GUVI Biblio

Occurrence of Ionospheric irregularities over Brazil and Africa during the 2019 Antarctic minor sudden stratospheric warming

The influence of sudden stratospheric warming (SSW) on the ionosphere and ionospheric irregularities has been studied extensively over the years. However, majority of these

Agyei-Yeboah, Ebenezer; Fagundes, Paulo; Tardelli, Alexandre; Pillat, Valdir; Vieira, Francisco; Arcanjo, Mateus;

Published by: Advances in Space Research      Published on:

YEAR: 2022     DOI: 10.1016/j.asr.2022.08.065

Positive and negative GPS-TEC ionospheric storm effects during the extreme space weather event of March 2015 over the Brazilian sector

We studied the response of the ionosphere (F region) in the Brazilian sector during extreme space weather event of 17 March 2015 using a large network of 102 GPS- total electron content (TEC) stations. It is observed that the vertical total electron content (VTEC) was severely disturbed during the storm main and recovery phases. A wavelike oscillation with three peaks was observed in the TEC diurnal variation from equator to low latitudes during the storm main phase on 17\textendash18 March 2015. The latitudinal ...

Fagundes, P.; Cardoso, F.; Fejer, B.; Venkatesh, K.; Ribeiro, B.; Pillat, V.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 05/2016

YEAR: 2016     DOI: 10.1002/2015JA022214

Effects observed in the equatorial and low latitude ionospheric F-region in the Brazilian sector during low solar activity geomagnetic storms and comparison with the COSMIC measurements

The main objective of the present investigation has been to compare the ionospheric parameters (NmF2 and hmF2) observed by two ground-based ionospheric sounders (one at PALMAS- located near the magnetic equator and the other at Sao Jose dos Campos-located in the low-latitude region) in the Brazilian sector with that by the satellite FORMOSAT-3/COSMIC radio occultation (RO) measurements during two geomagnetic storms which occurred in December 2006 and July 2009. It should be pointed out that in spite of increasing the lati ...

Sahai, Y.; de Jesus, R.; Fagundes, P.R.; Selhorst, C.L.; de Abreu, A.J.; Ram, Tulasi; Aragon-Angel, A.; Pillat, V.G.; Abalde, J.R.; Lima, W.L.C.; Bittencourt, J.A.;

Published by: Advances in Space Research      Published on: 11/2012

YEAR: 2012     DOI: 10.1016/j.asr.2012.07.006

COSMIC satellite; F-region; geomagnetic storm; Ionosphere; Low solar activity

Studies of ionospheric F-region response in the Latin American sector during the geomagnetic storm of 21--22 January 2005

Sahai, Y.; Fagundes, P.; de Jesus, R.; de Abreu, A.; Crowley, G.; Kikuchi, T.; Huang, C.-S.; Pillat, V.; Guarnieri, F.; Abalde, J.; Bittencourt, J.;

Published by: Annales Geophysicae      Published on: Jan-01-2011

YEAR: 2011     DOI: 10.5194/angeo-29-919-2011

Effects of geomagnetic super storms on the ionospheric F-region in the South American sector using a GPS technique: A review

Sahai, Y; De Abreu, AJ; Fagundes, PR; De Jesus, R; Crowley, G; Klimenko, MV; Klimenko, VV; Brunini, C; Gende, M; Pillat, VG; , others;

Published by: Asian Journal of Physics      Published on:

YEAR: 2011     DOI:

Seasonal variations in ionospheric F-region parameters during the low solar activity period in the Brazilian sector and comparison with ionospheric models

Sahai, Yogeshwar; de Jesus, Rodolfo; Fagundes, Paulo; de Abreu, Alessandro; Crowley, Geoff; Pillat, Valdir; Guede, Jose; Bittencourt, Jose;

Published by: 38th COSPAR Scientific Assembly      Published on:

YEAR: 2010     DOI:

Response of the Ionospheric F-region in the Latin American Sector During the Intense Geomagnetic Storm of 21-22 January 2005

Sahai, Y; Fagundes, PR; De Jesus, R; De Abreu, AJ; Crowley, G; Pillat, VG; Guarnieri, FL; , Abalde; Bittencourt, JA;

Published by:       Published on:

YEAR: 2009     DOI:

Unusual ionospheric effects observed during the intense 28 October 2003 solar flare in the Brazilian sector

Sahai, Y.; Becker-Guedes, F.; Fagundes, P.R.; Lima, W.L.C.; de Abreu, A.J.; Guarnieri, F.L.; Candido, C.M.N.; Pillat, V.G.;

Published by:       Published on:

YEAR: 2008     DOI:

Brazilian ionosphere behavior during an intense solar flare

The 28 October 2003 solar flare was one of the most intense solar flares observed in the recent past. In the present investigation we show the ionospheric effects observed in the

Becker-Guedes, F; Sahai, Y; Fagundes, PR; Abreu, A; Pillat, VG; Lima, WLC;

Published by:       Published on:

YEAR: 2007     DOI: https://doi.org/10.3997/2214-4609-pdb.172.SBGF0393_07

Unusual ionospheric effects observed during the intense 28 October 2003 solar flare in the Brazilian sector

Sahai, Y; Becker-Guedes, F; Fagundes, PR; Lima, WLC; De Abreu, AJ; Guarnieri, FL; Candido, CMN; Pillat, VG;

Published by:       Published on:

YEAR: 2007     DOI:

The ionospheric response in the Brazilian sector during the super geomagnetic storm on 20 November 2003

Becker-Guedes, F; Sahai, Y; Fagundes, PR; Espinoza, ES; Pillat, VG; Lima, WLC; Basu, Su; Basu, Sa; Otsuka, Y; Shiokawa, K; MacKenzie, E.; Bittencourt, J.;

Published by:       Published on:

YEAR: 2007     DOI:

Effects of the major geomagnetic storms of October 2003 on the equatorial and low-latitude F region in two longitudinal sectors

Sahai, Y; Fagundes, PR; Becker-Guedes, F; Bolzan, MJA; , Abalde; Pillat, VG; De Jesus, R; Lima, WLC; Crowley, G; Shiokawa, K; , others;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2005     DOI: