Analysis of Ionospheric GNSS TEC Measurements During the Annular Solar Eclipse Observed at Horseshoe Island, Antarctica

The short-term reduction in solar high-energy radiation during solar eclipses triggers complex responses in the upper atmosphere. In polar regions, ionospheric variability is strongly governed by fluctuations in solar wind conditions and the orientation of the interplanetary magnetic field. Therefore, evaluating eclipse-induced forcing separately from simultaneous space weather effects requires a specialized analytical approach. This study aims to investigate the ionospheric responses that may emerge during the observation of the annular solar eclipse on February 17, 2026, over Antarctica, under partial obscuration conditions at Horseshoe Island. Within the scope of the study, Total Electron Content (TEC) time series derived from data obtained via low-cost GNSS receivers will be analyzed. During the analysis process, necessary calibration controls, data filtering, and systematic error correction steps will be implemented, and the results will be compared with reference data provided by the TUR 1 and TUR 2 GNSS networks. The acquired GNSS data will be processed using Gopi Seemala software. In addition to the generated time-series plots, wavelet analysis will be employed to identify fluctuations across different time-frequency scales. Time-frequency coherences between variables will be examined in detail by utilizing simultaneous atmospheric parameter measurements and space weather indices (IMF Bz, Vsw, Kp, AE, and SYM-H) during the eclipse. This pioneering study, conducted at Horseshoe Island where the Turkish Scientific Research Camp is located, aims to establish a reliable observation and analysis framework for the holistic evaluation of the short- term effects of partial obscuration on the ionosphere within the regional space weather context under Antarctic conditions. “This study was supported by projects numbered “124G057” and “118Y322” within the scope of TÜBİTAK Kutup (Polar) 1001 program.” The authors thanks TUBITAK for their support.

Keywords: Antarctica, Ionosphere, Total Electron Content, Annular Solar Eclipse, Low-cost GNSS