@Article{KlippPeSoPaFaCa:2020:IoToEl,
author = "Klipp, Telmo dos Santos and Petry, Adriano and Souza, Jonas
Rodrigues de and Paula, Eurico Rodrigues de and Falc{\~a}o,
Gabriel Sandim and Campos Velho, Haroldo Fraga de",
affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto
Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de
Pesquisas Espaciais (INPE)} and {Instituto Nacional de Pesquisas
Espaciais (INPE)} and {Instituto Nacional de Pesquisas Espaciais
(INPE)} and {Instituto Nacional de Pesquisas Espaciais (INPE)}",
title = "Ionosonde total electron content evaluation using International
Global Navigation Satellite System Service data",
journal = "Annales Geophysicae",
year = "2020",
volume = "38",
number = "2",
pages = "347--357",
month = "mar.",
abstract = "In this work, a period of 2 years (2016-2017) of ionospheric total
electron content (ITEC) from ionosondes operating in Brazil is
compared to the International GNSS (Global Navigation Satellite
System) Service (IGS) vertical total electron content (vTEC) data.
Sounding instruments from the National Institute for Space
Research (INPE) provided the ionograms used, which were filtered
based on confidence score (CS) and C-Level flag evaluation.
Differences between vTEC from IGS maps and ionosonde IBC were
accumulated in terms of root mean squared error (RMSE). As
expected, we noticed that the ITEC values provided by ionosondes
are systematically underestimated, which is attributed to a
limitation in the electron density modeling for the ionogram
topside that considers a fixed scale height, which makes density
values decay too rapidly above similar to 800 km, while IGS takes
in account electron density from GNSS stations up to the satellite
network orbits. The topside density profiles covering the
plasmasphere were re-modeled using two different approaches: an
optimization of the adapted alpha-Chapman exponential decay that
includes a transition function between the F2 layer and
plasmasphere and a corrected version of the NeQuick topside
formulation. The electron density integration height was extended
to 20 000 km to compute TEC. Chapman parameters for the F2 layer
were extracted from each ionogram, and the plasmaspheric scale
height was set to 10 000 km. A criterion to optimize the
proportionality coefficient used to calculate the plasmaspheric
basis density was introduced in this work. The NeQuick variable
scale height was calculated using empirical parameters determined
with data from Swarm satellites. The mean RMSE for the whole
period using adapted alpha-Chapman optimization reached a minimum
of 5.32 TECU, that is, 23 % lower than initial ITEC errors, while
for the NeQuick topside formulation the error was reduced by 27
%.",
doi = "10.5194/angeo-38-347-2020",
url = "http://dx.doi.org/10.5194/angeo-38-347-2020",
issn = "0992-7689",
language = "en",
urlaccessdate = "27 abr. 2024"
}