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Evaluation of Different Methods for Calculating the ROTI index over Brazilian Sector
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  • Carolina de Sousa do Carmo,
  • Clezio M. De Nardin,
  • Cosme Alexandre O. B. Figueiredo,
  • Laysa Cristina Araujo Resende,
  • Giorgio Arlan da Silva Picanço,
  • Paulo França Barbosa Neto,
  • Paulo Alexandre Bronzato Nogueira,
  • Juliano Moro,
  • Sony Su Chen
Carolina de Sousa do Carmo
National Institute for Space Research

Corresponding Author:[email protected]

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Clezio M. De Nardin
Instituto Nacional de Pesquisas Espaciais
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Cosme Alexandre O. B. Figueiredo
Instituto Nacional de Pesquisas Espaciais
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Laysa Cristina Araujo Resende
National Institute for Space Research/China-Brazil Joint Laboratory of Space Weather
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Giorgio Arlan da Silva Picanço
National Institute for Space Research
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Paulo França Barbosa Neto
National Institute for Space Research
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Paulo Alexandre Bronzato Nogueira
Federal Institute of Education, Science and Technology of Sao Paulo
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Juliano Moro
Southern Regional Space Research Center - CRS/COCRE/INPE
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Sony Su Chen
National Institute for Space Research
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Abstract

The ROTI index based on the variation of the TEC is used to detect and characterize the ionospheric irregularities. In the present work, we present a comparative study of five different methodologies to ROTI calculation in order to evaluate the most suitable for the Brazilian region. This was performed over three GNSS stations at different latitudes: São Luís (SALU, 2°31′ S, 44°16′ W; dip: -6.60°) that is located near the dip equator; Cachoeira Paulista (CHPI, 22°40’ S, 44°59’ W; dip: -35.99°) which set close to the southern crest of the EIA at low latitude); and Santa Maria (SMAR, 29° 41′ S, 53° 48′ W, dip: -43.51°) a low-to-mid latitude station close to center of the SAMA region. The period of analysis covered January and December 2015. Our results show that only one out of the five techniques proposed seems to be appropriated for ROTI construction in the Brazilian sector. Our results are supported by comparison of the ROTI with TEC maps obtained over Brazil, ionograms acquired at Fortaleza (FZA0M), SALU, and CHPI ionosonde stations, and All-Sky imagers collected at the São João do Cariri, and CHPI. In addition, we were able to observe the typical irregularities of the Brazilian ionosphere by using the ROTI which we have classified as EPB.
Aug 2021Published in Radio Science volume 56 issue 8. 10.1029/2020RS007140