EQUINOCTIAL ASYMMETRY IN GEOMAGNETIC ACTIVITY IN AURORAL AND SUBAURORAL REGIONS Page No: 1665-1674

Falayi, EO, and Beloff, N

Keywords: Time derivatives of geomagnetic fields, auroral and subauroral region, geomagnetic disturbances, geomagnetically induced current (GIC), seasons

Abstract: Geomagnetically induced current (GIC) affect the normal operation of technological systems and are manifestations at ground level of space weather. The maximum GIC values are proxy to the maximum value of time derivatives of the horizontal field (dH/dt). 264 substorms events were obtained from IMAGE magnetometer data from Northern Europe, using Dst to determine the substorm events of varying strengths (from -90nT up to -1800nT) from 1992-2007, and were statistically analysed. In this study we found the maximum time derivatives of the horizontal magnetic field to be statistically significant in October at auroral and subauroral regions. Seasonal variations are also seen, Autumn being more geomagnetically active than other seasons. Our result shows a high correlation of 0.886 and 0.854 in auroral and subauroral regions between the max dH/dt and max AE index. The test of correlation between dH/dt and measured ionospheric response (AE) shows a close relationship between dH/dt and geomagnetic disturbance, and which could improve our space weather prediction systems.



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