Abstract Geomagnetic indices can be used to quantify variations in geomagnetic activity caused by Sun‐Earth interactions across the magnetosphere and ionosphere. The global Kp index is widely used as a global geomagnetic indicator, but it is based mostly on the Northern Hemisphere with no contributions from South American observatories. As a result, regional features such as the South American Magnetic Anomaly (SAMA) are not represented. To address this limitation, the regional Ksa index was developed using magnetometer data collected from the Embrace Magnetometer Network (Embrace MagNet), which consists exclusively of South American stations. This study analyzes data from Ksa and Kp and introduces two additional hybrid indices, Kp * and Ksa *. The Kp * index uses global data from the International Real‐time Magnetic Observatory Network processed with the Embrace MagNet algorithm, while the Ksa * index applies the Finnish Meteorological Institute algorithm to South American data. The analysis was conducted over the year 2020, a period characterized by low solar activity, to investigate the behavior of the indices under quiet conditions during three seasonal periods: December solstice, Equinoxes, and June solstice. Pearson correlation coefficients were computed to evaluate the relationships between the indices. The results revealed significant discrepancies between indices derived from different data sets, even when processed with the same algorithm. These differences emphasize the impact of regional geomagnetic phenomena such as the SAMA and Sq current variability.
Guizelli et al. (Sun,) studied this question.
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