Dependencies of GPS Scintillation Indices on the Ionospheric Plasma Drift and Rate of Change of TEC Around the Dawn Sector of the Polar Ionosphere. Issue 11 (2nd November 2022)

• Record Type: Journal Article
• Authors: Wang, Y.; Jayachandran, P. T.; Ma, Y.‐Z.; Zhang, Q.‐H.; Xing, Z.‐Y.; Ruohoniemi, J. M.; Shepherd, S. G.; Lester, M.
• Is Part Of: Journal of geophysical research. Volume 127:Issue 11(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-11-02
• Subjects: the polar ionosphere -- standard scintillation indices -- TEC variations -- dependencies -- SuperDARN radars; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2022JA030870
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: The dependencies of global positioning system (GPS) scintillation indices on ionospheric plasma flow and the rate of change of total electron content (TEC) around the dawn sector for the first time of the polar ionosphere are investigated. The phase scintillation index ( σ φ ) derived from GPS measurements of the Canadian High Arctic Ionospheric Network (CHAIN) shows linear dependencies on both the plasma drift speed measured by the SuperDARN radar and on the rate of change of TEC estimated from the GPS receivers of CHAIN. However, the amplitude scintillation index (S4 ) does not show any dependence on the plasma flow or the rate of change of TEC. These results further support Wang et al. (2018), https://doi.org/10.1002/2017JA024805 at the noon sector. The dependence of the phase scintillation index on the plasma flow further evidences that the standard phase scintillation index is dominated by refractive variations due to the use of a fixed cut‐off frequency of 0.1 Hz while detrending the phase observable. The dependence of the phase scintillation index on the rate of change of TEC consolidates the dominance of refractive variations inside. Plain Language Summary: In decades, the standard scintillation indices are widely used to represent the strength of scintillations in the ionosphere, which were usually calculated from the sixth order Butterworth filter with a fixed cut‐off frequency of 0.1 Hz by the ground‐based Global Navigation Satellite System (GNSS) receiver automatically. At middle‐to‐low latitudes, the applications of these indices are working very well. However, over the polar ionosphere, the completely different scintillation phenomenon "Phase without Amplitude" occurred when confronting the hazard conditions. Then, in order to explaining this weird, many researchers have carried out a lot of valuable approaches, fundamentally challenging the direct adopt of standard phase scintillation index. Here, for the first time, we present an experimental evidence on the dawn sector to prove the clear positive dependence of phase scintillation index on the convection flow speed and also the TEC variations. It reminds us to be careful when using the standard phase scintillation index over the polar region, in particular with high‐speed flows. Key Points: The dependencies of global positioning system scintillation indices on plasma flow and total electron content (TEC) variation were evaluated around the dawn sector of polar ionosphere The phase scintillation index depends linearly only on the plasma flow speed and the rate of change of TEC However, the amplitude scintillation index does not rely on the plasma flow and also the rate of change of TEC