Statistical Features of the Time Series of Variations in the Critical Frequencies of the F2 Layer

Abstract

The features of a time series of variations in the critical frequencies of the ionospheric F2 layer have been studied out based on a large file of experimental data. The stationarity of the δfoF2 samples and relative variations in the critical frequency of the F2 layer with different time resolutions have been verified. Based on a statistical analysis of δfoF2 distribution curves obtained from monthly samples of data from seven stations over a three-year period, it is shown that the distribution law of the δfoF2 set is far from normal. A model with excess and asymmetry based on a Poisson random process is proposed as a means to interpret the experimental curves of probability density functions. The analysis suggests that the model based on Poisson noise is applicable for the statistical description and probability estimations of f₀F₂ variations with both 1-h and 5-min resolutions during heliospheric disturbances.