Dependencies of GPS Scintillation Indices on the Ionospheric Plasma Drift and Rate of Change of TEC Around the Dawn Sector of the Polar Ionosphere

Wang, Yong; Jayachandran, P. T.; Ma, Yuntao; Zhang, Q.; Zou, Xing; Ruohoniemi, J. M.; Shepherd, Simon; Lester, M.

doi:10.1029/2022ja030870

Cited by 5 publications

(10 citation statements)

References 38 publications

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“…The correlation between σ ϕ,1min and |∆TEC| suggests that much of the elevated σ ϕ,1min is refractive due to time-varying TEC. Wang et al (2022) showed that σ ϕ is correlated with the drift speed of plasma, and they concluded that localized TEC structures drift across the LOS of each GPS satellite-receiver pair and increase σ ϕ . In the present study, enhanced σ ϕ,1min was indeed located in the region of enhanced flows but the enhanced flows were also found in the regions without enhanced σ ϕ,1min (Figure 1c).…”

Section: Scintillation Evolution: 1-min Scintillation Indicesmentioning

confidence: 99%

“…Traditionally, scintillation is characterized by the phase and amplitude scintillation indices that measure variation of GNSS signals (at a sampling of tens of Hz) after detrending them at a cutoff frequency of 0.1 Hz. High‐latitude scintillation is often seen only in the phase of the radio signal without amplitude scintillation (Doherty et al., 2000; Jiao et al., 2013; Sreenivash et al., 2020; Wang et al., 2022). Many works consider that the elevated phase scintillation index means scintillation, but a caution should be raised for the interpretation of the scintillation indices.…”

Section: Introductionmentioning

confidence: 99%

“…scintillation is often seen only in the phase of the radio signal without amplitude scintillation (Doherty et al, 2000;Jiao et al, 2013;Sreenivash et al, 2020;Wang et al, 2022). Many works consider that the elevated phase scintillation index means scintillation, but a caution should be raised for the interpretation of the scintillation indices.…”

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confidence: 99%

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Nightside High‐Latitude Phase and Amplitude Scintillation During a Substorm Using 1‐Second Scintillation Indices

et al. 2023

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We examined evolution of Global Positioning System (GPS) scintillation during a substorm in the nightside high latitude ionosphere, using 1‐second phase and amplitude scintillation indices from the Canadian High Arctic Ionospheric Network (CHAIN) network. The traditional 1‐minute scintillation indices showed that the phase scintillation was dominant, while the amplitude scintillation was weak. However, the 1‐second amplitude scintillation occurred more often in association with major auroral structures (polar cap arc, growth phase arc, onset arc, poleward expanding arc, poleward boundary intensification, and diffuse aurora) that were detected by the THEMIS all‐sky imagers (ASIs). The 1‐minute index missed much of the amplitude fluctuations because they only lasted ∼10 seconds near a local peak or at the gradients of the auroral structures. The 1‐second phase scintillation was concurrent with the amplitude scintillation but was much weaker than the 1‐minute phase scintillation. The frequency spectral analysis showed that the spectral power above ∼1 Hz was diffractive and below ∼1 Hz was refractive. We suggest that the amplitude scintillation in the high‐latitude ionosphere is much more common than previously considered, and that a short time window of the order of 1 second should be used to detect the scintillation. The 1‐minute phase scintillation index is largely influenced by refractive effects due to total electron content (TEC) variations, and the spectral power below ∼1 Hz should be removed to identify diffractive scintillation.

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Section: Scintillation Evolution: 1-min Scintillation Indicesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nightside High‐Latitude Phase and Amplitude Scintillation During a Substorm Using 1‐Second Scintillation Indices

et al. 2023

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“…Enhancements in σ Φ indices have also been shown to be adequately represented by ROTI on larger scales above the Fresnel scale (Rino et al, 2019), and can additionally be dependent on the plasma flow and rate of change of TEC (ROT) at high latitudes (Y. Wang et al, 2018Wang et al, , 2022. Recent literature has proposed that only fluctuations of the former nature, namely of stochastic nature, are deemed scintillations (De Franceschi et al, 2019;Ghobadi et al, 2020;McCaffrey & Jayachandran, 2019;Spogli et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Statistical Studies of Plasma Structuring in the Auroral Ionosphere by the Swarm Satellites

Buschmann,

Clausen,

Spicher

et al. 2024

JGR Space Physics

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This study uses over 2 years of 16 Hz density measurements, 50 Hz magnetic field data and ROTI data from the Swarm mission to perform long term statistics of plasma structuring in the polar ionosphere. The timeframe covers more than 2 years near the 24th solar cycle peak. We additionally use 3 years of data obtained from a timeframe close to solar minimum for discussion. We present power spectral densities (PSD) of electron density irregularities and magnetic field for 1‐min intervals. These PSD have been characterized by the probability of a slope steepening, and by integrating the power deposited within frequency intervals corresponding to kilometer scales. For the electron density, we observe seasonal dependencies for both the integrated power and slope characteristics. While the dual slope probability, especially within the polar cap, varies with solar EUV‐radiation, the integrated power is strongest around the equinoxes. Additionally, while we found similar results for the slope probability for both hemispheres, the integrated power exhibits strong hemispheric asymmetries with stronger enhancements within local summer in the southern hemisphere. The ROTI data shows a similar seasonal variability as the density PSD integrated power, in both seasonal dependency and interhemispheric variability. However, for the ROTI data the strongest fluctuations were found within the nightside auroral oval and the cusp. For the PSD of the magnetic field data, we obtain the strongest enhancements within the cusp for all seasons and all hemispheres. The fluctuations may indicate an increase in Alfvénic energy associated with a downward Poynting flux.

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“…Within this scale range, the rate of total electron content (TEC) change index (ROTI) has recently been shown by Rino et al (2019) to give some good hints about possible stochastic features of ionospheric effects caused by large-scale and medium-scale structures. Most of the recent research on the GNSS scintillation has been dedicated to efficiently evaluate the diffractive and refractive contribution in the recorded GNSS fluctuations, especially in the high-latitude ionosphere, where the highly dynamic plasma complicates such a task (Conroy et al, 2022;Ghobadi et al, 2020;McCaffrey & Jayachandran, 2019;Spogli et al, 2021;Wang et al, 2018Wang et al, , 2022. In this study, we investigate the role of the particle precipitation in small-scale plasma structuring in the E and F-region ionosphere and its effects on trans-ionospheric radio wave propagation over Svalbard (Norway).…”

mentioning

confidence: 99%

Investigation of Ionospheric Small‐Scale Plasma Structures Associated With Particle Precipitation

Enengl,

Spogli,

Kotova

et al. 2024

Space Weather

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We investigate the role of auroral particle precipitation in small‐scale (below hundreds of meters) plasma structuring in the auroral ionosphere over the Arctic. In this scope, we analyze together data recorded by an Ionospheric Scintillation Monitor Receiver (ISMR) of Global Navigation Satellite System (GNSS) signals and by an All‐Sky Imager located in Longyearbyen, Svalbard (Norway). We leverage on the raw GNSS samples provided at 50 Hz by the ISMR to evaluate amplitude and phase scintillation indices at 1 s time resolution and the Ionosphere‐Free Linear Combination at 20 ms time resolution. The simultaneous use of the 1 s GNSS‐based scintillation indices allows identifying the scale size of the irregularities involved in plasma structuring in the range of small (up to few hundreds of meters) and medium‐scale size ranges (up to few kilometers) for GNSS frequencies and observational geometry. Additionally, they allow identifying the diffractive and refractive nature of fluctuations on the recorded GNSS signals. Six strong auroral events and their effects on plasma structuring are studied. Plasma structuring down to scales of hundreds of meters is seen when strong gradients in auroral emissions at 557.7 nm cross the line of sight between the GNSS satellite and receiver. Local magnetic field measurements confirm small‐scale structuring processes coinciding with intensification of ionospheric currents. Since 557.7 nm emissions primarily originate from the ionospheric E‐region, plasma instabilities from particle precipitation at E‐region altitudes are considered to be responsible for the signatures of small‐scale plasma structuring highlighted in the GNSS scintillation data.

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Dependencies of GPS Scintillation Indices on the Ionospheric Plasma Drift and Rate of Change of TEC Around the Dawn Sector of the Polar Ionosphere

Cited by 5 publications

References 38 publications

Nightside High‐Latitude Phase and Amplitude Scintillation During a Substorm Using 1‐Second Scintillation Indices

Nightside High‐Latitude Phase and Amplitude Scintillation During a Substorm Using 1‐Second Scintillation Indices

Statistical Studies of Plasma Structuring in the Auroral Ionosphere by the Swarm Satellites

Investigation of Ionospheric Small‐Scale Plasma Structures Associated With Particle Precipitation

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