@Article{BolzanTarPilFagRos:2013:MuAnVe,
               author = "Bolzan, Mauricio J. A. and Tardelli, A. and Pillat, V. G. and 
                         Fagundes, P. R. and Rosa, Reinaldo Roberto",
          affiliation = "Laborat{\'o}rio de F{\'{\i}}sica, Universidade Federal de 
                         Goi{\'a}s (UFG), Jata{\'{\i}}, GO, Brazil; Laborat{\'o}rio de 
                         F{\'{\i}}sica e Astronomia, IPandD, Universidade Do Vale Do 
                         Para{\'{\i}}ba (UNIVAP), S{\~a}o Jos{\'e} dos Campos, SP, 
                         Brazil and Laborat{\'o}rio de F{\'{\i}}sica e Astronomia, 
                         IP\&D, Universidade Do Vale Do Para{\'{\i}}ba (UNIVAP), 
                         S{\~a}o Jos{\'e} dos Campos, SP, Brazil and Laborat{\'o}rio de 
                         F{\'{\i}}sica e Astronomia, IP\&D, Universidade Do Vale Do 
                         Para{\'{\i}}ba (UNIVAP), S{\~a}o Jos{\'e} dos Campos, SP, 
                         Brazil and Laborat{\'o}rio de F{\'{\i}}sica e Astronomia, 
                         IP\&D, Universidade Do Vale Do Para{\'{\i}}ba (UNIVAP), 
                         S{\~a}o Jos{\'e} dos Campos, SP, Brazil and Laborat{\'o}rio 
                         Associado de Computa{\c{c}}{\~a}o e Matem{\'a}tica Aplicada 
                         (LAC), Instituto Nacional de Pesquisas Espaciais (INPE), S{\~a}o 
                         Jos{\'e} dos Campos, SP, Brazil",
                title = "Multifractal analysis of vertical total electron content (VTEC) at 
                         equatorial region and low latitude, during low solar activity",
              journal = "Annales Geophysicae",
                 year = "2013",
               volume = "31",
               number = "1",
                pages = "127--133",
             keywords = "fractal analysis, geomagnetic field, GPS, ionosphere, solar 
                         activity, ultraviolet radiation, Brazil, Sao Jose dos Campos, Sao 
                         Paulo [Brazil].",
             abstract = "This paper analyses the multifractal aspects of the GPS data 
                         (measured during a period of low solar activity) obtained from two 
                         Brazilian stations: Bel{\'e}m (01.3°S, 48.3°W) and S{\~a}o 
                         Jos{\'e} dos Campos (SJC) (23.2°S, 45.9°W). The results show that 
                         the respective geographic sites show important scaling differences 
                         as well as similarities when their multifractal signatures for 
                         vertical total electron content (VTEC) are compared. The 
                         <I>f</I>(\α) spectra have a narrow shape for great scales, 
                         which indicates the predominance of deterministic phenomena, such 
                         as solar rotation (27 days) over intermittent phenomena. 
                         Furthermore, the <I>f</I>(\α) spectra for both sites have a 
                         strong multifractality degree at small scales. This strong 
                         multifractality degree observed at small scales (1 to 12 h) at 
                         both sites is because the ionosphere over Brazil is a 
                         non-equilibrium system. The differences found were that Bel{\'e}m 
                         presented a stronger multifractality at small scales (1 h to 12 h) 
                         compared with SJC, particularly in 2006. The reason for this 
                         behaviour may be associated with the location of Bel{\'e}m, near 
                         the geomagnetic equator, where at this location the actions of 
                         X-rays, ultraviolet, and another wavelength from the Sun are more 
                         direct, strong, and constant throughout the whole year. Although 
                         the SJC site is near ionospheric equatorial anomaly (IEA) peaks, 
                         this interpretation could explain the higher values found for the 
                         intermittent parameter \μ for Bel{\'e}m compared with SJC. 
                         Bel{\'e}m also showed the presence of one or two flattening 
                         regions for <I>f</I>(\α) spectra at the same scales 
                         mentioned before. These differences and similarities also were 
                         interpreted in terms of the IEA content, where this phenomenon is 
                         an important source of intermittence due the presence of the VTEC 
                         peaks at ±20° geomagnetic latitudes.",
                  doi = "10.5194/angeo-31-127-2013",
                  url = "http://dx.doi.org/10.5194/angeo-31-127-2013",
                 issn = "0992-7689",
                label = "scopus",
             language = "en",
           targetfile = "angeo-31-127-2013.pdf",
                  url = "www.ann-geophys.net/31/127/2013/",
        urlaccessdate = "10 maio 2024"
}