Assessing the GNSS scintillation climate over Brazil under increasing solar activity

Spogli, Luca; Alfonsi, Lucilla; Romano, Vincenzo; Franceschi, Giorgiana De; Monico, J. F. Galera; Shimabukuro, Milton Hirokazu; Bougard, Bruno; Aquino, Márcio

doi:10.1016/j.jastp.2013.10.003

Cited by 56 publications

(62 citation statements)

References 10 publications

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“…(7) is valid under the conditions of weak scattering and when the single-phase screen approximation is applicable. However, we decided to apply the same formula also to characterize the moderate/strong scintillation, following the recommendations of Spogli et al (2013), in which the verticalization procedure is justified by the climatological nature of the study and by the need of having a geometry-free mapping.…”

Section: Scintillation and Tec Data Mappingmentioning

confidence: 99%

L-band scintillations and calibrated total electron content gradients over Brazil during the last solar maximum

Cesaroni

Spogli

Alfonsi

et al. 2015

J. Space Weather Space Clim.

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This work presents a contribution to the understanding of the ionospheric triggering of L-band scintillation in the region over São Paulo state in Brazil, under high solar activity. In particular, a climatological analysis of Global Navigation Satellite Systems (GNSS) data acquired in 2012 is presented to highlight the relationship between intensity and variability of the total electron content (TEC) gradients and the occurrence of ionospheric scintillation. The analysis is based on the GNSS data acquired by a dense distribution of receivers and exploits the integration of a dedicated TEC calibration technique into the Ground Based Scintillation Climatology (GBSC), previously developed at the Istituto Nazionale di Geofisica e Vulcanologia. Such integration enables representing the local ionospheric features through climatological maps of calibrated TEC and TEC gradients and of amplitude scintillation occurrence. The disentanglement of the contribution to the TEC variations due to zonal and meridional gradients conveys insight into the relation between the scintillation occurrence and the morphology of the TEC variability. The importance of the information provided by the TEC gradients variability and the role of the meridional TEC gradients in driving scintillation are critically described.

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Section: Scintillation and Tec Data Mappingmentioning

confidence: 99%

L-band scintillations and calibrated total electron content gradients over Brazil during the last solar maximum

Cesaroni

Spogli

Alfonsi

et al. 2015

J. Space Weather Space Clim.

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“…The work of Aarons (1982) clearly depicts how the scintillation intensities, produced by the smaller-scale irregularity structures coexisting with the plasma bubbles, are maximized in the regions of the Appleton anomaly. More recently, relevant features of ionospheric radio-wave scintillations at the equatorial anomaly region have been extensively investigated for different longitudinal sectors (Spogli et al, 2013;Chatterjee and Chakraborty, 2013;Bhattacharyya et al, 2014;Akala et al, 2015;Cesaroni et al, 2015;Zhang et al, 2015;Srinivasu et al, 2016;Moraes et al, 2017). In the South American sector, particularly for the L-band frequencies, the occurrence characteristics of scintillation-producing irregularities have been demonstrated using ground-based global navigation satellite system (GNSS) receiver networks (e.g., de Akala et al, 2011;Muella et al, 2013Muella et al, , 2014.…”

Section: Introductionmentioning

confidence: 99%

Climatology and modeling of ionospheric scintillations and irregularity zonal drifts at the equatorial anomaly crest region

et al. 2017

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Abstract. In this study the climatology of ionospheric scintillations and the zonal drift velocities of scintillationproducing irregularities are depicted for a station located under the southern crest of the equatorial ionization anomaly. Then, the α−µ ionospheric fading model is used for the firstand second-order statistical characterization of amplitude scintillations. In the statistical analyzes, data are used from single-frequency GPS receivers acquired during ∼ 17 years (September 1997-November 2014 at Cachoeira Paulista (22.4 • S; 45.0 • W), Brazil. The results reveal that the nocturnal occurrence of scintillations follows the seasonal distribution of plasma bubble irregularities observed in the longitudinal sector of eastern South America. In addition to the solar cycle dependence, the results suggest that the occurrence climatology of scintillations is also modulated by the secular variation in the dip latitude of Cachoeira Paulista, since the maximum occurrence of scintillations during the peak of solar cycle 24 was ∼ 20 % lower than that observed during the maximum of solar cycle 23. The dynamics of the irregularities throughout a solar cycle, as investigated from the estimates of the mean zonal drift velocities, presented a good correlation with the EUV and F10.7 cm solar fluxes. Meanwhile, the seasonal behavior showed that the magnitude of the zonal drift velocities is larger during the December solstice months than during the equinoxes. In terms of modeling, the results for the α − µ distribution fit quite well with the experimental data and with the temporal characteristics of fading events independently of the solar activity level.

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“…Compared to ROTI index, the time series of S 4 index show more significant fluctuation. Several studies showed that at low‐latitude regions the amplitude scintillation occurrence is generally more frequent than that of phase scintillation (e.g., Gwal et al, ; Spogli et al, ).…”

Section: Analysis and Resultsmentioning

confidence: 99%

“…Journal of Geophysical Research: Space Physics scintillation occurrence is generally more frequent than that of phase scintillation (e.g., Gwal et al, 2006;Spogli et al, 2013).…”

Section: 1029/2019ja026515mentioning

confidence: 99%

Geomagnetically Conjugate Observations of Equatorial Plasma Irregularities From Swarm Constellation and Ground‐Based GPS Stations

Luo

Xiong

et al. 2019

JGR Space Physics

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The near‐polar orbit satellites of Swarm mission provide a good opportunity to investigate the conjugacy of equatorial plasma irregularities (EPIs) since their trajectories at low latitudes are basically aligned with fixed geographical longitude. However, the Swarm in situ electron density occasionally shows EPIs at only one hemisphere at this longitude. In this study, we provide detailed analysis of such EPI events from the in situ electron densities and onboard global positioning system (GPS) measurements of Swarm low pair satellites, and simultaneous GPS data from two geomagnetically conjugate ground stations at the Africa longitudes. The result indicates that when Swam in situ electron density sometime shows EPIs at only one hemisphere, the GPS scintillations are still observed from the Swarm onboard receiver and by the two conjugate ground stations. It implies that the EPIs should generally elongate along the geomagnetic flux tube. More than two‐year statistic results show that the onset time of scintillation in the northern station is on average 16 and 18 min earlier than that in the southern station for September equinox and December solstice in 2015, while for March equinox in 2016 the onset time of scintillation of northern station is about 11 min later than that of southern station, which indicates the asymmetry features of EPIs along the flux tube. Further analysis of nearly three‐year GPS data from two conjugate stations at the Asia longitudes, we find that during solar maximum years the local sunset time plays an important role for causing the difference of onset time of scintillation between two conjugate stations.

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Assessing the GNSS scintillation climate over Brazil under increasing solar activity

Cited by 56 publications

References 10 publications

L-band scintillations and calibrated total electron content gradients over Brazil during the last solar maximum

L-band scintillations and calibrated total electron content gradients over Brazil during the last solar maximum

Climatology and modeling of ionospheric scintillations and irregularity zonal drifts at the equatorial anomaly crest region

Geomagnetically Conjugate Observations of Equatorial Plasma Irregularities From Swarm Constellation and Ground‐Based GPS Stations

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