@Article{AndrioliXBPRSFYJCWL:2020:NoSeVa,
               author = "Andrioli, V{\^a}nia F{\'a}tima and Xu, Jiyao and Batista, Paulo 
                         Prado and Pimenta, Alexandre Alvares and Resende, Laysa Cristina 
                         de Ara{\'u}jo and Savio, Siomel and Fagundes, Paulo Roberto and 
                         Yang, Guotao and Jiao, J. and Cheng, X. and Wang, Chi and Liu, 
                         Z.",
          affiliation = "{Chinese Academy of Sciences} and {Chinese Academy of Sciences} 
                         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 {Chinese Academy of Sciences} and 
                         {Chinese Academy of Sciences} and {Chinese Academy of Sciences} 
                         and {Chinese Academy of Sciences} and {Chinese Academy of 
                         Sciences}",
                title = "Nocturnal and seasonal variation of Na and K layers simultaneously 
                         observed in the MLT region at 23°S",
              journal = "Journal of Geophysical Research: Space Physics",
                 year = "2020",
               volume = "125",
               number = "3",
                pages = "e2019JA027164",
                month = "Mar.",
             abstract = "The present work shows for the first time the study of morphology 
                         of the mesopause sodium (Na) and potassium (K) layers 
                         simultaneously observed by a dual\‐beam LIDAR in the 
                         Southern Hemisphere. We analyze these two alkali metal layers from 
                         November 2016 to February 2019 measured at S{\~a}o Jos{\'e} dos 
                         Campos (23.1°S, 45.9°W) and present their nocturnal and seasonal 
                         behavior. The night of 25 April 2017 was investigated as a 
                         representative of the vertical descending structure frequently 
                         observed in the metal density data at this location. We discuss 
                         here the chemical and dynamical contribution in the formation of 
                         these distinct layers, using simultaneous meteor radar wind and 
                         ionosonde data. These downward structures are seen in 66% of Na/K 
                         LIDAR data and seem to occur preferentially around April. The good 
                         agreement with diurnal tide and the presence of Es layer, suggest 
                         a combining mechanism in the formation of these structures. 
                         Moreover, semiannual variations are observed in both layers; 
                         however, they present different maxima location. The Na density 
                         presents its maxima around May and September; whereas, K density 
                         shows a strong maximum around July and a weaker one around 
                         December. Likewise, semiannual variation with maxima at the 
                         equinoxes is observed in the centroid height for both layers. 
                         However, the column abundances of these two metals show distinct 
                         seasonal variation: Annual variation peaking from one equinox to 
                         the other is observed in Na and semiannual with maxima in the 
                         solstices in K. The same behavior of centroid height for both 
                         layers indicates the same mechanism acting in the seasonal 
                         variation, which is not yet completely understood.",
                  doi = "10.1029/2019JA027164",
                  url = "http://dx.doi.org/10.1029/2019JA027164",
                 issn = "2169-9402",
             language = "en",
           targetfile = "andrioli_nocturnal.pdf",
        urlaccessdate = "27 abr. 2024"
}