Superposition Property of the Ionospheric Scintillation S4 Index

Yeh, Wen-Hao; Lin, Chia Ying; Liu, Jann-Yenq; Chen, Shih-Ping; Hsiao, Tung‐Yuan; Huang, C. Y.

doi:10.1109/lgrs.2019.2928588

Cited by 13 publications

(10 citation statements)

References 17 publications

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“…Liu et al (2016b) developed a method for integrating the distributed F3/C S4max in the ionosphere vertically to an equivalent quantity at the ground in a worst-case scenario. Yeh et al (2020) conducted numerical analyses and confirmed that the scintillation is linearly proportional to the irregularity amount along the ray path. Chen et al (2017a, b) applied the method developed by Liu et al (2016b) to construct a global empirical model of S4, which is termed F3CGS4 (F3/C global S4).…”

Section: Ionospheric L-band S4 Scintillationmentioning

confidence: 79%

Retrospect and prospect of ionospheric weather observed by FORMOSAT-3/COSMIC and FORMOSAT-7/COSMIC-2

Liu

Lin

et al. 2022

TAO

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FORMOSAT-3/COSMIC (F3/C) constellation of six micro-satellites was launched into the circular low-earth orbit at 800 km altitude with a 72-degree inclination angle on 15 April 2006, uniformly monitoring the ionosphere by the GPS (Global Positioning System) Radio Occultation (RO). Each F3/C satellite is equipped with a TIP (Tiny Ionospheric Photometer) observing 135.6 nm emissions and a TBB (Tri-Band Beacon) for conducting ionospheric tomography. More than 2000 RO profiles per day for the first time allows us globally studying three-dimensional ionospheric electron density structures and formation mechanisms of the equatorial ionization anomaly, middle-latitude trough, Weddell/Okhotsk Sea anomaly, etc. In addition, several new findings, such as plasma caves, plasma depletion bays, etc., have been reported. F3/C electron density profiles together with ground-based GPS total electron contents can be used to monitor, nowcast, and forecast ionospheric space weather. The S4 index of GPS signal scintillations recorded by F3/C is useful for ionospheric irregularities monitoring as well as for positioning, navigation, and communication applications. F3/C was officially decommissioned on 1 May 2020 and replaced by FORMOSAT-7/COSMIC-2 (F7/C2). F7/C2 constellation of six small satellites was launched into the circular low-Earth orbit at 550 km altitude with a 24-degree inclination angle on 25 June 2019. F7/C2 carries an advanced TGRS (Tri Gnss (global navigation satellite system) Radio occultation System) instrument, which tracks more than 4000 RO profiles per day. Each F7/C2 satellite also has a RFB (Radio Reference Beacon) on board for ionospheric tomography and an IVM (Ion Velocity Meter) for measuring ion temperature, velocity, and density. F7/C2 TGRS, IVM, and RFB shall continue to expand the F3/C success in the ionospheric space weather forecasting.

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Section: Ionospheric L-band S4 Scintillationmentioning

confidence: 79%

Retrospect and prospect of ionospheric weather observed by FORMOSAT-3/COSMIC and FORMOSAT-7/COSMIC-2

Liu

Lin

et al. 2022

TAO

Self Cite

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“…The available instantaneous observations are very limited, thus the evolution model has been built in such a way that it imposes connectivity and smoothness between neighboring values which then are propagated in the next time instant. This consideration is in-line with the use of the thin shell model which imposes the projection of a 3D phenomenon into a 2D plane and therefore a 2D ionospheric image reflects the scintillation activity as a result of the superposition of medium to small-scale plasma irregularities [56]. In the current implementation, matrix L in (5), is the normalized Graph Laplace [39], given by…”

Section: Laplace Smoothnessmentioning

confidence: 97%

Real-time Ionospheric Imaging of S4 Scintillation from Limited Data with Parallel Kalman Filters and Smoothness

Koulouri

2021

Preprint

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In this paper, we propose a Bayesian framework to create two dimensional ionospheric images of high spatio-temporal resolution to monitor ionospheric irregularities as measured by the S4 index. Here, we recast the standard Bayesian recursive filtering for a linear Gaussian state-space model, also referred to as the Kalman filter, first by augmenting the (pierce point) observation model with connectivity information stemming from the insight and assumptions/standard modeling about the spatial distribution of the scintillation activity on the ionospheric shell at 350 km altitude. Thus, we achieve to handle the limited spatiotemporal observations. Then, by introducing a set of Kalman filters running in parallel, we mitigate the uncertainty related to a tuning parameter of the proposed augmented model. The output images are a weighted average of the state estimates of the individual filters. We demonstrate our approach by rendering two dimensional real-time ionospheric images of S4 amplitude scintillation at 350 km over South America with temporal resolution of one minute. Furthermore, we employ extra S4 data that was not used in producing these ionospheric images, to check and verify the ability of our images to predict this extra data in particular ionospheric pierce points. Our results show that in areas with a network of ground receivers with a relatively good coverage (e.g. within a couple of kilometers distance) the produced images can provide reliable real-time results. Our proposed algorithmic framework can be readily used to visualize real-time ionospheric images taking as inputs the available scintillation data provided from freely available web-servers.

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“…The occurrence of ionospheric scintillation depends on various spatial and temporal factors, including time of day, season, and geographical location [2]. Ionospheric irregularities may be detected by continuously monitoring GNSS signals using ground-based receivers, or by radars, such as the ionosonde or multi-static high-frequency radars [3]- [5].…”

Section: Introductionmentioning

confidence: 99%

Mapping of S4 Over the Arabian Peninsula During Solar Minimum

Darya

Shaikh

Fernini

et al. 2022

IEEE Geosci. Remote Sensing Lett.

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In this letter, we study the temporal and spatial variability of ionospheric irregularities by generating high-resolution maps of the observed amplitude scintillation index (S4) using data from a multi-constellation and multi-frequency GNSS receiver. The study region is the Arabian Peninsula, which falls under the northern crest of the equatorial ionization anomaly (EIA). Even though the study was conducted during a solar minimum period, considerable occurrences of pre-sunset scintillation have been observed between 15-17 local time, particularly during the winter solstices. While most scintillation occurrences have been observed at low elevation (15 to 30 degrees), a considerable number of scintillation patches have been observed towards the north, east, and southeast of the receiver location, for elevation angles ranging from 40 to 60 degrees. Our analysis shows that BeiDou geostationary orbit (GEO) and inclined GEO (IGSO) satellites may have been the main contributor to the increased number of scintillation occurrences observed around the eastern side of the receiver as compared to the western side. Out of all the GNSS constellations with MEO satellites, GPS was the most impacted by amplitude scintillation, while BeiDou and Galileo satellites were the least affected. It is anticipated that the patches of ionospheric irregularities reported in this work would be further enhanced as the solar activity increases in the coming years. Therefore, this work can serve as a reference for future studies during periods of increased geomagnetic activity.

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Superposition Property of the Ionospheric Scintillation S4 Index

Cited by 13 publications

References 17 publications

Retrospect and prospect of ionospheric weather observed by FORMOSAT-3/COSMIC and FORMOSAT-7/COSMIC-2

Retrospect and prospect of ionospheric weather observed by FORMOSAT-3/COSMIC and FORMOSAT-7/COSMIC-2

Real-time Ionospheric Imaging of S4 Scintillation from Limited Data with Parallel Kalman Filters and Smoothness

Mapping of S4 Over the Arabian Peninsula During Solar Minimum

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