Geomagnetic activity related NOx enhancements and polar surface air temperature variability in a chemistry climate model: modulation of the NAM index
The atmospheric chemistry general circulation model ECHAM5/MESSy is used to simulate polar surface air temperature effects of geomagnetic activity variations. A transient model simulation was performed for the years 1960-2004 and is shown to develop polar surface air temperature patterns that depend...
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ftnerc:oai:nora.nerc.ac.uk:14660 2023-05-15T17:36:01+02:00 Geomagnetic activity related NOx enhancements and polar surface air temperature variability in a chemistry climate model: modulation of the NAM index Baumgaertner, A.J.G. Seppala, Annika Jockel, P. Clilverd, Mark A. 2011 text http://nora.nerc.ac.uk/id/eprint/14660/ https://nora.nerc.ac.uk/id/eprint/14660/1/acp-11-4521-2011.pdf http://www.atmos-chem-phys.net/11/4521/2011/acp-11-4521-2011.html en eng Copernicus https://nora.nerc.ac.uk/id/eprint/14660/1/acp-11-4521-2011.pdf Baumgaertner, A.J.G.; Seppala, Annika; Jockel, P.; Clilverd, Mark A. orcid:0000-0002-7388-1529 . 2011 Geomagnetic activity related NOx enhancements and polar surface air temperature variability in a chemistry climate model: modulation of the NAM index. Atmospheric Chemistry and Physics, 11 (9). 4521-4531. https://doi.org/10.5194/acp-11-4521-2011 <https://doi.org/10.5194/acp-11-4521-2011> Atmospheric Sciences Chemistry Publication - Article PeerReviewed 2011 ftnerc https://doi.org/10.5194/acp-11-4521-2011 2023-02-04T19:29:23Z The atmospheric chemistry general circulation model ECHAM5/MESSy is used to simulate polar surface air temperature effects of geomagnetic activity variations. A transient model simulation was performed for the years 1960-2004 and is shown to develop polar surface air temperature patterns that depend on geomagnetic activity strength, similar to previous studies. In order to eliminate influencing factors such as sea surface temperatures (SST) or UV variations, two nine-year long simulations were carried out, with strong and weak geomagnetic activity, respectively, while all other boundary conditions were held to year 2000 levels. Statistically significant temperature effects that were observed in previous reanalysis and model results are also obtained from this set of simulations, suggesting that such patterns are indeed related to geomagnetic activity. In the model, strong geomagnetic activity and the associated NOx (=NO+NO2) enhancements lead to polar stratospheric ozone loss. Compared with the simulation with weak geomagnetic activity, the ozone loss causes a decrease in ozone radiative cooling and thus a temperature increase in the polar winter mesosphere. Similar to previous studies, a cooling is found below the stratopause, which other authors have attributed to a decrease in the mean meridional circulation. In the polar stratosphere this leads to a more stable vortex. A strong (weak) Northern Hemisphere vortex is known to be associated with a positive (negative) Northern Annular Mode (NAM) index; our simulations exhibit a positive NAM index for strong geomagnetic activity, and a negative NAM for weak geomagnetic activity. Such NAM anomalies have been shown to propagate to the surface, and this is also seen in the model simulations. NAM anomalies are known to lead to specific surface temperature anomalies: a positive NAM is associated with warmer than average northern Eurasia and colder than average eastern North Atlantic. This is also the case in our simulation. Our simulations suggest a link between ... Article in Journal/Newspaper North Atlantic Natural Environment Research Council: NERC Open Research Archive Atmospheric Chemistry and Physics 11 9 4521 4531 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
topic |
Atmospheric Sciences Chemistry |
spellingShingle |
Atmospheric Sciences Chemistry Baumgaertner, A.J.G. Seppala, Annika Jockel, P. Clilverd, Mark A. Geomagnetic activity related NOx enhancements and polar surface air temperature variability in a chemistry climate model: modulation of the NAM index |
topic_facet |
Atmospheric Sciences Chemistry |
description |
The atmospheric chemistry general circulation model ECHAM5/MESSy is used to simulate polar surface air temperature effects of geomagnetic activity variations. A transient model simulation was performed for the years 1960-2004 and is shown to develop polar surface air temperature patterns that depend on geomagnetic activity strength, similar to previous studies. In order to eliminate influencing factors such as sea surface temperatures (SST) or UV variations, two nine-year long simulations were carried out, with strong and weak geomagnetic activity, respectively, while all other boundary conditions were held to year 2000 levels. Statistically significant temperature effects that were observed in previous reanalysis and model results are also obtained from this set of simulations, suggesting that such patterns are indeed related to geomagnetic activity. In the model, strong geomagnetic activity and the associated NOx (=NO+NO2) enhancements lead to polar stratospheric ozone loss. Compared with the simulation with weak geomagnetic activity, the ozone loss causes a decrease in ozone radiative cooling and thus a temperature increase in the polar winter mesosphere. Similar to previous studies, a cooling is found below the stratopause, which other authors have attributed to a decrease in the mean meridional circulation. In the polar stratosphere this leads to a more stable vortex. A strong (weak) Northern Hemisphere vortex is known to be associated with a positive (negative) Northern Annular Mode (NAM) index; our simulations exhibit a positive NAM index for strong geomagnetic activity, and a negative NAM for weak geomagnetic activity. Such NAM anomalies have been shown to propagate to the surface, and this is also seen in the model simulations. NAM anomalies are known to lead to specific surface temperature anomalies: a positive NAM is associated with warmer than average northern Eurasia and colder than average eastern North Atlantic. This is also the case in our simulation. Our simulations suggest a link between ... |
format |
Article in Journal/Newspaper |
author |
Baumgaertner, A.J.G. Seppala, Annika Jockel, P. Clilverd, Mark A. |
author_facet |
Baumgaertner, A.J.G. Seppala, Annika Jockel, P. Clilverd, Mark A. |
author_sort |
Baumgaertner, A.J.G. |
title |
Geomagnetic activity related NOx enhancements and polar surface air temperature variability in a chemistry climate model: modulation of the NAM index |
title_short |
Geomagnetic activity related NOx enhancements and polar surface air temperature variability in a chemistry climate model: modulation of the NAM index |
title_full |
Geomagnetic activity related NOx enhancements and polar surface air temperature variability in a chemistry climate model: modulation of the NAM index |
title_fullStr |
Geomagnetic activity related NOx enhancements and polar surface air temperature variability in a chemistry climate model: modulation of the NAM index |
title_full_unstemmed |
Geomagnetic activity related NOx enhancements and polar surface air temperature variability in a chemistry climate model: modulation of the NAM index |
title_sort |
geomagnetic activity related nox enhancements and polar surface air temperature variability in a chemistry climate model: modulation of the nam index |
publisher |
Copernicus |
publishDate |
2011 |
url |
http://nora.nerc.ac.uk/id/eprint/14660/ https://nora.nerc.ac.uk/id/eprint/14660/1/acp-11-4521-2011.pdf http://www.atmos-chem-phys.net/11/4521/2011/acp-11-4521-2011.html |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
https://nora.nerc.ac.uk/id/eprint/14660/1/acp-11-4521-2011.pdf Baumgaertner, A.J.G.; Seppala, Annika; Jockel, P.; Clilverd, Mark A. orcid:0000-0002-7388-1529 . 2011 Geomagnetic activity related NOx enhancements and polar surface air temperature variability in a chemistry climate model: modulation of the NAM index. Atmospheric Chemistry and Physics, 11 (9). 4521-4531. https://doi.org/10.5194/acp-11-4521-2011 <https://doi.org/10.5194/acp-11-4521-2011> |
op_doi |
https://doi.org/10.5194/acp-11-4521-2011 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
11 |
container_issue |
9 |
container_start_page |
4521 |
op_container_end_page |
4531 |
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1766135351376609280 |