@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/ibi/8JMKD3MGP3W34P/3QJNJHE",
targetfile = "publicacao.pdf",
urlaccessdate = "11 maio 2024"
}