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