University of Oulu

Asikainen, T., Salminen, A., Maliniemi, V., & Mursula, K. ( 2020). Influence of enhanced planetary wave activity on the polar vortex enhancement related to energetic electron precipitation. Journal Geophysical Research: Atmospheres, 125, e2019JD032137.

Influence of enhanced planetary wave activity on the polar vortex enhancement related to energetic electron precipitation

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Author: Asikainen, Timo1; Salminen, Antti1; Maliniemi, Ville2;
Organizations: 1Space Physics and Astronomy Research Unit, University of Oulu, Oulu, Finland
2Centre 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, 2.9 MB)
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Language: English
Published: American Geophysical Union, 2020
Publish Date: 2020-05-04


The Northern polar vortex experiences considerable interannual variability, which is also reflected to tropospheric weather. Recent research has established a link between polar vortex variations and energetic electron precipitation (EEP) from the near‐Earth space into the polar atmosphere, which is mediated by EEP‐induced chemical changes causing ozone loss in the mesosphere and stratosphere. The most dramatic changes in the polar vortex are due to sudden stratospheric warmings (SSWs). Enhanced planetary wave convergence and meridional circulation may cause an SSW, a temporary breakdown of the polar vortex. Here we study the relation of SSWs to the atmospheric response to EEP in 1957–2017 using combined ERA‐40 and ERA‐Interim reanalysis data and geomagnetic activity as a proxy of EEP. We find that the EEP‐related enhancement of the polar vortex and other associated dynamical responses are seen only during winters when an SSW occurs and that the EEP‐related changes are observed systematically slightly before the SSW onset.

We show that during these times, the planetary wave activity into the stratosphere is systematically increased, thus favoring enhanced wave‐mean‐flow interaction, which can dynamically amplify the initial polar vortex enhancement caused by ozone loss. These results highlight the importance of considering planetary wave activity as a necessary condition for observing the effects of EEP on the polar vortex.

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Series: Journal of geophysical research. Atmospheres
ISSN: 2169-897X
ISSN-E: 2169-8996
ISSN-L: 2169-897X
Volume: 125
Issue: 9
Article number: e2019JD032137
DOI: 10.1029/2019JD032137
Type of Publication: A1 Journal article – refereed
Field of Science: 114 Physical sciences
115 Astronomy and space science
1171 Geosciences
Funding: We acknowledge the financial support by the Academy of Finland to the ReSoLVE Center of Excellence (Project 307411) and to the PRediction of SPace climate and its Effects in ClimaTe (PROSPECT, Project 321440) research project. We also acknowledge the financial support by the Kvantum Institute of the University of Oulu for the Climate and Atmospheric Effects of Sun in Arctic Regions (CAESAR) project.
Academy of Finland Grant Number: 307411
Detailed Information: 307411 (Academy of Finland Funding decision)
321440 (Academy of Finland Funding decision)
Dataset Reference: The atmospheric data used in this study are available from the European Centre for Medium Range Weather Forecasts (ECMWF) at The geomagnetic Ap index data can be obtained from International Service of Geomagnetic Indices at
Copyright information: ©2020. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.