Superposed epoch analyses of geoelectric field disturbances in Japan in response to different geomagnetic activities

An increase in geomagnetically induced currents (GICs) is an inevitable result of geomagnetic field disturbances, and harmful to the power grid, particular, at high latitudes. At mid low latitudes, amplitude GICs is, general, small, but large-amplitude are often observed during magnetic storms. It importance understand major characteristics extreme values For geoelectric disturbances ΔE Kakioka (27.8° latitude) Japan 1996–2004, we performed superposed epoch analyses with respect three types disturbances: (a) storm sudden commencements (SSCs)/sudden impulses (SIs), (b) main phase storms, (c) bay disturbances. shown that SSCs/SIs storms equally important for causing Kakioka. thought be amplified when SIs and/or occur The maximum value tends correlated ΔH events, where horizontal component field. Assuming a quasi-linear relationship between valid, estimated substations SSCs/SIs, This scheme could applicable estimate roughly against forecast real-time manner.