Impact of North Atlantic SST and Jet Stream anomalies on European Heat Waves
European heat waves have increased during the two recent decades. Particularly 2015 and 2018 were characterized by a widespread area of cold North Atlantic sea surface temperatures (SSTs) in early summer as well as positive surface temperature anomalies across large parts of the European continent d...
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ftoceanrep:oai:oceanrep.geomar.de:50304 2023-05-15T17:25:34+02:00 Impact of North Atlantic SST and Jet Stream anomalies on European Heat Waves Krüger, Julian Pilch Kedzierski, Robin Bumke, Karl Matthes, Katja 2020-08-07 text https://oceanrep.geomar.de/id/eprint/50304/ https://oceanrep.geomar.de/id/eprint/50304/1/wcd-2020-32.pdf https://doi.org/10.5194/wcd-2020-32 en eng Copernicus Publications (EGU) https://oceanrep.geomar.de/id/eprint/50304/1/wcd-2020-32.pdf Krüger, J., Pilch Kedzierski, R. , Bumke, K. and Matthes, K. (2020) Impact of North Atlantic SST and Jet Stream anomalies on European Heat Waves. Open Access Weather amd Climate Dynamics Discussion . DOI 10.5194/wcd-2020-32 <https://doi.org/10.5194/wcd-2020-32>. doi:10.5194/wcd-2020-32 cc_by_4.0 info:eu-repo/semantics/openAccess Article NonPeerReviewed 2020 ftoceanrep https://doi.org/10.5194/wcd-2020-32 2023-04-07T15:51:29Z European heat waves have increased during the two recent decades. Particularly 2015 and 2018 were characterized by a widespread area of cold North Atlantic sea surface temperatures (SSTs) in early summer as well as positive surface temperature anomalies across large parts of the European continent during later summer. The European heat wave of 2018 is further suggested to be induced by a quasi-stationary and high-amplified Rossby wave pattern associated with the so-called quasi-resonant amplification (QRA) mechanism. In this study, we evaluate the North Atlantic SST anomalies and the QRA theory as potential drivers for European heat waves for the first time in combination by using the ERA-5 reanalysis product. A composite and correlation study reveals that cold North Atlantic SST anomalies in early summer favour a more undulating jet stream and a preferred trough-ridge pattern in the North Atlantic–European sector. Further we found that cold North Atlantic SSTs promote a stronger double jet occurrence in this sector. Thus, favorite conditions for a QRA signature are evident together with a necessary preconditioning of a double jet. However, our wave analysis covering two-dimensional probability density distributions of phase speed and amplitude does not confirm a relationship between cold North Atlantic SSTs and the QRA theory, compositing cold SSTs, high double jet indices (DJIs) or both together. Instead, we can show that cold North Atlantic SST events enhance the dominance of transient waves. In the presence of a trough during cold North Atlantic events, we obtain a slow-down of the transient waves, but not necessarily an amplification or stationarity. The deceleration of the transient waves result in a longer duration of a trough over the North Atlantic accompanied by a ridge downstream over Europe, triggering European heat episodes. Although a given DJI preconditioning may also be subject to the onset of certain QRA events, our study found no general relation between cold North Atlantic SST events and the ... Article in Journal/Newspaper North Atlantic OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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Open Polar |
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OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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ftoceanrep |
language |
English |
description |
European heat waves have increased during the two recent decades. Particularly 2015 and 2018 were characterized by a widespread area of cold North Atlantic sea surface temperatures (SSTs) in early summer as well as positive surface temperature anomalies across large parts of the European continent during later summer. The European heat wave of 2018 is further suggested to be induced by a quasi-stationary and high-amplified Rossby wave pattern associated with the so-called quasi-resonant amplification (QRA) mechanism. In this study, we evaluate the North Atlantic SST anomalies and the QRA theory as potential drivers for European heat waves for the first time in combination by using the ERA-5 reanalysis product. A composite and correlation study reveals that cold North Atlantic SST anomalies in early summer favour a more undulating jet stream and a preferred trough-ridge pattern in the North Atlantic–European sector. Further we found that cold North Atlantic SSTs promote a stronger double jet occurrence in this sector. Thus, favorite conditions for a QRA signature are evident together with a necessary preconditioning of a double jet. However, our wave analysis covering two-dimensional probability density distributions of phase speed and amplitude does not confirm a relationship between cold North Atlantic SSTs and the QRA theory, compositing cold SSTs, high double jet indices (DJIs) or both together. Instead, we can show that cold North Atlantic SST events enhance the dominance of transient waves. In the presence of a trough during cold North Atlantic events, we obtain a slow-down of the transient waves, but not necessarily an amplification or stationarity. The deceleration of the transient waves result in a longer duration of a trough over the North Atlantic accompanied by a ridge downstream over Europe, triggering European heat episodes. Although a given DJI preconditioning may also be subject to the onset of certain QRA events, our study found no general relation between cold North Atlantic SST events and the ... |
format |
Article in Journal/Newspaper |
author |
Krüger, Julian Pilch Kedzierski, Robin Bumke, Karl Matthes, Katja |
spellingShingle |
Krüger, Julian Pilch Kedzierski, Robin Bumke, Karl Matthes, Katja Impact of North Atlantic SST and Jet Stream anomalies on European Heat Waves |
author_facet |
Krüger, Julian Pilch Kedzierski, Robin Bumke, Karl Matthes, Katja |
author_sort |
Krüger, Julian |
title |
Impact of North Atlantic SST and Jet Stream anomalies on European Heat Waves |
title_short |
Impact of North Atlantic SST and Jet Stream anomalies on European Heat Waves |
title_full |
Impact of North Atlantic SST and Jet Stream anomalies on European Heat Waves |
title_fullStr |
Impact of North Atlantic SST and Jet Stream anomalies on European Heat Waves |
title_full_unstemmed |
Impact of North Atlantic SST and Jet Stream anomalies on European Heat Waves |
title_sort |
impact of north atlantic sst and jet stream anomalies on european heat waves |
publisher |
Copernicus Publications (EGU) |
publishDate |
2020 |
url |
https://oceanrep.geomar.de/id/eprint/50304/ https://oceanrep.geomar.de/id/eprint/50304/1/wcd-2020-32.pdf https://doi.org/10.5194/wcd-2020-32 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
https://oceanrep.geomar.de/id/eprint/50304/1/wcd-2020-32.pdf Krüger, J., Pilch Kedzierski, R. , Bumke, K. and Matthes, K. (2020) Impact of North Atlantic SST and Jet Stream anomalies on European Heat Waves. Open Access Weather amd Climate Dynamics Discussion . DOI 10.5194/wcd-2020-32 <https://doi.org/10.5194/wcd-2020-32>. doi:10.5194/wcd-2020-32 |
op_rights |
cc_by_4.0 info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/wcd-2020-32 |
_version_ |
1766117040100212736 |