Based on an expanded network of world magnetic observatory data, a comprehensive analysis of secular geomagnetic variations observed over a 100-year period has been carried out to determine the role of jerks in the formation of secular variations belonging to the high-frequency range of the spectrum of variations of the Earths main magnetic field. Jerks – sharp changes in the direction of the linear trend characteristic of time series of values of secular variations of the magnetic field generated in the Earths liquid core over decades – have been identified. Epochs of global jerks, manifesting on the scale of the entire Earths surface with an interval of about ten years, have been identified and their spherical harmonic models have been constructed. Analysis of the morphology of the global jerk fields confirmed the idea that their source are processes occurring in the Earths liquid core. Spectral analysis of series of secular variations, performed by the Fourier series decomposition method, made it possible to identify the main periods constituting the spectrum of secular variations with T 10 years. Taking into account the jerk phenomena showed that all identified periods of secular variations can be interpreted within the framework of the concept of geomagnetic jerks, stochastic in the variability of manifestation both in regional and temporal aspects. Based on the analysis of the results of the conducted comprehensive research, a hypothesis is put forward that the dynamics of the Earths main magnetic field, within centennial intervals, is formed due to the spatio-temporal superposition of global jerks caused by a sharp restructuring of the flow system on the surface of the Earths liquid core.
Simonyan et al. (Wed,) studied this question.