@Article{SahaiBFLOHEPABAPB:2007:ReNiEq,
               author = "Sahai, Y. and Becker-Guedes, F. and Fagundes, P. R. and Lima, W. 
                         L. C. and Otsuka, Y. and Huang, C. S. and Espinoza, E. S. and Pi, 
                         X. and Abreu, A. J. and Bolzan, M. J. A. and Abalde, J. R. and 
                         Pimenta, Alexandre Alvares and Bittencourt, Jos{\'e} Augusto",
          affiliation = "{Universidade do Vale do Para{\'{\i}}ba (UNIVAP)} and 
                         {Universidade do Vale do Para{\'{\i}}ba (UNIVAP)} and 
                         {Universidade do Vale do Para{\'{\i}}ba (UNIVAP)} and {Centro 
                         Universit{\'a}rio Luterano de Palmas} and STELAB and Haystack 
                         Observatory, Massachusetts Institute of Technology and Radio 
                         Observatorio de Jicamarca, Instituto Geofisico del Peru and {Jet 
                         Propulsion Laboratory} and {Universidade do Vale do 
                         Para{\'{\i}}ba (UNIVAP)} and {Universidade do Vale do 
                         Para{\'{\i}}ba (UNIVAP)} and {Universidade do Vale do 
                         Para{\'{\i}}ba (UNIVAP)} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {Instituto Nacional de Pesquisas Espaciais 
                         (INPE)}",
                title = "Response of nighttime equatorial and low latitude F-region to the 
                         geomagnetic storm of August 18, 2003, in the Brazilian sector",
              journal = "Advances in Space Research",
                 year = "2007",
               volume = "39",
               number = "8",
                pages = "1325--1334",
             keywords = "Equatorial and low latitude F-region, Geomagnetic storm, 
                         Spread-F.",
             abstract = "This paper presents an investigation of geomagnetic storm effects 
                         in the equatorial and low latitude F-region in the Brazilian 
                         sector during the intense geomagnetic storm on 18 August, 2003 
                         (SSC 14:21 UT on 17/08; {\'O}Kp = 52+; Ap = 108; Dstmax = 168 at 
                         1600 UT on 18/08). Simultaneous ionospheric sounding measurements 
                         from two stations, viz., Palmas (10.2°S, 48.2°W; dip latitude 
                         5.7°S) and Sao Jose dos Campos (23.2°S, 45.9°W; dip latitude 
                         17.6°S), Brazil, are presented for the nights of 1617, 1718 and 
                         1819 August, 2003 (quiet, disturbed and recovery phases). Both 
                         stations are equipped with the Canadian Advanced Digital Ionosonde 
                         (CADI). Quiet and disturbed conditions of the F-region ionosphere 
                         are compared using data collected from the two stations. The 
                         relationship between magnetospheric disturbance and low-latitude 
                         ionospheric dynamics, and generation of ionospheric irregularities 
                         are discussed. On the disturbed nights (1718 and 1819 August), the 
                         low latitude station S. J. Campos showed strong enhancements in 
                         the F-region critical frequency (foF2), whereas the near 
                         equatorial station Palmas showed strong uplifting of the F-layer 
                         about 1 h earlier. Normally during the June solstice months 
                         (MayAugust) in the Brazilian sector, large-scale ionospheric 
                         irregularities in form of plasma bubbles are rarely observed. On 
                         the night of 1718 August, ionsospheric sounding observations at 
                         Palmas showed the presence of bottomside spread-F, whereas on the 
                         night of 1819 August, the observations at Palmas and S. J. Campos 
                         showed the presence of plasma bubbles when the storm recovery 
                         phase had just started. The complementary GPS data available from 
                         several stations in the Rede Brasileira de Monitoramento Continuo 
                         de GPS (Brazilian Network for Continuous GPS Monitoring) are used 
                         to obtain the vertical total electron content (VTEC) and the rate 
                         of change of TEC per minute on UT days 18 and 19 August, 2003 and 
                         presented. Also, several global ionospheric TEC maps from the 
                         worldwide network of GPS receivers are presented, showing 
                         widespread latitudinal and longitudinal TEC changes during the 
                         different phases of the storm. All the observations (local 
                         ionospheric sounding and GPS network measurements, and global GPS 
                         measurements) presented in this investigation related to the 
                         geomagnetic storm on 18 August indicate that the equatorial and 
                         low latitude region in the Brazilian sector had much stronger 
                         effect during the recovery phase compared with the main phase. A 
                         comparison of the observed disturbance drifts with the 
                         FejerScherliess storm-time model drifts indicate that the modeled 
                         drifts are not consistent with the present observations.",
           copyholder = "SID/SCD",
                 issn = "0273-1177",
             language = "en",
           targetfile = "response of nightime.pdf",
        urlaccessdate = "09 maio 2024"
}