author = "Becker-Guedes, E. and Sahai, Y. and Fagundes, P. R. and Espinoza, 
                         E. S. and Pillat, V. G. and Lima, W. L. C. and Basu, Su and Basu, 
                         Sa and Otsuka, Y. and Shiokawa, K. and Mackenzie, E. M. and Pi, X 
                         and Bittencourt, Jos{\'e} Augusto",
          affiliation = "{Universidade do Vale do Paraiba (UNIVAP)} and Radio Observatorio 
                         de Jicamarca, Instituto Geofisico del Peru and {Universidade do 
                         Vale do Paraiba (UNIVAP)} and Radio Observatorio de Jicamarca, 
                         Instituto Geofisico del Peru and {Universidade do Vale do Paraiba 
                         (UNIVAP)} and Centro Univ. Luterano de Palmas (CEULP), 
                         Universidade Luterana do Brasil (ULBRA) and Center for Space 
                         Physics, Boston University and Space Vehicles Directorate, Air 
                         Force Research Laboratory and STELAB, Nagoya University and 
                         STELAB, Nagoya University and Institute for Scientific Research, 
                         Boston College and Jet Propulsion Laboratory, California Institute 
                         of Technology and {Instituto Nacional de Pesquisas Espaciais 
                title = "The ionospheric response in the Brazilian sector during the super 
                         geomagnetic storm on 20 November 2003",
              journal = "Annales Geophysicae",
                 year = "2007",
               volume = "25",
               number = "4",
                pages = "863--873",
             keywords = "Ionosphere (Equatorial ionosphere, Ionospheremagnetosphere 
                         interactions, Ionospheric irregularities).",
             abstract = "A very intense geomagnetic storm (superstorm) began with storm 
                         sudden commencement (SSC) at 08:03 UT on 20 November 2003, as a 
                         result of the coronal mass ejection (CME) by sunspot 484 hurled 
                         into space on 18 November 2003. The geomagnetic storm attained 
                         |Dst |max=472 nT at 20:00 UT (20 November). In this paper we 
                         present the simultaneous ionospheric sounding observations, using 
                         the Canadian Advanced Digital Ionosondes (CADIs), carried out from 
                         Palmas (PAL; 10.2 S, 48.2W; dip latitude 5.5 S; a near equatorial 
                         station) and Sao Jos´e dos Campos (SJC; 23.2 S, 45.9W; dip 
                         latitude 17.6 S; station located under the crest of equatorial 
                         ionospheric anomaly), Brazil. In addition, total electron content 
                         (TEC) measurements from several GPS receiving stations in the 
                         Brazilian sector during this storm are presented. The simultaneous 
                         ionospheric sounding observations carried out at SJC and PAL, and 
                         TEC observations on 3 consecutive days viz., 19 November (quiet), 
                         20 November (disturbed) and 21 November (recovery phase) are 
                         presented. Salient features from the ionospheric observations in 
                         the Brazilian sector during the superstorm are discussed. The 
                         difference in the observed ionospheric response at the two 
                         stations (PAL and SJC) is considerable. This is not surprising 
                         given that PAL is close to the magnetic equator and SJC is near 
                         the crest of the equatorial ionospheric anomaly (EIA). It should 
                         be pointed out that soon after the SSC (about 4 h later), the 
                         F-region critical frequency (foF2), the F-region peak height 
                         (hpF2), and variations of virtual heights at different frequencies 
                         (iso-frequency plots) all show wavelike oscillations of the 
                         F-region during daytime at both the ionospheric sounding stations. 
                         Unusual rapid uplifting of F-region at PAL was observed during 
                         both the main and recovery phases of the storm.",
           copyholder = "SID/SCD",
                 issn = "0992-7689",
             language = "en",
           targetfile = "the ionospheric.pdf",
        urlaccessdate = "18 jan. 2021"