Bibliography

Local Persistent Ionospheric Positive Responses to the Geomagnetic Storm in August 2018 Using BDS-GEO Satellites over Low-Latitude Regions in Eastern Hemisphere

We present the ionospheric disturbance responses over low-latitude regions by using total electron content from Geostationary Earth Orbit (GEO) satellites of the BeiDou Navigation Satellite System (BDS), ionosonde data and Swarm satellite data, during the geomagnetic storm in August 2018. The results show that a prominent total electron content (TEC) enhancement over low-latitude regions is observed during the main phase of the storm. There is a persistent TEC increase lasting for about 1–2 days and a moderately positive disturbance response during the recovery phase on 27–28 August, which distinguishes from the general performance of ionospheric TEC in the previous storms. We also find that this phenomenon is a unique local-area disturbance of the ionosphere during the recovery phase of the storm. The enhanced foF2 and hmF2 of the ionospheric F2 layer is observed by SANYA and LEARMONTH ionosonde stations during the recovery phase. The electron density from Swarm satellites shows a strong equatorial ionization anomaly (EIA) crest over the low-latitude area during the main phase of storm, which is simultaneous with the uplift of the ionospheric F2 layer from the SANYA ionosonde. Meanwhile, the thermosphere O/N2 ratio shows a local increase on 27–28 August over low-latitude regions. From the above results, this study suggests that the uplift of F layer height and the enhanced O/N2 ratio are possibly main factors causing the local-area positive disturbance responses during the recovery phase of the storm in August 2018.

Tang, Jun; Gao, Xin; Yang, Dengpan; Zhong, Zhengyu; Huo, Xingliang; Wu, Xuequn;

Published by: Remote Sensing      Published on: jan

YEAR: 2022     DOI: 10.3390/rs14092272

BDS-GEO; differential code biases; geomagnetic storm; Ionospheric disturbance; TEC

Geomagnetic and Solar Dependencies of Midlatitude E-Region Irregularity Occurrence Rate: A Climatology Based on Wuhan VHF Radar Observations

By using Wuhan VHF radar, we show the morphological features of E-region field-aligned irregularity (FAI) occurrence at Wuhan during 2015–2020. Statistical results present that E-region FAI occurrence reaches a maximum after sunset in summer season. According to Doppler spectrum features, type-2 irregularity is predominantly observed at Wuhan. In addition, we observed a remarkable correlation between E-region FAI occurrence and geomagnetic activity, which includes periods of positive correlation and negative correlation depending on different geomagnetic conditions. The strong negative correlation also exists between E-region FAI occurrence and solar activity. In our observed results, we find that E-region FAI occurrence shows a strong linkage with local sporadic E (ES) layer. A quantitative analysis of linear theory of plasma instability in the E-region at midlatitudes is also presented in our study. The calculated results of linear growth rate indicate the importance of plasma density gradient of local ES layer and field-line-integrated Pedersen conductivity on the generation of E-region FAI. The geomagnetic and solar variations of E-region FAI occurrence are also discussed in this study, which show a dependence on the geomagnetic and solar variations of both meteor rate and medium-scale traveling ionospheric disturbance occurrence.

Liu, Yi; Zhou, Chen; Xu, Tong; Deng, Zhongxin; Du, Zhitao; Lan, Ting; Tang, Qiong; Zhu, Yunzhou; Wang, Zhuangkai; Zhao, Zhengyu;

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

YEAR: 2022     DOI: 10.1029/2021JA029597

A ROTI-Aided Equatorial Plasma Bubbles Detection Method

In this study, we present a Rate of Total Electron Content Index (ROTI)-aided equatorial plasma bubbles (EPBs) detection method based on a Global Navigation Satellite System (GNSS) ionospheric Total Electron Content (TEC). This technique seeks the EPBs occurrence time according to the ROTI values and then extracts the detrended ionospheric TEC series, which include EPBs signals using a low-order, partial polynomial fitting strategy. The EPBs over the Hong Kong area during the year of 2014 were detected using this technique. The results show that the temporal distribution and occurrence of EPBs over the Hong Kong area are consistent with that of previous reports, and most of the TEC depletion error is smaller than 1.5 TECU (average is 0.63 TECU), suggesting that the detection method is feasible and highly accurate. Furthermore, this technique can extract the TEC depletion series more effectively, especially for those with a long duration, compared to previous method.

Tang, Long; Louis, Osei-Poku; Chen, Wu; Chen, Mingli;

Published by: Remote Sensing      Published on: jan

YEAR: 2021     DOI: 10.3390/rs13214356

Ionosphere; detection method; equatorial plasma bubbles; GNSS; ROTI

Ionospheric response to the 17 March and 22 June 2015 geomagnetic storms over Wuhan region using GNSS-based tomographic technique

By using the data of GNSS (Global Navigation Satellite System) observation from Crustal Movement Observation Network of China (CMONOC), ionospheric electron density (IED) distributions reconstructed by using computerized ionospheric tomography (CIT) technique are used to investigate the ionospheric storm effects over Wuhan region during 17 March and 22 June 2015 geomagnetic storm periods. F-region critical frequency (foF2) at Wuhan ionosonde station shows an obvious decrease during recovery phase of the St. Patrick’s Day geomagnetic storm. Moreover, tomographic results present that the decrease in electron density begins at 12:00 UT on 17 March during the storm main phase. Also, foF2 shows a long-lasting negative storm effect during the recovery phase of the 22 June 2015 geomagnetic storm. Electron density chromatography presents the evident decrease during the storm day in accordance with the ionosonde observation. These ionospheric negative storm effects are probably associated with changes of chemical composition, PPEF and DDEF from high latitudes.

Feng, Jian; Zhou, Yufeng; Zhou, Yan; Gao, Shuaihe; Zhou, Chen; Tang, Qiong; Liu, Yi;

Published by: Advances in Space Research      Published on: jan

YEAR: 2021     DOI: 10.1016/j.asr.2020.10.008

Ionospheric electron density distributions; ionospheric storm effects; Multiplication algebraic reconstruction technique

Correction of astigmatism and coma using analytic theory of aberrations in imaging spectrometer based on concentric off-axis dual reflector system

A specific imaging spectrometer based on a concentric off-axis dual reflector system is proposed, free of astigmatism and coma. The described imaging spectrometer consists of four spherical mirrors and a plane grating. The analytic theory of aberrations and the optical path-length concept are used to derive the astigmatism elimination and coma removal. It is shown that the astigmatism in these imaging spectrometers is eliminated by characterizing three angles, and the coma is corrected when unequal mirror radii are configured in collimating and condensing optics. The developed aberration principle is verified by comparing the performance of the astigmatism-eliminated spectrometer with the spectrometer which has neither astigmatism nor coma.

Chen, Ting; Tang, Yi; Zhang, Li; Chang, Yue; Zheng, Cheng;

Published by: Applied Optics      Published on: 01/2014

YEAR: 2014     DOI: 10.1364/AO.53.000565

Retrieving ionospheric electron density profile from FUV spectral remote sensing measurements

WANG, Jing; Tang, Yi; ZHANG, Zhi-Ge; ZHENG, Xu-Li; Ni, Guo-qiang;

Published by: Chinese Journal of Geophysics      Published on:

YEAR: 2013     DOI:

A Quality Assessment Method for Retrieved O/N\_2 Images from FUV Remote Sensing

WANG, Jing; Tang, Yi; Peng, Sheng-feng; ZHENG, Xu-Li; Ni, Guo-qiang;

Published by: Infrared      Published on:

YEAR: 2013     DOI:

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 established. Finally, applying the proposed method to retrieve O/N₂\ during a magnetic period(29, September\textemdash4, October, 2002), it was shown that magnetic storms could induce significant O/N₂\ depletion, extending from the polar regions towards the equator.

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

AURIC; GUVI; Magnetic storm; O/N2

The ground calibration of far ultraviolet scanning imaging spectrometer (FUSIS)

The far ultraviolet scanning imaging spectrometer (FUSIS) is used to measure the composition and distribution of the main molecules and atoms in the Earth s upper atmosphere. It is an important instrument in investigation of the physical and chemical processes in the Earth s upper atmosphere. FUSIS works between 120nm to 180nm, its spectral resolution is better than 1.0nm and its spatial resolution is 8 pixels. This paper describes a kind of ground calibration method and facility of FUSIS. The FUV light is invisible, so all works must be done in high vacuum.

Wu, Yan; Tang, Yi; Liu, Jianpeng; Zhang, Zhige; Ni, Guoqiang;

Published by:       Published on:

YEAR: 2010     DOI: 10.1117/12.870475

Retrieval of ionospheric O/N2 based on FUV imaging data

Solar storms in the ionosphere have a great impact on human\textquoterights life. It\textquoterights of great significance to find an effective way for an accurate prediction of solar storms. In this paper, we present a method based on GUVI FUV day-glow imaging data to derive O/N₂, an environmental parameter used to forecast Space Weather. In the retrieval, we selected two channels of the FUV wavelengths, OI135.6nm and LBH2. In accordance with the linear relationship between O/N₂ and 135.6/LBH, we proposed 135.6/LBH to describe O/N₂. With the method described in this paper, the data of a 4-day solar storm, October 1 to 4, 2002, have been processed. Subsequently, the obtained O/N₂ maps were in good agreement with previous results. It demonstrated the retrieval process we put up is efficient.

Jing, Wang; Tang, Yi; Tang, Li-jun; Ni, Guo-qiang;

Published by:       Published on:

YEAR: 2009     DOI: 10.1117/12.833985

Retrieval of ionospheric O/N2 based on FUV imaging data

Solar storms in the ionosphere have a great impact on human\textquoterights life. It\textquoterights of great significance to find an effective way for an accurate prediction of solar storms. In this paper, we present a method based on GUVI FUV day-glow imaging data to derive O/N₂, an environmental parameter used to forecast Space Weather. In the retrieval, we selected two channels of the FUV wavelengths, OI135.6nm and LBH2. In accordance with the linear relationship between O/N₂ and 135.6/LBH, we proposed 135.6/LBH to describe O/N₂. With the method described in this paper, the data of a 4-day solar storm, October 1 to 4, 2002, have been processed. Subsequently, the obtained O/N₂ maps were in good agreement with previous results. It demonstrated the retrieval process we put up is efficient.

Jing, Wang; Tang, Yi; Tang, Li-jun; Ni, Guo-qiang;

Published by:       Published on:

YEAR: 2009     DOI: 10.1117/12.833985

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

Retrieval of ionospheric O/N2 based on FUV imaging data

Jing, Wang; Tang, Yi; Tang, Li-jun; Ni, Guo-qiang;

Published by:       Published on:

YEAR: 2009     DOI:

Retrieval of ionospheric O/N2 based on FUV imaging data

Jing, Wang; Tang, Yi; Tang, Li-jun; Ni, Guo-qiang;

Published by:       Published on:

YEAR: 2009     DOI: