joule heating. Two high-speed stream (HSS) and two coronal mass ejec ...

Mannucci, A.; Tsurutani, B.; Verkhoglyadova, O.; Komjathy, A.; Pi, X.;

Published by: Atmospheric Measurement Techniques      Published on: 07/2015

YEAR: 2015     DOI: 10.5194/amt-8-2789-2015

A case study of ionospheric storm effects in the Chinese sector during the October 2013 geomagnetic storm

In this study, we investigate the ionospheric storm effects in the Chinese sector during 2 October 2013 geomagnetic storm. The TEC map over China sector (1\textdegree\ \texttimes\ 1\textdegree) and eight ionosondes data along the longitude of 110\textdegreeE are used to show significant positive ionospheric phases (enhancements in TEC and ionospheric peak electron density NmF2) in the high-middle latitude region and the negative effects at the low latitude and equatorial region during the storm. A wave structure ...

Mao, Tian; Sun, Lingfeng; Hu, Lianhuan; Wang, Yungang; Wang, Zhijun;

Published by: Advances in Space Research      Published on: 06/2015

YEAR: 2015     DOI: 10.1016/j.asr.2015.05.045

Ionospheric storm; Neutral wind; LSTIDs; PPEF; DDEF

Characteristics of ionospheric north-south asymmetry and their relationship with irregularity

Using the empirical ionospheric model, the flux-tube integrated electron density and the ratio between the F-region Pedersen conductivity and the total E- and F-region Pedersen conductivity are calculated to investigate the characteristics of the ionospheric asymmetry after sunset during a solar cycle. Furthermore, two indices representing the asymmetric strength of the parameters respectively are defined to study its relationship with the occurrences of the irregularities during different seasons and with different solar ...

Luo, Weihua; Zhu, Zhengping; Lan, Jiaping; Li, Xuejing;

Published by: Wuhan University Journal of Natural Sciences      Published on: 06/2015

YEAR: 2015     DOI: 10.1007/s11859-015-1088-7

asymmetry; Electron density; Ionosphere; irregularity; Pedersen conductivity

Ionospheric effects of solar flares and their associated particle ejections in March 2012

Flares of March 4\textendash9, 2012 were accompanied by an intensification of solar electromagnetic and corpuscular radiations and five coronal mass ejections. Bursts of X-rays and increased solar cosmic ray fluxes caused an increase in ionospheric absorption manifesting itself in data from vertical sounding stations as enhancements of the lowest frequency of reflections up to 4\textendash6\ MHz at the daytime and as the disappearance of reflections in the ionograms of high latitude stations. Interplanetary coronal m ...

Zolotukhina, N.; Polekh, N.; Kurkin, V.; Romanova, E.;

Published by: Advances in Space Research      Published on: 06/2015

YEAR: 2015     DOI: 10.1016/j.asr.2015.03.004

Ionospheric disturbance; Magnetic storm; X-ray flare; Solar cosmic rays; Coronal mass ejection

Global ionospheric response to the 2009 sudden stratospheric warming event using Ionospheric Data Assimilation Four-Dimensional (IDA4D) algorithm

A data assimilation algorithm is used to delineate the time-dependent three-dimensional ionospheric response to the 2009 sudden stratospheric warming (SSW) event. We use the Ionospheric Data Assimilation Four-Dimensional (IDA4D) algorithm to study the global ionospheric response to the 2009 SSW. This is the first study to utilize global ionospheric measurements in a data assimilation framework to unambiguously characterize atmosphere-ionosphere coupling via tidal modifications during the 2009 SSW event. Model results reve ...

Azeem, I.; Crowley, G.; Honniball, C.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 05/2015

YEAR: 2015     DOI: 10.1002/2015JA020993

Atmospheric tides; data assimilation; ionosphere/atmosphere interactions; sudden stratospheric warming

Multiday thermospheric density oscillations associated with variations in solar radiation and geomagnetic activity

Thermospheric densities observed by Challenging Minisatellite Payload and Gravity Recovery and Climate Experiment satellites during 2002\textendash2010 and the globally averaged thermospheric densities from 1967 to 2007 have been used to investigate latitudinal, longitudinal, and height dependences of the multiday oscillations of thermospheric densities. The data show that the main multiday oscillations in thermospheric densities are 27, 13.5, 9, and 7 day oscillations. The high-correlation coefficients between the densit ...

Xu, JiYao; Wang, Wenbin; Zhang, Shunrong; Liu, Xiao; Yuan, Wei;

Published by: Journal of Geophysical Research: Space Physics      Published on: 05/2015

YEAR: 2015     DOI: 10.1002/2014JA020830

oscillation; thermospheric density

Radar observations of simultaneous traveling ionospheric disturbances and atmospheric gravity waves

Simultaneous observations of atmospheric gravity waves (AGWs) and traveling ionospheric disturbances (TIDs) measured by an incoherent scatter radar at high latitudes are shown. The measurements were made using a beam swing experiment of the EISCAT UHF radar. The\ F\ region TID is seen as wavefronts in electron density, whereas the\ E\ region AGW is seen in the oscillations of the neutral wind. The wave vector of the TID has a downward component indicating that energy propagates upward ...

en, Nygr\; Aikio, A.; Voiculescu, M.; Cai, L.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 05/2015

YEAR: 2015     DOI: 10.1002/2014JA020794

atmospheric gravity wave; incoherent scatter; solar terminator; traveling ionospheric disturbance

Transpolar arc observation after solar wind entry into the high-latitude magnetosphere

Recently, Cluster observations have revealed the presence of new regions of solar wind plasma entry at the high-latitude magnetospheric lobes tailward of the cusp region, mostly during periods of northward interplanetary magnetic field. In this study, observations from the Global Ultraviolet Imager (GUVI) experiment on board the TIMED spacecraft and Wideband Imaging Camera imager on board the IMAGE satellite are used to investigate a possible link between solar wind entry and the formation of transpolar arcs in the polar ...

Mailyan, B.; Shi, Q.; Kullen, A.; Maggiolo, R.; Zhang, Y.; Fear, R.; Zong, Q.-G.; Fu, S; Gou, X.; Cao, X.; Yao, Z.; Sun, W.; Wei, Y.; Pu, Z;

Published by: Journal of Geophysical Research: Space Physics      Published on: 05/2015

YEAR: 2015     DOI: 10.1002/2014JA020912

magnetosphere-ionosphere coupling; transpolar arcs; in situ measurements

Characteristics and mechanisms of the annual asymmetry of thermospheric mass density

In this paper, globally-averaged, thermospheric total mass density, derived from the orbits of \~5000 objects at 250, 400, and 550 km that were tracked from 1967 to 2006, has been used to quantitatively study the annual asymmetry of thermospheric mass density and its mechanism(s). The results show that thermospheric mass density had a significant annual asymmetry, which changed from year to year. The annual asymmetry at the three altitudes varied synchronously and its absolute value increased with altitudes. The results s ...

Ma, RuiPing; Xu, JiYao; Wang, Wenbin; Chen, GuangMing; Yuan, Wei; Lei, Jiuhou; Burns, Alan; Jiang, Guoying;

Published by: Science China Earth Sciences      Published on: 04/2015

YEAR: 2015     DOI: 10.1007/s11430-014-5020-3

annual asymmetry of thermospheric mass density; solar EUV radiation; Sun-Earth distance



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