@Article{SantosBBSASJMT:2023:CoObDa,
               author = "Santos, Angela Machado dos and Brum, Christiano G. M. and Batista, 
                         Inez Staciarini and Sobral, Jos{\'e} Humberto Andrade and Abdu, 
                         Mangalathayil Ali and Souza, Jonas Rodrigues de and Jesus, Rodolfo 
                         de and Manoharan, Periasamy K. and Terra, Pedrina",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {University 
                         of Central Florida} 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 {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {University of Central Florida} 
                         and {University of Central Florida}",
                title = "Ionospheric Variability over the Brazilian Equatorial Region 
                         during the Minima Solar Cycles 1996 and 2009: Comparison between 
                         Observational Data and the IRI Model",
              journal = "Atmosphere",
                 year = "2023",
               volume = "14",
               number = "1",
                pages = "e87",
                month = "Jan.",
             keywords = "atmospheric tides, deep solar minimum, F layer parameters, IRI 
                         model, PRE.",
             abstract = "The behavior of the Brazilian equatorial ionosphere during the 
                         solar minimum periods, 1996 and 2009, which cover the solar cycles 
                         22/23 and 23/24, respectively, is investigated. For this, the F2 
                         layer critical frequency (foF2) and peak height (hmF2) registered 
                         by a Digisonde operated at S{\~a}o Luis (2.33° S; 44° W) are 
                         carefully analyzed. The results show that the seasonal mean values 
                         of the foF2 and the hmF2 in the equinoxes and winter during 2009 
                         were lower than in 1996. In the summer, an anomalous response to 
                         solar variability was observed. In this case, the hmF2 in 2009 is 
                         higher than in 1996 during a specific daytime interval. Besides 
                         that, it was verified that the prereversal enhancement of the 
                         zonal electric field (PRE) during the equinoxes in 2009 occurred a 
                         few minutes earlier than in 1996. Additionally, a Fast Fourier 
                         Transform (FFT) analysis was used to investigate the impacts of 
                         solar atmospheric tides (amplitude, diurnal, semidiurnal, and 
                         terdiurnal modes) on foF2 and hmF2 parameters with respect to its 
                         seasonality. Significant differences were observed between their 
                         values during the two minima, mainly in the amplitude of hmF2, 
                         which was higher in 1996 than in 2009 for all days analyzed. 
                         Moreover, the seasonality in the diurnal and semidiurnal modes for 
                         both periods presented an annual variability, while the terdiurnal 
                         mode exhibited annual and semiannual components. The results are 
                         compared with the International Reference Ionosphere (IRI) model, 
                         and the main differences between the observation and the model 
                         results are discussed in this work.",
                  doi = "10.3390/atmos14010087",
                  url = "http://dx.doi.org/10.3390/atmos14010087",
                 issn = "2073-4433",
                label = "self-archiving-INPE-MCTIC-GOV-BR",
             language = "en",
           targetfile = "atmosphere-14-00087.pdf",
        urlaccessdate = "12 maio 2024"
}