Volumes and Issues      Contents of Issue 3     
Ann. Geophys., 26, 593-598, 2008
www.ann-geophys.net/26/593/2008/
© European Geosciences Union 2008


Long-term trends in foF2: their estimating and origin

J. Laštovička1, X. Yue2,3,4, and W. Wan2
1Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic, 14131 Prague, Czech Republic
2Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
3Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
4Graduate School, Chinese Academy of Sciences, Beijing 100049, China

Abstract. This paper deals with two problems, methods of foF2 trend determination and origin of trends in foF2, both being controversial in current literature. We found that various regression-based methods and artificial neural network-based method of Yue et al. (2006) provided comparable results within uncertainties caused mainly by various ways of removing/suppressing the dominant solar cycle effect. The role of geomagnetic activity in the observed trends in foF2 was probably substantial and might be still even rather dominant in the last quarter of the 20th century.

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