Speaker
Description
A dataset of 102 geomagnetic sudden commencements (SC) observed between 2020 and 2024 was analyzed using ground measurements from eight geomagnetic observatories located at middle and low latitudes. The network includes three observatories in Italy, together with one in India, one in Australia, and three in the region associated with the South Atlantic Anomaly (SAA). For each event, we examined the ground magnetic steady state response to solar wind dynamic pressure variations, normalized by the SYMH index. We investigated its dependence on local time; the location of the Italian observatories also allowed an analysis of the latitudinal dependence. We found that in the Italian sector the response is systematically lower in the morning hours compared to the evening, and this contrast becomes more pronounced at higher latitudes. A similar morning reduction is also identified at the Indian and Australian sites. In contrast, the SAA observatories show a distinct behaviour, characterized by a pronounced maximum response around the magnetic local noon.
