University of Oulu

Vokhmyanin, M., Apatenkov, S., Gordeev, E., Andreeva, V., Partamies, N., Kauristie, K., & Juusola, L. (2021). Statistics on omega band properties and related geomagnetic variations. Journal of Geophysical Research: Space Physics, 126, e2021JA029468.

Statistics on omega band properties and related geomagnetic variations

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Author: Vokhmyanin, M.1,2; Apatenkov, S.3; Gordeev, E.1;
Organizations: 1Department of Earth's Physics, St. Petersburg State University, St. Petersburg, Russia
2Space Climate Research Group, Space Physics and Astronomy Research Unit, University of Oulu, Oulu, Finland
3Department of Earth's Physics, St. Petersburg State University, St. Petersburg, RussiaDepartment of Earth's Physics, St. Petersburg State University, St. Petersburg, Russia
4Department of Geophysics, University Centre in Svalbard, Longyearbyen, Norway
5Finnish Meteorological Institute, Helsinki, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.4 MB)
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Language: English
Published: American Geophysical Union, 2021
Publish Date: 2022-01-03


Using the list of the omega structures based on the Magnetometers-Ionospheric Radars-All-sky Cameras Large Experiment network (Partamies et al., 2017,, we obtained a number of important statistical characteristics describing the surface magnetic field. Based on 438 events, typical magnetic variations associated with the passage of the single omega were obtained. The typical variation, obtained using superposed epoch analysis, is associated with a local bending of the westward electrojet and statistically confirms the distribution of equivalent ionospheric currents obtained in earlier observations of single omegas. It was found that during low and moderate geomagnetic activity, the appearance of the omega structures in the dark morning magnetic local time (MLT) sector results in two times higher than average dB/dt on the ground surface. Also, the velocity, direction of movement, and area of omega structures were calculated. It is shown that faster and bigger omegas produce larger time derivatives of the ground magnetic field. Furthermore, we demonstrate that in the 03–08 MLT sector, superposed magnetic variations for the arbitrary events of very high time derivatives |dB/dt| > 10 nT/s, reveal magnetic signatures similar to omegas. Our findings, together with the results described by Apatenkov et al. (2020,, emphasize the important role of omega structures in the formation of large geomagnetically induced currents.

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Series: Journal of geophysical research. Space physics
ISSN: 2169-9380
ISSN-E: 2169-9402
ISSN-L: 2169-9380
Volume: 126
Issue: 7
Article number: e2021JA029468
DOI: 10.1029/2021JA029468
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: The study by M. Vokhmyanin, V. Andreeva, S. Apatenkov, and E. Gordeev was supported by Russian Science Foundation grant 19-77-10016. The study of L. Juusola and K. Kauristie was supported by the Academy of Finland (decision 314670).
Copyright information: © 2021. American Geophysical Union.