@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 = "16 jun. 2024"
}