European summer weather linked to North Atlantic freshwater anomalies in preceding years
Amplified Arctic ice loss in recent decades has been linked to the increased occurrence of extreme mid-latitude weather. The underlying mechanisms remain elusive, however. One potential link occurs through the ocean as the loss of sea ice and glacial ice leads to increased freshwater fluxes into the...
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ftcopernicus:oai:publications.copernicus.org:wcd109046 2024-09-15T18:20:40+00:00 European summer weather linked to North Atlantic freshwater anomalies in preceding years Oltmanns, Marilena Holliday, N. Penny Screen, James Moat, Ben I. Josey, Simon A. Evans, D. Gwyn Bacon, Sheldon 2024-02-02 application/pdf https://doi.org/10.5194/wcd-5-109-2024 https://wcd.copernicus.org/articles/5/109/2024/ eng eng doi:10.5194/wcd-5-109-2024 https://wcd.copernicus.org/articles/5/109/2024/ eISSN: 2698-4016 Text 2024 ftcopernicus https://doi.org/10.5194/wcd-5-109-2024 2024-08-28T05:24:15Z Amplified Arctic ice loss in recent decades has been linked to the increased occurrence of extreme mid-latitude weather. The underlying mechanisms remain elusive, however. One potential link occurs through the ocean as the loss of sea ice and glacial ice leads to increased freshwater fluxes into the ocean. Thus, in this study, we examine the link between North Atlantic freshwater anomalies and European summer weather. Combining a comprehensive set of observational products, we show that stronger freshwater anomalies are associated with a sharper sea surface temperature front between the subpolar and the subtropical North Atlantic in winter, an increased atmospheric instability above the sea surface temperature front, and a large-scale atmospheric circulation that induces a northward shift in the North Atlantic Current, strengthening the sea surface temperature front. In the following summer, the lower-tropospheric winds are deflected northward along the enhanced sea surface temperature front and the European coastline, forming part of a large-scale atmospheric circulation anomaly that is associated with warmer and drier weather over Europe. The identified statistical links are significant on timescales from years to decades and indicate an enhanced predictability of European summer weather at least a winter in advance, with the exact regions and amplitudes of the warm and dry weather anomalies over Europe being sensitive to the location, strength, and extent of North Atlantic freshwater anomalies in the preceding winter. Text north atlantic current North Atlantic Sea ice Copernicus Publications: E-Journals Weather and Climate Dynamics 5 1 109 132 |
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Copernicus Publications: E-Journals |
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English |
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Amplified Arctic ice loss in recent decades has been linked to the increased occurrence of extreme mid-latitude weather. The underlying mechanisms remain elusive, however. One potential link occurs through the ocean as the loss of sea ice and glacial ice leads to increased freshwater fluxes into the ocean. Thus, in this study, we examine the link between North Atlantic freshwater anomalies and European summer weather. Combining a comprehensive set of observational products, we show that stronger freshwater anomalies are associated with a sharper sea surface temperature front between the subpolar and the subtropical North Atlantic in winter, an increased atmospheric instability above the sea surface temperature front, and a large-scale atmospheric circulation that induces a northward shift in the North Atlantic Current, strengthening the sea surface temperature front. In the following summer, the lower-tropospheric winds are deflected northward along the enhanced sea surface temperature front and the European coastline, forming part of a large-scale atmospheric circulation anomaly that is associated with warmer and drier weather over Europe. The identified statistical links are significant on timescales from years to decades and indicate an enhanced predictability of European summer weather at least a winter in advance, with the exact regions and amplitudes of the warm and dry weather anomalies over Europe being sensitive to the location, strength, and extent of North Atlantic freshwater anomalies in the preceding winter. |
format |
Text |
author |
Oltmanns, Marilena Holliday, N. Penny Screen, James Moat, Ben I. Josey, Simon A. Evans, D. Gwyn Bacon, Sheldon |
spellingShingle |
Oltmanns, Marilena Holliday, N. Penny Screen, James Moat, Ben I. Josey, Simon A. Evans, D. Gwyn Bacon, Sheldon European summer weather linked to North Atlantic freshwater anomalies in preceding years |
author_facet |
Oltmanns, Marilena Holliday, N. Penny Screen, James Moat, Ben I. Josey, Simon A. Evans, D. Gwyn Bacon, Sheldon |
author_sort |
Oltmanns, Marilena |
title |
European summer weather linked to North Atlantic freshwater anomalies in preceding years |
title_short |
European summer weather linked to North Atlantic freshwater anomalies in preceding years |
title_full |
European summer weather linked to North Atlantic freshwater anomalies in preceding years |
title_fullStr |
European summer weather linked to North Atlantic freshwater anomalies in preceding years |
title_full_unstemmed |
European summer weather linked to North Atlantic freshwater anomalies in preceding years |
title_sort |
european summer weather linked to north atlantic freshwater anomalies in preceding years |
publishDate |
2024 |
url |
https://doi.org/10.5194/wcd-5-109-2024 https://wcd.copernicus.org/articles/5/109/2024/ |
genre |
north atlantic current North Atlantic Sea ice |
genre_facet |
north atlantic current North Atlantic Sea ice |
op_source |
eISSN: 2698-4016 |
op_relation |
doi:10.5194/wcd-5-109-2024 https://wcd.copernicus.org/articles/5/109/2024/ |
op_doi |
https://doi.org/10.5194/wcd-5-109-2024 |
container_title |
Weather and Climate Dynamics |
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5 |
container_issue |
1 |
container_start_page |
109 |
op_container_end_page |
132 |
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1810459061826617344 |