Fechar
Metadados

@MastersThesis{Carmo:2018:EsDiTé,
               author = "Carmo, Carolina de Sousa do",
                title = "Estudo de diferentes t{\'e}cnicas para o c{\'a}lculo do 
                         conte{\'u}do eletr{\^o}nico total absoluto na ionosfera 
                         equatorial e de baixas latitudes",
               school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
                 year = "2018",
              address = "S{\~a}o Jos{\'e} dos Campos",
                month = "2018-03-02",
             keywords = "ionosfera, sistema de posicionamento global, conte{\'u}do 
                         eletr{\^o}nico total, ionosphere, global positioning system, 
                         total electron content.",
             abstract = "O Conte{\'u}do Eletr{\^o}nico Total (do ingl{\^e}s Total 
                         Electron Content - TEC) da ionosfera pode ser calculado a partir 
                         da combina{\c{c}}{\~a}o linear livre da geometria utilizando as 
                         observa{\c{c}}{\~o}es coletadas com receptores do Sistema de 
                         Posicionamento Global (do ingl{\^e}s Global Positioning System - 
                         GPS) localizados no solo. As observ{\'a}veis GPS sofrem atrasos 
                         de propaga{\c{c}}{\~a}o devido ao TEC, aos atrasos instrumentais 
                         (do ingl{\^e}s biases) e {\`a}s reflex{\~o}es m{\'u}ltiplas 
                         (multi-caminho) recebidas na antena. Como resultado do 
                         c{\'a}lculo diferencial de fase e de grupo, os termos n{\~a}o 
                         dispersivos s{\~a}o cancelados, restando apenas os termos dos 
                         biases do receptor e do sat{\'e}lite na forma de um TEC inclinado 
                         (do ingl{\^e}s Slant Total Electron Content - STEC). O STEC 
                         corresponde a um arco de TEC para cada sat{\'e}lite medido por um 
                         determinado receptor em solo. Esse trabalho visa comparar 
                         tr{\^e}s t{\'e}cnicas de c{\'a}lculo do TEC e avaliar o seu 
                         desempenho para caracterizar a ionosfera no setor brasileiro. Para 
                         isso foi selecionado um per{\'{\i}}odo de m{\'{\i}}nima 
                         atividade solar, de novembro de 2008 a outubro de 2009; e um 
                         per{\'{\i}}odo de m{\'a}xima atividade solar, de novembro de 
                         2014 a outubro de 2015, onde observou-se a variabilidade sazonal 
                         do TEC e o seu comportamento durante um per{\'{\i}}odo 
                         perturbado (Tempestade de St. Patrick). Para a an{\'a}lise do 
                         per{\'{\i}}odo perturbado comparou-se tamb{\'e}m o modelo 
                         ionosf{\'e}rico NeQuick2, desenvolvido pelo ICTP (International 
                         Centre for Theoretical Physics). A fim de testar o desempenho do 
                         TEC obtido pelas t{\'e}cnicas selecionadas sob as 
                         condi{\c{c}}{\~o}es espec{\'{\i}}ficas da ionosfera no setor 
                         brasileiro, utilizou-se uma esta{\c{c}}{\~a}o na regi{\~a}o 
                         equatorial, S{\~a}o Lu{\'{\i}}s (SALU), e uma de baixa latitude 
                         compreendida na crista da Anomalia de Ioniza{\c{c}}{\~a}o 
                         Equatorial (do ingl{\^e}s Equatorial Ionization Anomaly - EIA), 
                         Cachoeira Paulista (CHPI). As t{\'e}cnicas utilizadas neste 
                         trabalho foram: a) a t{\'e}cnica desenvolvida por Yuichi Otsuka, 
                         e adaptada no Instituto Nacional de Pesquisas Espaciais (INPE), 
                         Brasil, pelo Dr. Jo{\~a}o Francisco Galera Monico, para uso no 
                         programa de Estudo e Monitoramento Brasileiro do Clima Espacial 
                         (Embrace); b) a t{\'e}cnica desenvolvida por Gopi Seemala, no 
                         Boston College (BC); c) o m{\'e}todo proposto por Ciraolo e 
                         colaboradores em 2006, no International Centre for Theoretical 
                         Physics (ICTP). Foram analisadas e comparadas as diferen{\c{c}}as 
                         entre as t{\'e}cnicas estudadas nas regi{\~o}es equatorial e de 
                         baixas latitudes, comparando-se tamb{\'e}m as diferen{\c{c}}as 
                         apresentadas pelas variabilidades sazonais do TEC e conforme a 
                         atividade geomagn{\'e}tica e o ciclo solar. Neste trabalho 
                         tamb{\'e}m foi feito um teste de qualidade para duas 
                         t{\'e}cnicas (INPE e BC). O estudo realizado neste trabalho 
                         apresentou os seguintes resultados gerais: a) a diferen{\c{c}}a 
                         entre a t{\'e}cnica do INPE e as outras duas geralmente mostraram 
                         valores pr{\'o}ximos a zero; b) foram observadas algumas 
                         diferen{\c{c}}as pontuais de comportamento da curva do TEC no 
                         m{\'a}ximo solar, sendo que nestes casos os resultados da 
                         t{\'e}cnica do INPE foram corroborados por uma das outras duas 
                         t{\'e}cnicas. Realizou-se a m{\'e}dia entre as tr{\^e}s 
                         t{\'e}cnicas para se obter curvas representativas para o TEC para 
                         se observar a sua variabilidade di{\'a}ria na regi{\~a}o 
                         brasileira. Por{\'e}m, este estudo mostrou que o m{\'e}todo 
                         utilizado pelo INPE {\'e} suficientemente adequado para descrever 
                         o TEC da ionosfera brasileira com as suas varia{\c{c}}{\~o}es 
                         dia-a-dia, sazonais, espaciais, com o ciclo solar e em diferentes 
                         condi{\c{c}}{\~o}es de atividade geomagn{\'e}tica. ABSTRACT: 
                         The Total Electron Content (TEC) of the ionosphere can be 
                         calculated through parameters observed by GPS (Global Positioning 
                         System) receivers located on the ground. GPS observables suffer 
                         propagation delays due to TEC, instrumental delays (biases) and 
                         multiple reflections (multipath) received on the antenna. As a 
                         result of the differential phase and group calculation, the 
                         non-dispersive terms are canceled, leaving only the terms of the 
                         receiver and satellite biases in the form of a Slant Total 
                         Electron Content (STEC). The STEC corresponds to a TEC arc for 
                         each satellite measured by a given receiver on the ground. This 
                         work aims to compare three TEC calculation techniques and to 
                         evaluate their performance to characterize the ionosphere in the 
                         Brazilian sector. In order to do this a period of solar activity 
                         minimum, from November 2008 to October 2009, and a period of solar 
                         activity maximum, from November 2014 to October 2015, were 
                         selected. The TEC seasonal variability and variations of the 
                         electron content during a disturbed period (St. Patricks Storm) 
                         were studied. The NeQuick2 ionospheric model, developed by ICTP 
                         (International Center for Theoretical Physics), was also compared 
                         for the disturbed period analysis. In order to test the 
                         performance of the TEC obtained by the selected techniques under 
                         the specific conditions of the ionosphere in the Brazilian sector, 
                         a station was selected in the equatorial region, S{\~a}o 
                         Lu{\'{\i}}s (SALU), and another one at lowlatitudes, under the 
                         crest of the Equatorial Ionization Anomaly (EIA), Cachoeira 
                         Paulista (CHPI). The techniques used in this work were: a) the 
                         technique developed by Yuichi Otsuka, and adapted by the National 
                         Institute for Space Research (INPE), Brazil, by Dr. Jo{\~a}o 
                         Francisco Galera Monico, to be used in the the Brazilian Space 
                         Weather Program (Embrace); b) the technique developed by Gopi 
                         Seemala, Boston College (BC); and c) the method proposed by 
                         Ciraolo et al. in 2006 at the International Center for Theoretical 
                         Physics (ICTP). Differences between the techniques studied in the 
                         equatorial and low latitude regions were analyzed, comparing the 
                         differences presented by the seasonal variability of the TEC and 
                         according to the geomagnetic activity and the solar cycle. In this 
                         work a quality test was also made for two techniques (INPE and 
                         BC). The study carried out in this work presented the following 
                         general results: a) the difference between the INPE technique and 
                         the other two techniques generally showed values close to zero; b) 
                         some specific differences in the behavior of the TEC curve during 
                         the solar maximum were observed, and in these cases the results of 
                         the INPE technique were corroborated by one of the other two 
                         techniques. The average between the three techniques was made to 
                         obtain representative TEC curves to observe its daily variability 
                         in the Brazilian region. However, this study shows that the method 
                         used by INPE is adequate enough to describe the TEC of the 
                         Brazilian ionosphere with its day-to-day, seasonal and spatial 
                         variations with the solar cycle, and in different conditions of 
                         geomagnetic activity.",
            committee = "Lago, Alisson Dal (presidente) and Guedes, F{\'a}bio Becker 
                         (orientador) and Camargo, Paulo de Oliveira (orientador) and 
                         Negreti, Patr{\'{\i}}cia Mara de Siqueira and Oliveira Junior, 
                         Paulo S{\'e}rgio de and Klausner, Virg{\'{\i}}nia de Oliveira",
         englishtitle = "Study of different techniques for the calculation of the total 
                         electronic content in equatorial and low latitude ionosphere",
             language = "pt",
                pages = "147",
                  ibi = "8JMKD3MGP3W34P/3QJNJHE",
                  url = "http://urlib.net/rep/8JMKD3MGP3W34P/3QJNJHE",
           targetfile = "publicacao.pdf",
        urlaccessdate = "03 dez. 2020"
}


Fechar