Specific features of resonance structures in spectra of ULF electromagnetic noise at high latitudes (Barentsburg observatory)

Results of studying resonance spectral structures (RSSs) of the noise background in the frequency range 0.1–5 Hz at Barentsburg high-latitude observatory (Spitsbergen) are presented. It has been indicated that the diurnal variations in the observation probability and the long-term variations in the RSS observation cannot be explained by variations in the illumination of the ionosphere by the Sun. Based on an analysis of the magnetic measurements, the conclusion is drawn that a decrease in the RSS registration probability in daytime hours and in winter months are related to an increase in the variability of ionospheric parameters. It has been indicated that the RSS source is located in the region above an observation point, and the horizontal scale of this source is 100–200 km, which agrees with the concepts of the role of the ionospheric Alfvén resonator in the formation of RSS.