The application of interactive statistical methods to the electron content of the ionosphere

Ionospheric electron-content data are investigated statistically. Data for the period since 1974 were obtained by means of Faraday rotation measurements on GEO satellites and differential Doppler measurements of polar-orbiting satellites and compiled in a computer data base at Graz. The quality and general features of the data are analyzed; the need for more sophisticated statistical methods is demonstrated; and the results are presented in extensive tables and graphs, including box plots (showing seasonal changes and the effects of solar activity at a given latitude) and two-dimensional histograms (showing seasonal, solar-activity, and day-to-night variations in the medium- and large-scale latitudinal structures).