@Article{FagundesMBSLBPFL:2008:ThCoOb,
               author = "Fagundes, P. R. and Muella, M{\'a}rcio Tadeu de Assis Honorato 
                         and Bittencourt, Jos{\'e} Augusto and Sahay, Y. and Lima, W. L. . 
                         C and Becker-Guedes, F. and Pillat, V. G. and Ferreira, A. S. and 
                         Lima, N. S.",
          affiliation = "{Universidade do Vale do Para{\'{\i}}ba (UNIVAP)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Universidade do Vale do 
                         Para{\'{\i}}ba (UNIVAP)} and {Centro Universit{\'a}rio Luterano 
                         de Palmas (CEULP)} 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 Manaus (CEULM)} and 
                         {Centro Universit{\'a}rio Luterano de Manaus (CEULM)}",
                title = "Nighttime ionosphere - thermosphere coupling observed during an 
                         intense geomagnetic storm",
              journal = "Advances in Space Research",
                 year = "2008",
               volume = "41",
               number = "4",
                pages = "539--547",
             keywords = "Geomagnetic storms, Equatorial region, Low latitude.",
             abstract = "The electrodynamics of the ionosphere in the tropical region 
                         presents various scientific aspects, which remain subject of 
                         intensive investigations and debates by the scientific community. 
                         During the year 2002, in a joint project between the Universidade 
                         do Vale do Para{\'{\i}}ba (UNIVAP) and Universidade Luterana do 
                         Brasil (ULBRA), a chain of three Canadian Advanced Digital 
                         Ionosondes (CADIs) was established nearly along the geomagnetic 
                         meridian direction, for tropical ionospheric studies, such as, 
                         changes and response due to geomagnetic disturbances and 
                         thermosphere-ionosphere coupling and the generation and dynamics 
                         of ionospheric irregularities, in the Brazilian sector. The 
                         locations of the three ionosondes stations are S{\~a}o Jos{\'e} 
                         dos Campos (23.2o S, 45.9o W, dip latitude 17.6o S - under the 
                         southern crest of equatorial ionospheric anomaly), Palmas (10.2o 
                         S, 48.2o W, dip latitude 5.5o S near the magnetic equator) and 
                         Manaus (2.9o S, 60.0o W, dip latitude 6.4o N between the 
                         geographic and geomagnetic dip equators). It should be pointed out 
                         that Palmas and Manaus are located on the opposite sides of the 
                         magnetic equator but both are south of the geographic equator. The 
                         three CADIs work in time-synchronized mode and obtain ionograms 
                         every 5 minutes. This configuration of the ionospheric sounding 
                         stations allowed us to study the F-region dynamics during 
                         geomagnetically disturbed period in the meridional direction. Just 
                         after the installation and testing of the three CADIs, on 
                         September 05, 2002 a coronal mass ejection (CME) left the Sun and 
                         about two days after the CME left the Sun, it reached the Earths 
                         magnetosphere and complex and multi step events took place during 
                         the period September 07- 09. In the study we note that the 
                         equatorial stations located north, (Manaus, dip latitude 6.4o N) 
                         and south (Palmas, dip latitude 5.5o S) of the dip equator 
                         presented significant F-layer height asymmetries during the storm 
                         main phase. In addition, the low-latitude station SJC (dip 
                         latitude 17.6o S) presented decrease in the F-layer densities 
                         (negative phase), whereas Palmas presented increase in the F-layer 
                         densities (positive phase) during the main phase. This was 
                         followed by positive phase at both the stations. During the first 
                         night of the recovery phase a strong formation and evolution of 
                         large-scale ionospheric irregularities (equatorial spread-F (ESF)) 
                         was observed, but on the second night of the recovery phase, there 
                         was strong and almost simultaneous sporadic-E (Es) formation at 
                         all three stations. During the presence of Es, spread-F formation 
                         is not observed, indicating the suppression of spread F, possibly 
                         by sporadic E.",
                  doi = "10.1016/j.asr.2007.11.005",
                  url = "http://dx.doi.org/10.1016/j.asr.2007.11.005",
                 issn = "0273-1177",
             language = "en",
           targetfile = "nighttime ionospheric.pdf",
        urlaccessdate = "12 maio 2024"
}