Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-03-10T21:45:20Z No. of bitstreams: 1 ElioPessoaCazuza_DISSERT.pdf: 2126001 bytes, checksum: 4fa47b05b18f49f1aa7cb69c7272dd79 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-03-17T23:16:07Z (GMT) No. of bitstreams: 1 ElioPessoaCazuza_DISSERT.pdf: 2126001 bytes, checksum: 4fa47b05b18f49f1aa7cb69c7272dd79 (MD5) / Made available in DSpace on 2016-03-17T23:16:07Z (GMT). No. of bitstreams: 1 ElioPessoaCazuza_DISSERT.pdf: 2126001 bytes, checksum: 4fa47b05b18f49f1aa7cb69c7272dd79 (MD5) 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.