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

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

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A HIGH SUBCLUTTER VISIBILITY NONCOHERENT vhf radar

A HIGH SUBCLUTTER VISIBILITY NONCOHERENT VHF RADAR

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1996 CIE International Conference of radar(ICR’96)

作者： Yan Yi Zhang Wenzhi Lu Lingen Beijing Institute of Radio Measurement

ISBN: (纸本)0780329147

＜正＞A high sub-clutter visibility（SCV） noncoherent vhf radar is introduced in this *** increasing the frequency stability of the system through de-Q amplitude stabilized circuit,four-port circulator, decimal frequency divided phase locked loop and so on, and improving the capability of the signal processor through digital convolution,three-pulse cancellation, CFAR,sliding window integration and so on,the SCV is more than 30 dB.

关键词： Noncoherent radar vhf radar Subclutter visibility Signal processing

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

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

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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

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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

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