Journal cover Journal topic
Annales Geophysicae An open-access journal of the European Geosciences Union
Ann. Geophys., 34, 1069-1084, 2016
http://www.ann-geophys.net/34/1069/2016/
doi:10.5194/angeo-34-1069-2016
© Author(s) 2016. This work is distributed
under the Creative Commons Attribution 3.0 License.
Regular paper
22 Nov 2016
Identification of the different magnetic field contributions during a geomagnetic storm in magnetospheric and ground observations
Tommaso Alberti1, Mirko Piersanti2, Antonio Vecchio3, Paola De Michelis4, Fabio Lepreti1, Vincenzo Carbone1, and Leonardo Primavera1 1Department of Physics, University of Calabria, Rende (CS), Italy
2Department of Physical and Chemical Sciences, University of L'Aquila, Italy
3LESIA-Observatoire de Paris, 5 place Jules Janssen, 92190 Meudon, France
4Section of Geomagnetism, Aeronomy and Enviromental Geophysics, Istituto Nazionale di Geofisica e Vulcanologia, Roma, Italy
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.

Citation: Alberti, T., Piersanti, M., Vecchio, A., De Michelis, P., Lepreti, F., Carbone, V., and Primavera, L.: Identification of the different magnetic field contributions during a geomagnetic storm in magnetospheric and ground observations, Ann. Geophys., 34, 1069-1084, doi:10.5194/angeo-34-1069-2016, 2016.
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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.
We investigate the time variation of the magnetospheric and Earth's magnetic field during both...
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