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The first time observations of low-latitude ionospheric irregularities by VHF radar in Hainan

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Science China(Technological Sciences) 2012年第5期55卷 1189-1197页

作者： NING BaiQi hu lianhuan LI GuoZhu LIU LiBo WAN WeiXing Institute of Geology and Geophysics Chinese Academy of SciencesBeijing 100029China Beijing National Observatory of Space Environment Beijing 102213China Graduate University of Chinese Academy of Sciences Beijing 100081China

Sanya VHF radar （18.4°N, 109.6°E, dip latitude 12.8°N） at Hainan Island is the first coherent backscatter radar for sounding low-latitude ionospheric irregularities in the mainland of China. In this paper, we present the first results of low-latitude iono- spheric E and F region irregularities using the radar data during the period from February 2009 to March 2010. The Doppler velocity of radar echoes from E region field aligned irregularities （FAIs） was about several tens of meters per second, while the Doppler spectral width was appreciably larger than the velocity, and could reach one hundred meters per second, indicating that the observed E region FAls belonged to type 2 irregularities. The observations of range time intensity （RTI） maps of FAIs showed that E region irregularities most often occurred at night within the altitude range 85-115 kin, and were rarely observed at afternoon hours. The percentage occurrence of E region FAIs maximized during spring months （Feb.-May） with a peak value over 80%. The heights at which the strongest echo related FAIs occurred were mainly around 100 kin, lower than h＇Es and the difference is mostly 10-20 km. December solstice seemed to be the minimum period of occurrence when the FA! ech- oes were commonly detected at a narrow altitude range 90-100 km. Moreover, simultaneous radar and GPS observations dur- ing spread F events in the pre-midnight hours of solar minimum revealed that significant GPS L band scintillations coincided with the appearance of F region plasma plume structures, which extended up to 450 km in altitude.

关键词： low-latitude ionosphere ionospheric irregularities VHF radar

A comparison of mesospheric winds measured by FPI and meteor radar located at 40N

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Science China(Technological Sciences) 2012年第5期55卷 1245-1250页

作者： JIANG GuoYing XU JiYao YUAN Wei NING BaiQi WAN WeiXing hu lianhuan State Key Laboratory of Space Weather Center for Space Science and Applied ResearchChinese Academy of SciencesBeijing 100190China Beijing National Observatory of Space Environment Institute of Geology and GeophysicsChinese Academy of Sciences Beijing 100029China

In this paper, winds derived from OH Meinel 892.0 nm detection by an FPI （Fabry-Perot Interferometer） are compared with the simultaneous wind measurements from a meteor radar during April-May of 2010. The peak height of OH Meinel 892.0 nm is about 87 km. The variations of FPI wind at 87 km mostly have the similar track to meteor radar wind at 87 km, and the data values of FPI wind mainly fall into the range of meteor radar wind. However, there are still quantitative differences between the observations of the two systems. The best cross-correlation occurs in rneridional winds from two systems in April of 2010. An obvious wave signal with 0.2 cycle/d frequency is found in meridional winds observed by both FPI and meteor radar.

关键词： FPI meteor radar mesospheric wind

Seasonal variations of night mesopause temperature in Beijing observed by SATI4

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Science China(Technological Sciences) 2012年第5期55卷 1295-1301页

作者： XIONG JianGang WAN WeiXing NING BaiQi LIU LiBo WU BaoYuan hu lianhuan XU Tao Beijing National Observatory of Space Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China

The data observed by a spectral airglow temperature imager （SATI） at Beijing National Observatory of Space Environment from July 23, 2008 to July 3l, 2009 are used to study night mesopause temperature in Beijing. From variations of temperature at 87 and 94 km obtained from OH （6-2） and 02 （0-1） airglow spectra, temperature at night is shown lowest in the summer and highest in the winter. In summer, average temperature at 87 km is 173.9 K, lower than average temperature 180.1 K at 94 km. But in winter, average temperature at 87 Ion is 201.2 K, higher than average temperature 194.8 K at 94 kin. The altitude of mesopause in Beijing is below 87 km in summer and above 94 km in winter. There are about 120-150 days when the mesopause locates below 87 km, which is in agreement with the results of SABER/TIMED. Variations of temperatures at 87 and 94 km are analyzed by harmonic method. Our results show that amplitudes of annual oscillation of temperature at 87 and 94 km are 17.5 and 7.8 K respectively. Amplitudes of semi-annual oscillation at 87 and 94 km are 1.6 and 5.3 K, which are smaller than those of annual oscillation. Although there are differences among different observations because of different locations and different instruments, our results are in general agreement with observation at similar latitude as Beijing.

关键词： mesopause temperature airglow seasonal variations SATI

The possibility of using all-sky meteor radar to observe ionospheric E-region field-aligned irregularities

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Science China(Technological Sciences) 2019年第8期62卷 1431-1437页

作者： XIE HaiYong LI GuoZhu NING BaiQi REID Iain hu lianhuan WU BaoYuan YU You YANG SiPeng Key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Beijing National Observatory' of Space Environment Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China College of Earth and Planetary Sciences University of Chinese Academy of Science Beijing 100029 China ATmospheric RAD ar (ATRAD) Pty Ltd Thebarton 5031 Australia School of Physical Sciences University of Adelaide Adelaide 5005 Australia

All-sky meteor radars are primarily used for meteor observations. This paper reports the first observations of ionospheric Eregion field-aligned irregularities(FAIs) from a conventional all-sky meteor radar located at Wuhan(31°N, 114°E) for the period of March–June 2018. E-region FAI echoes evident in range-time intensity(RTI) maps show quasiperiodic striations with positive and negative slopes, which are consistent with multiple FAI structures moving across the wide beam of the meteor radar. A statistical analysis shows that out of a total of 111 d, there are 73 d with E-region FAI echoes detected by the meteor radar. The FAI events correspond well with the presence of sporadic-E layers which provide the necessary plasma density gradient for the development of gradient drift instability producing FAIs. The results demonstrate the capability of conventional meteor radars to make simultaneous routine observations of meteors and ionospheric E-region FAIs through incorporating RTI and spectral analysis into the online realtime data processing. Meteor radar observations could potentially address the limitations of ionospheric radars, which cannot provide simultaneous measurements of neutral winds and irregularity structures, and thereby contribute to better understanding of the dynamical processes producing E-region irregularities.

关键词： meteor radar ionospheric irregularities sporadic E layer

Onset location of scintillation-producing spread-F plume over Sanya

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Science China Earth Sciences 2016年第8期59卷 1692-1699页

作者： ZHENG JianChang huANG ZhaoGuo WU Zhi HAO XiQing JI JiaLun NING BaiQi hu lianhuan ZHAO XiuKuan LI GuoZhu Key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Beijing National Observatory of Space Environment Institute of Geology and Geophysics Chinese Academy of Sciences

Equatorial spread-F (ESF) backscatter plumes are often observed in radar range-time-intensity (RTI) maps at low latitude. Except case studies, few statistical investigations on the onset locations of scintillation-producing ESF plumes at given sites have been conducted. In this study, a statistical analysis is carried out on onset locations of ESF backscatter plumes observed at a low-latitude location Sanya (18.4°N, 109.6°E; dip lat 12.8°N) during equinoctial months of 2013. By employing a tracing method to locate backscatter plumes, we estimate the onset longitudes of periodic plumes obtained from the Sanya VHF radar five-beam steering measurements. The results show that the inter-plume distances (in longitude) are mostly confined within 200–600 km, and the ESF plumes producing ionospheric scintillations over Sanya are almost exclusively generated at the longitudes of 94°–110°E. The results indicate the necessity to monitor ESF plume initial generation in the longitude region of 94°–110°E to better understand the day-to-day variability in the occurrence of ionospheric scintillations over Sanya.

关键词： Equatorial spread-F Backscatter plume Onset location VHF radar Zonal drift

Interferometry observations of low-latitude E-region irregularity patches using the Sanya VHF radar

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Interferometry observations of low-latitude E-region irregul...

中国科学院地质与地球物理研究所2014年度（第14届）学术年会

Interferometry plays an important role in revealing fine-scale structures of ionospheric *** placing an additional receiving array of four 5-element Yagi antennas in the north of the main East-West array of the Sanya VHF radar,multiple interferometry baselines with components parallel and perpendicular to the magnetic meridian are *** baselines allow us to study the three-dimensional(3D) behavior of low-latitude ionospheric field-aligned irregularity(FAI) over *** multiple non-collinear receiving baselines,an experiment for which the Sanya VHF radar operated as an interferometer was performed on 10 July *** E-region FAI echoes with periods of several minutes were observed during 0745-0915 UT;mean Doppler velocity was around-30 m/s with spectral widths of about 50 m/*** interferometry results show fine-scale structures of E-region FAT with a zonal scale size of 15 km or *** addition,we found that the periodic variations of echo intensity shown in radar range-time-intensity(RTI) maps were produced by spatially separated E-region irregularity *** patches drifted westward with a velocity of about 40-60 m/s and could be associated with propagating gravity *** results provide a clearer picture of the characteristics of FAI and thus help to investigate the generation and dynamics of low-latitude ionospheric irregularities in the Chinese sector.

关键词： ionospheric E-region field-aligned irregularity patch radar interferometry

Characteristics of GPS L-band ionospheric scintillation over a low-latitude location Sanya

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Characteristics of GPS L-band ionospheric scintillation over...

2014年中国地球科学联合学术年会——专题29：空间天气与人类活动

作者： Kangkang Liu Guozhu Li Baiqi Ning lianhuan hu Hongke Li Beijing National Observatory of Space Environment Institute of Geology and Geophysics Chinese Academy of Sciences University of Chinese Academy of Science Institute of Geology and Geophysics

The GPS L-band ionospheric scintillation produced by electron density irregularity in the ionospheric E- and F-regions, is mainly a low- and high-latitude phenomenon. In this study, the statistical behavior of GPS ionospheric scintillation over a Chinese low-latitude station Sanya(18.3°N, 109.6°E;dip lat: 12.8°N), including the seasonal and solar activity dependence, the onset time, and the zonal drifts of irregularities producing GPS ionospheric scintillation during the period from July 2004 to December 2012 has been investigated. The amplitude scintillation pattern, with a maximum occurrence during equinox of solar maximum, agrees with plasma bubble observations by in-situ satellites in this longitude. The drifts of irregularities estimated using two spatially separated GPS receivers over Sanya show a similar behavior during two equinoxes, slowly decreasing from 150 m/s at post sunset to 50 m/s near midnight. A significant equinoctial asymmetry of scintillation onset time is found. The initiation of scintillation during the spring equinoctial months(March-April) is on average earlier than that of autumn months(September-October) about 25 min. In addition, daytime periodic scintillation was recorded during June solstitial months of solar minimum. Possible mechanisms responsible for the occurrence characteristics of GPS scintillation over Sanya are discussed.

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The first time observations of low-latitude ionospheric irregularities by VHF radar in Hainan

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The first time observations of low-latitude ionospheric irre...

中国科学院地质与地球物理研究所2012年度（第12届）学术年会

作者： NING BaiQi hu lianhuan LI GuoZhu LIU LiBo WAN WeiXing Institute of Geology and Geophysics Chinese Academy of Sciences Beijing National Observatory of Space Environment Graduate University of Chinese Academy of Sciences Beijing National Observatory of Space Environment

Sanya VHF radar(18.4°N,109.6°E,dip latitude 12.8°N) at Hainan Island is the first coherent backscatter radar for sounding low-latitude ionospheric irregularities in the mainland of *** this paper,we present the first results of low-latitude ionospheric E and F region irregularities using the radar data during the period from February 2009 to March *** Doppler velocity of radar echoes from E region field aligned irregularities(FAIs) was about several tens of meters per second,while the Doppler spectral width was appreciably larger than the velocity,and could reach one hundred meters per second,indicating that the observed E region FAIs belonged to type 2 *** observations of range time intensity(RTI) maps of FAIs showed that E region irregularities most often occurred at night within the altitude range 85-115 km,and were rarely observed at afternoon *** percentage occurrence of F region FATs maximized during spring months(Feb.-May) with a peak value over 80%.The heights at which the strongest echo related FAIs occurred were mainly around 100 km,lower than h’Es and the difference is mostly 10-20 *** solstice seemed to be the minimum period of occurrence when the FAI echoes were commonly detected at a narrow altitude range 90-100 ***,simultaneous radar and GPS observations during spread F events in the pre-rmdnight hours of solar minimum revealed that significant GPS L band scintillations coincided with the appearance of F region plasma plume structures,which extended up to 450 km in altitude.

关键词： low-latitude ionosphere ionospheric irregularities VHF radar

Statistical characteristics of low-latitude ionospheric scintillation over China

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Statistical characteristics of low-latitude ionospheric scin...

中国科学院地质与地球物理研究所2015年度（第15届）学术年会

作者： Kangkang Liu Guozhu Li Baiqi Ning lianhuan hu Hongke Li Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of Sciences Beijing National Observatory of Space Environment Institute of Geology and GeophysicsChinese Academy of Sciences University of Chinese Academy of Sciences

The Global Positioning System(GPS) L-band ionospheric scintillation produced by electron density irregularities in the ionospheric E-and F-regions,is mainly a low-and high-latitude *** this study,the statistical behavior of GPS ionospheric scintillation over a Chinese low-latitude station Sanya(18.3°N,109.6°E;dip lat:12.8°N) has been investigated.A detailed study on the seasonal and solar activity dependence of scintillation occurrence during July 2004–December 2012 show that the amplitude scintillation pattern,with a maximum occurrence during equinox of solar maximum,agrees with plasma bubble observations by in situ satellites in this longitude.A few daytime periodic scintillation events are found during June solstice months of solar ***,a significant equinoctial asymmetry of scintillation onset time is found in 2011–*** initiation of scintillation during September–October is on average earlier than that of March–April about 25 ***,the zonal drifts of irregularities estimated using two spatially separated GPS receivers over Sanya show a similar behavior during the two equinoxes,slowly decreasing from 150 m/s at post-sunset to 50 m/s near *** possible mechanisms responsible for the occurrence characteristics of GPS scintillation over Sanya,and relevant aspects of the zonal drifts of the irregularities are discussed.

关键词： GPS ionospheric scintillation Irregularity zonal drift Equinoctial asymmetry