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@InProceedings{PimentaCaAmSaBiFaGo:2008:ReAsTh,
               author = "Pimenta, Alexandre Alvares and Candido, Claudia Maria Nicoli and 
                         Amorim, Danielle Cristina de Morais and Sahai, Yogeshwar and 
                         Bittencourt, Jos{\'e} Augusto and Fagundes, P. R. and Gobbi, 
                         Delano",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {Instituto Nacional de Pesquisas Espaciais 
                         (INPE)} and {Universidade do Vale do Para{\'{\i}}ba (Univap)} 
                         and {Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "Relevant aspects of thermospheric dark band structures observed by 
                         ground-based optical and radio techniques over the Brazilian 
                         low-latitude sector under different solar activity conditions",
            booktitle = "Proceedings...",
                 year = "2008",
         organization = "International Symposium on Equatorial Aeronomy, 12.",
             abstract = "Using ground-based measurements we investigate the occurrence of 
                         dark band structures in the OI 630 nm nightglow emission all-sky 
                         images in the Brazilian low latitudes region during the periods 
                         from January 1990 to December 1990 and from January 2000 to 
                         December 2000 (high solar activity period; average 10.7 cm solar 
                         cycle flux > 180x10\−22Wm\−2Hz\−1 ), January 
                         1995 to December 1996 (low solar activity period; average 10.7cm 
                         solar cycle flux < 90x10\−22Wm\−2Hz\−1 ) and 
                         from January 1997 to December 1999 (ascending solar activity 
                         period; average 10.7 cm solar cycle flux 
                         from130x10\−22Wm\−2Hz\−1 
                         to170x10\−22Wm\−2Hz\−1 ). The OI 630 nm 
                         images obtained during these periods show thermospheric Dark Band 
                         Structures (DBS) in low latitudes region propagating from 
                         southeast to northwest. These dark patches moved with average 
                         speed of about 80-250 m/s at an altitude of 220-300 km, which is 
                         the typical altitude range of the OI 630.0 nm airglow emission. 
                         Also, digisonde observations registered abrupt increases in both 
                         the F-layer peak height (hmF2) and base height (hF) when the low 
                         intensity band passed over Cachoeira Paulista. During the period 
                         studied a strong solar cycle and seasonal variations were noticed 
                         in the DBS. Only during low solar activity period (LSA) and 
                         ascending solar activity period (ASA) the DBS occurrences were 
                         observed in the OI630 nm nightglow emission all-sky images. It 
                         should be pointed out that these thermospheric/ionospheric events 
                         are not related to geomagnetic disturbed conditions. In this paper 
                         we present important features from these set of observations in 
                         the nighttime thermosphere/ionosphere under different solar 
                         activity conditions. A possible mechanism for generation of these 
                         dark band structures is presented.",
  conference-location = "Crete, Greece",
      conference-year = "18-24 may",
                label = "self-archiving-INPE-MCTIC-GOV-BR",
             language = "en",
           targetfile = "pimenta_relevant.pdf",
        urlaccessdate = "24 jan. 2021"
}


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