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@MastersThesis{Souza:1992:EsCiSu,
               author = "Souza, Ronald Buss de",
                title = "Estudo da circula{\c{c}}{\~a}o superficial ao norte do Estreito 
                         de Bransfield, Ant{\'a}rtica",
               school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
                 year = "1992",
              address = "Sao Jose dos Campos",
                month = "1992-09-08",
             keywords = "oceanografia, estreito de Bransfield, Ant{\'a}rtica 
                         (Regi{\~a}o), b{\'o}ias de deriva, NOAA-10, NOAA-11, 
                         meteorol{\'o}gia, sat{\'e}lites NOAA, fen{\^o}meno mesoescala, 
                         correntes oce{\^a}nicas, superf{\'{\i}}cie do mar, analise de 
                         trajet{\'o}ria, analise espectral, paramentos 
                         oceanogr{\'a}ficos, oscila{\c{c}}{\~a}o, ocean{\'o}grafo, 
                         autocorrelation, buoys, maximum entropy method, mesoscale 
                         phenomena, ocean current, ocean surface, spectrun analysis, 
                         trajectory analysis, NOAA satellites, oscilation.",
             abstract = "Um estudo sobre a circula{\c{c}}{\~a}o superficial em 
                         meso-escala na regi{\~a}o ao Norte do Estreito de Bransfield, 
                         Ant{\'a}rtica (61-62S, 52.5-58.5W) e apresentado, utilizando-se 
                         medidas de corrente efetuadas por uma boia de deriva brasileira 
                         rastreada pelos sat{\'e}lites NOAA 10 e 11 no per{\'{\i}}odo de 
                         26/01-21/02/89. Dados de posicionamento da boia, juntamente com 
                         dados oceanogr{\'a}ficos e meteorol{\'o}gicos auxiliares tomados 
                         {"}in situ{"} serviram para uma descri{\c{c}}{\~a}o detalhada da 
                         corrente superficial na {\'a}rea de estudo. Com uma velocidade 
                         m{\'e}dia de 7.5 cm/s e dire{\c{c}}{\~a}o altamente zonal 
                         (89), a corrente medida pela boia foi, em grande parte, regida 
                         pelos ventos da regi{\~a}o, conforme o modelo de Ekman. As 
                         correntes de Ekman foram calculadas para 0 e 10 metros, obtendo-se 
                         21 e 8.5 cm/s nas dire{\c{c}}{\~o}es 108 e 25, 
                         respectivamente. O padr{\~a}o de circula{\c{c}}{\~a}o medido 
                         pela boia n{\~a}o concordou com a circula{\c{c}}{\~a}o 
                         geostr{\'o}fica regional. As correntes geostr{\'o}ficas 
                         m{\'e}dias em 0 e 10 metros foram cerca de 2 cm/s na 
                         dire{\c{c}}{\~a}o para Norte. An{\'a}lises das energias 
                         cin{\'e}ticas Total (ECT), Media (ECM) e de V{\'o}rtices (ECV) 
                         demonstraram que as flutua{\c{c}}{\~o}es de meso-escala medidas 
                         pela ECV compreenderam 91.7% da ECT. Em valores absolutos, a ECM e 
                         a ECV foram iguais a 28.1 cm2/s2 e 357.4 cm2/s2, respectivamente. 
                         Atrav{\'e}s da auto-correla{\c{c}}{\~a}o, determinou-se que as 
                         s{\'e}ries de deslocamento da boia cont{\'e}m per{\'{\i}}odos 
                         dominantes de 21.7 na s{\'e}rie zonal, e de 11.5 dias na 
                         s{\'e}rie meridional. Usando a an{\'a}lise espectral pelo 
                         M{\'e}todo da M{\'a}xima Entropia (MEM), determinou-se que 75.9% 
                         da energia total da componente zonal foi relacionada a 
                         per{\'{\i}}odos de 14.9 a 37.7 dias. Para a componente 
                         meridional do deslocamento da boia, 66.2% da energia relacionou-se 
                         a per{\'{\i}}odos entre 11.5 e 21.2 dias. A MEM tamb{\'e}m 
                         demonstrou que per{\'{\i}}odos de 4-5 dias e 1 dia (causado por 
                         mar{\'e}s) foram importantes nas duas s{\'e}ries componentes. 
                         Compara{\c{c}}{\~o}es entre os per{\'{\i}}odos obtidos pela 
                         MEM para os dados da boia, e os obtidos para dados de press{\~a}o 
                         atmosf{\'e}rica recolhidos na Esta{\c{c}}{\~a}o Ant{\'a}rtica 
                         Brasileira, mostraram que a for{\c{c}}ante atmosf{\'e}rica foi 
                         respons{\'a}vel por oscila{\c{c}}{\~o}es sentidas na corrente 
                         em per{\'{\i}}odos de 25.5, 11-12 e 5-6 dias. An{\'a}lises de 
                         correla{\c{c}}{\~a}o cruzada dos dados da boia e de dados de 
                         press{\~a}o atmosf{\'e}rica mostraram que a corrente responde ao 
                         for{\c{c}}amento atmosf{\'e}rico com um retardo de tempo de 14 
                         dias. Este per{\'{\i}}odo parece estar relacionado a 
                         varia{\c{c}}{\~o}es em grande escala do sistema 
                         atmosf{\'e}rico. An{\'e}is ou {"}loops{"} presentes na 
                         trajet{\'o}ria da boia foram produzidos por mar{\'e}s diurnas, 
                         as componentes de mar{\'e} mais importantes na {\'a}rea de 
                         estudo. O aparecimento destes {"}loops{"} na trajet{\'o}ria da 
                         boia esteve relacionado {\`a} presen{\c{c}}a de uma frente 
                         oce{\^a}nica localizada a Oeste da {\'a}rea de estudo. Uma 
                         segunda frente, a Leste, com encontro de {\'a}guas de 
                         influ{\^e}ncia do Mar de Bellingshausen com {\'a}guas mais frias 
                         e salinas do Mar de Weddell resultou em uma corrente que causou 
                         uma forte deflec{\c{c}}{\~a}o da boia para a dire{\c{c}}{\~a}o 
                         Sul. A utiliza{\c{c}}{\~a}o da boia de deriva brasileira 
                         compat{\'{\i}}vel com o sistema ARGOS comprovou ser uma 
                         ferramenta eficiente para estudos em meso-escala, com a 
                         possibilidade de evid{\^e}ncia de frentes oce{\^a}nicas, fluxos 
                         de massas de {\'a}gua de caracter{\'{\i}}sticas conhecidas, e 
                         influ{\^e}ncias da atmosfera e mar{\'e}s nas correntes 
                         superficiais. Resultados de estudos como o realizado aqui servem 
                         de base para trabalhos mais complexos na {\'a}rea de 
                         intera{\c{c}}{\~a}o ar-mar, climatologia e 
                         distribui{\c{c}}{\~a}o de organismos plact{\^o}nicos de 
                         interesse comercial, por exemplo. ABSTRACT: A study of the 
                         meso-seale circulation to the North of Bransfield Strait, 
                         Antarctica (61-62S, 52.5-58.5W), utilizing the displacement 
                         trajectory of a Brazilian drifting buoy, tracked by NOAA 10 and 11 
                         satellites during 01/26-02/21/89, is presented. Buoy positional 
                         data, together with in situ oceanographic and meteorological data, 
                         were used to obtain a detailed description of the surface current. 
                         With a mean velocity of 7.5 cm/s, and a highly zonal direction 
                         (89), the current derived from the buoy trajectory was, in great 
                         part, forced by the winds, in agreement with the Ekman model. The 
                         Ekman currents were computed for O and 10 meter depths, obtaining 
                         21 and 8.5 cm/s toward 108 and 25, respectively. The regional 
                         geostrophic circulation for the surface and 10 meter levels 
                         disagreed with the circulation pattern measured by the buoy. The 
                         mean geostrophic currents at those levels were about 2 cm/s to the 
                         North. Analysing the Total, Mean and the Eddy Kinetic Energies 
                         (EKT, EKM and EKE, respectively), it was found that time-variable 
                         flutuations measured by EKE comprised 91.7% of the EKT. In 
                         absolute values, EKM and EKE were equal to 28.1 cm2 /s2 and 357.4 
                         cm2 /s2, respectively. With the use of auto-correlational 
                         analysis, it was determined that the displacement series of the 
                         buoy' s trajectory contain dominant zonal and meridional component 
                         periods of 21.7 and 11.5 days, respectively. Using the Maximum 
                         Entropy Method (MEM) of spectral analysis, it was determined that 
                         75.9% of total zonal energy was related to periods of 14.9 to 37.7 
                         days. For the meridional component of the residual displacement 
                         series, 66.2% of the energy was related to periods between 11.5 
                         and 21.2 days. The MEM analysis also shows that periods of 4-5 
                         days and 1 day (tidal) were important in both displacement series. 
                         Comparison of the periods obtained from MEM for buoy and 
                         atmospheric pressure time series measured at the Brazilian 
                         Antarctic Station, showed that the atmospheric forcing was 
                         responsable for the 25.5, 11-12 and 5-6 days oscillations in the 
                         current. Cross-correlational analysis of buoy dispacement and 
                         atmospheric pressure series shows that the currents follow the 
                         atmospheric forcing with a lag of 14 days. This period seems to be 
                         related to large-scale variation in the atmospheric system. 
                         Displacement loops present in the buoy' s trajectory are shown to 
                         be caused by diurnal tides, the most important tidal component in 
                         the study region. The appearance of these loops in the buoy's 
                         trajectory was related to the presence of an oceanic front, 
                         localized in the western part of the study area. A second front to 
                         the East, formed by the justaposition of water influenced by the 
                         Bellingshausen Sea and the more cold and saline water from the 
                         Weddell Sea, resulted in a current that caused a strong southward 
                         deflection of the buoy. The utilization of the ARGOS compatible 
                         Brazilian drifting buoy is shown to be an efficient tool in 
                         meso-scale studies, offering the possibility of delineating 
                         oceanic fronts, fluxes of water masses with known characteristics, 
                         and atmospheric and tidal influences on the surface currents. 
                         Results of studies like this one can be used as support to more 
                         complexes studies in the areas of air-sea interaction, 
                         climatology, and distribution of planctonic organisms of economic 
                         interest, for example.",
            committee = "Stevenson, Merrit Raymond (presidente/orientador) and Lorenzzetti, 
                         Jo{\~a}o Antonio and Ferreira, Nelson Jesus and Miranda, Luiz 
                         Bruner de",
           copyholder = "SID/SCD",
         englishtitle = "Study of the surface circulation to the North of Bransfield 
                         Strait, Antarctica",
                label = "6619",
             language = "pt",
                pages = "189",
                  ibi = "6qtX3pFwXQZ3r59YD6/GP3oJ",
                  url = "http://urlib.net/rep/6qtX3pFwXQZ3r59YD6/GP3oJ",
           targetfile = "publicacao.pdf",
        urlaccessdate = "10 dez. 2019"
}


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