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Long‐term trends in the total electron content
Author(s) -
Lastovicka Jan,
Urbar Jaroslav,
Kozubek Michal
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl075063
Subject(s) - tec , total electron content , environmental science , ionosphere , satellite , homogeneous , trend analysis , atmospheric sciences , meteorology , climatology , geodesy , mathematics , geography , geology , physics , statistics , statistical physics , geophysics , astronomy
The total electron content (TEC) is important among others for Global Navigation Satellite Systems/GPS signal propagation and applications. However, there is only one comprehensive analysis of TEC trends, and the resulted trends are not consistent with trends in other ionospheric parameters. Here we use the TEC data of Lean et al. (2011) and the JPL35 homogeneous TEC data series derived by Emmert et al. (2017). This analysis results in three main conclusions: (1) Too positive TEC trends by Lean et al. (2011) are caused by data problems in 1995–2001, particularly by too low Center for Orbit Determination data. (2) TEC reveals a weak negative trend at the edge of reliability; no trend or trend break is also possible; longer data series than 1994–2015 is required. (3) About 99% of the total variance of yearly average global TEC values is explained by variability of solar activity.