A Case Study of Spatio-Temporal Analysis of Global Ionosphere Maps Using Multi-Channel Singular Spectrum Analysis

Vertical Total Electron Content (VTEC), derived from global GNSS tracking networks, such as the International GNSS Service (IGS), is used to generate the Global Ionosphere Maps (GIMs). These ionospheric time-series exhibit composed periodic patterns. There are diurnal and annual signals; moreover, 27 days can be seen in the ionosphere maps, representing irregularities related to the solar revolution period. In contrast to previous parametric methods for extracting diurnal and modulated signals, we use Multi-Channel Singular Spectrum Analysis (MSSA) as a non-parametric method that is a multi-variate variant of the Singular Spectrum Analysis (SSA). In this work, we demonstrate the capabilities of a non-parametric approach in extracting superimposed signals from the Global Ionosphere Maps (GIMs), capturing both their temporal periodicity and spatial structures.