Automatic estimation of dynamics of ionospheric disturbances with 1–15 minute lifetimes as derived from ISTP SB RAS fast chirp-ionosonde data

Abstract

We propose and test a method of analyzing ionograms of vertical ionospheric sounding, which is based on detecting deviations of the shape of an ionogram from its regular (averaged) shape. We interpret these deviations in terms of reflection from the electron density irregularities at heights corresponding to the effective height. We examine the irregularities thus discovered within the framework of a model of a localized uniformly moving irregularity, and determine their characteristic parameters: effective heights and observed vertical velocities. We analyze selected experimental data for three seasons (spring, winter, autumn) obtained nearby Irkutsk with a fast chirp ionosonde of ISTP SB RAS in 2013–2015. The analysis of six days of observations conducted in these seasons has shown that in the observed vertical drift of the irregularities there are two characteristic distributions: wide velocity distribution with nearly 0 m/s mean and with standard deviation of ~250 m/s and narrow distribution with nearly –160 m/s mean. The analysis has demonstrated the effectiveness of the proposed algorithm for the automatic analysis of vertical sounding data with high repetition rate.