Predictability of European winter 2019/20: Indian Ocean dipole impacts on the NAO
Northern Europe and the UK experienced an exceptionally warm and wet winter in 2019/20, driven by an anomalously positive North Atlantic Oscillation (NAO). This positive NAO was well forecast by several seasonal forecast systems, suggesting that this winter the NAO was highly predictable at seasonal...
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ftoceanrep:oai:oceanrep.geomar.de:50285 2023-05-15T17:27:30+02:00 Predictability of European winter 2019/20: Indian Ocean dipole impacts on the NAO Hardiman, Steven C. Dunstone, Nick J. Scaife, Adam A. Smith, Doug M. Knight, Jeff R. Davies, Paul Claus, Martin Greatbatch, Richard John 2020-12 text https://oceanrep.geomar.de/id/eprint/50285/ https://oceanrep.geomar.de/id/eprint/50285/7/asl.1005.pdf https://doi.org/10.1002/asl.1005 en eng Royal Meteorological Society https://oceanrep.geomar.de/id/eprint/50285/7/asl.1005.pdf Hardiman, S. C. , Dunstone, N. J. , Scaife, A. A. , Smith, D. M., Knight, J. R. , Davies, P., Claus, M. and Greatbatch, R. J. (2020) Predictability of European winter 2019/20: Indian Ocean dipole impacts on the NAO . Open Access Atmospheric Science Letters, 21 (12). Art.Nr. e1005. DOI 10.1002/asl.1005 <https://doi.org/10.1002/asl.1005>. doi:10.1002/asl.1005 cc_by_4.0 info:eu-repo/semantics/openAccess Article PeerReviewed 2020 ftoceanrep https://doi.org/10.1002/asl.1005 2023-04-07T15:51:29Z Northern Europe and the UK experienced an exceptionally warm and wet winter in 2019/20, driven by an anomalously positive North Atlantic Oscillation (NAO). This positive NAO was well forecast by several seasonal forecast systems, suggesting that this winter the NAO was highly predictable at seasonal lead times. A very strong positive Indian Ocean dipole (IOD) event was also observed at the start of winter. Here we use composite analysis and model experiments, to show that the IOD was a key driver of the observed positive NAO. Using model experiments that perturb the Indian Ocean initial conditions, two teleconnection pathways of the IOD to the north Atlantic emerge: a tropospheric teleconnection pathway via a Rossby wave train travelling from the Indian Ocean over the Pacific and Atlantic, and a stratospheric teleconnection pathway via the Aleutian region and the stratospheric polar vortex. These pathways are similar to those for the El Niño Southern Oscillation link to the north Atlantic which are already well documented. The anomalies in the north Atlantic jet stream location and strength, and the associated precipitation anomalies over the UK and northern Europe, as simulated by the model IOD experiments, show remarkable agreement with those forecast and observed. Article in Journal/Newspaper North Atlantic North Atlantic oscillation OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Indian Pacific Atmospheric Science Letters 21 12 |
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OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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ftoceanrep |
language |
English |
description |
Northern Europe and the UK experienced an exceptionally warm and wet winter in 2019/20, driven by an anomalously positive North Atlantic Oscillation (NAO). This positive NAO was well forecast by several seasonal forecast systems, suggesting that this winter the NAO was highly predictable at seasonal lead times. A very strong positive Indian Ocean dipole (IOD) event was also observed at the start of winter. Here we use composite analysis and model experiments, to show that the IOD was a key driver of the observed positive NAO. Using model experiments that perturb the Indian Ocean initial conditions, two teleconnection pathways of the IOD to the north Atlantic emerge: a tropospheric teleconnection pathway via a Rossby wave train travelling from the Indian Ocean over the Pacific and Atlantic, and a stratospheric teleconnection pathway via the Aleutian region and the stratospheric polar vortex. These pathways are similar to those for the El Niño Southern Oscillation link to the north Atlantic which are already well documented. The anomalies in the north Atlantic jet stream location and strength, and the associated precipitation anomalies over the UK and northern Europe, as simulated by the model IOD experiments, show remarkable agreement with those forecast and observed. |
format |
Article in Journal/Newspaper |
author |
Hardiman, Steven C. Dunstone, Nick J. Scaife, Adam A. Smith, Doug M. Knight, Jeff R. Davies, Paul Claus, Martin Greatbatch, Richard John |
spellingShingle |
Hardiman, Steven C. Dunstone, Nick J. Scaife, Adam A. Smith, Doug M. Knight, Jeff R. Davies, Paul Claus, Martin Greatbatch, Richard John Predictability of European winter 2019/20: Indian Ocean dipole impacts on the NAO |
author_facet |
Hardiman, Steven C. Dunstone, Nick J. Scaife, Adam A. Smith, Doug M. Knight, Jeff R. Davies, Paul Claus, Martin Greatbatch, Richard John |
author_sort |
Hardiman, Steven C. |
title |
Predictability of European winter 2019/20: Indian Ocean dipole impacts on the NAO |
title_short |
Predictability of European winter 2019/20: Indian Ocean dipole impacts on the NAO |
title_full |
Predictability of European winter 2019/20: Indian Ocean dipole impacts on the NAO |
title_fullStr |
Predictability of European winter 2019/20: Indian Ocean dipole impacts on the NAO |
title_full_unstemmed |
Predictability of European winter 2019/20: Indian Ocean dipole impacts on the NAO |
title_sort |
predictability of european winter 2019/20: indian ocean dipole impacts on the nao |
publisher |
Royal Meteorological Society |
publishDate |
2020 |
url |
https://oceanrep.geomar.de/id/eprint/50285/ https://oceanrep.geomar.de/id/eprint/50285/7/asl.1005.pdf https://doi.org/10.1002/asl.1005 |
geographic |
Indian Pacific |
geographic_facet |
Indian Pacific |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_relation |
https://oceanrep.geomar.de/id/eprint/50285/7/asl.1005.pdf Hardiman, S. C. , Dunstone, N. J. , Scaife, A. A. , Smith, D. M., Knight, J. R. , Davies, P., Claus, M. and Greatbatch, R. J. (2020) Predictability of European winter 2019/20: Indian Ocean dipole impacts on the NAO . Open Access Atmospheric Science Letters, 21 (12). Art.Nr. e1005. DOI 10.1002/asl.1005 <https://doi.org/10.1002/asl.1005>. doi:10.1002/asl.1005 |
op_rights |
cc_by_4.0 info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1002/asl.1005 |
container_title |
Atmospheric Science Letters |
container_volume |
21 |
container_issue |
12 |
_version_ |
1766119642569375744 |