@InProceedings{CarmoBeckCamaMoni:2018:CoDiTe,
author = "Carmo, Carolina de Sousa do and Becker Guedes, F{\'a}bio and
Camargo, P. O. and Monico, J. F. G.",
affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto
Nacional de Pesquisas Espaciais (INPE)} and {Universidade Estadual
Paulista (UNESP)} and {Universidade Estadual Paulista (UNESP)}",
title = "Comparison between different tec calculation techniques to
characterize the ionosphere in the brazilian sector",
year = "2018",
organization = "Latin American Conference on Space Geophysics, 11. (COLAGE)",
abstract = "The Total Electron Content (TEC) of the ionosphere can be
calculated by parameters observed by GPS receivers located in the
ground. As a result of the differential phase and group
calculation, the non-dispersive terms are canceled, leaving terms
due to biases of the satellites and the receiver together with the
ionospheric error contribution to the signal. The slant TEC (STEC)
corresponds to an arc of TEC for each satellite measured by a
given receiver. The combination of the various STECs observed by a
receiver using selected methods and mapping functions results in a
vertical TEC (VTEC) over the ground station. In this work, the
performance of three different VTEC calculation techniques, each
one using their own methods to eliminate biases and to obtain VTEC
from STECs, is evaluated to describe the ionosphere conditions in
the equatorial and low latitude regions in the Brazilian sector. I
order to do this, data from a station in the equatorial region,
Sao Luis, and a station in the southern crest of the Equatorial
Ionization Anomaly (EIA), Cachoeira Paulista, were used. The study
was made for a period of minimum solar activity (November 2008 to
October 2009) and one of maximum solar activity (November 2014 to
October 2015) and the seasonality of TEC along the year was also
studied. The three techniques used are: (I) the technique
developed by the University of Nagoya, Japan, and adjusted at the
National Institute of Space Research (INPE), Brazil, to be used by
the Brazilian Space Weather Program (EMBRACE), (II) a technique
developed at Boston College, USA, and (III) the method proposed by
the International Centre for Theoretical Physics (ICTP), Italy.
The evaluation of the TEC curves obtained showed that all three
techniques present results consistent with each other but with
some small divergences in certain periods. The three techniques
show the significant reduction of the TEC in the period of minimum
solar activity and during the winter in any condition of solar
activity. All techniques showed an increase in TEC at the station
under the crest of the EIA in the summer and during the equinoxes
due to the intensification of the fountain effect during the day
and the pre-reversion peak at the sunset. The large discrepancies
between the results obtained by the three techniques were observed
during the beginning of the night hours due to the presence of
ionospheric irregularities. The method used in INPE responds well
to the daily, seasonal and solar cycle variations of the TEC,
presenting, on several occasions, intermediate results with
respect to the other techniques in the Brazilian region, showing
to be suitable to be used by EMBRACE program to monitoring this
region.",
conference-location = "Buenos Aires, Argentina",
conference-year = "16-20 abr.",
language = "en",
urlaccessdate = "28 abr. 2024"
}