@Article{SahaiFBACPIAPB:2004:LoDiOb,
               author = "Sahai, Y. and Fagundes, P. R. and Becker Guedes, F. and Abalde, J. 
                         R. and Crowley, G. and Pi, X. and Igarashi, K. and Amarante, G. M. 
                         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 
                         {Universidade do Vale do Para{\'{\i}}ba (UNIVAP)} and {Southwest 
                         Research Institute} and {Jet Propulsion Laboratory} and 
                         {Communications Research Laboratory} and {The Abdus Salam (ICTP)} 
                         and Instituto Nacional de Pesquisas Espaciais, Divis{\~a}o de 
                         Aeronomia (INPE.DAE) and Instituto Nacional de Pesquisas 
                         Espaciais, Divis{\~a}o de Aeronomia (INPE.DAE)",
                title = "Longitudinal differences observed in the ionospheric F-region 
                         during the major geomagnetic storm of 31 March 2001",
              journal = "Annales Geophysicae",
                 year = "2004",
               volume = "22",
               number = "9",
                pages = "3221--3229",
             keywords = "AERONOMY, Ionosphere, Ionospheric disturbances, Modelling and 
                         forecasting, Magnetospheric physics, Storms and substorms, 
                         Atmospheric, Gravity waves, Equatorial ionosphere, Imaging 
                         observations, Plasma depletions, Mangetic storms, Wags campaign, 
                         Disturbances, AERONOMIA, Ionosfera, Dist{\'u}rbios 
                         ionosf{\'e}ricos, F{\'{\i}}sica magnetosf{\'e}rica, 
                         Tempestades, Ondas da gravidade atmosf{\'e}rica, Ionosfera 
                         equatorial, Observa{\c{c}}{\~a}o de imagens, Tempestades 
                         magn{\'e}ticas.",
             abstract = "A new ionospheric sounding station using a Canadian Advanced 
                         Digital Ionosonde (CADI) was established for routine measurements 
                         by the {"}Universidade do Vale do Paraiba (UNIVAP){"} at Sao Jose 
                         dos Campos (23.2degrees S, 45.9degrees W), Brazil, in August 2000. 
                         A major geomagnetic storm with gradual commencement at about 01:00 
                         UT was observed or 31 March 2001. In this paper, we present and 
                         discuss salient features from the ionospheric sounding 
                         measurements carried out at S. J. Campos on the three consecutive 
                         UT days 30 March (quiet), 31 March (disturbed) and I April 
                         (recovery) 2001. During most of the storm period. the foF2 values 
                         showed negative phase, whereas during the two storm-time peaks, 
                         large F-region height variations were observed. In order to study 
                         the longitudinal differences observed in the F-realon during the 
                         storm, the simultaneous ionospheric sounding measurements carried 
                         out at S. J. Campos. El Arenosillo (37.1degrees N, 6.7degrees W), 
                         Spain, Okinawa (26.3degrees N, 127.8degrees E), Japan and Wakkanai 
                         (45.5degrees N, 141.7degrees E), Japan, during the period 30 
                         March-1 April 2001, have been analyzed. A comparison of the 
                         observed ionospheric parameters (h'F and foF2) in the two 
                         longitudinal zones (1. Japanese and 2. Brazilian-Spanish) shows 
                         both similarities and differences associated with the geomagnetic 
                         disturbances. Some latitudinal differences are also observed in 
                         the two longitudinal zones. In addition, global ionospheric TEC 
                         maps from the worldwide network of GPS receivers are presented, 
                         showing widespread TEC changes during both the main and recovery 
                         phases of the storm. The ionospheric sounding measurements are 
                         compared with the ASPEN-TIMEGCM model runs appropriate for the 
                         storm conditions. The model results produce better agreement 
                         during the quiet period. During the disturbed period, some of the 
                         observed F-region height variations are well reproduced by the 
                         model results. The model foF2 and TEC results differ considerably 
                         during the recovery period and indicate much stronger negative 
                         phase at all the stations, particularly at the low-latitude 
                         ones.",
           copyholder = "SID/SCD",
                 issn = "0992-7689",
             language = "en",
           targetfile = "longitudinal differences.pdf",
        urlaccessdate = "10 maio 2024"
}