Articles | Volume 34, issue 11
https://doi.org/10.5194/angeo-34-1069-2016
https://doi.org/10.5194/angeo-34-1069-2016
Regular paper
 | 
22 Nov 2016
Regular paper |  | 22 Nov 2016

Identification of the different magnetic field contributions during a geomagnetic storm in magnetospheric and ground observations

Tommaso Alberti, Mirko Piersanti, Antonio Vecchio, Paola De Michelis, Fabio Lepreti, Vincenzo Carbone, and Leonardo Primavera

Abstract. We used the empirical mode decomposition (EMD) to investigate the time variation of the magnetospheric and ground-based observations of the Earth's magnetic field during both quiet and disturbed periods. We found two timescale variations in magnetospheric data which are associated with different magnetospheric current systems and the characteristic diurnal orbital variation, respectively. On the ground we identified three timescale variations related to the solar-wind–magnetosphere high-frequency interactions, the ionospheric processes, and the internal dynamics of the magnetosphere. This approach is able to identify the different physical processes involved in solar-wind–magnetosphere–ionosphere coupling. In addition, the large-timescale contribution can be used as a local index for the identification of the intensity of a geomagnetic storm on the ground.

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Short summary
We investigate the time variation of the magnetospheric and Earth's magnetic field during both quiet and disturbed periods. We identify the timescale variations associated with different magnetospheric current systems, solar-wind–magnetosphere high-frequency interactions, ionospheric processes, and internal dynamics of the magnetosphere. In addition, we propose a new local index for the identification of the intensity of a geomagnetic storm on the ground.