A statistical study of the occurrence characteristic of GPS ionospheric scintillation and irregularity in the ...
Guozhu Li·Baiqi Ning·Zhipeng Ren·Lianhuan Hu Beijing National Observatory of Space Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences,Beijing,China
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.
