University of Oulu

Mursula, K., & Holappa, L. (2017). Principal Component Analysis of Geomagnetic Activity: New Information on Solar Wind. Proceedings of the International Astronomical Union, 13(S335), 197-200. doi:10.1017/S1743921317010146

Principal component analysis of geomagnetic activity : new information on solar wind

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Author: Mursula, Kalevi1; Holappa, Lauri1
Organizations: 1ReSoLVE Centre of Excellence, Space Climate Research Unit, University of Oulu, Finland
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 0.1 MB)
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Language: English
Published: Cambridge University Press, 2017
Publish Date: 2018-09-11


We use the principal component analysis to study geomagnetic activity at annual resolution using a network of 26 magnetic stations in 1966–2015, and an extended network of 40 stations in 1980–2015. The first principal component describes the long-term evolution of global geomagnetic activity, and has an excellent correlation with indices like the Kp/Ap index. The two networks give identical results for the first principal component. The second principal component is highly correlated with the annual percentage of high-speed streams (HSS). The extended network has a slightly higher sensitivity to HSSs. We verify the non-trivial latitudinal distribution of the second empirical orthogonal function. We find that the amplitude of the 22-year variation of geomagnetic activity has a closely similar latitudinal distribution as the second empirical orthogonal function. This verifies that the 22-year variation of geomagnetic activity is related to HSSs. The most likely cause is the Russell-McPherron mechanism.

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Series: Proceedings of the International Astronomical Union
ISSN: 1743-9213
ISSN-E: 1743-9221
ISSN-L: 1743-9213
Volume: 13
Issue: S335
Pages: 197 - 200
DOI: 10.1017/S1743921317010146
Host publication: Proceedings IAU Symposium No. 335, 2017. Space Weather of the Heliosphere: Processes and Forecasts. 17-21 July, University of Exeter, United Kindom
Host publication editor: Foullon, C.
Malandraki, O. E.
Conference: Symposium of the International Astronomical Union
Type of Publication: A4 Article in conference proceedings
Field of Science: 115 Astronomy and space science
Funding: We acknowledge the financial support by the Academy of Finland to the ReSoLVE Centre of Excellence (project no. 272157).
Academy of Finland Grant Number: 272157
Detailed Information: 272157 (Academy of Finland Funding decision)
Copyright information: © International Astronomical Union 2018.