Variability of the topside thermal plasma parameters during a period of high solar activity for IRI Original Research Article

The variability of the electron temperature, ion composition and the upper transition height in the topside ionosphere as given bythe IRI models is studied. A variability index based on quartiles is introduced and its global distribution is presented in the form of contour plots for the individual parameters. The obtained global distribution of the variability index described by the associated Legendre polynomials could be used as a complement to the previously developed global models.