University of Oulu

Maliniemi, V, Asikainen, T, Salminen, A, Mursula, K. Assessing North Atlantic winter climate response to geomagnetic activity and solar irradiance variability. Q J R Meteorol Soc. 2019; 145: 3780– 3789.

Assessing North Atlantic winter climate response to geomagnetic activity and solar irradiance variability

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Author: Maliniemi, Ville1,2; Asikainen, Timo1; Salminen, Antti1;
Organizations: 1ReSoLVE Centre of Excellence, Space Climate Research Unit, University of Oulu, Oulu, Finland
2Birkeland Centre for Space Science, Department of Physics and Technology, University of Bergen, Bergen, Norway
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 13.3 MB)
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Language: English
Published: John Wiley & Sons, 2019
Publish Date: 2020-01-17


Recent studies suggest a response in the North Atlantic winter circulation which lags by a couple of years with respect to sunspot maximum. This has been explained by two different top‐down mechanisms: a solar wind driven particle effect in the polar atmosphere during the declining phase of the solar cycle, and the re‐emergence and amplification of heat anomalies in the Atlantic Ocean produced by enhanced solar ultraviolet (UV). Here we study how December to February climate is affected by two solar‐related drivers: geomagnetic activity (proxy of particle precipitation) and sunspot activity (proxy of solar UV) during 1948–2017. We use reanalysis data of sea‐level pressure (SLP) and zonal wind (U) to show that both geomagnetic activity and sunspot activity independently and simultaneously produce atmospheric circulation responses in the North Atlantic whose evolutions clearly differ from each other. Geomagnetic activity produces a strengthening of the polar vortex and a negative poleward SLP gradient between mid‐ and high latitudes, resembling a positive NAO‐type circulation pattern during December to February. Solar UV produces a positive U anomaly in the low‐latitude stratosphere during December, which moves poleward and downward during the winter resulting in a negative poleward SLP gradient between mid‐ and high latitudes during February. We find the lagged sunspot activity responses in SLP to form zonal pressure patterns (wave‐train structure) resembling the Eurasian pattern. Geomagnetic activity responses remain essentially the same when we introduce the lag with respect to sunspot activity supporting its independency as a driving mechanism. Our results suggest that solar wind related particle precipitation and (lagged) solar UV mechanism provide independent, significant circulation signals in the North Atlantic winter.

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Series: Quarterly journal of the Royal Meteorological Society
ISSN: 0035-9009
ISSN-E: 1477-870X
ISSN-L: 0035-9009
Volume: 145
Issue: 725
Pages: 3780 - 3789
DOI: 10.1002/qj.3657
Type of Publication: A1 Journal article – refereed
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. 307411). V.M. was also paid in part by the Norwegian Research Council under contract 223252/F50.
Academy of Finland Grant Number: 307411
Detailed Information: 307411 (Academy of Finland Funding decision)
Copyright information: © 2019 The Authors. Quarterly Journal of the Royal Meteorological Society published by John Wiley & Sons Ltd on behalf of the Royal Meteorological Society. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.