Linear vs. nonlinear methods for detecting magnetospheric and ionospheric current systems patterns

We apply both the EOF and the MEMD methods to characterize spatial patterns of external vertical component of the geomagnetic field at low and middle latitudes as a function of geomagnetic activity level recorded by Swarm constellation during a period of two years from 1 April 2014 to 31 March 2016. We show how MEMD method is particularly suitable to avoid misleading results produced by the EOF one. Indeed, the MEMD method extracts the main modes which contribute to the determination of the geomagnetic field of external origin during quiet periods by using few modes to recognize the different contributions coming from sources external to the Earth in the magnetic signal and to reproduce the realistic equivalent currents responsible for the recorded magnetic field variations. This study is an example of the potential of MEMD method which can be used to give new insights into the analysis of the different sources responsible of the geomagnetic field of external origin and, at the same time, it can be used as a good filter in the analysis of the geomagnetic field of external origin permitting us to separate the ionospheric contribution from the magnetospheric one [1,2]

Presenter’s name
T. Alberti , F. Giannattasio , P. De Michelis , G. Consolini
Date of the meeting