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A decade of weather extremes

Dim Coumou, Stefan Rahmstorf
2012 Nature Climate Change  
A decade of weather extremes Dim Coumou and Stefan Rahmstorf* The ostensibly large number of recent extreme weather events has triggered intensive discussions, both in-and outside the scientific community  ... 
doi:10.1038/nclimate1452 fatcat:kfwcvicggbga3hfgfxhbq4vrxi

Global increase in record-breaking monthly-mean temperatures

Dim Coumou, Alexander Robinson, Stefan Rahmstorf
2013 Climatic Change  
All had severe impacts on society causing many heat-related deaths, massive forest fires or harvest losses (Coumou and Rahmstorf 2012; UNEP 2004; WMO 2011b) .  ...  In between these cases, monthly-mean temperatures typically have a standard deviation similar to the observed warming over the 20th century (Rahmstorf and Coumou 2011) .  ... 
doi:10.1007/s10584-012-0668-1 fatcat:x6cuitr4yvbonprajx36gcuczq

Erratum to: increased record-breaking precipitation events under global warming

Jascha Lehmann, Dim Coumou, Katja Frieler
2015 Climatic Change  
doi:10.1007/s10584-015-1466-3 fatcat:bbwphfwknfexxmxw4sqnisoio4

The influence of mid-latitude storm tracks on hot, cold, dry and wet extremes

Jascha Lehmann, Dim Coumou
2015 Scientific Reports  
Coumou et al. 31 proposed a physical mechanism to explain the observed weakening in summer circulation over recent decades.  ...  anomalies of EKE and temperature in summer.Regression slopes are shown for the 90 th -percentile (a), 50 th -percentile (b), and 10 th -percentile (c) with the middle panel being similar toFig. 4from Coumou  ... 
doi:10.1038/srep17491 pmid:26657163 pmcid:PMC4675986 fatcat:c6fdyknuzne25c7wcqg4wmju6u

Historic and future increase in the global land area affected by monthly heat extremes

Dim Coumou, Alexander Robinson
2013 Environmental Research Letters  
Introduction The recent decade has seen an exceptional number of extreme heat waves around the world that caused severe damage to society and ecosystems (WMO 2011, Coumou and Rahmstorf 2012) .  ...  At the same time, the number of record-breaking monthly temperatures increased strongly, in agreement with the increase expected by a shift in the mean towards warmer values (Coumou et al 2013) .  ... 
doi:10.1088/1748-9326/8/3/034018 fatcat:s62vfqtyzjhvrdrcbxuw4dgste

Impacts of compound hot–dry extremes on US soybean yields

Raed Hamed, Anne F. Van Loon, Jeroen Aerts, Dim Coumou
2021 Earth System Dynamics  
., 2020; Coumou et al., 2014; Kornhuber et al., 2019; Shepherd, 2014; Winter et al., 2015) .  ... 
doi:10.5194/esd-12-1371-2021 fatcat:gxhgpl7g5fb4vllbvfjjkmrytm

Regional Changes in the Mean Position and Variability of the Tropical Edge

Sonja Totz, Stefan Petri, Jascha Lehmann, Dim Coumou
2018 Geophysical Research Letters  
., & Coumou, D.(2018). Regional changes in the mean position and variability of the tropical edge. Geophysical Research Letters, 45, 12,076-12,084. https://doi.  ... 
doi:10.1029/2018gl079911 fatcat:eqxm7rfzkfbphjvmvkblulr4iq

A network-based detection scheme of the jet stream core

Sonja Molnos, Tarek Mamdouh, Stefan Petri, Thomas Nocke, Tino Weinkauf, Dim Coumou
2016 Earth System Dynamics Discussions  
Persistent weather can favour some type of extreme weather events (Coumou et al., 2014; Stadtherr et al., 2016) .  ...  Coumou analysed and interpreted the data. S. Molnos prepared the manuscript with contributions from all co-authors.  ... 
doi:10.5194/esd-2016-37 fatcat:lq54rhmn4nahdju7w3ttv7tps4

A network-based detection scheme for the jet stream core

Sonja Molnos, Tarek Mamdouh, Stefan Petri, Thomas Nocke, Tino Weinkauf, Dim Coumou
2017 Earth System Dynamics  
(Sonja Molnos, Dim Coumou).  ...  Sonja Molnos, Tarek Mamdouh, Stefan Petri, Thomas Nocke, Tino Weinkauf and Dim Coumou. Author contributions.  ...  Sonja Molnos and Dim Coumou analyzed and interpreted the data. Sonja Molnos prepared the paper with contributions from all co-authors.  ... 
doi:10.5194/esd-8-75-2017 fatcat:ex377s3ig5darhq6c5n2t7oqfi

Compound warm–dry and cold–wet events over the Mediterranean

Paolo De Luca, Gabriele Messori, Davide Faranda, Philip J. Ward, Dim Coumou
2020 Earth System Dynamics  
Abstract. The Mediterranean (MED) Basin is a climate change hotspot that has seen drying and a pronounced increase in heatwaves over the last century. At the same time, it is experiencing increased heavy precipitation during wintertime cold spells. Understanding and quantifying the risks from compound events over the MED is paramount for present and future disaster risk reduction measures. Here, we apply a novel method to study compound events based on dynamical systems theory and analyse
more » ... nd temperature and precipitation events over the MED from 1979 to 2018. The dynamical systems analysis quantifies the strength of the coupling between different atmospheric variables over the MED. Further, we consider compound warm–dry anomalies in summer and cold–wet anomalies in winter. Our results show that these warm–dry and cold–wet compound days are associated with large values of the temperature–precipitation coupling parameter of the dynamical systems analysis. This indicates that there is a strong interaction between temperature and precipitation during compound events. In winter, we find no significant trend in the coupling between temperature and precipitation. However in summer, we find a significant upward trend which is likely driven by a stronger coupling during warm and dry days. Thermodynamic processes associated with long-term MED warming can best explain the trend, which intensifies compound warm–dry events.
doi:10.5194/esd-11-793-2020 fatcat:gauss7fz6beo5phpmzkbvi45sq

Future changes in extratropical storm tracks and baroclinicity under climate change

Jascha Lehmann, Dim Coumou, Katja Frieler, Alexey V Eliseev, Anders Levermann
2014 Environmental Research Letters  
The weather in Eurasia, Australia, and North and South America is largely controlled by the strength and position of extratropical storm tracks. Future climate change will likely affect these storm tracks and the associated transport of energy, momentum, and water vapour. Many recent studies have analyzed how storm tracks will change under climate change, and how these changes are related to atmospheric dynamics. However, there are still discrepancies between different studies on how storm
more » ... s will change under future climate scenarios. Here, we show that under global warming the CMIP5 ensemble of coupled climate models projects only little relative changes in vertically averaged mid-latitude mean storm track activity during the northern winter, but agree in projecting a substantial decrease during summer. Seasonal changes in the Southern Hemisphere show the opposite behaviour, with an intensification in winter and no change during summer. These distinct seasonal changes in northern summer and southern winter storm tracks lead to an amplified seasonal cycle in a future climate. Similar changes are seen in the mid-latitude mean Eady growth rate maximum, a measure that combines changes in vertical shear and static stability based on baroclinic instability theory. Regression analysis between changes in the storm tracks and changes in the maximum Eady growth rate reveal that most models agree in a positive association between the two quantities over mid-latitude regions.
doi:10.1088/1748-9326/9/8/084002 fatcat:2h4tupgyxna6fjvux46auwewza

Assessing changes in risk of amplified planetary waves in a warming world

Chris Huntingford, Dann Mitchell, Kai Kornhuber, Dim Coumou, Scott Osprey, Myles Allen
2019 Atmospheric Science Letters  
Coumou et al. (2014) find that a decrease in meridional gradients favours QRA, which are positive values in our Figure 4 .  ...  Clusters of QRA events have occurred in recent decades (Petoukhov et al., 2013; Coumou et al., 2014; Petoukhov et al., 2016; Kornhuber et al., 2017b) .  ... 
doi:10.1002/asl.929 fatcat:iz63gra4zzhx5e2bjogdrxx7be

Using Causal Effect Networks to Analyze Different Arctic Drivers of Midlatitude Winter Circulation

Marlene Kretschmer, Dim Coumou, Jonathan F. Donges, Jakob Runge
2016 Journal of Climate  
Although a negative AO and meandering flow patterns have been linked to surface extremes (Thompson 2001; Coumou et al. 2014; Screen and Simmonds 2014) , it is intensively discussed what the mechanisms  ...  of how tropical mechanisms contribute to midlatitude winter circulation (Palmer 2014; Trenberth et al. 2014 ) and also the different hypotheses related to summer circulation (Overland et al. 2012; Coumou  ... 
doi:10.1175/jcli-d-15-0654.1 fatcat:tpnfqexuqbag5bl5czw2e7ay34

Influence of Anthropogenic Climate Change on Planetary Wave Resonance and Extreme Weather Events

Michael E. Mann, Stefan Rahmstorf, Kai Kornhuber, Byron A. Steinman, Sonya K. Miller, Dim Coumou
2017 Scientific Reports  
Miller & Dim Coumou Scientific Reports 7:45242; doi: 10.1038/srep45242; published online 27 March 2017; updated on 26 May 2017 This Article contains an error in Figure 1a, where the y-axis 'Temperature  ... 
doi:10.1038/srep45242 pmid:28345645 pmcid:PMC5366916 fatcat:hxfohbd4sfcppknihr34mcypti

The different stratospheric influence on cold-extremes in Eurasia and North America

Marlene Kretschmer, Judah Cohen, Vivien Matthias, Jakob Runge, Dim Coumou
2018 npj Climate and Atmospheric Science  
The stratospheric polar vortex can influence the tropospheric circulation and thereby winter weather in the mid-latitudes. Weak vortex states, often associated with sudden stratospheric warmings (SSW), have been shown to increase the risk of cold-spells especially over Eurasia, but its role for North American winters is less clear. Using cluster analysis, we show that there are two dominant patterns of increased polar cap heights in the lower stratosphere. Both patterns represent a weak polar
more » ... rtex but they are associated with different wave mechanisms and different regional tropospheric impacts. The first pattern is zonally symmetric and associated with absorbed upward-propagating wave activity, leading to a negative phase of the North Atlantic Oscillation (NAO) and cold-air outbreaks over northern Eurasia. This coupling mechanism is well-documented in the literature and is consistent with the downward migration of the northern annular mode (NAM). The second pattern is zonally asymmetric and linked to downward reflected planetary waves over Canada followed by a negative phase of the Western Pacific Oscillation (WPO) and coldspells in Central Canada and the Great Lakes region. Causal effect network (CEN) analyses confirm the atmospheric pathways associated with this asymmetric pattern. Moreover, our findings suggest the reflective mechanism to be sensitive to the exact region of upward wave-activity fluxes and to be state-dependent on the strength of the vortex. Identifying the causal pathways that operate on weekly to monthly timescales can pave the way for improved sub-seasonal to seasonal forecasting of cold spells in the mid-latitudes.
doi:10.1038/s41612-018-0054-4 fatcat:vf72antfl5btpf425lpnehr42a
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