Climatology of the scintillation onset over southern Brazil

Sousasantos, Jonas; Moraes, Alison de Oliveira; Sobral, J. H. A.; Muella, M. T. A. H.; Paula, E. R. de; Paolini, Rafael S.

doi:10.5194/angeo-36-565-2018

Cited by 32 publications

(22 citation statements)

References 39 publications

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“…Between 0:00 and 4:00 UT (between 9 p.m. and 1 a.m. local time in the central and eastern time zone of Brazil) and between 21:00 and 0:00 UTC (between 6 p.m. and 9 p.m. local time in the central and eastern time zone), the highest errors are observed. This is most likely due to the equatorial anomaly, EPBs time of occurrence (Sousasantos et al, 2018), and the high spatial variability of the ionosphere at these times (Sobral et al, 2002).…”

Section: Quality Controlmentioning

confidence: 99%

Regional Ionospheric Delay Mapping for Low‐Latitude Environments

et al. 2020

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The ionosphere in low‐latitude regions has strong dynamics reflected by unique phenomena such as the equatorial ionization anomaly and equatorial plasma bubbles. Since the ionosphere can significantly affect space‐to‐Earth technologies, notably communication systems and Global Navigation Satellite Systems (GNSS), the variations in ionospheric total electron content are of great interest to the space weather community and operators of these technologies. Motived by these issues, this paper proposes a new methodology to generate ionospheric delay maps using data from a network of GNSS monitoring stations. The methodology developed is suitable for low latitudes and has low level of complexity. It is based on the thin shell model of the ionosphere and uses groupings of measurements in time and space, triangulation, linear interpolation, and smoothing. The resulting maps show detailed coverage of large‐scale phenomena, like structures of equatorial plasma bubbles, in a way that other geophysical instruments are not able to provide. In a qualitative validation using a network of stations in Brazil, it was demonstrated that the maps were able to clearly identify plasma bubble structures also captured by other instruments, like scintillation monitors and all‐sky imager. The quantitative assessment showed errors less than 4 m in 99.9% of the times in days with high variability of the ionosphere and less than 1 m in a day with very low ionization. The quality of the generated maps with this new methodology using this density of data opens a wide range of possibilities for scientific and operational applications in low‐latitude ionosphere environment.

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Section: Quality Controlmentioning

confidence: 99%

Regional Ionospheric Delay Mapping for Low‐Latitude Environments

et al. 2020

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“…This behavior can be attributed to the scintillation intensity dependence on the electron density gradients and the thickness of irregularity layer, which are driven by the intensity of the solar extreme ultraviolet radiation (EUV). In addition, the fewer occurrences of scintillation in the maximum of the 24th solar cycle at Cachoeira Paulista could also be associated with the secular variation in the dip latitude, which changed ~3° in south direction from 1997 to 2014.These results on the long-term trend analysis and climatology of scintillations at the EIA region are shown in The climatology of the onset time of ionospheric scintillations near the southern crest of EIA over Brazilian territory, covering a period between solar cycles 23 and 24, showed that their start time is about 40 min earlier in the months of November and December when compared to January and February, suggesting an association with the ionospheric pre-reversal vertical drift (PRVD) magnitude and time [79].…”

Section: Quiet Geomagnetic Conditionsmentioning

confidence: 99%

GPS Scintillations and Total Electron Content Climatology in the Southern American Sector

Correia¹,

Muella²,

LucillaAlfonsi³

et al. 2019

Accuracy of GNSS Methods

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The radio communication and navigation systems can be strongly affected by the ionospheric conditions, which are controlled by solar phenomena associated with radiation variations and solar wind disturbances. These phenomena can generate ionospheric large-scale plasma redistribution and irregularities with scale sizes varying from centimeters to hundred kilometers. These ionospheric irregularities can produce rapid fluctuations in the amplitude and phase of global navigation satellite system (GNSS) signals, degrading the accuracy of GNSS measurements. Here we give a short review of the ionospheric variations associated with solar phenomena, and the actual state of art in the investigations of long-term (seasonal and solar cycle scales) TEC variations and climatology of scintillations, with focus on the southern American sector. It also presented a new TEC calibration procedure when applied to single-frequency PPP.

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“…Scintillation observations were recorded every night, starting at 18:00 LT and lasting until the next day at 06:00 LT. Normally, scintillation is observed between sunset and local midnight, but post-midnight cases may happen (Sousasantos et al, 2018). For this analysis, only scintillation data from GPS satellites with elevation greater or equal than 30°were considered.…”

Section: Scintillation Measurements and Datasetmentioning

confidence: 99%

Performance analysis of κ-μ distribution for Global Positioning System (GPS) L1 frequency-related ionospheric fading channels

Moraes

Sousasantos

Paula

et al. 2019

J. Space Weather Space Clim.

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The present work aims to evaluate the application of the κ-μ distribution as a representation of the fading effect caused by the phenomenon of scintillation on L-band transionospheric radio links. The ionospheric scintillation is a phenomenon defined as a rapid variation in the amplitude and phase of electromagnetic wave signals. This phenomenon starts in the first hours of the night, at latitudes near the geomagnetic equator. Scintillation occurs when radio signals cross ionospheric irregularities, also known as plasma bubbles. These plasma bubble structures are generated after the sunset due to instabilities in the F region of ionosphere. Distributions with non-single parameter usually present better results, however, this point requires further investigation by comparing different models. The goals of this study are: (1) the modeling of experimental data using the κ-μ distribution; (2) the κ-μ parameters characterization for empirical data and the evaluation of parameters estimation based in different approaches; (3) the comparison between the distribution proposed and other models adopted in the literature in order to verify the performance of two parameter models. The results of the analysis performed showed that the κ-μ distribution presents good fitting of the empirical scintillation data. These fitting results were calculated through the chi-square fit test under which the values reveal fair E[χ2] for κ-μ distribution in most of the cases. The evaluation of κ-μ parameters suggests that the distribution has a more conservative outcome than in the distributions traditionally used, but being a legitimate approximation due to its adjustable features in the tail region of the distribution. Typical pairs of κ-μ coefficients are presented for theoretical works. The comparison of κ-μ distribution to Rice, Nakagami-m and α-μ models showed that κ-μ is capable of describing more severe scintillation scenarios where the tail of the distribution is more raised in comparison to the other models.

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Climatology of the scintillation onset over southern Brazil

Cited by 32 publications

References 39 publications

Regional Ionospheric Delay Mapping for Low‐Latitude Environments

Regional Ionospheric Delay Mapping for Low‐Latitude Environments

GPS Scintillations and Total Electron Content Climatology in the Southern American Sector

Performance analysis of κ-μ distribution for Global Positioning System (GPS) L1 frequency-related ionospheric fading channels

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