TERRAPUB Earth, Planets and Space

Earth Planets Space, Vol. 64 (No. 6), pp. 531-543, 2012

A new global empirical model of the electron temperature with the inclusion of the solar activity variations for IRI

V. Truhlik1, D. Bilitza2,3, and L. Triskova1

1Institute of Atmospheric Physics, ASCR, Prague, 14131, Czech Republic
2George Mason University, Space Weather Laboratory, Fairfax, VA 22030, U.S.A.
3Goddard Space Flight Center, Heliospheric Physics Laboratory, Code 672, Greenbelt, MD 20771, U.S.A.

(Received August 17, 2010; Revised September 10, 2011; Accepted October 8, 2011; Online published July 27, 2012)

Abstract: A data-base of electron temperature (Te) comprising of most of the available LEO satellite measurements in the altitude range from 350 to 2000 km has been used for the development of a new global empirical model of Te for the International Reference Ionosphere (IRI). For the first time this will include variations with solar activity. Variations at five fixed altitude ranges centered at 350, 550, 850, 1400, and 2000 km and three seasons (summer, winter, and equinox) were represented by a system of associated Legendre polynomials (up to the 8th order) in terms of magnetic local time and the earlier introduced invdip latitude. The solar activity variations of Te are represented by a correction term of the Te global pattern and it has been derived from the empirical latitudinal profiles of Te for day and night (Truhlik et al., 2009a). Comparisons of the new Te model with data and with the IRI 2007 Te model show that the new model agrees well with the data generally within standard deviation limits and that the model performs better than the current IRI Te model.
Key words: Electron temperature, ionosphere, plasmasphere, empirical models, International Reference Ionosphere.

Corresponding author E-mail: vtr@ufa.cas.cz

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