1. Relationship of the largest GIC during geomagnetic storms with solar wind-IMF parameters
- Author
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Nanan Balan, Wen-Bin Li, Zan-Yang XING, R. Skoug, V. Manu, Li-Kai Liang, and Qing-He Zhang
- Abstract
The association of GIC (geomagnetically induced current) with various solar and geophysical conditions has been known. However, what determines the time of occurrence and amplitude of the largest GIC during geomagnetic storms, which during extreme storms can cause sudden damage of vulnerable utility systems, is not yet known. We address this important question by analyzing the GIC data measured in Finland for 21 years (1999–2019) during 106 geomagnetic activities (DstMin ≤-50 nT) at low, mid and high latitudes and the corresponding solar wind velocity V, dynamic pressure P, north-south component of interplanetary magnetic field (IMF Bz), and the products V×Bz and P×Bz. The results show for the first time that the largest GIC (≥ 10 A) occurs at the time of the largest -(V×Bz) in all seasons and solar activity levels with its time determined by the time of the largest -Bz and magnitude determined by both V and -Bz, except in one case. The two power outages happened in the 21-year period (06 November 2001 and 30 October 2003) also occurred at the UT time of the largest GICmax. The correlation of largest GICmax is also highest (0.92) with the largest -(V×Bz) at September equinox. The results highlight the importance of the single station GIC measurements and possibility of improving the forecasting of the rate of change of the local horizontal geomagnetic field (dH/dt) directly related to GIC.
- Published
- 2022
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