Publication Date:
2024-01-19
Description:
We investigate the response of the topside ionosphere, auroral and polar sectors, to the forcing of the geospace during September
2017. Specifically, we aim at characterizing such a response in terms of the involved spatial scales and of their intensification during
the different auroral and polar cap activity conditions experienced in the selected month, that is characterized by severe geomagnetic
storm conditions. For our purposes, we leverage on and compare various in situ plasma density data products provided by the Swarm
constellation of the European Space Agency (ESA). The spatio-temporal variability of the involved scales in the plasma density observation
is featured through the application of the Fast Iterative Filtering (FIF) signal decomposition technique and, for the first time in
the ionospheric field, of a FIF-derived dynamical spectrum called ‘‘IMFogram”. The instantaneous time-frequency representation provided
through the IMFogram illustrates the time development of the multi-scale processes with spatial and temporal resolutions higher
than those obtained with traditional signal processing techniques. To demonstrate this, the IMFogram is tested against Fast Fourier and
Continuous Wavelet Transforms. With our fine characterization, we highlight how scale cascading and intensification processes in the
plasma density observations follow the ionospheric currents activity, as depicted through the auroral activity and polar cap indices, and
through the field-aligned currents data product provided by Swarm.
Description:
Published
Description:
5490-5502
Description:
OSA3: Climatologia e meteorologia spaziale
Description:
JCR Journal
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
