@Article{AbreuFagSahJesBit:2010:HeAsIo,
               author = "Abreu, A. J. de and Fagundes, P. R. and Sahai, Y. and Jesus, R. de 
                         and Bittencourt, J. A.",
          affiliation = "Fisica e Astronomia, Universidade do Vale do Para{\'{\i}}ba 
                         (UNIVAP), S{\~a}o Jos{\'e} dos Campos, Brazil and Fisica e 
                         Astronomia, Universidade do Vale do Para{\'{\i}}ba (UNIVAP), 
                         S{\~a}o Jos{\'e} dos Campos, Brazil and Fisica e Astronomia, 
                         Universidade do Vale do Para{\'{\i}}ba (UNIVAP), S{\~a}o 
                         Jos{\'e} dos Campos, Brazil and Fisica e Astronomia, Universidade 
                         do Vale do Para{\'{\i}}ba (UNIVAP), S{\~a}o Jos{\'e} dos 
                         Campos, Brazil and {Instituto Nacional de Pesquisas Espaciais 
                         (INPE)}",
                title = "Hemispheric asymmetries in the ionospheric response observed in 
                         the American sector during an intense geomagnetic storm",
              journal = "Journal of Applied Geophysics",
                 year = "2010",
               volume = "115",
               number = "A12312",
                pages = "10",
                month = "Dec.",
             keywords = "hemispheric asymmetries, geomagnetic storm, ionospheric F 
                         region.",
             abstract = "The main purpose of this investigation is to study the ionospheric 
                         F region response induced by the intense geomagnetic storm that 
                         occurred on 78 September 2002. The geomagnetic index Dst reached a 
                         minimum of \−181 nT at 0100 UT on 8 September. In this 
                         study, we used observations from a chain of 12 GPS stations and 
                         another chain of 6 digital ionosonde stations. It should be 
                         mentioned that, soon after the sudden commencement (SC) at 1637 UT 
                         on 7 September, the TEC variations at midlatitude stations in both 
                         hemispheres showed an F region positive storm phase. However, 
                         during the recovery phase, a strong hemispheric asymmetry was 
                         observed in the ionospheric response. While a TID type soliton was 
                         observed to propagate in the Southern American sector, no TID 
                         activity was seen in the Northern American sector. Also, in the 
                         Southern Hemisphere, the TEC variations were less affected by the 
                         geomagnetic storm. The Northern Hemisphere observations showed a 
                         strong and long-lasting negative F region storm phase starting at 
                         about 1000 UT on 8 September (lasting for about 24 h). A perusal 
                         of TEC phase fluctuations and equatorial spread-F (ESF) 
                         ionospheric sounding data indicates that, on the disturbed night 
                         of 78 September, some stations showed the occurrence of ESF 
                         starting at about 0000 UT (2000 LT) on 8 September, whereas other 
                         stations showed that the ESF occurrence started much later, at 
                         about 0800 UT (0500 LT). This hemispheric asymmetric response of 
                         the ionospheric F region possibly indicates the presence of 
                         different mechanisms for the generation of ESF along the various 
                         latitudinal regions during the disturbed period.",
                  doi = "10.1029/2010JA015661",
                  url = "http://dx.doi.org/10.1029/2010JA015661",
                 issn = "0926-9851",
             language = "en",
           targetfile = "jgra20750.pdf",
        urlaccessdate = "01 maio 2024"
}