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Long-term trends in the total electron content

SYSNO ASEP	0478482
Document Type	J - Journal Article
R&D Document Type	Journal Article
Subsidiary J	Článek ve WOS
Title	Long-term trends in the total electron content
Author(s)	Laštovička, Jan (UFA-U)_{RID, ORCID} Urbář, Jaroslav (UFA-U)_{RID, ORCID} Kozubek, Michal (UFA-U)_{RID, ORCID}
Number of authors	3
Source Title	Geophysical Research Letters. - : Wiley - ISSN 0094-8276 Roč. 44, č. 16 (2017), s. 8186-8172
Number of pages	5 s.
Publication form	Print - P
Language	eng - English
Country	US - United States
Keywords	total electron content ; long-term trend ; solar control
Subject RIV	DG - Athmosphere Sciences, Meteorology
OECD category	Climatic research
R&D Projects	GA15-03909S GA ČR - Czech Science Foundation (CSF)
Institutional support	UFA-U - RVO:68378289
UT WOS	000410658800009
EID SCOPUS	85028333353
DOI	10.1002/2017GL075063
Annotation	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. Plain Language Summary The total electron content (TEC) is a number of free electrons in unit column throughout the ionosphere. It is important as global ionospheric characteristic and also for the GPS signal propagation and applications to positioning. The ionosphere is changing on long-term scale mainly due to the increasing concentration of greenhouse gases in the atmosphere. However, there is only one comprehensive analysis of TEC trends, and the resulted trends are not consistent with trends in other ionospheric parameters. Our analysis shows that (1) too positive TEC trends by Lean et al. (2011) are caused by data problems in 1995-2001, which were not known in 2011. (2) TEC reveals a weak negative trend at the edge of reliability, not a positive trend.
Workplace	Institute of Atmospheric Physics
Contact	Kateřina Adamovičová, adamovicova@ufa.cas.cz, Tel.: 272 016 012 ; Kateřina Potužníková, kaca@ufa.cas.cz, Tel.: 272 016 019
Year of Publishing	2018

Number of the records: 1