[P-EM13] Coupling Processes in the Atmosphere-Ionosphere System

[PEM13-02] Diagnose the diffractive contribution to GNSS scintillation at high latitude during the geomagnetic storm on 7-8 September 2017

*Chao Xiong^1,2, Yuhao Zheng¹, Yaqi Jin³, Dun Liu⁴, Chunyu Xu¹, Yixun Zhu¹, Kjellmar Oksavik³ (1.Department of Space Physics, Electronic Information School, Wuhan University, 430072, Wuhan, China., 2.Hubei Luojia Laboratory, 430079 Wuhan, China., 3.Department of Physics, University of Oslo, Oslo, Norway., 4.No. 22nd Research Institude, CETC, 266107 Qingdao, Shangdong, China.)

Keywords:Ionospheric plasma irregularities, Ionospheric scintillation, Refractive and diffractive variations, ionosphere-free linear combination

The ionospheric plasma irregularities can cause severe scintillation of the trans-ionospheric radio waves, e.g, signals from the global navigation satellite system (GNSS). The phase scintillation of GNSS signal are usually caused by both refractive and diffractive variations, while the amplitude scintillation is mainly attributed to diffractive process. At high latitude, the GNSS signals usually exhibit strong phase scintillation, but the meanwhile amplitude scintillation is very low. Such a feature leads to the commonly known issue as “phase without amplitude scintillation at high latitude”. In this study, we focused on the geomagnetic storm happened on 7-8 September 2017, and high-resolution data from four GNSS receivers at high latitudes were utilized. Quite intense phase and amplitude scintillations, represented by σ₄ and S₄, respectively, were observed during the storm mainly phase. By checking the ionosphere-free linear combination (IFLC) parameter, the intense phase and amplitude scintillations are found associated with diffractive effects. Simultaneous observations from the Swarm satellite have been further analyzed to resolve the possible reasons that causes the diffractive influence of scintillation.