University of Oulu

Macotela, E. L., Clilverd, M., Manninen, J., Moffat‐Griffin, T., Newnham, D. A., Raita, T., & Rodger, C. J. ( 2019). D‐region high‐latitude forcing factors. Journal of Geophysical Research: Space Physics, 124, 765– 781. https://doi.org/10.1029/2018JA026049

D‐region high‐latitude forcing factors

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Author: Macotela, Edith L.1; Clilverd, Mark2; Manninen, Jyrki1;
Organizations: 1Sodankylä Geophysical Observatory, University of Oulu, Sodankylä, Finland
2British Antarctic Survey (UKRI), Cambridge, UK
3Department of Physics, University of Otago, Dunedin, New Zealand
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 3.2 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe2019042613376
Language: English
Published: American Geophysical Union, 2019
Publish Date: 2019-01-12
Description:

Abstract

The subionospheric very low frequency (VLF) radio wave technique provides the possibility of investigating the response of the ionospheric D‐region to a diversity of transient and long‐term physical phenomena originating from above (e.g., energetic particle precipitation) and from below (e.g., atmospheric waves). In this study, we identify the periodicities that appear in VLF measurements and investigate how they may be related to changes in space weather and atmospheric activity. The powerful VLF signal transmitted from NAA (24 kHz) on the east coast of the United States, and received at Sodankylä, Finland, was analyzed. Wavelet transform, wavelet power spectrum, wavelet coherence, and cross‐wavelet spectrum were computed for daily averages of selected ionospheric, space weather, and atmospheric parameters from November 2008 until June 2018. Our results show that the significant VLF periods that appear during solar cycle 24 are the annual oscillation, semiannual oscillation, 121‐day, 86‐day, 61‐day, and solar rotation oscillations. We found that the annual oscillation corresponds to variability in mesospheric temperature and solar Lyman‐α (Ly‐α) flux and the semiannual oscillation to variability in space weather‐related parameters. The solar rotation oscillation observed in the VLF variability is mainly related to the Ly‐α flux variation at solar maximum and to geomagnetic activity variation during the declining phase of the solar cycle. Our results are important since they strengthen our understanding of the Earth’s D‐region response to solar and atmospheric forcing.

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Series: Journal of geophysical research. Space physics
ISSN: 2169-9380
ISSN-E: 2169-9402
ISSN-L: 2169-9380
Volume: 124
Issue: 1
Pages: 765 - 781
DOI: 10.1029/2018JA026049
OADOI: https://oadoi.org/10.1029/2018JA026049
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Subjects:
Funding: E.L.M. was supported by the Suomen Kulttuurirahasto (grant 00170658) and the Tauno Tönningin Säätiö (grant 20170007). D.A.N. and M.A.C. were supported in part by the Natural Environment Research Council (grant NE/J022187/1).
Copyright information: © 2019 American Geophysical Union. All Rights Reserved. This is the peer reviewed version of the following article: Macotela, E. L., Clilverd, M., Manninen, J., Moffat‐Griffin, T., Newnham, D. A., Raita, T., & Rodger, C. J. ( 2019). D‐region high‐latitude forcing factors. Journal of Geophysical Research: Space Physics, 124, 765– 781, which has been published in final form at https://doi.org/10.1029/2018JA026049. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.