Estudos de dist?rbios ionosf?ricos propagantes de larga escala (LSTID?S) na regi?o equatorial durante grandes tempestades magn?ticas: estudo de casos

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Previous issue date: 2014-08-28 / Os Dist?rbios Ionosf?ricos Propagantes (TID?s) s?o irregularidades no plasma ionosf?rico
propagando-se com velocidades da ordem de dezenas a poucas centenas de metros por
segundo. Nesse trabalho, detectamos e caracterizamos os do tipo LSTID?s (Large scale
Travelling Ionospheric Disturbances) em baixas latitudes durante intensas tempestades
geomagn?ticas e sua propaga??o sobre o setor brasileiro. Esse trabalho apresenta-se como o
primeiro a relatar, de forma sistematizada, propaga??es de ondas de gravidade sobre NatalRN.
Utilizamos registros ionosf?ricos obtidos a partir de digissondas do tipo CADI
(Canadian Advanced Digital Ionosonde) localizada em Natal-RN e do tipo DSP (Digisonde
Portable Souder) localizadas em Cachoeira Paulista-SP, Fortaleza-CE e S?o Lu?s-MA,
adotando uma s?rie de dados de 12 anos colhidos pelo Instituto Nacional de Pesquisas
Espaciais (INPE). Relacionamos tanto dias calmos, os quais antecediam as tempestades,
quanto dias geomagneticamente perturbados, durante os anos de 2000 e 2012, englobando um
per?odo de m?xima e m?nima atividade solar. Apresentando as varia??es ocorridas nas
densidades eletr?nicas da regi?o F da ionosfera sobre o setor brasileiro, principalmente
pr?ximo ao equador (Natal, Fortaleza e S?o Lu?s), causadas por dist?rbios ionosf?ricos
propagantes na regi?o equatorial durante intensas tempestades geomagn?ticas. Como
sabemos, de acordo com a literatura, nessa ?rea o fen?meno contribui positivamente para o
surgimento de LSTID?s na regi?o auroral, que podem se deslocar para a regi?o equatorial
onde poucos casos t?m sido documentados e estudados de forma sistematizada. A partir da
observa??o de assinaturas de TID?s em registros de ionogramas foi realizado um estudo da
morfologia desses eventos e comparados com as principais caracter?sticas de onda durante
grandes tempestades magn?ticas, isto ? DST < (-200 nT) e KP > 6. Com isso, obtivemos suas
caracter?sticas principais, como: per?odo, comprimento de onda vertical, velocidade de fase e
velocidade de propaga??o, bem como o atraso desses dist?rbios em rela??o ao in?cio das
tempestades magn?ticas para o setor brasileiro. / The Ionospheric Disturbances ? TIDs ? are irregularities on the ionospheric plasma
propagating in speeds in the order of tens to a few hundreds of meters per second. This
present study detected and characterized the TIDs of LSTIDs (Large Scale Travelling
Ionospheric Disturbance) type at low latitudes during intense geomagnetic storms and its
propagation over the Brazilian sector. This work also shows as being the first to report
systematically propagation of gravity waves over Natal. For this purpose, we used ionospheric
records obtained from type of digisonde CADI (Canadiam Advanced Digital Ionosonde)
located in Natal and the type DSP (Digisonde Portable Souder) located in Cachoeira Paulista,
Fortaleza and S?o Luis, whereupon we used a dataset of 12 years collected by INPE (National
Institute of Space Research). In this study, both calm days, that preceded the storms, and the
geomagnetically disturbed days were related during the years 2000 and 1012, which cover a
period of maximum and minimum solar activity. And it is presented the variations that
happened in the electron density from region F of the ionosphere over the Brazilian sector,
especially near the Equator (Natal, Fortaleza and S?o Luis), caused by ionospheric
disturbances in the equatorial region during intense geomagnetic storms, because, as we know
of the literature in this area, this phenomenon contributes positively to the emergence of
LSTIDs in the auroral region, which may move to the equatorial region where a few cases
have been documented and studied systematically. From the observation of signatures if TIDs
in ionogram records, a study of the morphology of these events was performed and compared
with the main characteristics of the wave of this phenomenon during great magnetic storms,
i.e., DST <(-200 nT) and KP > 6. Thus, we obtained the main characteristics of TIDs over our
region, i.e., period, vertical wavelength, phase and propagation speed, as well as the delay of
these disturbances compared to the beginning of the magnetic storms to the Brazilian Sector.

Identiferoai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/20066
Date28 August 2014
CreatorsCazuza, Elio Pessoa
Contributors10849572487, http://lattes.cnpq.br/0043059721601657, Bonelli, Enivaldo, 60025123815, http://lattes.cnpq.br/7116158054409962, Souza, Jonas Rodrigues de, 35820977491, http://lattes.cnpq.br/3848282835080232, Borba, Gilvan Luiz
PublisherUniversidade Federal do Rio Grande do Norte, PROGRAMA DE P?S-GRADUA??O EM CI?NCIAS CLIM?TICAS, UFRN, Brasil
Source SetsIBICT Brazilian ETDs
LanguagePortuguese
Detected LanguageEnglish
Typeinfo:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis
Sourcereponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN
Rightsinfo:eu-repo/semantics/openAccess

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