On the persistence of warm and cold spells in the Northern Hemisphere extratropics: regionalisation, synoptic-scale dynamics, and temperature budget

Tuel, Alexandre; Martius, Olivia (2 January 2023). On the persistence of warm and cold spells in the Northern Hemisphere extratropics: regionalisation, synoptic-scale dynamics, and temperature budget (EGUsphere). Copernicus 10.5194/egusphere-2022-1478

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Persistent warm and cold spells are often high-impact events that may lead to significant increases in mortality and crop damage, and can put substantial pressure on the power grid. Their spatial extent is seldom taken into account, or only based on case studies. Yet, the spatial dependence in prolonged warm or cold anomalies is critical to correctly understand the associated risks, whether in present-day or future climates. Here, we present a regionalisation of 3-week warm and cold spells in winter and summer across the Northern Hemisphere based on their sensitivity to the large-scale circulation. We identify spatially coherent regions and discuss the physical drivers responsible for persistent extreme temperature anomalies. Blocks are important precursors of such events – co-localized blocks for persistent summer warm spells and upstream blocks for winter cold spells. Recurrent Rossby wave patterns are also relevant for many mid-latitude regions. Additionally, summer warm spells are – unsurprisingly – often accompanied by negative precipitation anomalies that likely play an important role through land-atmosphere feedbacks

Item Type:

Working Paper

Division/Institute:

10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR) > MobiLab
08 Faculty of Science > Institute of Geography > Physical Geography > Unit Impact
10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)
08 Faculty of Science > Institute of Geography
08 Faculty of Science > Institute of Geography > Physical Geography

UniBE Contributor:

Tuel, Alexandre, Romppainen-Martius, Olivia

Subjects:

900 History > 910 Geography & travel
500 Science > 550 Earth sciences & geology
500 Science

Series:

EGUsphere

Publisher:

Copernicus

Funders:

[4] Swiss National Science Foundation

Language:

English

Submitter:

Lara Maude Zinkl

Date Deposited:

08 Jun 2023 09:16

Last Modified:

08 Jun 2023 09:16

Publisher DOI:

10.5194/egusphere-2022-1478

BORIS DOI:

10.48350/183211

URI:

https://boris.unibe.ch/id/eprint/183211

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