The Ionosphere

doi:10.1007/0-387-23671-6_3

Cited by 2 publications

(2 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, ionospheric space and time irregularities cannot be transparently predicted by such physical models, which may be able to explain the appearance of irregularities only if suitable initial conditions are assumed (e.g., local fluctuations from initially "seeded" plasma instabilities (Chapter 11 in [2])), despite the inability to analytically follow their full development and to consistently represent their intermittent occurrence. The Earth's ionosphere is highly structured throughout space and time scales such that when observed at different space or time resolutions, its behaviour is completely different [1,[3][4][5][6][7][8]. At some scales and under quiet solar and geomagnetic conditions, the ionosphere resembles a fluid system that can be described by smooth local variables undergoing classical partial derivative equations.…”

Section: Introductionmentioning

confidence: 99%

Multi-Time-Scale Analysis of Chaos and Predictability in vTEC

Materassi,

Migoya-Orué,

Radicella

et al. 2024

Atmosphere

View full text Add to dashboard Cite

Theoretical modelling of the local ionospheric medium (LIM) is made difficult by the occurrence of irregular ionospheric behaviours at many space and time scales, making prior hypotheses uncertain. Investigating the LIM from scratch with the tools of dynamical system theory may be an option, using the vertical total electron content (vTEC) as an appropriate tracer of the system variability. An embedding procedure is applied to vTEC time series to obtain the finite dimension (m∈N) of the phase space of an LIM-equivalent dynamical system, as well as its correlation dimension (D2) and Kolmogorov entropy rate (K2). In this paper, the dynamical features (m,D2,K2) are studied for the vTEC on the top of three GNSS stations depending on the time scale (τ) at which the vTEC is observed. First, the vTEC undergoes empirical mode decomposition; then (m,D2,K2) are calculated as functions of τ. This captures the multi-scale structure of the Earth’s ionospheric dynamics, demonstrating a net distinction between the behaviour at τ≤24h and τ≥24h. In particular, sub-diurnal-scale modes are assimilated to much more chaotic systems than over-diurnal-scale modes.

show abstract

Section: Introductionmentioning

confidence: 99%

Multi-Time-Scale Analysis of Chaos and Predictability in vTEC

Materassi,

Migoya-Orué,

Radicella

et al. 2024

Atmosphere

View full text Add to dashboard Cite

show abstract

“…The ionosphere is a heterogeneous atmospheric layer exposed to intense solar radiation [1], in which ionization and recombination processes cause a continuous electron density variation in different ionosphere regions. Its inhomogeneous nature is one of the causes of propagation disturbances to signals passing through it [2].…”

Section: Introductionmentioning

confidence: 99%

Spatio-Temporal Validation of GNSS-Derived Global Ionosphere Maps Using 16 Years of Jason Satellites Observations

Poniatowski,

Nykiel,

Borries

et al. 2023

Remote Sensing

View full text Add to dashboard Cite

Existing ionospheric models perform very well in mapping the calm state of the ionosphere. However, the problem is accurately determining the total electron content (TEC) for disturbed days. Knowledge of the exact electron density is essential for single−frequency receivers, which cannot eliminate the ionospheric delay. This study aims to investigate temporal and spatial variability in the distribution of TEC based on differences between maps of individual Ionospheric Associated Analysis Centers (IAACs) of the International GNSS Service (IGS) and aligned altimetry−TEC from 2005–2021. Based on the temporal distribution, we have observed a significant effect of solar activity on the mean and standard deviation behavior of the differences between global ionospheric maps (GIMs) and Jason−derived TEC. We determined the biases for the entire calculation period, through which it can be concluded that the upcg-Jason and igsg-Jason differences have the lowest standard deviation (±1.81 TECU). In addition, the temporal analysis made it possible to detect annual, semi−annual, and 117-day oscillations occurring in the Jason−TEC data, as well as 121-day oscillations in the GIMs. It also allowed us to analyze the potential sources of these cyclicities, solar and geomagnetic activity, in the case of the annual and semi−annual periodicities. When considering spatial variations, we have observed that the most significant average differences are in the intertropical areas. In contrast, the smallest differences were recorded in the southern hemisphere, below the Tropic of Capricorn (23.5°S). However, the slightest variations were noted for the northern hemisphere above the Tropic of Cancer (23.5°N). Our research presented in this paper allows a better understanding of how different methods of GNSS TEC approximation affect the model’s accuracy.

show abstract

The Ionosphere

Cited by 2 publications

References 45 publications

Multi-Time-Scale Analysis of Chaos and Predictability in vTEC

Multi-Time-Scale Analysis of Chaos and Predictability in vTEC

Spatio-Temporal Validation of GNSS-Derived Global Ionosphere Maps Using 16 Years of Jason Satellites Observations

Contact Info

Product

Resources

About