A simulated lagged response of the North Atlantic Oscillation to the solar cycle over the period 1960–2009
Numerous studies have suggested an impact of the 11 year solar cycle on the winter North Atlantic Oscillation (NAO), with an increased tendency for positive (negative) NAO signals to occur at maxima (minima) of the solar cycle. Climate models have successfully reproduced this solar cycle modulation...
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ftdoajarticles:oai:doaj.org/article:ccb60be9143f4fe6aeb477b88b2ace58 2023-09-05T13:21:24+02:00 A simulated lagged response of the North Atlantic Oscillation to the solar cycle over the period 1960–2009 M B Andrews J R Knight L J Gray 2015-01-01T00:00:00Z https://doi.org/10.1088/1748-9326/10/5/054022 https://doaj.org/article/ccb60be9143f4fe6aeb477b88b2ace58 EN eng IOP Publishing https://doi.org/10.1088/1748-9326/10/5/054022 https://doaj.org/toc/1748-9326 doi:10.1088/1748-9326/10/5/054022 1748-9326 https://doaj.org/article/ccb60be9143f4fe6aeb477b88b2ace58 Environmental Research Letters, Vol 10, Iss 5, p 054022 (2015) solar cycle North Atlantic Oscillation climate solar variability atmosphere–ocean interaction lagged response Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 article 2015 ftdoajarticles https://doi.org/10.1088/1748-9326/10/5/054022 2023-08-13T00:37:54Z Numerous studies have suggested an impact of the 11 year solar cycle on the winter North Atlantic Oscillation (NAO), with an increased tendency for positive (negative) NAO signals to occur at maxima (minima) of the solar cycle. Climate models have successfully reproduced this solar cycle modulation of the NAO, although the magnitude of the effect is often considerably weaker than implied by observations. A leading candidate for the mechanism of solar influence is via the impact of ultraviolet radiation variability on heating rates in the tropical upper stratosphere, and consequently on the meridional temperature gradient and zonal winds. Model simulations show a zonal mean wind anomaly that migrates polewards and downwards through wave–mean flow interaction. On reaching the troposphere this produces a response similar to the winter NAO. Recent analyses of observations have shown that solar cycle–NAO link becomes clearer approximately three years after solar maximum and minimum. Previous modelling studies have been unable to reproduce a lagged response of the observed magnitude. In this study, the impact of solar cycle on the NAO is investigated using an atmosphere–ocean coupled climate model. Simulations that include climate forcings are performed over the period 1960–2009 for two solar forcing scenarios: constant solar irradiance, and time-varying solar irradiance. We show that the model produces significant NAO responses peaking several years after extrema of the solar cycle, persisting even when the solar forcing becomes neutral. This confirms suggestions of a further component to the solar influence on the NAO beyond direct atmospheric heating and its dynamical response. Analysis of simulated upper ocean temperature anomalies confirms that the North Atlantic Ocean provides the memory of the solar forcing required to produce the lagged NAO response. These results have implications for improving skill in decadal predictions of the European and North American winter climate. Article in Journal/Newspaper North Atlantic North Atlantic oscillation Directory of Open Access Journals: DOAJ Articles Environmental Research Letters 10 5 054022 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
solar cycle North Atlantic Oscillation climate solar variability atmosphere–ocean interaction lagged response Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 |
spellingShingle |
solar cycle North Atlantic Oscillation climate solar variability atmosphere–ocean interaction lagged response Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 M B Andrews J R Knight L J Gray A simulated lagged response of the North Atlantic Oscillation to the solar cycle over the period 1960–2009 |
topic_facet |
solar cycle North Atlantic Oscillation climate solar variability atmosphere–ocean interaction lagged response Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 |
description |
Numerous studies have suggested an impact of the 11 year solar cycle on the winter North Atlantic Oscillation (NAO), with an increased tendency for positive (negative) NAO signals to occur at maxima (minima) of the solar cycle. Climate models have successfully reproduced this solar cycle modulation of the NAO, although the magnitude of the effect is often considerably weaker than implied by observations. A leading candidate for the mechanism of solar influence is via the impact of ultraviolet radiation variability on heating rates in the tropical upper stratosphere, and consequently on the meridional temperature gradient and zonal winds. Model simulations show a zonal mean wind anomaly that migrates polewards and downwards through wave–mean flow interaction. On reaching the troposphere this produces a response similar to the winter NAO. Recent analyses of observations have shown that solar cycle–NAO link becomes clearer approximately three years after solar maximum and minimum. Previous modelling studies have been unable to reproduce a lagged response of the observed magnitude. In this study, the impact of solar cycle on the NAO is investigated using an atmosphere–ocean coupled climate model. Simulations that include climate forcings are performed over the period 1960–2009 for two solar forcing scenarios: constant solar irradiance, and time-varying solar irradiance. We show that the model produces significant NAO responses peaking several years after extrema of the solar cycle, persisting even when the solar forcing becomes neutral. This confirms suggestions of a further component to the solar influence on the NAO beyond direct atmospheric heating and its dynamical response. Analysis of simulated upper ocean temperature anomalies confirms that the North Atlantic Ocean provides the memory of the solar forcing required to produce the lagged NAO response. These results have implications for improving skill in decadal predictions of the European and North American winter climate. |
format |
Article in Journal/Newspaper |
author |
M B Andrews J R Knight L J Gray |
author_facet |
M B Andrews J R Knight L J Gray |
author_sort |
M B Andrews |
title |
A simulated lagged response of the North Atlantic Oscillation to the solar cycle over the period 1960–2009 |
title_short |
A simulated lagged response of the North Atlantic Oscillation to the solar cycle over the period 1960–2009 |
title_full |
A simulated lagged response of the North Atlantic Oscillation to the solar cycle over the period 1960–2009 |
title_fullStr |
A simulated lagged response of the North Atlantic Oscillation to the solar cycle over the period 1960–2009 |
title_full_unstemmed |
A simulated lagged response of the North Atlantic Oscillation to the solar cycle over the period 1960–2009 |
title_sort |
simulated lagged response of the north atlantic oscillation to the solar cycle over the period 1960–2009 |
publisher |
IOP Publishing |
publishDate |
2015 |
url |
https://doi.org/10.1088/1748-9326/10/5/054022 https://doaj.org/article/ccb60be9143f4fe6aeb477b88b2ace58 |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_source |
Environmental Research Letters, Vol 10, Iss 5, p 054022 (2015) |
op_relation |
https://doi.org/10.1088/1748-9326/10/5/054022 https://doaj.org/toc/1748-9326 doi:10.1088/1748-9326/10/5/054022 1748-9326 https://doaj.org/article/ccb60be9143f4fe6aeb477b88b2ace58 |
op_doi |
https://doi.org/10.1088/1748-9326/10/5/054022 |
container_title |
Environmental Research Letters |
container_volume |
10 |
container_issue |
5 |
container_start_page |
054022 |
_version_ |
1776202010669875200 |