The Effect of the Madden–Julian Oscillation on the North Atlantic Oscillation Using Idealized Numerical Experiments
International audience The aim of the paper is to investigate the influence of the Madden-Julian oscillation (MJO) on the North Atlantic Oscillation (NAO) using a quasigeostrophic model on the sphere. A simplified forcing based on potential vorticity anomalies in the tropics is used to mimic the MJO...
Published in: | Journal of the Atmospheric Sciences |
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Main Authors: | , |
Other Authors: | , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2020
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Online Access: | https://hal.science/hal-02968711 https://hal.science/hal-02968711/document https://hal.science/hal-02968711/file/Fromang_and_Riviere20.pdf https://doi.org/10.1175/JAS-D-19-0178.1 |
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École des Ponts ParisTech: HAL |
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language |
English |
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[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment |
spellingShingle |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment Fromang, Sebastien Rivière, Gwendal The Effect of the Madden–Julian Oscillation on the North Atlantic Oscillation Using Idealized Numerical Experiments |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment |
description |
International audience The aim of the paper is to investigate the influence of the Madden-Julian oscillation (MJO) on the North Atlantic Oscillation (NAO) using a quasigeostrophic model on the sphere. A simplified forcing based on potential vorticity anomalies in the tropics is used to mimic the MJO. The idealized nature of our setup allows us to determine the distinct roles played by stationary and synoptic waves. This is done by means of several series of almost 10 000 short runs of 30 days. Ensemble averages and a streamfunction budget analysis are used to study the modifications of the flow induced by the MJO. We find that a stationary Rossby wave is excited in the tropics during MJO phase 3. The western part of the Pacific jet is displaced poleward, which modifies the transient eddy activity in that basin. These changes create a ridge south of Alaska, which favors equatorward propagation of synoptic waves and larger poleward eddy momentum fluxes from the eastern Pacific toward the Atlantic, increasing the frequency of occurrence of the positive NAO events. The situation is essentially reversed following phase 6 of the MJO and conducive to the negative phase of the NAO. For a realistic MJO forcing amplitude, we find increases in both NAO phases to be around 30%, in reasonable agreement with the observations given the model simplicity. Finally, we present a series of experiments to assess the relative importance of linear versus nonlinear effects. |
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) Modélisation du climat (CLIM) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)) Laboratoire de Météorologie Dynamique (UMR 8539) (LMD) Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL) |
format |
Article in Journal/Newspaper |
author |
Fromang, Sebastien Rivière, Gwendal |
author_facet |
Fromang, Sebastien Rivière, Gwendal |
author_sort |
Fromang, Sebastien |
title |
The Effect of the Madden–Julian Oscillation on the North Atlantic Oscillation Using Idealized Numerical Experiments |
title_short |
The Effect of the Madden–Julian Oscillation on the North Atlantic Oscillation Using Idealized Numerical Experiments |
title_full |
The Effect of the Madden–Julian Oscillation on the North Atlantic Oscillation Using Idealized Numerical Experiments |
title_fullStr |
The Effect of the Madden–Julian Oscillation on the North Atlantic Oscillation Using Idealized Numerical Experiments |
title_full_unstemmed |
The Effect of the Madden–Julian Oscillation on the North Atlantic Oscillation Using Idealized Numerical Experiments |
title_sort |
effect of the madden–julian oscillation on the north atlantic oscillation using idealized numerical experiments |
publisher |
HAL CCSD |
publishDate |
2020 |
url |
https://hal.science/hal-02968711 https://hal.science/hal-02968711/document https://hal.science/hal-02968711/file/Fromang_and_Riviere20.pdf https://doi.org/10.1175/JAS-D-19-0178.1 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
North Atlantic North Atlantic oscillation Alaska |
genre_facet |
North Atlantic North Atlantic oscillation Alaska |
op_source |
ISSN: 0022-4928 EISSN: 1520-0469 Journal of the Atmospheric Sciences https://hal.science/hal-02968711 Journal of the Atmospheric Sciences, 2020, 77 (5), pp.1613-1635. ⟨10.1175/JAS-D-19-0178.1⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1175/JAS-D-19-0178.1 hal-02968711 https://hal.science/hal-02968711 https://hal.science/hal-02968711/document https://hal.science/hal-02968711/file/Fromang_and_Riviere20.pdf doi:10.1175/JAS-D-19-0178.1 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1175/JAS-D-19-0178.1 |
container_title |
Journal of the Atmospheric Sciences |
container_volume |
77 |
container_issue |
5 |
container_start_page |
1613 |
op_container_end_page |
1635 |
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1801379727878914048 |
spelling |
ftecoleponts:oai:HAL:hal-02968711v1 2024-06-09T07:48:08+00:00 The Effect of the Madden–Julian Oscillation on the North Atlantic Oscillation Using Idealized Numerical Experiments Fromang, Sebastien Rivière, Gwendal 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) Modélisation du climat (CLIM) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)) Laboratoire de Météorologie Dynamique (UMR 8539) (LMD) Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL) 2020-05-01 https://hal.science/hal-02968711 https://hal.science/hal-02968711/document https://hal.science/hal-02968711/file/Fromang_and_Riviere20.pdf https://doi.org/10.1175/JAS-D-19-0178.1 en eng HAL CCSD American Meteorological Society info:eu-repo/semantics/altIdentifier/doi/10.1175/JAS-D-19-0178.1 hal-02968711 https://hal.science/hal-02968711 https://hal.science/hal-02968711/document https://hal.science/hal-02968711/file/Fromang_and_Riviere20.pdf doi:10.1175/JAS-D-19-0178.1 info:eu-repo/semantics/OpenAccess ISSN: 0022-4928 EISSN: 1520-0469 Journal of the Atmospheric Sciences https://hal.science/hal-02968711 Journal of the Atmospheric Sciences, 2020, 77 (5), pp.1613-1635. ⟨10.1175/JAS-D-19-0178.1⟩ [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment info:eu-repo/semantics/article Journal articles 2020 ftecoleponts https://doi.org/10.1175/JAS-D-19-0178.1 2024-05-16T13:00:32Z International audience The aim of the paper is to investigate the influence of the Madden-Julian oscillation (MJO) on the North Atlantic Oscillation (NAO) using a quasigeostrophic model on the sphere. A simplified forcing based on potential vorticity anomalies in the tropics is used to mimic the MJO. The idealized nature of our setup allows us to determine the distinct roles played by stationary and synoptic waves. This is done by means of several series of almost 10 000 short runs of 30 days. Ensemble averages and a streamfunction budget analysis are used to study the modifications of the flow induced by the MJO. We find that a stationary Rossby wave is excited in the tropics during MJO phase 3. The western part of the Pacific jet is displaced poleward, which modifies the transient eddy activity in that basin. These changes create a ridge south of Alaska, which favors equatorward propagation of synoptic waves and larger poleward eddy momentum fluxes from the eastern Pacific toward the Atlantic, increasing the frequency of occurrence of the positive NAO events. The situation is essentially reversed following phase 6 of the MJO and conducive to the negative phase of the NAO. For a realistic MJO forcing amplitude, we find increases in both NAO phases to be around 30%, in reasonable agreement with the observations given the model simplicity. Finally, we present a series of experiments to assess the relative importance of linear versus nonlinear effects. Article in Journal/Newspaper North Atlantic North Atlantic oscillation Alaska École des Ponts ParisTech: HAL Pacific Journal of the Atmospheric Sciences 77 5 1613 1635 |