Articles | Volume 3, issue 3
https://doi.org/10.5194/wcd-3-733-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/wcd-3-733-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
12 Jul 2022
Research article |
| 12 Jul 2022
| 12 Jul 2022
The role of cyclones and potential vorticity cutoffs for the occurrence of unusually long wet spells in Europe
Matthias Röthlisberger
CORRESPONDING AUTHOR
Department of Environmental Systems Science, Institute for Atmospheric and Climate Science, ETH Zürich, Zürich, Switzerland
Barbara Scherrer
Department of Environmental Systems Science, Institute for Atmospheric and Climate Science, ETH Zürich, Zürich, Switzerland
Andries Jan de Vries
Department of Environmental Systems Science, Institute for Atmospheric and Climate Science, ETH Zürich, Zürich, Switzerland
now at: Faculty of Geosciences and Environment, Institute of Earth Surface Dynamics, University of Lausanne, Lausanne, Switzerland
Raphael Portmann
Department of Environmental Systems Science, Institute for Atmospheric and Climate Science, ETH Zürich, Zürich, Switzerland
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Yonatan Givon, Or Hess, Emmanouil Flaounas, Jennifer Louise Catto, Michael Sprenger, and Shira Raveh-Rubin
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Talia Tamarin-Brodsky and Nili Harnik
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Blocking over Greenland has substantial impacts on the weather and climate in mid and high latitudes. This study applies a quasi-Lagrangian thinking on the dynamics of Greenland blocking and reveals two pathways of anticyclonic anomalies linked to the block. Moist processes were found to play a dominant role in the formation and maintenance of blocking. This emphasizes the necessity of the correct representation of moist processes in weather and climate models to realistically depict blocking.
Stephen Outten and Richard Davy
EGUsphere, https://doi.org/10.5194/egusphere-2023-2832, https://doi.org/10.5194/egusphere-2023-2832, 2023
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The North Atlantic Oscillation is linked to wintertime weather events over Europe. One feature often overlooked is how much the climate variability explained by the NAO has changed over time. We show that there has been a considerable increase in the percentage variance explained by the NAO over the 20th century, and that this is not reproduced by 50 CMIP6 climate models, which are generally biased too high. This has implications for projections and prediction of weather events in the region.
Lea Eisenstein, Benedikt Schulz, Joaquim G. Pinto, and Peter Knippertz
Weather Clim. Dynam., 4, 981–999, https://doi.org/10.5194/wcd-4-981-2023, https://doi.org/10.5194/wcd-4-981-2023, 2023
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Mesoscale high-wind features within extratropical cyclones can cause immense damage. In Part 1 of this work, we introduced RAMEFI (RAndom-forest-based MEsoscale wind Feature Identification), an objective, flexible identification tool for these wind features based on a probabilistic random forest. Here, we use RAMEFI to compile a climatology of the features over 19 extended winter seasons over western and central Europe, focusing on relative occurrence, affected areas and further characteristics.
Tiina Nygård, Lukas Papritz, Tuomas Naakka, and Timo Vihma
Weather Clim. Dynam., 4, 943–961, https://doi.org/10.5194/wcd-4-943-2023, https://doi.org/10.5194/wcd-4-943-2023, 2023
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Despite the general warming trend, wintertime cold-air outbreaks in Europe have remained nearly as extreme and as common as decades ago. In this study, we identify six principal cold anomaly types over Europe in 1979–2020. We show the origins of various physical processes and their contributions to the formation of cold wintertime air masses.
Andrea Marcheggiani and Thomas Spengler
Weather Clim. Dynam., 4, 927–942, https://doi.org/10.5194/wcd-4-927-2023, https://doi.org/10.5194/wcd-4-927-2023, 2023
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There is a gap between the theoretical understanding and model representation of moist diabatic effects on the evolution of storm tracks. We seek to bridge this gap by exploring the relationship between diabatic and adiabatic contributions to changes in baroclinicity. We find reversed behaviours in the lower and upper troposphere in the maintenance of baroclinicity. In particular, our study reveals a link between higher moisture availability and upper-tropospheric restoration of baroclinicity.
Alice Portal, Fabio D'Andrea, Paolo Davini, Mostafa E. Hamouda, and Claudia Pasquero
Weather Clim. Dynam., 4, 809–822, https://doi.org/10.5194/wcd-4-809-2023, https://doi.org/10.5194/wcd-4-809-2023, 2023
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The differences between climate models can be exploited to infer how specific aspects of the climate influence the Earth system. This work analyses the effects of a negative temperature anomaly over the Tibetan Plateau on the winter atmospheric circulation. We show that models with a colder-than-average Tibetan Plateau present a reinforcement of the eastern Asian winter monsoon and discuss the atmospheric response to the enhanced transport of cold air from the continent toward the Pacific Ocean.
Charlie C. Suitters, Oscar Martínez-Alvarado, Kevin I. Hodges, Reinhard K. H. Schiemann, and Duncan Ackerley
Weather Clim. Dynam., 4, 683–700, https://doi.org/10.5194/wcd-4-683-2023, https://doi.org/10.5194/wcd-4-683-2023, 2023
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Atmospheric blocking describes large and persistent high surface pressure. In this study, the relationship between block persistence and smaller-scale systems is examined. Persistent blocks result from more interactions with small systems, but a block's persistence does not depend as strongly on the strength of these smaller features. This work is important because it provides more knowledge as to how blocks can be allowed to persist, which is something we still do not fully understand.
Emmanouil Flaounas, Leonardo Aragão, Lisa Bernini, Stavros Dafis, Benjamin Doiteau, Helena Flocas, Suzanne L. Gray, Alexia Karwat, John Kouroutzoglou, Piero Lionello, Mario Marcello Miglietta, Florian Pantillon, Claudia Pasquero, Platon Patlakas, María Ángeles Picornell, Federico Porcù, Matthew D. K. Priestley, Marco Reale, Malcolm J. Roberts, Hadas Saaroni, Dor Sandler, Enrico Scoccimarro, Michael Sprenger, and Baruch Ziv
Weather Clim. Dynam., 4, 639–661, https://doi.org/10.5194/wcd-4-639-2023, https://doi.org/10.5194/wcd-4-639-2023, 2023
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Cyclone detection and tracking methods (CDTMs) have different approaches in defining and tracking cyclone centers. This leads to disagreements on extratropical cyclone climatologies. We present a new approach that combines tracks from individual CDTMs to produce new composite tracks. These new tracks are shown to correspond to physically meaningful systems with distinctive life stages.
Katharina Heitmann, Michael Sprenger, Hanin Binder, Heini Wernli, and Hanna Joos
EGUsphere, https://doi.org/10.5194/egusphere-2023-1092, https://doi.org/10.5194/egusphere-2023-1092, 2023
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Warm conveyor belts (WCBs) are coherently ascending air streams that occur in extratropical cyclones where they form precipitation and often affect the large-scale flow. We quantified the key characteristics and impacts of WCBs and linked them to different phases in the cyclone life cycle and to different WCB branches. A climatology of these metrics revealed that WCBs are most intense during cyclone intensification and that the cyclonic and anticyclonic WCB branches show distinct differences.
Deborah Morgenstern, Isabell Stucke, Georg J. Mayr, Achim Zeileis, and Thorsten Simon
Weather Clim. Dynam., 4, 489–509, https://doi.org/10.5194/wcd-4-489-2023, https://doi.org/10.5194/wcd-4-489-2023, 2023
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Two thunderstorm environments are described for Europe: mass-field thunderstorms, which occur mostly in summer, over land, and under similar meteorological conditions, and wind-field thunderstorms, which occur mostly in winter, over the sea, and under more diverse meteorological conditions. Our descriptions are independent of static thresholds and help to understand why thunderstorms in unfavorable seasons for lightning pose a particular risk to tall infrastructure such as wind turbines.
Florian Ruff and Stephan Pfahl
Weather Clim. Dynam., 4, 427–447, https://doi.org/10.5194/wcd-4-427-2023, https://doi.org/10.5194/wcd-4-427-2023, 2023
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In this study, we analyse the generic atmospheric processes of very extreme, 100-year precipitation events in large central European river catchments and the corresponding differences to less extreme events, based on a large time series (~1200 years) of simulated but realistic daily precipitation events from the ECMWF. Depending on the catchment, either dynamical mechanisms or thermodynamic conditions or a combination of both distinguish 100-year events from less extreme precipitation events.
Seraphine Hauser, Franziska Teubler, Michael Riemer, Peter Knippertz, and Christian M. Grams
Weather Clim. Dynam., 4, 399–425, https://doi.org/10.5194/wcd-4-399-2023, https://doi.org/10.5194/wcd-4-399-2023, 2023
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Blocking describes a flow configuration in the midlatitudes where stationary high-pressure systems block the propagation of weather systems. This study combines three individual perspectives that capture the dynamics and importance of various processes in the formation of a major blocking in 2016 from a weather regime perspective. In future work, this framework will enable a holistic view of the dynamics and the role of moist processes in different life cycle stages of blocked weather regimes.
Charles G. Gertler, Paul A. O'Gorman, and Stephan Pfahl
Weather Clim. Dynam., 4, 361–379, https://doi.org/10.5194/wcd-4-361-2023, https://doi.org/10.5194/wcd-4-361-2023, 2023
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The relationship between the time-mean state of the atmosphere and aspects of atmospheric circulation drives general understanding of the atmospheric circulation. Here, we present new techniques to calculate local properties of the time-mean atmosphere and relate those properties to aspects of extratropical circulation with important implications for weather. This relationship should help connect changes to the atmosphere, such as under global warming, to changes in midlatitude weather.
Colin Manning, Martin Widmann, Douglas Maraun, Anne F. Van Loon, and Emanuele Bevacqua
Weather Clim. Dynam., 4, 309–329, https://doi.org/10.5194/wcd-4-309-2023, https://doi.org/10.5194/wcd-4-309-2023, 2023
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Climate models differ in their representation of dry spells and high temperatures, linked to errors in the simulation of persistent large-scale anticyclones. Models that simulate more persistent anticyclones simulate longer and hotter dry spells, and vice versa. This information is important to consider when assessing the likelihood of such events in current and future climate simulations so that we can assess the plausibility of their future projections.
Edward Groot, Patrick Kuntze, Annette Katharina Miltenberger, and Holger Tost
EGUsphere, https://doi.org/10.5194/egusphere-2023-664, https://doi.org/10.5194/egusphere-2023-664, 2023
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Deep convective clouds systems are often associated with severe weather conditions. They can organise into coherent convective cloud systems. Accurate representation in numerical weather prediction is challenging due to the dynamics of the systems and its dependency on resolution. Here, the effect of convective organisation and geometry on outflow winds (altitudes of 7–14 km) is investigated. The divergent outflow originating from these systems is represented in more detail at higher resolution.
Franziska Teubler, Michael Riemer, Christopher Polster, Christian M. Grams, Seraphine Hauser, and Volkmar Wirth
Weather Clim. Dynam., 4, 265–285, https://doi.org/10.5194/wcd-4-265-2023, https://doi.org/10.5194/wcd-4-265-2023, 2023
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Weather regimes govern an important part of the sub-seasonal variability of the mid-latitude circulation. The year-round dynamics of blocked regimes in the Atlantic European region are investigated in over 40 years of data. We show that the dynamics between the regimes are on average very similar. Within the regimes, the main variability – starting from the characteristics of dynamical processes alone – dominates and transcends the variability in season and types of transitions.
Acacia S. Pepler and Irina Rudeva
Weather Clim. Dynam., 4, 175–188, https://doi.org/10.5194/wcd-4-175-2023, https://doi.org/10.5194/wcd-4-175-2023, 2023
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In recent decades, cold fronts have rained less often in southeast Australia, which contributes to decreasing cool season rainfall. The largest changes in front dynamics are found to the north of the area where rain changes. Wet fronts have strong westerly winds that reach much further north than dry fronts do, and these fronts are becoming less common, linked to weakening subtropical winds and changes in the Southern Hemisphere circulation.
Alexander Scherrmann, Heini Wernli, and Emmanouil Flaounas
Weather Clim. Dynam., 4, 157–173, https://doi.org/10.5194/wcd-4-157-2023, https://doi.org/10.5194/wcd-4-157-2023, 2023
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We investigate the dynamical origin of the lower-atmospheric potential vorticity (PV; linked to the intensity of cyclones) in Mediterranean cyclones. We quantify the contribution of the cyclone and the environment by tracing PV backward in time and space and linking it to the track of the cyclone. We find that the lower-tropospheric PV is produced shortly before the cyclone's stage of highest intensity. We investigate the driving processes and use a global dataset and a process-resolving one.
Felix Jäger, Philip Rupp, and Thomas Birner
Weather Clim. Dynam., 4, 49–60, https://doi.org/10.5194/wcd-4-49-2023, https://doi.org/10.5194/wcd-4-49-2023, 2023
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Mid-latitude weather is dominated by the growth, breaking and decay of baroclinic waves and associated jet shifts. A way to study this process is via idealised life-cycle simulations, which are often classified as LC1 (anticyclonic breaking, poleward shift) or LC2 (cyclonic breaking, equatorward shift), depending on details of the initial state. We show that all systems exhibit predominantly anticyclonic character and poleward net shifts if multiple wave modes are allowed to grow simultaneously.
Philipp Breul, Paulo Ceppi, and Theodore G. Shepherd
Weather Clim. Dynam., 4, 39–47, https://doi.org/10.5194/wcd-4-39-2023, https://doi.org/10.5194/wcd-4-39-2023, 2023
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Accurately predicting the response of the midlatitude jet stream to climate change is very important, but models show a variety of possible scenarios. Previous work identified a relationship between climatological jet latitude and future jet shift in the southern hemispheric winter. We show that the relationship does not hold in separate sectors and propose that zonal asymmetries are the ultimate cause in the zonal mean. This questions the usefulness of the relationship.
Patrick Johannes Stoll, Rune Grand Graversen, and Gabriele Messori
Weather Clim. Dynam., 4, 1–17, https://doi.org/10.5194/wcd-4-1-2023, https://doi.org/10.5194/wcd-4-1-2023, 2023
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The atmosphere is in motion and hereby transporting warm, cold, moist, and dry air to different climate zones. In this study, we investigate how this transport of energy organises in different manners. Outside the tropics, atmospheric waves of sizes between 2000 and 8000 km, which we perceive as cyclones from the surface, transport most of the energy and moisture poleward. In the winter, large-scale weather situations become very important for transporting energy into the polar regions.
Lisa Schielicke and Stephan Pfahl
Weather Clim. Dynam., 3, 1439–1459, https://doi.org/10.5194/wcd-3-1439-2022, https://doi.org/10.5194/wcd-3-1439-2022, 2022
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Projected future heatwaves in many European regions will be even warmer than the mean increase in summer temperature suggests. To identify the underlying thermodynamic and dynamic processes, we compare Lagrangian backward trajectories of airstreams associated with heatwaves in two time slices (1991–2000 and 2091–2100) in a large single-model ensemble (CEMS-LE). We find stronger future descent associated with adiabatic warming in some regions and increased future diabatic heating in most regions.
Iana Strigunova, Richard Blender, Frank Lunkeit, and Nedjeljka Žagar
Weather Clim. Dynam., 3, 1399–1414, https://doi.org/10.5194/wcd-3-1399-2022, https://doi.org/10.5194/wcd-3-1399-2022, 2022
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We show that the Eurasian heat waves (HWs) have signatures in the global circulation. We present changes in the probability density functions (PDFs) of energy anomalies in the zonal-mean state and in the Rossby waves at different zonal scales in relation to the changes in intramonthly variability. The skewness of the PDF of planetary-scale Rossby waves is shown to increase during HWs, while their intramonthly variability is reduced, a process referred to as blocking.
Anubhav Choudhary and Aiko Voigt
Weather Clim. Dynam., 3, 1199–1214, https://doi.org/10.5194/wcd-3-1199-2022, https://doi.org/10.5194/wcd-3-1199-2022, 2022
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The warm conveyor belt (WCB), which is a stream of coherently rising air parcels, is an important feature of extratropical cyclones. This work presents the impact of model grid spacing on simulation of cloud diabatic processes in the WCB of a North Atlantic cyclone. We find that the refinement of the model grid systematically enhances the dynamical properties and heat releasing processes within the WCB. However, this pattern does not have a strong impact on the strength of associated cyclones.
S. Mubashshir Ali, Matthias Röthlisberger, Tess Parker, Kai Kornhuber, and Olivia Martius
Weather Clim. Dynam., 3, 1139–1156, https://doi.org/10.5194/wcd-3-1139-2022, https://doi.org/10.5194/wcd-3-1139-2022, 2022
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Persistent weather can lead to extreme weather conditions. One such atmospheric flow pattern, termed recurrent Rossby wave packets (RRWPs), has been shown to increase persistent weather in the Northern Hemisphere. Here, we show that RRWPs are also an important feature in the Southern Hemisphere. We evaluate the role of RRWPs during south-eastern Australian heatwaves and find that they help to persist the heatwaves by forming upper-level high-pressure systems over south-eastern Australia.
Lea Eisenstein, Benedikt Schulz, Ghulam A. Qadir, Joaquim G. Pinto, and Peter Knippertz
Weather Clim. Dynam., 3, 1157–1182, https://doi.org/10.5194/wcd-3-1157-2022, https://doi.org/10.5194/wcd-3-1157-2022, 2022
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Mesoscale high-wind features within extratropical cyclones can cause immense damage. Here, we present RAMEFI, a novel approach to objectively identify the wind features based on a probabilistic random forest. RAMEFI enables a wide range of applications such as probabilistic predictions for the occurrence or a multi-decadal climatology of these features, which will be the focus of Part 2 of the study, with the goal of improving wind and, specifically, wind gust forecasts in the long run.
Lukas Jansing, Lukas Papritz, Bruno Dürr, Daniel Gerstgrasser, and Michael Sprenger
Weather Clim. Dynam., 3, 1113–1138, https://doi.org/10.5194/wcd-3-1113-2022, https://doi.org/10.5194/wcd-3-1113-2022, 2022
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This study presents a 5-year climatology of three main foehn types and three deep-foehn subtypes. The main types differ in their large-scale and Alpine-scale weather conditions and the subtypes in terms of the amount and extent of precipitation on the Alpine south side. The different types of foehn are found to strongly affect the local meteorological conditions at Altdorf. The study concludes by setting the new classification into a historic context.
Valerio Lembo, Federico Fabiano, Vera Melinda Galfi, Rune Grand Graversen, Valerio Lucarini, and Gabriele Messori
Weather Clim. Dynam., 3, 1037–1062, https://doi.org/10.5194/wcd-3-1037-2022, https://doi.org/10.5194/wcd-3-1037-2022, 2022
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Eddies in mid-latitudes characterize the exchange of heat between the tropics and the poles. This exchange is largely uneven, with a few extreme events bearing most of the heat transported across latitudes in a season. It is thus important to understand what the dynamical mechanisms are behind these events. Here, we identify recurrent weather regime patterns associated with extreme transports, and we identify scales of mid-latitudinal eddies that are mostly responsible for the transport.
Fei Luo, Frank Selten, Kathrin Wehrli, Kai Kornhuber, Philippe Le Sager, Wilhelm May, Thomas Reerink, Sonia I. Seneviratne, Hideo Shiogama, Daisuke Tokuda, Hyungjun Kim, and Dim Coumou
Weather Clim. Dynam., 3, 905–935, https://doi.org/10.5194/wcd-3-905-2022, https://doi.org/10.5194/wcd-3-905-2022, 2022
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Recent studies have identified the weather systems in observational data, where wave patterns with high-magnitude values that circle around the whole globe in either wavenumber 5 or wavenumber 7 are responsible for the extreme events. In conclusion, we find that the climate models are able to reproduce the large-scale atmospheric circulation patterns as well as their associated surface variables such as temperature, precipitation, and sea level pressure.
Meryl Wimmer, Gwendal Rivière, Philippe Arbogast, Jean-Marcel Piriou, Julien Delanoë, Carole Labadie, Quitterie Cazenave, and Jacques Pelon
Weather Clim. Dynam., 3, 863–882, https://doi.org/10.5194/wcd-3-863-2022, https://doi.org/10.5194/wcd-3-863-2022, 2022
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The effect of deep convection representation on the jet stream above the cold front of an extratropical cyclone is investigated in the global numerical weather prediction model ARPEGE. Two simulations using different deep convection schemes are compared with (re)analysis datasets and NAWDEX airborne observations. A deeper jet stream is observed with the less active scheme. The diabatic origin of this difference is interpreted by backward Lagrangian trajectories and potential vorticity budgets.
Paolo Davini, Federico Fabiano, and Irina Sandu
Weather Clim. Dynam., 3, 535–553, https://doi.org/10.5194/wcd-3-535-2022, https://doi.org/10.5194/wcd-3-535-2022, 2022
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In climate models, improvements obtained in the winter mid-latitude circulation following horizontal resolution increase are mainly caused by the more detailed representation of the mean orography. A high-resolution climate model with low-resolution orography might underperform compared to a low-resolution model with low-resolution orography. The absence of proper model tuning at high resolution is considered the potential reason behind such lack of improvements.
Joshua Dorrington, Kristian Strommen, and Federico Fabiano
Weather Clim. Dynam., 3, 505–533, https://doi.org/10.5194/wcd-3-505-2022, https://doi.org/10.5194/wcd-3-505-2022, 2022
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We investigate how well current state-of-the-art climate models reproduce the wintertime weather of the North Atlantic and western Europe by studying how well different "regimes" of weather are captured. Historically, models have struggled to capture these regimes, making it hard to predict future changes in wintertime extreme weather. We show models can capture regimes if the right method is used, but they show biases, partially as a result of biases in jet speed and eddy strength.
Jacopo Riboldi, Efi Rousi, Fabio D'Andrea, Gwendal Rivière, and François Lott
Weather Clim. Dynam., 3, 449–469, https://doi.org/10.5194/wcd-3-449-2022, https://doi.org/10.5194/wcd-3-449-2022, 2022
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A revisited space and time spectral decomposition allows us to determine which harmonics dominate the upper-tropospheric flow evolution over a given time period as well as their propagation. This approach is used to identify Rossby wave patterns with a circumglobal extent, affecting weather evolution over different Northern Hemisphere regions. The results cast light on the processes originating and supporting these wave patterns, advocating at the same time for the usefulness of the technique.
Philipp Zschenderlein and Heini Wernli
Weather Clim. Dynam., 3, 391–411, https://doi.org/10.5194/wcd-3-391-2022, https://doi.org/10.5194/wcd-3-391-2022, 2022
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Precipitation and temperature are two of the most important variables describing our weather and climate. The relationship between these variables has been studied extensively; however, the role of specific weather systems in shaping this relationship has not been analysed yet. We therefore analyse whether intense precipitation occurs on warmer or on colder days and identify the relevant weather systems. In general, weather systems strongly influence this relationship, especially in winter.
Deborah Morgenstern, Isabell Stucke, Thorsten Simon, Georg J. Mayr, and Achim Zeileis
Weather Clim. Dynam., 3, 361–375, https://doi.org/10.5194/wcd-3-361-2022, https://doi.org/10.5194/wcd-3-361-2022, 2022
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Wintertime lightning in central Europe is rare but has a large damage potential for tall structures such as wind turbines. We use a data-driven approach to explain why it even occurs when the meteorological processes causing thunderstorms in summer are absent. In summer, with strong solar input, thunderclouds have a large vertical extent, whereas in winter, thunderclouds are shallower in the vertical but tilted and elongated in the horizontal by strong winds that increase with altitude.
Matthew D. K. Priestley and Jennifer L. Catto
Weather Clim. Dynam., 3, 337–360, https://doi.org/10.5194/wcd-3-337-2022, https://doi.org/10.5194/wcd-3-337-2022, 2022
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We use the newest set of climate model experiments from CMIP6 to investigate changes to mid-latitude storm tracks and cyclones from global warming. The overall number of cyclones will decrease. However in winter there will be more of the most intense cyclones, and these intense cyclones are likely to be stronger. Cyclone wind speeds will increase in winter, and as a result the area of strongest wind speeds will increase. By 2100 the area of strong wind speeds may increase by over 30 %.
Lisa-Ann Kautz, Olivia Martius, Stephan Pfahl, Joaquim G. Pinto, Alexandre M. Ramos, Pedro M. Sousa, and Tim Woollings
Weather Clim. Dynam., 3, 305–336, https://doi.org/10.5194/wcd-3-305-2022, https://doi.org/10.5194/wcd-3-305-2022, 2022
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Atmospheric blocking is associated with stationary, self-sustaining and long-lasting high-pressure systems. They can cause or at least influence surface weather extremes, such as heat waves, cold spells, heavy precipitation events, droughts or wind extremes. The location of the blocking determines where and what type of extreme event will occur. These relationships are also important for weather prediction and may change due to global warming.
Manuel Saigger and Alexander Gohm
Weather Clim. Dynam., 3, 279–303, https://doi.org/10.5194/wcd-3-279-2022, https://doi.org/10.5194/wcd-3-279-2022, 2022
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In this work a special form of a foehn wind in an Alpine valley with a large-scale northwesterly flow is investigated. The study clarifies the origin of the air mass and the mechanisms by which this air enters the valley. A trajectory analysis shows that the location where the main airstream passes the crest line is more suitable for a foehn classification than the local or large-scale wind direction. Mountain waves and a lee rotor were crucial for importing air into the valley.
Antoine Blanc, Juliette Blanchet, and Jean-Dominique Creutin
Weather Clim. Dynam., 3, 231–250, https://doi.org/10.5194/wcd-3-231-2022, https://doi.org/10.5194/wcd-3-231-2022, 2022
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Precipitation variability and extremes in the northern French Alps are governed by the atmospheric circulation over western Europe. In this work, we study the past evolution of western Europe large-scale circulation using atmospheric descriptors. We show some discrepancies in the trends obtained from different reanalyses before 1950. After 1950, we find trends in Mediterranean circulations that appear to be linked with trends in seasonal and extreme precipitation in the northern French Alps.
Cited articles
Ali, S. M., Martius, O., and Röthlisberger, M.: Recurrent Rossby wave packets modulate the persistence of dry and wet spells across the globe, Geophys. Res. Lett., 48, e2020GL091452,
https://doi.org/10.1029/2020GL091452, 2021.
Appenzeller, C. and Davies, H. C.: Structure of stratospheric intrusions
into the troposphere, Nature, 358, 570–572, https://doi.org/10.1038/358570a0, 1992.
Berger, A. and Goossens, C.: Persistence of wet and dry spells at Uccle
(Belgium), J. Climatol., 3, 21–34, https://doi.org/10.1002/joc.3370030103, 1983.
Besson, P., Fischer, L. J., Schemm, S., and Sprenger, M.: A global analysis of the dry-dynamic forcing during cyclone growth and propagation, Weather Clim. Dynam., 2, 991–1009, https://doi.org/10.5194/wcd-2-991-2021, 2021.
Catto, J. L. and Pfahl, S.: The importance of fronts for extreme
precipitation, J. Geophys. Res.-Atmos., 118, 10791–10801,
https://doi.org/10.1002/jgrd.50852, 2013.
Dacre, H. F. and Pinto, J. G.: Serial clustering of extratropical cyclones:
A review of where, when and why it occurs, npj Clim. Atmos. Sci., 3, 1–10,
https://doi.org/10.1038/s41612-020-00152-9, 2020.
Dee, D. P., Uppala, S. M., Simmons, A. J., Berrisford, P., Poli, P.,
Kobayashi, S., Andrae, U., Balmaseda, M. A., Balsamo, G., Bauer, P.,
Bechtold, P., Beljaars, A. C. M., van de Berg, L., Bidlot, J., Bormann, N.,
Delsol, C., Dragani, R., Fuentes, M., Geer, A. J., Haimberger, L., Healy, S.
B., Hersbach, H., Hólm, E. V., Isaksen, L., Kållberg, P.,
Köhler, M., Matricardi, M., Mcnally, A. P., Monge-Sanz, B. M.,
Morcrette, J.-J., Park, B.-K., Peubey, C., de Rosnay, P., Tavolato, C.,
Thépaut, J. N., and Vitart, F.: The ERA-Interim reanalysis:
Configuration and performance of the data assimilation system, Q. J. Roy.
Meteor. Soc., 137, 553–597, https://doi.org/10.1002/qj.828, 2011.
de Vries, A. J.: A global climatological perspective on the importance of Rossby wave breaking and intense moisture transport for extreme precipitation events, Weather Clim. Dynam., 2, 129–161, https://doi.org/10.5194/wcd-2-129-2021, 2021.
Doswell, C. A., Ramis, C., Romero, R., and Alonso, S.: A diagnostic study of
three heavy precipitation episodes in the western Mediterranean region,
Weather Forecast., 13, 102–124,
https://doi.org/10.1175/1520-0434(1998)013<0102:ADSOTH>2.0.CO;2, 1998.
European Centre for Medium-Range Weather Forecasts:
ERA-Interim re-analysis data, ECMWF [data set], https://apps.ecmwf.int/datasets/data/interim-full-daily/levtype=sfc/,
last access: 6 July 2022.
Field, P. R. and Wood, R.: Precipitation and cloud structure in midlatitude
cyclones, J. Climate, 20, 233–254, https://doi.org/10.1175/JCLI3998.1, 2007.
Flaounas, E., Röthlisberger, M., Boettcher, M., Sprenger, M., and Wernli, H.: Extreme wet seasons – their definition and relationship with synoptic-scale weather systems, Weather Clim. Dynam., 2, 71–88, https://doi.org/10.5194/wcd-2-71-2021, 2021.
Graf, M. A., Wernli, H., and Sprenger, M.: Objective classification of
extratropical cyclogenesis, Q. J. Roy. Meteor. Soc., 143, 1047–1061,
https://doi.org/10.1002/qj.2989, 2017.
Grams, C. M., Binder, H., Pfahl, S., Piaget, N., and Wernli, H.: Atmospheric processes triggering the central European floods in June 2013, Nat. Hazards Earth Syst. Sci., 14, 1691–1702, https://doi.org/10.5194/nhess-14-1691-2014, 2014.
Hawcroft, M. K., Shaffrey, L. C., Hodges, K. I., and Dacre, H. F.: How much
Northern Hemisphere precipitation is associated with extratropical
cyclones?, Geophys. Res. Lett., 39, L24809, https://doi.org/10.1029/2012GL053866,
2012.
Hoskins, B. J., McIntyre, M. E., and Robertson, A. W.: On the use and
significance of isentropic potential vorticity maps, Q. J. Roy. Meteor.
Soc., 111, 877–946, https://doi.org/10.1002/qj.49711147002, 1985.
Lavers, D. A. and Villarini, G.: The nexus between atmospheric rivers and
extreme precipitation across Europe, Geophys. Res. Lett., 40, 3259–3264,
https://doi.org/10.1002/GRL.50636, 2013.
Lenderink, G. and Van Meijgaard, E.: Linking increases in hourly
precipitation extremes to atmospheric temperature and moisture changes,
Environ. Res. Lett., 5, 025208, https://doi.org/10.1088/1748-9326/5/2/025208, 2010.
Lenggenhager, S. and Martius, O.: Atmospheric blocks modulate the odds of
heavy precipitation events in Europe, Clim. Dynam., 53, 4155–4171,
https://doi.org/10.1007/s00382-019-04779-0, 2019.
Lenggenhager, S., Croci-Maspoli, M., Brönnimann, S., and Martius, O.: On
the dynamical coupling between atmospheric blocks and heavy precipitation
events: A discussion of the southern Alpine flood in October 2000, Q. J. Roy. Meteor. Soc., 145, 530–545, https://doi.org/10.1002/qj.3449, 2019.
Mailier, P. J., Stephenson, D. B., Ferro, C. A. T., and Hodges, K. I.:
Serial clustering of extratropical cyclones, Mon. Weather Rev., 134,
2224–2240, https://doi.org/10.1175/MWR3160.1, 2006.
Martius, O., Zenklusen, E., Schwierz, C., and Davies, H. C.: Episodes of
Alpine heavy precipitation with an overlying elongated stratospheric
intrusion: A climatology, Int. J. Climatol., 26, 1149–1164,
https://doi.org/10.1002/joc.1295, 2006.
Martius, O., Sodemann, H., Joos, H., Pfahl, S., Winschall, A.,
Croci-Maspoli, M., Graf, M., Madonna, E., Mueller, B., Schemm, S.,
Sedláček, J., Sprenger, M., and Wernli, H.: The role of upper-level
dynamics and surface processes for the Pakistan flood of July 2010, Q. J. Roy. Meteor. Soc., 139, 1780–1797, https://doi.org/10.1002/qj.2082, 2013.
Massacand, A. C., Wernli, H., and Davies, H. C.: Heavy precipitation on the
alpine southside: An upper-level precursor, Geophys. Res. Lett., 25,
1435–1438, https://doi.org/10.1029/98GL50869, 1998.
McIntyre, M. E. and Palmer, T. N.: Breaking planetary waves in the
stratosphere, Nature, 305, 593–600, https://doi.org/10.1038/305593a0, 1983.
Mohr, S., Wilhelm, J., Wandel, J., Kunz, M., Portmann, R., Punge, H. J., Schmidberger, M., Quinting, J. F., and Grams, C. M.: The role of large-scale dynamics in an exceptional sequence of severe thunderstorms in Europe May–June 2018, Weather Clim. Dynam., 1, 325–348, https://doi.org/10.5194/wcd-1-325-2020, 2020.
Moore, B. J., Neiman, P. J., Ralph, F. M., and Barthold, F. E.: Physical
processes associated with heavy flooding rainfall in Nashville, Tennessee,
and vicinity during 1–2 May 2010: The role of an atmospheric river and
mesoscale convective systems, Mon. Weather Rev., 140, 358–378,
https://doi.org/10.1175/MWR-D-11-00126.1, 2012.
Moore, B. J., Keyser, D., and Bosart, L. F.: Linkages between Extreme
Precipitation Events in the Central and Eastern United States and Rossby
Wave Breaking, Mon. Weather Rev., 147, 3327–3349,
https://doi.org/10.1175/MWR-D-19-0047.1, 2019.
Moore, B. J., White, A. B., Gottas, D. J., and Neiman, P. J.: Extreme
precipitation events in Northern California during winter 2016–17:
Multiscale analysis and climatological perspective, Mon. Weather Rev., 148,
1049–1074, https://doi.org/10.1175/MWR-D-19-0242.1, 2020.
Moore, B. J., White, A. B., and Gottas, D. J.: Characteristics of
long-duration heavy precipitation events along the West Coast of the United
States, Mon. Weather Rev., 149, 2255–2277, https://doi.org/10.1175/MWR-D-20-0336.1, 2021.
Newell, R. E., Newell, N. E., Zhu, Y., and Scott, C.: Tropospheric rivers?
– A pilot study, Geophys. Res. Lett., 19, 2401–2404,
https://doi.org/10.1029/92GL02916, 1992.
Pfahl, S. and Wernli, H.: Quantifying the relevance of cyclones for
precipitation extremes, J. Climate, 25, 6770–6780,
https://doi.org/10.1175/JCLI-D-11-00705.1, 2012.
Pfahl, S., Madonna, E., Boettcher, M., Joos, H., and Wernli, H.: Warm
conveyor belts in the ERA-Interim Dataset (1979–2010). Part II: Moisture
origin and relevance for precipitation, J. Climate, 27, 27–40,
https://doi.org/10.1175/JCLI-D-13-00223.1, 2014.
Pfleiderer, P., Schleussner, C. F., Kornhuber, K., and Coumou, D.: Summer
weather becomes more persistent in a 2 ∘C world, Nat. Clim. Chang., 9, 666–671, https://doi.org/10.1038/s41558-019-0555-0, 2019.
Pinto, J. G., Gómara, I., Masato, G., Dacre, H. F., Woollings, T., and
Caballero, R.: Large-scale dynamics associated with clustering of
extratropical cyclones affecting Western Europe, J. Geophys. Res., 119,
13704–13719, https://doi.org/10.1002/2014JD022305, 2014.
Portmann, R.: The life cycles of potential vorticity cutoffs: Climatology,
predictability and high impact weather, ETH Zürich, 232 pp.,
https://doi.org/10.3929/ethz-b-000466735, 2020.
Portmann, R., Crezee, B., Quinting, J., and Wernli, H.: The complex
life-cycles of two long-lived potential vorticity cutoffs over Europe, Q. J. Roy. Meteor. Soc., 144, 701–719, https://doi.org/10.1002/qj.3239, 2018.
Portmann, R., Sprenger, M., and Wernli, H.: The three-dimensional life cycles of potential vorticity cutoffs: a global and selected regional climatologies in ERA-Interim (1979–2018), Weather Clim. Dynam., 2, 507–534, https://doi.org/10.5194/wcd-2-507-2021, 2021.
Priestley, M. D. K., Pinto, J. G., Dacre, H. F., and Shaffrey, L. C.: Rossby
wave breaking, the upper level jet, and serial clustering of extratropical
cyclones in western Europe, Geophys. Res. Lett., 44, 514–521,
https://doi.org/10.1002/2016GL071277, 2017a.
Priestley, M. D. K., Pinto, J. G., Dacre, H. F., and Shaffrey, L. C.: The
role of cyclone clustering during the stormy winter of 2013/2014, Weather, 72, 187–192, https://doi.org/10.1002/WEA.3025, 2017b.
Ralph, F. M., Neiman, P. J., and Wick, G. A.: Satellite and CALJET aircraft
observations of atmospheric rivers over the Eastern North Pacific Ocean
during the winter of 1997/98, Mon. Weather Rev., 132, 1721–1745,
https://doi.org/10.1175/1520-0493(2004)132<1721:SACAOO>2.0.CO;2, 2004.
Raveh-Rubin, S. and Wernli, H.: Large-scale wind and precipitation extremes
in the Mediterranean: A climatological analysis for 1979–2012, Q. J. Roy. Meteor. Soc., 141, 2404–2417, https://doi.org/10.1002/qj.2531, 2015.
Rex, D. F.: Blocking action in the middle troposphere and its effect upon
regional climate, Tellus A, 2, 196–211, https://doi.org/10.1111/j.2153-3490.1950.tb00331.x, 1950.
Romero, R., Sumner, G., Ramis, C., and Genovés, A.: A classification of
the atmospheric circulation patterns producing significant daily rainfall in
the Spanish Mediterranean area, Int. J. Climatol., 19, 765–785,
https://doi.org/10.1002/(SICI)1097-0088(19990615)19:7<765::AID-JOC388>3.0.CO;2-T, 1999.
Rössler, O., Froidevaux, P., Börst, U., Rickli, R., Martius, O., and Weingartner, R.: Retrospective analysis of a nonforecasted rain-on-snow flood in the Alps – a matter of model limitations or unpredictable nature?, Hydrol. Earth Syst. Sci., 18, 2265–2285, https://doi.org/10.5194/hess-18-2265-2014, 2014.
Röthlisberger, M., Pfahl, S., and Martius, O.: Regional-scale jet
waviness modulates the occurrence of midlatitude weather extremes, Geophys.
Res. Lett., 43, 989–997, https://doi.org/10.1002/2016GL070944, 2016.
Röthlisberger, M., Frossard, L., Bosart, L. F., Keyser, D., and Martius,
O.: Recurrent synoptic-scale Rossby wave patterns and their effect on the
persistence of cold and hot spells, J. Climate, 32, 3207–3226,
https://doi.org/10.1175/JCLI-D-18-0664.1, 2019.
Rüdisühli, S., Sprenger, M., Leutwyler, D., Schär, C., and Wernli, H.: Attribution of precipitation to cyclones and fronts over Europe in a kilometer-scale regional climate simulation, Weather Clim. Dynam., 1, 675–699, https://doi.org/10.5194/wcd-1-675-2020, 2020.
Schmidli, J. and Frei, C.: Trends of heavy precipitation and wet and dry
spells in Switzerland during the 20th century, Int. J. Climatol., 25,
753–771, https://doi.org/10.1002/joc.1179, 2005.
Sousa, P. M., Trigo, R. M., Barriopedro, D., Soares, P. M. M., Ramos, A. M.,
and Liberato, M. L. R.: Responses of European precipitation distributions
and regimes to different blocking locations, Clim. Dynam., 48, 1141–1160,
https://doi.org/10.1007/s00382-016-3132-5, 2017.
Sprenger, M., Fragkoulidis, G., Binder, H., Croci-Maspoli, M., Graf, P., Grams, C. M., Knippertz, P., Madonna, E., Schemm, S., Škerlak, B., and Wernli, H.: Global climatologies of Eulerian and Lagrangian flow features based on ERA-Interim, B. Am. Meteorol. Soc., 98, 1739–1748, https://doi.org/10.1175/BAMS-D-15-00299.1, 2017.
Thorncroft, C. D., Hoskins, B. J., and McIntyre, M. E.: Two paradigms of
baroclinic-wave life-cycle behaviour, Q. J. Roy. Meteor. Soc., 119, 17–55,
https://doi.org/10.1002/qj.49711950903, 1993.
Tolika, K. and Maheras, P.: Spatial and temporal characteristics of wet
spells in Greece, Theor. Appl. Climatol., 81, 71–85,
https://doi.org/10.1007/s00704-004-0089-9, 2005.
Ulbrich, U., Brücher, T., Fink, A. H., Leckebusch, G. C., Krüger,
A., and Pinto, J. G.: The central European floods of August 2002: Part 2
– Synoptic causes and considerations with respect to climatic change, Weather, 58, 434–442, https://doi.org/10.1256/wea.61.03B, 2003.
Wernli, H. and Schwierz, C.: Surface cyclones in the ERA40 data set
(1958–2001). Part I: Novel identification method and global climatology, J.
Atmos. Sci., 63, 2486–2507, https://doi.org/10.1175/JAS3766.1, 2006.
Wernli, H. and Sprenger, M.: Identification and ERA-15 climatology of
potential vorticity streamers and cutoffs near the extratropical tropopause,
J. Atmos. Sci., 64, 1569–1586, https://doi.org/10.1175/JAS3912.1, 2007.
White, A. B., Moore, B. J., Gottas, D. J., and Neiman, P. J.: Winter storm
conditions leading to excessive runoff above California's Oroville Dam
during January and February 2017, B. Am. Meteorol. Soc., 100, 55–70,
https://doi.org/10.1175/BAMS-D-18-0091.1, 2019.
Wilks, D. S.: Statistical methods in the atmospheric sciences, 3rd edn.,
Elsevier Inc., 663 pp., https://doi.org/10.1016/B978-0-12-385022-5.00001-4,
2011.
Winschall, A., Pfahl, S., Sodemann, H., and Wernli, H.: Comparison of Eulerian and Lagrangian moisture source diagnostics – the flood event in eastern Europe in May 2010, Atmos. Chem. Phys., 14, 6605–6619, https://doi.org/10.5194/acp-14-6605-2014, 2014.
Zhu, Y. and Newell, R. E.: A proposed algorithm for moisture fluxes from
atmospheric rivers, Mon. Weather Rev., 126, 725–735,
https://doi.org/10.1175/1520-0493(1998)126<0725:APAFMF>2.0.CO;2, 1998.
Zolina, O., Simmer, C., Gulev, S. K., and Kollet, S.: Changing structure of
European precipitation: Longer wet periods leading to more abundant
rainfalls, Geophys. Res. Lett., 37, L06704, https://doi.org/10.1029/2010GL042468,
2010.
Zolina, O., Simmer, C., Belyaev, K., Gulev, S. K., and Koltermann, P.:
Changes in the duration of European wet and dry spells during the last 60 years, J. Climate, 26, 2022–2047, https://doi.org/10.1175/JCLI-D-11-00498.1, 2013.
Short summary
We examine the palette of synoptic storylines accompanying unusually long wet spells in Europe. Thereby, we identify a hitherto not documented mechanism for generating long wet spells which involves recurrent Rossby wave breaking and subsequent cutoff replenishment. Understanding the synoptic processes behind long wet spells is relevant in light of projected changes in wet spell characteristics as it is a prerequisite for evaluating climate models with regard to such events.
We examine the palette of synoptic storylines accompanying unusually long wet spells in Europe....
