Bibliography

Spatial-Temporal Behaviors of Large-Scale Ionospheric Perturbations During Severe Geomagnetic Storms on September 7—8 2017 Using the GNSS, SWARM and TIE-GCM Techniques

Geomagnetic storms on 7–8 September 2017 triggered severe ionospheric disturbances that had a serious effect on satellite navigation and radio communication. Multiple observations

Li, Wang; Zhao, Dongsheng; He, Changyong; Hancock, Craig; Shen, Yi; Zhang, Kefei;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2022     DOI: 10.1029/2021JA029830

Spatial-Temporal Behaviors of Large-Scale Ionospheric Perturbations During Severe Geomagnetic Storms on September 7–8 2017 Using the GNSS, SWARM and TIE-GCM Techniques

Geomagnetic storms on 7–8 September 2017 triggered severe ionospheric disturbances that had a serious effect on satellite navigation and radio communication. Multiple observations derived from Global Navigation Satellite System receivers, Earth s Magnetic Field and Environment Explorers (SWARM) and the Thermosphere-Ionosphere -Electrodynamics General Circulation Model s simulations are utilized to investigate the spatial-temporal ionospheric behaviors under storm conditions. The results indicate that the electron density in the Asia-Australia, Europe-Africa and America sectors suddenly changed with the Bz southward excursion, and the ionosphere over low-middle latitudes under the sunlit hemisphere is easily affected by the disturbed magnetic field. The SWARM observations verified the remarkable double-peak structure of plasma enhancements over the equator and middle latitudes. The physical mechanism of low-middle plasma disturbances can be explained by a combination effect of equatorial electrojets, vertical E × B drifts, meridional wind and thermospheric O/N2 change. Besides, the severe storms triggered strong Polar plasma disturbances on both dayside and nightside hemispheres, and the Polar disturbances had a latitudinal excursion associated with the offset of geomagnetic field. Remarkable plasma enhancements at the altitudes of 100–160 km were also observed in the auroral zone and middle latitudes (\textgreater47.5°N/S). The topside polar ionospheric plasma enhancements were dominated by the O+ ions. Furthermore, the TIE-GCM s simulations indicate that the enhanced vertical E × B drifts, cross polar cap potential and Joule heating play an important role in generating the topside plasma perturbations.

Li, Wang; Zhao, Dongsheng; He, Changyong; Hancock, Craig; Shen, Yi; Zhang, Kefei;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2022     DOI: 10.1029/2021JA029830

hemispheric asymmetry; ionospheric disturbances; Magnetic storms; thermospheric composition changes; TIE-GCM

Impact of Soft Electron Precipitation on the Thermospheric Neutral Mass Density During Geomagnetic Storms: GITM Simulations

In this study, the impact of improving soft (0.1–1 keV) electron precipitation on the F-region neutral mass density has been evaluated using the Global Ionosphere Thermosphere Model (GITM). Two types of electron energy spectra having the same total energy flux and average energy but different spectral shapes have been used to specify the electron precipitation in GITM. One is the Maxwellian spectrum and the other is from an empirical model, Auroral Spectrum and High-Latitude Electric field variabilitY (ASHLEY), which provides stronger (up to 2–3 orders of magnitude) soft electron precipitations than the Maxwellian spectrum. Data-model comparisons indicate that the storm-time orbital averaged neutral density can be increased by 10\%–40\% and is more consistent with the observation if the non-Maxwellian ASHLEY spectrum is used. This study reveals the importance of accurate soft electron precipitation specifications in the whole auroral zone to improving the F-region neutral mass density estimations.

Zhu, Qingyu; Deng, Yue; Sheng, Cheng; Anderson, Philip; Bukowski, Aaron;

Published by: Geophysical Research Letters      Published on:

YEAR: 2022     DOI: 10.1029/2021GL097260

ASHLEY; GITM; neutral mass density; soft electron precipitation

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:

YEAR: 2021     DOI:

Ionospheric Response Over Brazil to the August 2018 Geomagnetic Storm as Probed by CSES-01 and Swarm Satellites and by Local Ground-Based Observations

The geomagnetic storm that occurred on 25 August 25 2018, that is, during the minimum of solar cycle 24, is currently the strongest ever probed by the first China Seismo-Electromagnetic Satellite (CSES-01). By integrating the in situ measurements provided by CSES-01 (orbiting at altitude of 507 km) and by Swarm A satellite (orbiting at ca., 460 km) with ground-based observations (ionosondes, magnetometers, and Global Navigation Satellite System receivers), we investigate the ionospheric response at lower- and mid-latitudes over Brazil. Specifically, we investigate the electrodynamic disturbances driven by solar wind changes, by focusing on the disturbances driving modifications of the equatorial electrojet (EEJ). Our proposed multisensor technique analysis mainly highlights the variations in the topside and bottomside ionosphere, and the interplay between prompt penetrating electric fields and disturbance dynamo electric fields resulting in EEJ variations. Thanks to this approach and leveraging on the newly available CSES-01 data, we complement and extend what recently investigated in the Western South American sector, by highlighting the significant longitudinal differences, which mainly come from the occurrence of a daytime counter-EEJ during both 25 and 26 August at Braziliian longitudes and during part of 26 August only in the Peruvian sector. In addition, the increased thermospheric circulation driven by the storm has an impact on the EEJ during the recovery phase of the storm. The observations at the CSES-01/Swarm altitudes integrated with the ground-based observation recorded signatures of equatorial ionospheric anomaly crests formation and modification during daytime coupled with the positive ionospheric storm effects at midlatitude.

Spogli, L.; Sabbagh, D.; Regi, M.; Cesaroni, C.; Perrone, L.; Alfonsi, L.; Di Mauro, D.; Lepidi, S.; Campuzano, S.; Marchetti, D.; De Santis, A.; Malagnini, A.; Scotto, C.; Cianchini, G.; Shen, Xu; Piscini, A.; Ippolito, A.;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2020JA028368

Geomagnetic storms; Equatorial Electrojet; in situ plasma density; ionospheric elctroduamics; Ionospheric storms; low-latitude ionosphere

Comparison of electron density and temperature from the CSES satellite with other space-borne and ground-based observations

In this paper we provide a comprehensive comparison of in situ electron density (Ne) and temperature (Te) measured by Langmuir probe (LAP) on board the China Seismo‐

Yan, Rui; Zhima, Zeren; Xiong, Chao; Shen, Xuhui; Huang, Jianping; Guan, Yibing; Zhu, Xinghong; Liu, Chao;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2020     DOI: 10.1029/2019JA027747

Development of a new aurora model for the small-and meso-scale structures through deep-learning methods and their influence on the upper atmosphere

Deng, Y; Chen, Z; , Wang; Sheng, Cheng; , Jin; Zhang, Yongliang; Paxton, Larry; Deng, Xiaohua; Huang, Chung-Ming;

Published by:       Published on:

YEAR: 2018     DOI:

A severe negative response of the ionosphere to the intense geomagnetic storm on March 17, 2015 observed at mid- and low-latitude stations in the China zone

In this paper, the critical frequency of F2 layer of the ionosphere (foF₂₎ and the total electron content (TEC) recorded at mid- and low-latitude observation sites near 120\textdegreeE in the China zone were used to investigate the response to a severe geomagnetic storm on March 17, 2015 (the minimum Dst -223 nT at 23 UT). The results showed that the strong geomagnetic storm caused a massive effect on the ionosphere. The characteristics of foF₂ and TEC did not show obvious perturbation during the main phase. Severe depletion of foF₂ and TEC was observed at all stations during the storm recovery period. The maximum absolute discrepancy in TEC compared with the past 27-day average value was 78 TECU, and the minimum percentage deviations reached -71\% at Fuzhou (26.1\textdegreeN,\ 119.3\textdegreeE). The minimum percentage deviations of decrease in foF₂ reached -65\% at Sanya (18.1\textdegreeN,\ 109.3\textdegreeE) and Mohe (53.5\textdegreeN,\ 122.3\textdegreeE). This was an infrequent negative effect that foF₂ and TEC sustained throughout the day with extremely low level on March 18. The O/N₂ rate showed a distinct reduction on March 18 in the China zone, which may be mainly responsible for the severe depletion of foF₂ and TEC. The spread-F seemed to be developed at first but was then suppressed to some extent during the main phase. During the recovery phase, the spread-F was suppressed at Sanya, while it developed at Wuhan and Mohe. The disturbance electric fields and thermospheric circulation may contribute to this phenomenon.

Liu, Guoqi; Shen, Hua;

Published by: Advances in Space Research      Published on: 05/2017

YEAR: 2017     DOI: 10.1016/j.asr.2017.02.021

A severe negative response of the ionosphere to the intense geomagnetic storm on March 17, 2015 observed at mid-and low-latitude stations in the China zone

Liu, Guoqi; Shen, Hua;

Published by: Advances in Space Research      Published on:

YEAR: 2017     DOI:

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\textendashionosphere\textendashthermosphere system. Dramatic changes in the ionosphere are seen at every one of the active radar stations, extending from Greenland down to equatorial Peru in the American sector and at middle latitudes in Ukraine. Data from TIMED and THEMIS are shown to support initial interpretations of the observations, where we focus on processes in the middle latitude afternoon sector during main phase, and the formation of a dense equatorial ionosphere during storm recovery. The combined measurements strongly suggest that the changes in ionospheric conditions observed after the main storm phase can be attributed in large part to changes in the stormtime thermosphere. This is through the generation of disturbance dynamo winds and also global neutral composition changes that either reduce or enhance plasma densities in a manner that depends mainly upon latitude. Unlike larger storms with possibly more sustained forcing, this storm exhibits minimal effects of persistent meridional stormtime wind drag, and little penetration of solar wind electric potentials to low latitudes. It is, therefore, an outstanding example of an impulsive event that exhibits longer-term effects through modification of the background atmosphere.

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

Observations and modeling of UHF-band scintillation occurrence probability over the low-latitude region of China during the maximum activity of solar cycle 24

The climatological characteristics of UHF-band scintillations over the low-latitude region of China were investigated by analyzing the observations recorded at three stations of our

Zhang, Hongbo; Liu, Yumei; Wu, Jian; Xu, T; Sheng, D;

Published by:       Published on:

YEAR: 2015     DOI: 10.5194/angeo-33-93-2015

Height-integrated Pedersen conductivity in both E and F regions from COSMIC observations

Altitudinal distribution of Joule heating is very important to the thermosphere and ionosphere, which is roughly proportional to the Pedersen conductance at high latitudes. Based on the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites observations from 2008 to 2011, the height-integrated Pedersen conductivities in both E (100\textendash150\ km) and F (150\textendash600\ km) regions and their ratio _γPγP (_∑PE/_∑PF∑PE/∑PF) have been calculated. The result shows that the maximum ratio in the northern summer hemisphere is ~5.5, which is smaller than that from the Thermosphere\textendashIonosphere\textendashElectrodynamics General Circulation Model (TIE-GCM v1.94) simulation (~9). This indicates that the energy inputs into the F region may be underestimated in the model. The seasonal variations of the ratio have been investigated for both hemispheres, and an interhemispheric asymmetry has been identified. The variational trend of the ratio is similar in both hemispheres, which reaches minimum at local summer and maximum at local winter. However, the difference of the ratio from local summer to local winter in the southern hemisphere is larger than that in the northern hemisphere.

Sheng, Cheng; Deng, Yue; Yue, Xinan; Huang, Yanshi;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: 08/2014

YEAR: 2014     DOI: 10.1016/j.jastp.2013.12.013

COSMIC; Interhemispheric asymmetry; Joule heating; Pedersen conductivity

Optical System Design of a Spaceborne Broadband Far Ultraviolet Hyperspectral Imager

According to the application requirements for remote sensing of upper atmosphere,a reflective optical system of spaceborne far ultraviolet hyperspectral imager is designed.Which is composed of a scan mirror,an off-axis parabolic telescope and a toroidal grating spectrometer.An aberration-correction method for concave toroidal grating is developed.The initial parameters are solved based on the geometrical aberration theory of concave grating and then optimized using the optical design software Zemax,and the toroidal gating spectrometer is designed.The root mean square of spot radius is less than 16 μm in the working waveband.Aberration is corrected simultaneously in broadband and the requirement of spectral resolution of 0.6 nm is satisfied,which indicates the aberration-correction method is feasible.Ray tracing and analysing are performed by Zemax software.Analyzed results demonstrate that the modulation transfer function for different wavelength is more than 0.8,which satisfies the design requirements.The construction is compact and suitable for application in space remote sensing.

Qingsheng, Xue;

Published by: Acta Optica Sinica      Published on:

YEAR: 2012     DOI:

optical design hyperspectral imager toroidal grating far ultraviolet geometrical aberration

Design of FUV imaging spectrometer based on crossed Czerny-Turner structure

This article describes the characteristics of the far ultraviolet (FUV) radiation and its applications in the space weather s research and prediction. The FUV imaging spectrometer is irreplaceable to get the FUV radiation data of the earth s upper atmosphere. Some key technologies of FUV spectrometer are analyzed respectively, including window materials, FUV light source, FUV detectors and FUV coating, which offer theoretical foundation for FUV imaging spectrometer. The paper presents a FUV band imaging spectrometer s optical system which is based on crossed Czerny-Turner structure with all reflective components in it. The wavelength range of the FUV spectrometer optical system is from 100nm to 200nm and the initial structure is simulated and optimized by Zemax in order to improve the spectral resolution. The theoretical spectral resolution of the system is better than 1nm, and it has a certain imaging capacity.

Wu, Yan; Tang, Yi; Ni, Guoqiang; Sheng, Yunlong; Wang, Yongtian; Zeng, Lijiang;

Published by:       Published on:

YEAR: 2009     DOI: 10.1117/12.806967

space weather; far ultraviolet; Imaging spectrometer; crossed Czerny-Turner system; optical design