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@PhDThesis{Antunes:2018:EsOnGr,
               author = "Antunes, Cassio Espindola",
                title = "Estudo de ondas de gravidade-ac{\'u}stica observadas na MLT sobre 
                         a regi{\~a}o Amaz{\^o}nica e no Sul do Brasil",
               school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
                 year = "2018",
              address = "S{\~a}o Jos{\'e} dos Campos",
                month = "2018-05-30",
             keywords = "ondas de gravidade-ac{\'u}stica, fontes de gera{\c{c}}{\~a}o de 
                         ondas de gravidade ac{\'u}stica, luminesc{\^e}ncia 
                         atmosf{\'e}rica, simula{\c{c}}{\~o}es num{\'e}ricas, frentes 
                         mesosf{\'e}ricas, acoustic gravity waves, acoustic gravity waves 
                         sources, agrilow, numeric simulations, mesospheric bores.",
             abstract = "Neste trabalho s{\~a}o investigadas as caracter{\'{\i}}sticas 
                         das ondas de gravidade na alta atmosfera sobre duas regi{\~o}es 
                         distintas do Brasil. Foram analisados dados da luminesc{\^e}ncia 
                         atmosf{\'e}rica na MLT (Mesosphere and Lower Thermosphere), das 
                         emiss{\~o}es do OI 557,7 nm e NaD 589,3 nm, obtidos por um 
                         imageador all-sky. A esta{\c{c}}{\~a}o SMS (29,442S; 53,822O) 
                         fica localizada no extremo sul do Brasil, entre baixas e 
                         m{\'e}dias latitudes, na cidade de S{\~a}o Martinho da Serra, 
                         RS. Os dados analisados foram coletados entre mar{\c{c}}o de 2011 
                         a maio de 2012. Nos eventos analisados neste s{\'{\i}}tio 
                         observou-se uma anisotropia na dire{\c{c}}{\~a}o de 
                         propaga{\c{c}}{\~a}o em torno do eixo NO-SE. A 
                         propaga{\c{c}}{\~a}o preferencial no inverno foi para NO, 
                         enquanto que no ver{\~a}o ocorreu no sentido SE. A 
                         esta{\c{c}}{\~a}o MAN (2,589S; 60,221O) fica na regi{\~a}o 
                         Norte do Brasil em meio a floresta Amaz{\^o}nica, a cerca de 60 
                         km de Manaus, AM. Os dados analisados para este s{\'{\i}}tio 
                         compreendem o per{\'{\i}}odo de julho de 2015 a agosto de 2017. 
                         Somente no per{\'{\i}}odo do outono observou-se uma 
                         dire{\c{c}}{\~a}o preferencial para N na propaga{\c{c}}{\~a}o 
                         das ondas de gravidade. Nas demais esta{\c{c}}{\~o}es do ano 
                         n{\~a}o houve dire{\c{c}}{\~a}o preferencial, sendo que no 
                         inverno, per{\'{\i}}odo com maior n{\'u}mero de 
                         observa{\c{c}}{\~o}es, a propaga{\c{c}}{\~a}o foi quase 
                         isotr{\'o}pica. Frentes mesosf{\'e}ricas foram observadas em 
                         ambas regi{\~o}es e estudo de casos abordando este tipo de evento 
                         s{\~a}o apresentados. Duas frentes mesosf{\'e}ricas duplas (twin 
                         mesospheric bores) foram observadas na esta{\c{c}}{\~a}o MAN. 
                         Mais de 50% dos eventos observados em SMS n{\~a}o tem 
                         rela{\c{c}}{\~a}o com atividade convectiva na troposfera, 
                         sugerindo que as fontes est{\~a}o acima dessa regi{\~a}o. Sobre 
                         a esta{\c{c}}{\~a}o MAN a atividade convectiva troposf{\'e}rica 
                         {\'e} praticamente cont{\'{\i}}nua ao longo do ano, sendo 
                         tipicamente observadas m{\'u}ltiplas zonas de 
                         convec{\c{c}}{\~a}o na regi{\~a}o Amaz{\^o}nica. A 
                         posi{\c{c}}{\~a}o destas zonas de convec{\c{c}}{\~a}o 
                         troposf{\'e}ricas apresentou alta correla{\c{c}}{\~a}o com a 
                         dire{\c{c}}{\~a}o de propaga{\c{c}}{\~a}o das ondas de 
                         gravidade observadas na MLT. Um novo mecanismo de 
                         gera{\c{c}}{\~a}o de ondas de gravidade-ac{\'u}stica in situ na 
                         baixa termosfera, devido a aquecimento Joule associado {\`a}s 
                         camadas E-espor{\'a}dicas foi proposto. Simula{\c{c}}{\~o}es 
                         num{\'e}ricas da gera{\c{c}}{\~a}o e propaga{\c{c}}{\~a}o de 
                         ondas de gravidade-ac{\'u}stica foram conduzidas para o mecanismo 
                         proposto e para m{\'u}ltiplas for{\c{c}}antes 
                         troposf{\'e}ricas. ABSTRACT: In this work is presented an 
                         investigation of gravity waves observed in the upper atmosphere 
                         over two distinct regions of Brazil. Nightime airglow data 
                         emissions of the OI 557.7 nm and NaD 589.3 nm from the MLT 
                         Mesosphere and Lower Thermosphere, obtained by an all-sky imager 
                         are analyzed. The SMS station (29.442S, 53.822W) is located in the 
                         Southern Brazil, between low and middle latitudes, in the city of 
                         S{\~a}o Martinho da Serra, RS state. The data were collected from 
                         March 2011 to May 2012. An anisotropy was observed in the 
                         propagation direction NW-SE for the events analyzed at SMS 
                         station. The preferential propagation in the winter was to NW, 
                         whereas in the summer it occurred in the SE direction. The MAN 
                         station (2.589S, 60.221W) is in the Northern Brazil in the Amazon 
                         forest region, located about 60 km from Manaus, AM state. The MAN 
                         analyzed data comprise the period from July 2015 to August 2017. A 
                         northward preferential propagation was observed during fall period 
                         while during the other seasons there was no preferential 
                         direction. In the winter, the period with the highest number of 
                         observations, the propagation was almost isotropic. Mesospheric 
                         fronts were observed in both regions and studies addressing this 
                         type of event are presented. Two double mesospheric bores (twin 
                         mesospheric bores) were observed at the MAN station. Investigation 
                         of possible sources indicated that more than 50 % of the events 
                         observed in SMS have no evident relation with convective ativity, 
                         therefore probably have their sources above the troposphere. On 
                         the other hand, the tropospheric convective activity is 
                         practically continuous throughout the year on the MAN station, 
                         being usual to observe multiple convection zones in the Amazon 
                         region. These tropospheric convection zones position showed a high 
                         correlation with the propagation direction of gravity waves 
                         observed in the MLT. A new mechanism for acoustic gravity wave 
                         generation in the low thermosphere due to Joule heating associated 
                         with E-sporadic layers is proposed. Numerical simulations of 
                         acoustic gravity waves generation and propagation were conducted 
                         for the proposed in situ generation mechanism and for multiple 
                         tropospheric forcing.",
            committee = "Dal Lago, Alisson (presidente) and Pimenta, Alexandre Alvares 
                         (orientador) and Silva, V{\^a}nia F{\'a}tima Andrioli Novaes 
                         (orientador) and De Nardin, Clezio Marcos and Fagundes, Paulo 
                         Roberto and Guede, Jos{\'e} Ricardo Abalde",
         englishtitle = "Study of acoustic gravity waves observed in the MLT over the 
                         Amazonic region and in the Southern Brazil",
             language = "pt",
                pages = "179",
                  ibi = "8JMKD3MGP3W34R/3R453E8",
                  url = "http://urlib.net/rep/8JMKD3MGP3W34R/3R453E8",
           targetfile = "publicacao.pdf",
        urlaccessdate = "04 dez. 2020"
}


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