TitleTraits of sub-kilometre F-region irregularities as seen with the Swarm satellites
Publication TypeJournal Article
Year of Publication2020
AuthorsAol, S, Buchert, S, Jurua, E
JournalAnnales Geophysicae
Volume38
Issue1
Pagination243 - 261
Date Published02/2020
Abstract

During the night, in the F-region, equatorial ionospheric irregularities manifest as plasma depletions observed by satellites, and they may cause radio signals to fluctuate. In this study, the distribution characteristics of ionospheric F-region irregularities in the low latitudes were investigated using 16 Hz electron density observations made by a faceplate which is a component of the electric field instrument (EFI) onboard Swarm satellites of the European Space Agency (ESA). The study covers the period from October 2014 to October 2018 when the 16 Hz electron density data were available. For comparison, both the absolute (dNe) and relative (dNeNe) density perturbations were used to quantify the level of ionospheric irregularities. The two methods generally reproduced the local-time (LT), seasonal and longitudinal distribution of equatorial ionospheric irregularities as shown in earlier studies, demonstrating the ability of Swarm 16 Hz electron density data. A difference between the two methods was observed based on the latitudinal distribution of ionospheric irregularities where (dNe) showed a symmetrical distribution about the magnetic equator, while dNeNe showed a magnetic-equator-centred Gaussian distribution. High values of dNe and dNeNe were observed in spatial bins with steep gradients of electron density from a longitudinal and seasonal perspective. The response of ionospheric irregularities to geomagnetic and solar activities was also investigated using Kp index and solar radio flux index (F10.7), respectively. The reliance of dNeNe on solar and magnetic activity showed little distinction in the correlation between equatorial and off-equatorial latitudes, whereas dNe showed significant differences. With regard to seasonal and longitudinal distribution, high dNe and dNeNe values were often found during quiet magnetic periods compared to magnetically disturbed periods. The dNe increased approximately linearly from low to moderate solar activity. Using the high-resolution faceplate data, we were able to identify ionospheric irregularities on the scale of only a few hundred of metres.

URLhttps://www.ann-geophys.net/38/243/2020/angeo-38-243-2020.pdf
DOI10.5194/angeo-38-243-2020
Short TitleAnn. Geophys.


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