Detecting Phase and Amplitude Scintillation with 1 Second Indices Using a Closely Spaced GNSS Array at Poker Flat Research Range

Scintillation has often been observed for Global Navigation Satellite Systems (GNSS) radio frequencies in the auroral zones and many researchers use 60-100s scintillation indices to detect scintillation. Refractive effects are believed to be the dominant contributor to scintillation in the high-latitude ionosphere; however, this could be due to sensing times. The dynamics in the high-latitude ionosphere cause rapid changes that may last only a few seconds. Thus, traditional scintillation indices calculated over 60-second intervals and above are not sensitive enough to characterize such abrupt changes in the ionosphere and thus cannot capture scintillation precisely (Y. Nishimura, T. Kelly, P.T. Jayachandran, S. Mrak, J. L. Semeter, E. F. Donovan, V. Angelopoulos and N. Nishitani, “Nightside High-Latitude Phase and Amplitude Scintillation During a Substorm Using 1-Second Scintillation Indices,” Journal of Geophysical Research: Space Physics, vol. 128, 2023). A smaller averaging window of 1 second is needed to capture more of the ionosphere's diffractive effects (K. Guo, S. V. Veettil, B. J. Weaver and M. Aquino, “Mitigating high latitude ionospheric scintillation effects on GNSS Precise Point Positioning exploiting 1 s scintillation indices,” Journal of Geodesy, 2021).

In this work, for the first time, data from a tightly spaced collocated array of 6 Connected Autonomous Space Environment Sensors (CASES) GNSS receivers are used to calculate 1-second scintillation indices at Poker Flat Research Range, Alaska, USA. This is also the first time scintillation indices at this short time scale are used to detect scintillation at Poker Flat. This work uses a survey of scintillation events (84 events) detected using 100-second scintillation indices and compares to the scintillation detected using the new 1-second indices, showing that amplitude scintillation in the high latitude ionosphere occurs more often than previously thought.