Role of the North Atlantic Oscillation in decadal temperature trends
International audience Global temperatures have undergone periods of enhanced warming and pauses over the last century, with greater variations at local scales due to internal variability of the climate system. Here we investigate the role of the North Atlantic Oscillation (NAO) in decadal temperatu...
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ftuniparissaclay:oai:HAL:hal-03226698v1 2024-06-16T07:38:21+00:00 Role of the North Atlantic Oscillation in decadal temperature trends Iles, Carley Hegerl, Gabriele Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA) School of Geosciences Edinburgh University of Edinburgh (Edin.) 2017 https://hal.science/hal-03226698 https://hal.science/hal-03226698/document https://hal.science/hal-03226698/file/Iles_2017_Environ._Res._Lett._12_114010.pdf https://doi.org/10.1088/1748-9326/aa9152 en eng HAL CCSD IOP Publishing info:eu-repo/semantics/altIdentifier/doi/10.1088/1748-9326/aa9152 hal-03226698 https://hal.science/hal-03226698 https://hal.science/hal-03226698/document https://hal.science/hal-03226698/file/Iles_2017_Environ._Res._Lett._12_114010.pdf doi:10.1088/1748-9326/aa9152 info:eu-repo/semantics/OpenAccess ISSN: 1748-9326 Environmental Research Letters https://hal.science/hal-03226698 Environmental Research Letters, 2017, 12 (11), pp.114010. ⟨10.1088/1748-9326/aa9152⟩ [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology info:eu-repo/semantics/article Journal articles 2017 ftuniparissaclay https://doi.org/10.1088/1748-9326/aa9152 2024-05-17T00:05:47Z International audience Global temperatures have undergone periods of enhanced warming and pauses over the last century, with greater variations at local scales due to internal variability of the climate system. Here we investigate the role of the North Atlantic Oscillation (NAO) in decadal temperature trends in the Northern Hemisphere for periods with large decadal NAO trends. Using a regression based technique we find a best estimate that trends in the NAO more than halved (reduced by 57%, 5%–95%: 47%–63%) the winter warming over the Northern Hemisphere extratropics (NH; 30N–90N) from 1920–1971 and account for 45% (±14%) of the warming there from 1963–1995, with larger impacts on regional scales. Over the period leading into the so-called warming hiatus, 1989–2013, the NAO reduced NH winter warming to around one quarter (24%; 19%–31%) of what it would have been, and caused large negative regional trends, for example, in Northern Eurasia. Warming is more spatially uniform across the Northern Hemisphere after removing the NAO influence in winter, and agreement with multi-model mean simulated trends improves. The impact of the summer NAO is much weaker, but still discernible over Europe, North America and Greenland, with the downward trend in the summer NAO from 1988–2012 reducing warming by about a third in Northern Europe and a half in North America. A composite analysis using CMIP5 control runs suggests that the ocean response to prolonged NAO trends may increase the influence of decadal NAO trends compared to estimates based on interannual regressions, particularly in the Arctic. Results imply that the long-term NAO trends over the 20th century alternately masked or enhanced anthropogenic warming, and will continue to temporarily offset or enhance its effects in the future. Article in Journal/Newspaper Arctic Greenland North Atlantic North Atlantic oscillation Archives ouvertes de Paris-Saclay Arctic Greenland Environmental Research Letters 12 11 114010 |
institution |
Open Polar |
collection |
Archives ouvertes de Paris-Saclay |
op_collection_id |
ftuniparissaclay |
language |
English |
topic |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology |
spellingShingle |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology Iles, Carley Hegerl, Gabriele Role of the North Atlantic Oscillation in decadal temperature trends |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology |
description |
International audience Global temperatures have undergone periods of enhanced warming and pauses over the last century, with greater variations at local scales due to internal variability of the climate system. Here we investigate the role of the North Atlantic Oscillation (NAO) in decadal temperature trends in the Northern Hemisphere for periods with large decadal NAO trends. Using a regression based technique we find a best estimate that trends in the NAO more than halved (reduced by 57%, 5%–95%: 47%–63%) the winter warming over the Northern Hemisphere extratropics (NH; 30N–90N) from 1920–1971 and account for 45% (±14%) of the warming there from 1963–1995, with larger impacts on regional scales. Over the period leading into the so-called warming hiatus, 1989–2013, the NAO reduced NH winter warming to around one quarter (24%; 19%–31%) of what it would have been, and caused large negative regional trends, for example, in Northern Eurasia. Warming is more spatially uniform across the Northern Hemisphere after removing the NAO influence in winter, and agreement with multi-model mean simulated trends improves. The impact of the summer NAO is much weaker, but still discernible over Europe, North America and Greenland, with the downward trend in the summer NAO from 1988–2012 reducing warming by about a third in Northern Europe and a half in North America. A composite analysis using CMIP5 control runs suggests that the ocean response to prolonged NAO trends may increase the influence of decadal NAO trends compared to estimates based on interannual regressions, particularly in the Arctic. Results imply that the long-term NAO trends over the 20th century alternately masked or enhanced anthropogenic warming, and will continue to temporarily offset or enhance its effects in the future. |
author2 |
Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA) School of Geosciences Edinburgh University of Edinburgh (Edin.) |
format |
Article in Journal/Newspaper |
author |
Iles, Carley Hegerl, Gabriele |
author_facet |
Iles, Carley Hegerl, Gabriele |
author_sort |
Iles, Carley |
title |
Role of the North Atlantic Oscillation in decadal temperature trends |
title_short |
Role of the North Atlantic Oscillation in decadal temperature trends |
title_full |
Role of the North Atlantic Oscillation in decadal temperature trends |
title_fullStr |
Role of the North Atlantic Oscillation in decadal temperature trends |
title_full_unstemmed |
Role of the North Atlantic Oscillation in decadal temperature trends |
title_sort |
role of the north atlantic oscillation in decadal temperature trends |
publisher |
HAL CCSD |
publishDate |
2017 |
url |
https://hal.science/hal-03226698 https://hal.science/hal-03226698/document https://hal.science/hal-03226698/file/Iles_2017_Environ._Res._Lett._12_114010.pdf https://doi.org/10.1088/1748-9326/aa9152 |
geographic |
Arctic Greenland |
geographic_facet |
Arctic Greenland |
genre |
Arctic Greenland North Atlantic North Atlantic oscillation |
genre_facet |
Arctic Greenland North Atlantic North Atlantic oscillation |
op_source |
ISSN: 1748-9326 Environmental Research Letters https://hal.science/hal-03226698 Environmental Research Letters, 2017, 12 (11), pp.114010. ⟨10.1088/1748-9326/aa9152⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1088/1748-9326/aa9152 hal-03226698 https://hal.science/hal-03226698 https://hal.science/hal-03226698/document https://hal.science/hal-03226698/file/Iles_2017_Environ._Res._Lett._12_114010.pdf doi:10.1088/1748-9326/aa9152 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1088/1748-9326/aa9152 |
container_title |
Environmental Research Letters |
container_volume |
12 |
container_issue |
11 |
container_start_page |
114010 |
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1802005030961676288 |