Schumann resonance as a remote sensor of lower ionosphere and global thunderstorms as based on the long-term observations at Antarctic and Arctic stations

Abstract

We evaluate the impact of solar activity on the global ionosphere and the position of world thunderstorms by analyzing the peak frequency of the first Schumann resonance (SR) mode in the simultaneous records of the horizontal magnetic field components at the high-latitude observatories in the Southern and Northern hemispheres. The long-term monitoring was conducted at the Ukrainian Antarctic Station (UAS) “Akademik Vernadsky” (geographic coordinates: 65.25° S and 64.25° W) and the SOUSY Arctic Svalbard observatory (78.15° N and 16.05° E). A specialized technique was applied to process observational data that exploits the half-sum and semi-difference of the peak frequencies measured simultaneously at these observatories. This approach enables the separation and quantification of the impact of solar activity on the effective height of the lower ionosphere and the distance to the global thunderstorms. The following findings are demonstrated: (i) Alterations in the position of global thunderstorms can be separated from modifications of the lower ionosphere height; (ii) The employment of pivoted vertical profile of the middle atmosphere conductivity indicates that an increase occurs of the upper characteristic height h_L of the lower ionosphere during the decline in the solar activity. (iii) Kilometer-scale changes in the ionospheric height are linked to variations in the solar activity, and this effect is accompanied by minute (approximately 1° of latitude) displacements of global thunderstorms.