@PhDThesis{Figueiredo:2017:EsDiIo,
author = "Figueiredo, Cosme Alexandre Oliveira Barros",
title = "Estudo de dist{\'u}rbios ionosf{\'e}ricos propagantes no
continente Sul Americano",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2017",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2017-03-15",
keywords = "Ondas de gravidade, ionosfera terrestre, dist{\'u}rbios
ionosf{\'e}ricos propagantes, sat{\'e}lites NAVSTAR,
emiss{\~a}o do OI 630,0 nm, gravity waves, earth ionosphere,
traveling inospheric disturbances, NAVSTAR satellites, OI 630.0 nm
emission.",
abstract = "Dist{\'u}rbios ionosf{\'e}ricos propagantes (TIDs) s{\~a}o
fen{\^o}menos comuns na ionosfera, os quais induzem
perturba{\c{c}}{\~o}es na aeroluminesc{\^e}ncia
atmosf{\'e}rica e no conte{\'u}do eletr{\^o}nico total (TEC).
Neste trabalho abordamos a an{\'a}lise dos TIDs noturnos
observados na emiss{\~a}o do OI 630,0 nm em Cachoeira Paulista
(22,4\${o}\$S; 45,0\${o}\$O), S{\~a}o Paulo. As medidas foram
realizadas entre junho de 2013 e dezembro de 2015, totalizando 58
casos. Um extenso estudo de TIDs diurnos tamb{\'e}m foi realizado
utilizando mapas de TEC perturbado, sobre a regi{\~a}o sul
sudeste do brasil (15-30\${o}\$S; 35-55\${o}\$O). Os dados
analisados foram obtidos por tr{\^e}s redes de receptores GNSS de
solo entre dezembro de 2012 e fevereiro de 2016. No total foram
observados 826 eventos de TIDs. Algumas evid{\^e}ncias
observacionais de TIDs, origin{\'a}rias em regi{\~o}es aurorais,
tamb{\'e}m foram registradas. A maior contribui{\c{c}}{\~a}o do
presente trabalho foi a caracteriza{\c{c}}{\~a}o dos
par{\^a}metros dos TIDs, como comprimento de onda, velocidade de
fase, per{\'{\i}}odo e dire{\c{c}}{\~a}o de
propaga{\c{c}}{\~a}o, tanto diurnos quanto noturnos, no setor
Sul-Sudeste do Brasil, no qual foi observada uma anisotropia na
dire{\c{c}}{\~a}o de propaga{\c{c}}{\~a}o das ondas; no
inverno as ondas se propagam para Norte-Nordeste e nas demais
esta{\c{c}}{\~o}es do ano em dire{\c{c}}{\~o}es distintas.
Para explicarmos esta anisotropia na dire{\c{c}}{\~a}o de
propaga{\c{c}}{\~a}o, discutimos os resultados a partir da
teoria da filtragem de ondas pelos ventos atmosf{\'e}ricos, e das
poss{\'{\i}}veis fontes de gera{\c{c}}{\~a}o na baixa
atmosfera. Os principais resultados desta tese foram: as ondas
observadas sobre a regi{\~a}o Sul-Sudeste do Brasil est{\~a}o
possivelmente associadas com convec{\c{c}}{\~o}es intensas; a
anisotropia na dire{\c{c}}{\~a}o de propaga{\c{c}}{\~a}o
deve-se, em parte, {\`a} localiza{\c{c}}{\~a}o e a
varia{\c{c}}{\~a}o sazonal das fontes de gera{\c{c}}{\~a}o dos
TIDs; os TIDs noturnos s{\~a}o mais suscept{\'{\i}}veis a
filtragem do vento neutro do que os TIDs diurnos; os processos
dissipativos tais como a viscosidade molecular e a difusividade
t{\'e}rmica tamb{\'e}m exercem influ{\^e}ncia tanto nos TIDs
diurnos quanto noturnos. ABSTRACT: Travelling Ionospheric
Disturbances (TIDs) are common phenomena in the ionosphere, which
usually induces disturbances in atmospheric airglow layers and in
the Total Electron Content (TEC). In this work, we analized
nocturnal TIDs, observed by OI 630,0 emission at Cachoeira
Paulista (22.4\${o}\$S, 45.0\${o}\$W), S{\~a}o Paulo. The
observations were carried out from June 2013 to December 2015, and
we found 58 TIDs. An extensive study of diurnal TIDs was conducted
using detrend TEC maps, over South-Southeast region of Brazil
(15-30\${o}\$S, 35-55\${o}\$W). The analysed data were
obtained by three GNSS receivers networks between December 2012
and February 2016. In total, were observed 826 events of TIDs.
Observational evidence of TIDs originating in auroral regions was
also been observed. The major contribution of this work was to
find out the main characteristics of the TIDs parameters in terms
of horizontal wavelength, phase velocity, period and propagation
direction in the South- Southeast sector of Brazil in which an
anisotropy was observed in the propagation direction of the waves;
during winter the waves propagates to North-Northeast while in the
other seasons to different directions. To explain this
characteristic, we discuss the anisotropy in terms of wind
filtering theory and tropospheric wave sources. The main result of
this thesis were: the TIDs are mainly generated by intense
tropospheric convections; the observed anisotropy in the
propagation direction may be due to the locations of the wave
sources; the nightime TIDs are more susceptible to neutral wind
filtering process than the daytime TIDs; dissipative processes
such as molecular viscosity and thermal diffusivity may also
influence both daytime and nighttime TIDs.",
affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)}",
committee = "Alves, Maria Virg{\'{\i}}nia (presidente) and Takahashi, Hisao
(orientador) and Wrasse, Cristiano Max (orientador) and Dal Lago,
Alisson and Kherani, Esfhan Alam and Muella, Marcio Tadeu de Assis
Honorato and Silva, Igo Paulino da",
englishtitle = "Study of travelling ionospheric disturbances in the South America
continent",
language = "pt",
pages = "199",
ibi = "8JMKD3MGP3W34P/3NCM7GP",
url = "http://urlib.net/ibi/8JMKD3MGP3W34P/3NCM7GP",
targetfile = "publicacao.pdf",
urlaccessdate = "20 abr. 2024"
}