Articles | Volume 7, issue 4
https://doi.org/10.5194/wcd-7-2065-2026
© Author(s) 2026. 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-7-2065-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
20 Oct 2026
Research article |
| 20 Oct 2026
| 20 Oct 2026
Grid-spacing sensitivity of Rossby wave breaking to mesoscale diabatic processes
Marius Rixen
CORRESPONDING AUTHOR
Institute for Atmospheric and Climate Science, ETH Zürich, 8092 Zurich, Switzerland
Praveen K. Pothapakula
Institute for Atmospheric and Climate Science, ETH Zürich, 8092 Zurich, Switzerland
Michael Sprenger
Institute for Atmospheric and Climate Science, ETH Zürich, 8092 Zurich, Switzerland
Christian Zeman
Institute for Atmospheric and Climate Science, ETH Zürich, 8092 Zurich, Switzerland
Andreas F. Prein
Institute for Atmospheric and Climate Science, ETH Zürich, 8092 Zurich, Switzerland
Related authors
Andreas F. Prein, Praveen K. Pothapakula, Christian Zeman, Morgane Lalonde, Marius Rixen, Anurag Dipankar, Matthieu Leclair, and Andreas Jocksch
Geosci. Model Dev., 19, 5277–5303, https://doi.org/10.5194/gmd-19-5277-2026, https://doi.org/10.5194/gmd-19-5277-2026, 2026
Short summary
Short summary
We produce one of the world's most detailed global weather and climate simulations, spanning 4 years and enabling the direct representation of storms rather than approximations. This allows the capture of dangerous events such as strong wind gusts, heavy rain, and powerful tropical and mid-latitude storms everywhere on Earth. Our results show major improvements over traditional climate models, but also reveal remaining challenges in representing large, organized storm systems in the tropics.
Marius Winkler, Marius Rixen, Florent Beucher, Fleur Couvreux, Chaehyeon C. Nam, Philippe Peyrillé, Hauke Schmidt, Hans Segura, Karl-Hermann Wieners, Ezri Alkilani-Brown, Abdou Aziz Coly, Giovanni Biagioli, Michael M. Bell, Ester Brito, Emma Chauvin, Julie Capo, Delián Colón-Burgos, Akeem Dawes, Jose Carlos da Luz, Zekican Demiralay, Vincent Douet, Vincent Ducastin, Clarisse Dufaux, Jean-Louis Dufresne, Florence Favot, Thomas Fiolleau, Emilie Fons, Geet George, Helene M. Gloeckner, Suelly Gonçalves, Laurent Gouttesoulard, Lennéa Hayo, Wei-Ting Hsiao, Sarah Kennison, Michael Kopelman, Tsung-Yung Lee, Enora Le Gall, Mateo Lovato, Emily Luschen, Nicolas Maury, Brett McKim, Louis Netz, Diouf Ousseynou, Karsten Peters-von Gehlen, Chavez Pope, Basile Poujol, Niwde Rivera Maldonado, Nina Robbins-Blanch, Nicolas Rochetin, Daniel Rowe, Paula Romero Jure, James H. Ruppert Jr., Jairo Segura Bermudez, Jarrett C. Starr, Martin Stelzner, Connor Stoll, Macintyre Syrett, Abraham Tekoe, Jeremie Trules, Colin Welty, Daniel Klocke, Raphaela Vogel, Sandrine Bony, Allison A. Wing, and Bjorn Stevens
Earth Syst. Sci. Data, 18, 1833–1854, https://doi.org/10.5194/essd-18-1833-2026, https://doi.org/10.5194/essd-18-1833-2026, 2026
Short summary
Short summary
The RAPSODI dataset compiles 624 radiosonde profiles collected during the 2024 ORCESTRA campaign across the tropical Atlantic: from Cape Verde (INMG), the R/V Meteor, and the Barbados Cloud Observatory. It provides high-resolution temperature, humidity, wind, and pressure data to study convection, tropical waves, and ITCZ dynamics. Data are quality-controlled and openly available in Zarr format via IPFS.
Edgar Dolores-Tesillos, Praveen K. Pothapakula, Christian Zeman, and Daniela I. V. Domeisen
EGUsphere, https://doi.org/10.5194/egusphere-2026-5758, https://doi.org/10.5194/egusphere-2026-5758, 2026
This preprint is open for discussion and under review for Weather and Climate Dynamics (WCD).
Short summary
Short summary
We tested whether increasing climate-model resolution and changing how convection is represented improve the simulation of heatwaves. Using a hierarchy of global atmosphere-only simulations, we found that finer resolution does not consistently reduce heatwave biases. Heatwave persistence depends on regional interactions among convection, rainfall, land conditions, and large-scale circulation, showing that higher resolution alone is not enough.
Cuiqi Zhang, Xiaoli Shen, Justin Jacquot, Larissa Lacher, Selvakumar Vishnupriya, Benjamin T. Brem, Robin L. Modini, Nora Nowak, Michael Sprenger, Martin Steinbacher, Stephan Henne, Martine Collaud Coen, Franz Conen, Kristina Höhler, Ottmar Möhler, Martin Gysel-Beer, Daniel J. Cziczo, and Zamin A. Kanji
EGUsphere, https://doi.org/10.5194/egusphere-2026-5645, https://doi.org/10.5194/egusphere-2026-5645, 2026
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
Short summary
Short summary
Clouds play a key role in weather and climate, but the particles that trigger cloud ice formation are difficult to identify directly. By simulating clouds in a cloud chamber and particle measurements at a mountain station, we found that mineral dust was the main trigger of cloud ice formation. Dust from local construction and transported from higher atmospheric layers both contributed. The study shows that both human activities and atmospheric processes can influence cloud formation.
Ming Hon Franco Lee, Hanna Joos, Heini Wernli, Richard Forbes, and Michael Sprenger
EGUsphere, https://doi.org/10.5194/egusphere-2026-4609, https://doi.org/10.5194/egusphere-2026-4609, 2026
This preprint is open for discussion and under review for Weather and Climate Dynamics (WCD).
Short summary
Short summary
Warm conveyor belts are coherent, rapidly ascending airstreams in extratropical cyclones, creating divergent outflows at upper levels. Using a numerical simulation, turbulence is found modifying potential vorticity near the tropopause in an outflow region. Despite the complex flow, changes in potential vorticity are retained due to the coordination provided by the outflow, leading to a potential upscale effect on the dynamics on larger scales, possibly affecting weather predictability.
Andres Barrio-Martin, Carlos Calvo-Sancho, Nuria P. Plaza-Martin, Cesar Azorin-Molina, Andreas F. Prein, Tim R. McVicar, Sergio M. Vicente-Serrano, Luis Gimeno, Raquel Nieto, Zhenzhong Zeng, Ana Morata, and Deliang Chen
EGUsphere, https://doi.org/10.5194/egusphere-2026-5202, https://doi.org/10.5194/egusphere-2026-5202, 2026
This preprint is open for discussion and under review for Natural Hazards and Earth System Sciences (NHESS).
Short summary
Short summary
We identified the atmospheric conditions that distinguish ordinary thunderstorms from four severe weather hazards, highlighting numerical proxies for their modelling in the Mediterranean. Severe winds occur in warm, unstable air (summer) or with strong mid-level winds (other seasons); tornadoes are favored by instability near the ground; large hail occurs when instability and strong winds combine; and short-duration heavy precipitation is favored by high moisture and slow-moving thunderstorms.
Anna Kuhn, Chenhui Jin, Elizabeth Ritchie, and Michael Armand Sprenger
EGUsphere, https://doi.org/10.5194/egusphere-2026-4836, https://doi.org/10.5194/egusphere-2026-4836, 2026
This preprint is open for discussion and under review for Weather and Climate Dynamics (WCD).
Short summary
Short summary
We apply a clustering approach to analyze winter jet stream variability over Australia, defining five jet configurations. We find high variability, especially in the longitudinal jet maximum. Patterns of vertical motion show the strongest ascent south of the jet maximum, coinciding with enhanced precipitation. Extreme precipitation events for six Australian capital cities are linked to either a strong or weakened jet stream, highlighting the important role of the jet in driving those events.
Samir Pokhrel, Verma Utkarsh, Patita Kalyana Sahoo, Praveen K. Pothapakula, Anusha Sunkisala, Nishant Gautam, Kolady P. Pribin, Shivamurthy Yashas, Hemantkumar S. Chaudhari, Archana Rai, Hasibur Rahaman, Andreas F. Prein, Anurag Dipankar, and Subodh Kumar Saha
Weather Clim. Dynam., 7, 1447–1477, https://doi.org/10.5194/wcd-7-1447-2026, https://doi.org/10.5194/wcd-7-1447-2026, 2026
Short summary
Short summary
We studied how well climate models simulate Indian monsoon rainfall at different time scales, from daily cycles to longer variations. We found that models may match seasonal averages but still fail to capture when and how rainfall occurs. These errors differ over land and ocean and affect overall monsoon patterns. Improving how models represent rainfall processes across scales is essential for better prediction.
Stefania Gilardoni, Annachiara Bellini, Paolo Bonasoni, Henri Diémoz, Christian Gencarelli, Angela Marinoni, Eros Mariani, Luigi Mazari Villanova, Bruno Neininger, Mattia Perilli, Michael Sprenger, and Francesco Petracchini
Atmos. Chem. Phys., 26, 11135–11152, https://doi.org/10.5194/acp-26-11135-2026, https://doi.org/10.5194/acp-26-11135-2026, 2026
Short summary
Short summary
This study presents the first high-time-resolution aerosol data collected from the Testa Grigia Observatory (3,480 m) in the Italian Alps, from 2021 to 2023. We identified three transport pathways: Saharan Dust Events (SDE), which occurred with a frequency of 6 %, regional and long-range transported pollution (28 %), and clean air from the free troposphere. The timing of SDE, observed mainly in spring, and the mixing of dust particles with black carbon, enhance SDE impact on snow melting.
Matthias Röthlisberger, Michael Sprenger, Urs Beyerle, Erich M. Fischer, and Heini Wernli
Weather Clim. Dynam., 7, 1363–1384, https://doi.org/10.5194/wcd-7-1363-2026, https://doi.org/10.5194/wcd-7-1363-2026, 2026
Short summary
Short summary
This study investigates yearly heat extremes simulated with the global climate model CESM2. A trajectory-based method is used, which allows quantifying the contributions to temperature anomalies from advection, subsidence, and diabatic heating. The results show that the magnitude of CESM2 heat extremes agrees fairly well with ERA5 reanalyses, but it is often
for the partly wrong physical reasons.
Ming Hon Franco Lee, Hanna Joos, Heini Wernli, Richard Forbes, and Michael Sprenger
EGUsphere, https://doi.org/10.5194/egusphere-2026-4184, https://doi.org/10.5194/egusphere-2026-4184, 2026
Short summary
Short summary
Turbulence near jet streams modifies the atmospheric flow, but there is limited research on the underlying mechanism. In this study, we infer this feedback by tracing the change in potential vorticity. We use an analytical framework to explain the systematic changes caused by turbulence in a numerical simulation of a jet stream. A typical tripolar pattern appears repeatedly, and it is highly related to the coherence of the jet. The improved understanding may help advance weather forecasts.
Ellina Agayar, Moshe Armon, Michael Sprenger, and Heini Wernli
Nat. Hazards Earth Syst. Sci., 26, 3025–3043, https://doi.org/10.5194/nhess-26-3025-2026, https://doi.org/10.5194/nhess-26-3025-2026, 2026
Short summary
Short summary
This study investigates the hydrometeorological features of the major floods of 2008, 2010, and 2020 in western Ukraine. All cases were linked to upper-level potential vorticity (PV) anomalies. We also conducted a climatological analysis of PV structure associated with 22 summer heavy precipitation events (2000–2022), highlighting their key role in determining the location and intensity of flood-inducing rainfall events in the Carpathians.
Andreas F. Prein, Praveen K. Pothapakula, Christian Zeman, Morgane Lalonde, Marius Rixen, Anurag Dipankar, Matthieu Leclair, and Andreas Jocksch
Geosci. Model Dev., 19, 5277–5303, https://doi.org/10.5194/gmd-19-5277-2026, https://doi.org/10.5194/gmd-19-5277-2026, 2026
Short summary
Short summary
We produce one of the world's most detailed global weather and climate simulations, spanning 4 years and enabling the direct representation of storms rather than approximations. This allows the capture of dangerous events such as strong wind gusts, heavy rain, and powerful tropical and mid-latitude storms everywhere on Earth. Our results show major improvements over traditional climate models, but also reveal remaining challenges in representing large, organized storm systems in the tropics.
Praveen K. Pothapakula, Andreas F. Prein, Anusha Sunkisala, and Anurag Dipankar
Weather Clim. Dynam., 7, 979–1007, https://doi.org/10.5194/wcd-7-979-2026, https://doi.org/10.5194/wcd-7-979-2026, 2026
Short summary
Short summary
Monsoons provide vital rainfall for billions but are hard to forecast. Using a next-generation climate model, we simulated monsoons at different grid spacings. The model captures key seasonal patterns, but finer grids do not always improve accuracy. They can worsen predictions by overproducing intense rain, as they artificially strengthen weather systems like monsoon lows and waves. Our work shows that smarter model physics is needed for reliable future forecasts and climate projections.
Alexander Pietak, Langwen Huang, Luigi Fusco, Michael Sprenger, Sebastian Schemm, and Torsten Hoefler
Geosci. Model Dev., 19, 3893–3922, https://doi.org/10.5194/gmd-19-3893-2026, https://doi.org/10.5194/gmd-19-3893-2026, 2026
Short summary
Short summary
As meteorological models grow in complexity, the volume of output data increases, making compression increasingly desirable. However, no specialized methods currently exist for compressing data in the Lagrangian frame. To address this gap, we developed psit, a pipeline for the lossy compression of Lagrangian flow data. In most cases, psit achieves performance that is equivalent or superior to non specialized alternatives, with compression errors behaving similar to measurement inaccuracies.
Huw C. Davies and Michael A. Sprenger
Weather Clim. Dynam., 7, 717–741, https://doi.org/10.5194/wcd-7-717-2026, https://doi.org/10.5194/wcd-7-717-2026, 2026
Short summary
Short summary
The Stratospheric Polar Vortex with its strong circumpolar jet is a dominant feature of the wintertime stratosphere. Evidence is presented of the characteristics of its distinctive sub-planetary scale features. The scale and dynamics of the features are linked to the break-up of an annular band of strong vorticity at the vortex's periphery, and moreover its aggregation into one or two vortices due to forcing from below can have ramifications for the occurrence of Sudden Stratospheric Warmings.
Tuule Müürsepp, Michael Sprenger, Heini Wernli, and Hanna Joos
Weather Clim. Dynam., 7, 547–565, https://doi.org/10.5194/wcd-7-547-2026, https://doi.org/10.5194/wcd-7-547-2026, 2026
Short summary
Short summary
The tropopause region of the atmosphere is greatly impacted by the exchange of mass and constituents between the troposphere and the stratosphere. This study quantifies the role of radiation in troposphere-to-stratosphere transport using reanalysis data. We find that radiation contributes to this transport most of the time, albeit it might not be the dominant process. We provide a new insight into the complex interplay of processes that air parcels experience on their way to the stratosphere.
Marius Winkler, Marius Rixen, Florent Beucher, Fleur Couvreux, Chaehyeon C. Nam, Philippe Peyrillé, Hauke Schmidt, Hans Segura, Karl-Hermann Wieners, Ezri Alkilani-Brown, Abdou Aziz Coly, Giovanni Biagioli, Michael M. Bell, Ester Brito, Emma Chauvin, Julie Capo, Delián Colón-Burgos, Akeem Dawes, Jose Carlos da Luz, Zekican Demiralay, Vincent Douet, Vincent Ducastin, Clarisse Dufaux, Jean-Louis Dufresne, Florence Favot, Thomas Fiolleau, Emilie Fons, Geet George, Helene M. Gloeckner, Suelly Gonçalves, Laurent Gouttesoulard, Lennéa Hayo, Wei-Ting Hsiao, Sarah Kennison, Michael Kopelman, Tsung-Yung Lee, Enora Le Gall, Mateo Lovato, Emily Luschen, Nicolas Maury, Brett McKim, Louis Netz, Diouf Ousseynou, Karsten Peters-von Gehlen, Chavez Pope, Basile Poujol, Niwde Rivera Maldonado, Nina Robbins-Blanch, Nicolas Rochetin, Daniel Rowe, Paula Romero Jure, James H. Ruppert Jr., Jairo Segura Bermudez, Jarrett C. Starr, Martin Stelzner, Connor Stoll, Macintyre Syrett, Abraham Tekoe, Jeremie Trules, Colin Welty, Daniel Klocke, Raphaela Vogel, Sandrine Bony, Allison A. Wing, and Bjorn Stevens
Earth Syst. Sci. Data, 18, 1833–1854, https://doi.org/10.5194/essd-18-1833-2026, https://doi.org/10.5194/essd-18-1833-2026, 2026
Short summary
Short summary
The RAPSODI dataset compiles 624 radiosonde profiles collected during the 2024 ORCESTRA campaign across the tropical Atlantic: from Cape Verde (INMG), the R/V Meteor, and the Barbados Cloud Observatory. It provides high-resolution temperature, humidity, wind, and pressure data to study convection, tropical waves, and ITCZ dynamics. Data are quality-controlled and openly available in Zarr format via IPFS.
Anurag Dipankar, Mauro Bianco, Mona Bukenberger, Till Ehrengruber, Nicoletta Farabullini, Oliver Fuhrer, Abishek Gopal, Daniel Hupp, Andreas Jocksch, Samuel Kellerhals, Clarissa A. Kroll, Xavier Lapillonne, Matthieu Leclair, Magdalena Luz, Christoph Müller, Chia Rui Ong, Carlos Osuna, Praveen Pothapakula, Andreas Prein, Matthias Röthlin, William Sawyer, Christoph Schär, Sebastian Schemm, Giacomo Serafini, Hannes Vogt, Ben Weber, Robert C. Jnglin Wills, Nicolas Gruber, and Thomas C. Schulthess
Geosci. Model Dev., 19, 713–729, https://doi.org/10.5194/gmd-19-713-2026, https://doi.org/10.5194/gmd-19-713-2026, 2026
Short summary
Short summary
Climate models are becoming more detailed and accurate by simulating weather at scales of just a few kilometers. Simulating at km-scale is computationally demanding requiring powerful supercomputers and efficient code. This work presents a refactored dynamical core of a state-of-the-art climate model using a Python-based approach. The refactored code has passed through a sequence of verification and validation demonstrating its usability in performing km-scale global simulations.
Jacopo Riboldi, Robin Noyelle, Ellina Agayar, Hanin Binder, Marc Federer, Katharina Hartmuth, Michael Sprenger, Iris Thurnherr, and Selvakumar Vishnupriya
Weather Clim. Dynam., 7, 65–87, https://doi.org/10.5194/wcd-7-65-2026, https://doi.org/10.5194/wcd-7-65-2026, 2026
Short summary
Short summary
Storm Boris led to record-breaking precipitation over central Europe in September 2024. By incorporating event-specific meteorological information, this work introduces a methodology to strengthen our comprehension of how global warming affects similar hazards. Furthermore, it contextualizes how the answer to the question "How will Boris-like storms change in a warmer climate?" depends on explicit and implicit methodological choices, with the aim to inform future attribution research.
Ming Hon Franco Lee and Michael Sprenger
Weather Clim. Dynam., 6, 1583–1604, https://doi.org/10.5194/wcd-6-1583-2025, https://doi.org/10.5194/wcd-6-1583-2025, 2025
Short summary
Short summary
Turbulence can occur in clear-air conditions at cruising altitude. From around 5000 clear-air turbulence events identified using aircraft measurements, nonlinear breaking of large-scale waves and rapidly ascending airstreams associated with cyclones are found concurrent with 40 % and 30 % of them respectively. The results further show that these weather systems may trigger turbulence by generating highly deformed flow or flow instability, improving our understanding of clear-air turbulence.
Emmanouil Flaounas, Stavros Dafis, Silvio Davolio, Davide Faranda, Christian Ferrarin, Katharina Hartmuth, Assaf Hochman, Aristeidis Koutroulis, Samira Khodayar, Mario Marcello Miglietta, Florian Pantillon, Platon Patlakas, Michael Sprenger, and Iris Thurnherr
Weather Clim. Dynam., 6, 1515–1538, https://doi.org/10.5194/wcd-6-1515-2025, https://doi.org/10.5194/wcd-6-1515-2025, 2025
Short summary
Short summary
Storm Daniel (2023) is one of the most catastrophic storms ever documented in the Mediterranean. Our results highlight the different dynamics and therefore the different predictability skill of precipitation, its extremes and impacts that have been produced in Greece and Libya, the two most affected countries. Our approach concerns an analysis of the storm by articulating dynamics, weather prediction, hydrological and oceanographic implications, climate extremes, and attribution theory.
Selvakumar Vishnupriya, Michael Sprenger, Hanna Joos, and Heini Wernli
Weather Clim. Dynam., 6, 1195–1219, https://doi.org/10.5194/wcd-6-1195-2025, https://doi.org/10.5194/wcd-6-1195-2025, 2025
Short summary
Short summary
Extratropical cyclones feature rapidly ascending airstreams known as warm conveyor belts, which could influence upper-level flow dynamics. This study classifies interactions between warm conveyor belt outflows and the jet stream into four types: no interactions, ridges, blocks, and tropospheric cutoffs. We use reanalysis data to demonstrate that the interaction type depends on the structure of the ambient flow than on the outflow, improving our understanding of extratropical flow variability.
Killian P. Brennan, Iris Thurnherr, Michael Sprenger, and Heini Wernli
Nat. Hazards Earth Syst. Sci., 25, 3693–3712, https://doi.org/10.5194/nhess-25-3693-2025, https://doi.org/10.5194/nhess-25-3693-2025, 2025
Short summary
Short summary
Hailstorms can cause severe damage to homes, crops, and infrastructure. Using high-resolution climate simulations, we tracked thousands of hailstorms across Europe to study future changes. Large hail will become more frequent, hail-covered areas will expand, and instances of extreme hail combined with heavy rain will double. These shifts could increase risks for communities and businesses, highlighting the need for better preparedness and adaptation.
Sofía Segovia, Pablo A. Mendoza, Miguel Lagos-Zúñiga, Lucía Scaff, and Andreas Prein
EGUsphere, https://doi.org/10.5194/egusphere-2025-3061, https://doi.org/10.5194/egusphere-2025-3061, 2025
Short summary
Short summary
High-resolution climate simulations can improve our understanding of precipitation and temperature patterns in regions with complex terrain. We evaluate a new climate dataset against in-situ observations, and its potencial for hydrological modeling. Results show that, despite some limitations in dry areas, high-resolution climate models can provide information of a quality comparable to that of observation-based products, supporting their use in water resources planning and decision-making.
Killian P. Brennan, Michael Sprenger, André Walser, Marco Arpagaus, and Heini Wernli
Weather Clim. Dynam., 6, 645–668, https://doi.org/10.5194/wcd-6-645-2025, https://doi.org/10.5194/wcd-6-645-2025, 2025
Short summary
Short summary
We studied severe hailstorms that occurred in Switzerland on 28 June 2021 using a weather prediction model to understand how they evolved. We found that the storms moved toward areas with more storm energy. Hailfall was quickly followed by heavy rain. Just before the storms died out, the air feeding them stopped coming from near the ground. We also observed a delay between different types of precipitation forming in the incoming air.
Nicolai Krieger, Heini Wernli, Michael Sprenger, and Christian Kühnlein
Weather Clim. Dynam., 6, 447–469, https://doi.org/10.5194/wcd-6-447-2025, https://doi.org/10.5194/wcd-6-447-2025, 2025
Short summary
Short summary
This study investigates the Laseyer, a local windstorm in a narrow Swiss valley characterized by strong southeasterly winds during northwesterly ambient flow. Using large-eddy simulations (LESs) with 30 m grid spacing, this is the first study to reveal that the extreme gusts in the valley are caused by an amplifying interplay of two recirculation regions. Modifying terrain and ambient wind conditions affects the windstorm's intensity and highlights the importance of topographic details in LES.
Marc Federer, Lukas Papritz, Michael Sprenger, and Christian M. Grams
Weather Clim. Dynam., 6, 211–230, https://doi.org/10.5194/wcd-6-211-2025, https://doi.org/10.5194/wcd-6-211-2025, 2025
Short summary
Short summary
Although extratropical cyclones in the North Atlantic are among the most impactful midlatitude weather systems, their intensification is not entirely understood. Here, we explore how individual cyclones convert available potential energy (APE) into kinetic energy and relate these conversions to the synoptic development of the cyclones. By combining potential vorticity thinking with a local APE framework, we offer a novel perspective on established concepts in dynamic meteorology.
Philip Rupp, Jonas Spaeth, Hilla Afargan-Gerstman, Dominik Büeler, Michael Sprenger, and Thomas Birner
Weather Clim. Dynam., 5, 1287–1298, https://doi.org/10.5194/wcd-5-1287-2024, https://doi.org/10.5194/wcd-5-1287-2024, 2024
Short summary
Short summary
We quantify the occurrence of strong synoptic storms as contributing about 20 % to the uncertainty of subseasonal geopotential height forecasts over northern Europe. We further show that North Atlantic storms are less frequent, weaker and shifted southward following sudden stratospheric warming events, leading to a reduction in northern European forecast uncertainty.
Hugo Banderier, Christian Zeman, David Leutwyler, Stefan Rüdisühli, and Christoph Schär
Geosci. Model Dev., 17, 5573–5586, https://doi.org/10.5194/gmd-17-5573-2024, https://doi.org/10.5194/gmd-17-5573-2024, 2024
Short summary
Short summary
We investigate the effects of reduced-precision arithmetic in a state-of-the-art regional climate model by studying the results of 10-year-long simulations. After this time, the results of the reduced precision and the standard implementation are hardly different. This should encourage the use of reduced precision in climate models to exploit the speedup and memory savings it brings. The methodology used in this work can help researchers verify reduced-precision implementations of their model.
Bjorn Stevens, Stefan Adami, Tariq Ali, Hartwig Anzt, Zafer Aslan, Sabine Attinger, Jaana Bäck, Johanna Baehr, Peter Bauer, Natacha Bernier, Bob Bishop, Hendryk Bockelmann, Sandrine Bony, Guy Brasseur, David N. Bresch, Sean Breyer, Gilbert Brunet, Pier Luigi Buttigieg, Junji Cao, Christelle Castet, Yafang Cheng, Ayantika Dey Choudhury, Deborah Coen, Susanne Crewell, Atish Dabholkar, Qing Dai, Francisco Doblas-Reyes, Dale Durran, Ayoub El Gaidi, Charlie Ewen, Eleftheria Exarchou, Veronika Eyring, Florencia Falkinhoff, David Farrell, Piers M. Forster, Ariane Frassoni, Claudia Frauen, Oliver Fuhrer, Shahzad Gani, Edwin Gerber, Debra Goldfarb, Jens Grieger, Nicolas Gruber, Wilco Hazeleger, Rolf Herken, Chris Hewitt, Torsten Hoefler, Huang-Hsiung Hsu, Daniela Jacob, Alexandra Jahn, Christian Jakob, Thomas Jung, Christopher Kadow, In-Sik Kang, Sarah Kang, Karthik Kashinath, Katharina Kleinen-von Königslöw, Daniel Klocke, Uta Kloenne, Milan Klöwer, Chihiro Kodama, Stefan Kollet, Tobias Kölling, Jenni Kontkanen, Steve Kopp, Michal Koran, Markku Kulmala, Hanna Lappalainen, Fakhria Latifi, Bryan Lawrence, June Yi Lee, Quentin Lejeun, Christian Lessig, Chao Li, Thomas Lippert, Jürg Luterbacher, Pekka Manninen, Jochem Marotzke, Satoshi Matsouoka, Charlotte Merchant, Peter Messmer, Gero Michel, Kristel Michielsen, Tomoki Miyakawa, Jens Müller, Ramsha Munir, Sandeep Narayanasetti, Ousmane Ndiaye, Carlos Nobre, Achim Oberg, Riko Oki, Tuba Özkan-Haller, Tim Palmer, Stan Posey, Andreas Prein, Odessa Primus, Mike Pritchard, Julie Pullen, Dian Putrasahan, Johannes Quaas, Krishnan Raghavan, Venkatachalam Ramaswamy, Markus Rapp, Florian Rauser, Markus Reichstein, Aromar Revi, Sonakshi Saluja, Masaki Satoh, Vera Schemann, Sebastian Schemm, Christina Schnadt Poberaj, Thomas Schulthess, Cath Senior, Jagadish Shukla, Manmeet Singh, Julia Slingo, Adam Sobel, Silvina Solman, Jenna Spitzer, Philip Stier, Thomas Stocker, Sarah Strock, Hang Su, Petteri Taalas, John Taylor, Susann Tegtmeier, Georg Teutsch, Adrian Tompkins, Uwe Ulbrich, Pier-Luigi Vidale, Chien-Ming Wu, Hao Xu, Najibullah Zaki, Laure Zanna, Tianjun Zhou, and Florian Ziemen
Earth Syst. Sci. Data, 16, 2113–2122, https://doi.org/10.5194/essd-16-2113-2024, https://doi.org/10.5194/essd-16-2113-2024, 2024
Short summary
Short summary
To manage Earth in the Anthropocene, new tools, new institutions, and new forms of international cooperation will be required. Earth Virtualization Engines is proposed as an international federation of centers of excellence to empower all people to respond to the immense and urgent challenges posed by climate change.
Katharina Heitmann, Michael Sprenger, Hanin Binder, Heini Wernli, and Hanna Joos
Weather Clim. Dynam., 5, 537–557, https://doi.org/10.5194/wcd-5-537-2024, https://doi.org/10.5194/wcd-5-537-2024, 2024
Short summary
Short summary
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.
Lukas Jansing, Lukas Papritz, and Michael Sprenger
Weather Clim. Dynam., 5, 463–489, https://doi.org/10.5194/wcd-5-463-2024, https://doi.org/10.5194/wcd-5-463-2024, 2024
Short summary
Short summary
Using an innovative approach, the descent of foehn is diagnosed from a Lagrangian perspective based on 15 kilometer-scale simulations combined with online trajectories. The descent is confined to distinct hotspots in the immediate lee of local mountain peaks and chains. Two detailed case studies reveal a varying wave regime to be associated with the descent. Furthermore, additional controlling factors, such as the diurnal cycle, likewise influence the descent activity.
Hilla Afargan-Gerstman, Dominik Büeler, C. Ole Wulff, Michael Sprenger, and Daniela I. V. Domeisen
Weather Clim. Dynam., 5, 231–249, https://doi.org/10.5194/wcd-5-231-2024, https://doi.org/10.5194/wcd-5-231-2024, 2024
Short summary
Short summary
The stratosphere is a layer of Earth's atmosphere found above the weather systems. Changes in the stratosphere can affect the winds and the storm tracks in the North Atlantic region for a relatively long time, lasting for several weeks and even months. We show that the stratosphere can be important for weather forecasts beyond 1 week, but more work is needed to improve the accuracy of these forecasts for 3–4 weeks.
Yonatan Givon, Or Hess, Emmanouil Flaounas, Jennifer Louise Catto, Michael Sprenger, and Shira Raveh-Rubin
Weather Clim. Dynam., 5, 133–162, https://doi.org/10.5194/wcd-5-133-2024, https://doi.org/10.5194/wcd-5-133-2024, 2024
Short summary
Short summary
A novel classification of Mediterranean cyclones is presented, enabling a separation between storms driven by different atmospheric processes. The surface impact of each cyclone class differs greatly by precipitation, winds, and temperatures, providing an invaluable tool to study the climatology of different types of Mediterranean storms and enhancing the understanding of their predictability, on both weather and climate scales.
Stefania Gilardoni, Dominic Heslin-Rees, Mauro Mazzola, Vito Vitale, Michael Sprenger, and Radovan Krejci
Atmos. Chem. Phys., 23, 15589–15607, https://doi.org/10.5194/acp-23-15589-2023, https://doi.org/10.5194/acp-23-15589-2023, 2023
Short summary
Short summary
Models still fail in reproducing black carbon (BC) temporal variability in the Arctic. Analysis of equivalent BC concentrations in the European Arctic shows that BC seasonal variability is modulated by the efficiency of removal by precipitation during transport towards high latitudes. Short-term variability is controlled by synoptic-scale circulation patterns. The advection of warm air from lower latitudes is an effective pollution transport pathway during summer.
Thomas Trickl, Martin Adelwart, Dina Khordakova, Ludwig Ries, Christian Rolf, Michael Sprenger, Wolfgang Steinbrecht, and Hannes Vogelmann
Atmos. Meas. Tech., 16, 5145–5165, https://doi.org/10.5194/amt-16-5145-2023, https://doi.org/10.5194/amt-16-5145-2023, 2023
Short summary
Short summary
Tropospheric ozone have been measured for more than a century. Highly quantitative ozone measurements have been made at monitoring stations. However, deficits have been reported for vertical sounding systems. Here, we report a thorough intercomparison effort between a differential-absorption lidar system and two types of balloon-borne ozone sondes, also using ozone sensors at nearby mountain sites as references. The sondes agree very well with the lidar after offset corrections.
Melanie Lauer, Annette Rinke, Irina Gorodetskaya, Michael Sprenger, Mario Mech, and Susanne Crewell
Atmos. Chem. Phys., 23, 8705–8726, https://doi.org/10.5194/acp-23-8705-2023, https://doi.org/10.5194/acp-23-8705-2023, 2023
Short summary
Short summary
We present a new method to analyse the influence of atmospheric rivers (ARs), cyclones, and fronts on the precipitation in the Arctic, based on two campaigns: ACLOUD (early summer 2017) and AFLUX (early spring 2019). There are differences between both campaign periods: in early summer, the precipitation is mostly related to ARs and fronts, especially when they are co-located, while in early spring, cyclones isolated from ARs and fronts contributed most to the precipitation.
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
Short summary
Short summary
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.
Qinggang Gao, Christian Zeman, Jesus Vergara-Temprado, Daniela C. A. Lima, Peter Molnar, and Christoph Schär
Weather Clim. Dynam., 4, 189–211, https://doi.org/10.5194/wcd-4-189-2023, https://doi.org/10.5194/wcd-4-189-2023, 2023
Short summary
Short summary
We developed a vortex identification algorithm for realistic atmospheric simulations. The algorithm enabled us to obtain a climatology of vortex shedding from Madeira Island for a 10-year simulation period. This first objective climatological analysis of vortex streets shows consistency with observed atmospheric conditions. The analysis shows a pronounced annual cycle with an increasing vortex shedding rate from April to August and a sudden decrease in September.
Hanna Joos, Michael Sprenger, Hanin Binder, Urs Beyerle, and Heini Wernli
Weather Clim. Dynam., 4, 133–155, https://doi.org/10.5194/wcd-4-133-2023, https://doi.org/10.5194/wcd-4-133-2023, 2023
Short summary
Short summary
Warm conveyor belts (WCBs) are strongly ascending, cloud- and precipitation-forming airstreams in extratropical cyclones. In this study we assess their representation in a climate simulation and their changes under global warming. They become moister, become more intense, and reach higher altitudes in a future climate, implying that they potentially have an increased impact on the mid-latitude flow.
Andreas Schäfler, Michael Sprenger, Heini Wernli, Andreas Fix, and Martin Wirth
Atmos. Chem. Phys., 23, 999–1018, https://doi.org/10.5194/acp-23-999-2023, https://doi.org/10.5194/acp-23-999-2023, 2023
Short summary
Short summary
In this study, airborne lidar profile measurements of H2O and O3 across a midlatitude jet stream are combined with analyses in tracer–trace space and backward trajectories. We highlight that transport and mixing processes in the history of the observed air masses are governed by interacting tropospheric weather systems on synoptic timescales. We show that these weather systems play a key role in the high variability of the paired H2O and O3 distributions near the tropopause.
Hanin Binder, Hanna Joos, Michael Sprenger, and Heini Wernli
Weather Clim. Dynam., 4, 19–37, https://doi.org/10.5194/wcd-4-19-2023, https://doi.org/10.5194/wcd-4-19-2023, 2023
Short summary
Short summary
Warm conveyor belts (WCBs) are the main cloud- and precipitation-producing airstreams in extratropical cyclones. The latent heat release that occurs during cloud formation often contributes to the intensification of the associated cyclone. Based on the Community Earth System Model Large Ensemble coupled climate simulations, we show that WCBs and associated latent heating will become stronger in a future climate and be even more important for explosive cyclone intensification than in the present.
Michael A. Barnes, Thando Ndarana, Michael Sprenger, and Willem A. Landman
Weather Clim. Dynam., 3, 1291–1309, https://doi.org/10.5194/wcd-3-1291-2022, https://doi.org/10.5194/wcd-3-1291-2022, 2022
Short summary
Short summary
Stratospheric air can intrude into the troposphere and is associated with cyclonic development throughout the atmosphere. Through a highly idealized systematic approach, the effect that different intrusion characteristics have on surface cyclogenetic forcing is investigated. The proximity of stratospheric intrusions to the surface is shown to be the main factor in surface cyclogenetic forcing, whilst its width is an additional contributing factor.
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
Short summary
Short summary
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.
Praveen Kumar Pothapakula, Amelie Hoff, Anika Obermann-Hellhund, Timo Keber, and Bodo Ahrens
Earth Syst. Dynam. Discuss., https://doi.org/10.5194/esd-2022-24, https://doi.org/10.5194/esd-2022-24, 2022
Preprint withdrawn
Short summary
Short summary
The Vb-cyclones simulated with a coupled regional climate model with two different driving data sets are compared against each other in historical period, thereafter the future climate predictions were analyzed. The Vb-cyclones in two simulations agree well in terms of their occurrence, intensity and track in two simulations, though there are discrepancies in seasonal cycles and their process linking Mediterranean Sea in historical period. So significant changes were observed in the future.
James M. Done, Gary M. Lackmann, and Andreas F. Prein
Weather Clim. Dynam., 3, 693–711, https://doi.org/10.5194/wcd-3-693-2022, https://doi.org/10.5194/wcd-3-693-2022, 2022
Short summary
Short summary
We know that warm oceans generally favour tropical cyclones (TCs). Less is known about the role of air temperature above the oceans extending into the lower stratosphere. Our global analysis of historical records and computer simulations suggests that TCs strengthen in response to historical temperature change while also being influenced by other environmental factors. Ocean warming drives much of the strengthening, with relatively small contributions from temperature changes aloft.
Christian Zeman and Christoph Schär
Geosci. Model Dev., 15, 3183–3203, https://doi.org/10.5194/gmd-15-3183-2022, https://doi.org/10.5194/gmd-15-3183-2022, 2022
Short summary
Short summary
Our atmosphere is a chaotic system, where even a tiny change can have a big impact. This makes it difficult to assess if small changes, such as the move to a new hardware architecture, will significantly affect a weather and climate model. We present a methodology that allows to objectively verify this. The methodology is applied to several test cases, showing a high sensitivity. Results also show that a major system update of the underlying supercomputer did not significantly affect our model.
Jan Clemens, Felix Ploeger, Paul Konopka, Raphael Portmann, Michael Sprenger, and Heini Wernli
Atmos. Chem. Phys., 22, 3841–3860, https://doi.org/10.5194/acp-22-3841-2022, https://doi.org/10.5194/acp-22-3841-2022, 2022
Short summary
Short summary
Highly polluted air flows from the surface to higher levels of the atmosphere during the Asian summer monsoon. At high levels, the air is trapped within eddies. Here, we study how air masses can leave the eddy within its cutoff, how they distribute, and how their chemical composition changes. We found evidence for transport from the eddy to higher latitudes over the North Pacific and even Alaska. During transport, trace gas concentrations within cutoffs changed gradually, showing steady mixing.
Jörg Wieder, Claudia Mignani, Mario Schär, Lucie Roth, Michael Sprenger, Jan Henneberger, Ulrike Lohmann, Cyril Brunner, and Zamin A. Kanji
Atmos. Chem. Phys., 22, 3111–3130, https://doi.org/10.5194/acp-22-3111-2022, https://doi.org/10.5194/acp-22-3111-2022, 2022
Short summary
Short summary
We investigate the variation in ice-nucleating particles (INPs) relevant for primary ice formation in mixed-phased clouds over the Alps based on simultaneous in situ observations at a mountaintop and a nearby high valley (1060 m height difference). In most cases, advection from the surrounding lower regions was responsible for changes in INP concentration, causing a diurnal cycle at the mountaintop. Our study underlines the importance of the planetary boundary layer as an INP reserve.
Lukas Bösiger, Michael Sprenger, Maxi Boettcher, Hanna Joos, and Tobias Günther
Geosci. Model Dev., 15, 1079–1096, https://doi.org/10.5194/gmd-15-1079-2022, https://doi.org/10.5194/gmd-15-1079-2022, 2022
Short summary
Short summary
Jet streams are coherent air flows that interact with atmospheric structures such as warm conveyor belts (WCBs) and the tropopause. Individually, these structures have a significant impact on the weather evolution. A first step towards a deeper understanding of the meteorological processes is to extract jet stream core lines, for which we develop a novel feature extraction algorithm. Based on the line geometry, we automatically detect and visualize potential interactions between WCBs and jets.
Philippe Besson, Luise J. Fischer, Sebastian Schemm, and Michael Sprenger
Weather Clim. Dynam., 2, 991–1009, https://doi.org/10.5194/wcd-2-991-2021, https://doi.org/10.5194/wcd-2-991-2021, 2021
Short summary
Short summary
The strongest cyclone intensification is associated with a strong dry-dynamical forcing. Moreover, strong forcing and strong intensification correspond to a tendency for poleward cyclone propagation, which occurs in distinct regions in the Northern Hemisphere. There is a clear spatial pattern in the occurrence of certain forcing combinations. This implies a fundamental relationship between dry-dynamical processes and the intensification as well as the propagation of extratropical cyclones.
Cited articles
Abbott, T. H., Jeevanjee, N., Cheng, K.-Y., Zhou, L., and Harris, L.: The Land-Ocean Contrast in Deep Convective Intensity in a Global Storm-Resolving Model, J. Adv. Model. Earth Syst., 17, e2024MS004467, https://doi.org/10.1029/2024MS004467, 2025. a
Baumgart, M., Riemer, M., Wirth, V., Teubler, F., and Lang, S. T. K.: Potential Vorticity Dynamics of Forecast Errors: A Quantitative Case Study, Mon. Weather Rev., 146, 1405–1425, https://doi.org/10.1175/MWR-D-17-0196.1, 2018. a, b
Bechtold, P., Köhler, M., Jung, T., Doblas-Reyes, F., Leutbecher, M., Rodwell, M. J., Vitart, F., and Balsamo, G.: Advances in simulating atmospheric variability with the ECMWF model: From synoptic to decadal time-scales, Q. J. Roy. Meteorol. Soc., 134, 1337–1351, https://doi.org/10.1002/qj.289, 2008. a
Blanchard, N., Pantillon, F., Chaboureau, J.-P., and Delanoë, J.: Organization of convective ascents in a warm conveyor belt, Weather Clim. Dynam., 1, 617–634, https://doi.org/10.5194/wcd-1-617-2020, 2020. a
Bosart, L. F., Moore, B. J., Cordeira, J. M., and Archambault, H. M.: Interactions of North Pacific Tropical, Midlatitude, and Polar Disturbances Resulting in Linked Extreme Weather Events over North America in October 2007, Mon. Weather Rev., 145, 1245–1273, https://doi.org/10.1175/MWR-D-16-0230.1, 2017. a
Clark, P., Roberts, N., Lean, H., Ballard, S. P., and Charlton-Perez, C.: Convection-permitting models: a step-change in rainfall forecasting, Meteorol. Appl., 23, 165–181, https://doi.org/10.1002/met.1538, 2016. a
Clarke, S. J., Gray, S. L., and Roberts, N. M.: Downstream influence of mesoscale convective systems. Part 1: influence on forecast evolution, Q. J. Roy. Meteorol. Soc., 145, 2933–2952, https://doi.org/10.1002/qj.3593, 2019. a
Couto, F., Kartsios, S., Lacroix, M., and Andrade, H.: A Quick Look at the Atmospheric Circulation Leading to Extreme Weather Phenomena on a Continental Scale, Atmosphere, 15, 1205, https://doi.org/10.3390/atmos15101205, 2024. a
Davies, H. C. and Didone, M.: Diagnosis and Dynamics of Forecast Error Growth, Mon. Weather Rev., 141, 2483–2501, https://doi.org/10.1175/MWR-D-12-00242.1, 2013. a, b
Davini, P. and D’Andrea, F.: From CMIP3 to CMIP6: Northern Hemisphere Atmospheric Blocking Simulation in Present and Future Climate, J. Climate, 33, 10021–10038, https://doi.org/10.1175/JCLI-D-19-0862.1, 2020. a
Dipankar, A.: EXCLAIM use cases, Zenodo [code], https://doi.org/10.5281/zenodo.17255275, 2025. a
Dipankar, A., Bianco, M., Bukenberger, M., Ehrengruber, T., Farabullini, N., Fuhrer, O., Gopal, A., Hupp, D., Jocksch, A., Kellerhals, S., Kroll, C. A., Lapillonne, X., Leclair, M., Luz, M., Müller, C., Ong, C. R., Osuna, C., Pothapakula, P., Prein, A., Röthlin, M., Sawyer, W., Schär, C., Schemm, S., Serafini, G., Vogt, H., Weber, B., Wills, R. C. J., Gruber, N., and Schulthess, T. C.: Toward exascale climate modelling: a python DSL approach to ICON's (icosahedral non-hydrostatic) dynamical core (icon-exclaim v0.2.0), Geosci. Model Dev., 19, 713–729, https://doi.org/10.5194/gmd-19-713-2026, 2026. a
Dolores-Tesillos, E., Martius, O., and Pfahl, S.: Atmospheric blocking representation in storm-resolving climate models under historical and future forcing, Weather Clim. Dynam., 7, 1089–1116, https://doi.org/10.5194/wcd-7-1089-2026, 2026. a
Doms, G., Forstner, J., Heise, E., Reinhardt, T., Ritter, B., and Schrodin, R.: A Description of the Nonhydrostatic Regional COSMO Model, Deutscher Wetterdienst, Business Area “Research and Development”, https://doi.org/10.5676/DWD_pub/nwv/cosmo-doc_5.00_II, 2011. a
Flaounas, E., Dafis, S., Davolio, S., Faranda, D., Ferrarin, C., Hartmuth, K., Hochman, A., Koutroulis, A., Khodayar, S., Miglietta, M. M., Pantillon, F., Patlakas, P., Sprenger, M., and Thurnherr, I.: Dynamics, predictability, impacts and climate change considerations of the catastrophic Mediterranean Storm Daniel (2023), Weather Clim. Dynam., 6, 1515–1538, https://doi.org/10.5194/wcd-6-1515-2025, 2025. a
Good, S. and Embury, O.: ESA Sea Surface Temperature Climate Change Initiative (SST_cci): Level 4 Analysis product, version 3.0, NERC EDS Centre for Environmental Data Analysis, https://doi.org/10.5285/4A9654136A7148E39B7FEB56F8BB02D2, 2024. a
Grams, C. M. and Archambault, H. M.: The Key Role of Diabatic Outflow in Amplifying the Midlatitude Flow: A Representative Case Study of Weather Systems Surrounding Western North Pacific Extratropical Transition, Mon. Weather Rev., 144, 3847–3869, https://doi.org/10.1175/MWR-D-15-0419.1, 2016. a
Grams, C. M. and Blumer, S. R.: European high-impact weather caused by the downstream response to the extratropical transition of North Atlantic Hurricane Katia (2011), Geophys. Res. Lett., 42, 8738–8748, https://doi.org/10.1002/2015GL066253, 2015. a
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. a
Grams, C. M., Magnusson, L., and Madonna, E.: An atmospheric dynamics perspective on the amplification and propagation of forecast error in numerical weather prediction models: A case study, Q. J. Roy. Meteorol. Soc., 144, 2577–2591, https://doi.org/10.1002/qj.3353, 2018. a, b, c
Harvey, B., Methven, J., Sanchez, C., and Schäfler, A.: Diabatic generation of negative potential vorticity and its impact on the North Atlantic jet stream, Q. J. Roy. Meteorol. Soc., 146, 1477–1497, https://doi.org/10.1002/qj.3747, 2020. a
Hauser, S., Cavallo, S. M., Magnusson, L., Martin, J. E., and Parsons, D. B.: Exceptionally poor and good medium-range forecasts of the large-scale circulation over Europe in ERA5 reforecasts, Q. J. Roy. Meteorol. Soc., 152, e70117, https://doi.org/10.1002/qj.70117, 2026. a, b
Heitmann, K., Sprenger, M., Binder, H., Wernli, H., and Joos, H.: Warm conveyor belt characteristics and impacts along the life cycle of extratropical cyclones: case studies and climatological analysis based on ERA5, Weather Clim. Dynam., 5, 537–557, https://doi.org/10.5194/wcd-5-537-2024, 2024. a, b, c, d
Hersbach, H., Bell, B., Berrisford, P., Hirahara, S., Horányi, A., Muñoz-Sabater, J., Nicolas, J., Peubey, C., Radu, R., Schepers, D., Simmons, A., Soci, C., Abdalla, S., Abellan, X., Balsamo, G., Bechtold, P., Biavati, G., Bidlot, J., Bonavita, M., De Chiara, G., Dahlgren, P., Dee, D., Diamantakis, M., Dragani, R., Flemming, J., Forbes, R., Fuentes, M., Geer, A., Haimberger, L., Healy, S., Hogan, R. J., Hólm, E., Janisková, M., Keeley, S., Laloyaux, P., Lopez, P., Lupu, C., Radnoti, G., de Rosnay, P., Rozum, I., Vamborg, F., Villaume, S., and Thépaut, J.-N.: The ERA5 global reanalysis, Q. J. Roy. Meteorol. Soc., 146, 1999–2049, https://doi.org/10.1002/qj.3803, 2020. a, b
Hersbach, H., Bell, B., Berrisford, P., Biavati, G., Horányi, A., Muñoz Sabater, J., Nicolas, J., Peubey, C., Radu, R., Rozum, I., Schepers, D., Simmons, A., Soci, C., Dee, D., and Thépaut, J.-N.: ERA5 hourly data on single levels from 1940 to present, Copernicus Climate Change Service (C3S) Climate Data Store (CDS) [data set], https://doi.org/10.24381/cds.adbb2d47, 2023. a
Hitchman, M. H. and Rowe, S. M.: On the Similarity of Lower-Stratospheric Potential Vorticity Dipoles above Tropical and Midlatitude Deep Convection, J. Atmos. Sci., 74, 2593–2613, https://doi.org/10.1175/JAS-D-16-0239.1, 2017. a
Hogan, R. J. and Bozzo, A.: A Flexible and Efficient Radiation Scheme for the ECMWF Model, J. Adv. Model. Earth Syst., 10, 1990–2008, https://doi.org/10.1029/2018MS001364, 2018. a
Huffman, G. J., Stocker, E. F., Bolvin, D. T., Nelkin, E. J., and Tan, J.: GPM IMERG Final Precipitation L3 Half Hourly 0.1 degree × 0.1 degree V07, Greenbelt, MD, Goddard Earth Sciences Data and Information Services Center (GES DISC), https://doi.org/10.5067/GPM/IMERG/3B-HH/07, 2023. a, b
Judt, F. and Rios-Berrios, R.: Resolved Convection Improves the Representation of Equatorial Waves and Tropical Rainfall Variability in a Global Nonhydrostatic Model, Geophys. Res. Lett., 48, e2021GL093265, https://doi.org/10.1029/2021GL093265, 2021. a
Katragkou, E., Zanis, P., Tsikerdekis, A., Kapsomenakis, J., Melas, D., Eskes, H., Flemming, J., Huijnen, V., Inness, A., Schultz, M. G., Stein, O., and Zerefos, C. S.: Evaluation of near-surface ozone over Europe from the MACC reanalysis, Geosci. Model Dev., 8, 2299–2314, https://doi.org/10.5194/gmd-8-2299-2015, 2015. a
Keller, J. P., Martínez-Alvarado, O., Harvey, B. J., Sanchez, C., and Vannière, B.: A Predictability Pathway from Franklin to Daniel: Linking Extratropical Transition, European Blocking, and Devastating Mediterranean Cyclone Daniel, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2026-4273, 2026. a
Kendon, M. and McCarthy, M.: The United Kingdom's wettest day on record – so far – 3 October 2020, Weather, 76, 316–319, https://doi.org/10.1002/wea.3910, 2021. a
Khain, P., Shtivelman, A., Levi, Y., Baharad, A., Amitai, E., Carmona, Y., Vadislavsky, E., Savir, A., and Stav, N.: Optimizing convection-permitting ensemble via selection of the coarse ensemble driving members, Meteorol. Appl., 30, e2137, https://doi.org/10.1002/met.2137, 2023. a
Kinne, S.: The MACv2 aerosol climatology, Tellus B, 71, https://doi.org/10.1080/16000889.2019.1623639, 2019. a
Lapillonne, X., Hupp, D., Gessler, F., Walser, A., Pauling, A., Lauber, A., Cumming, B., Osuna, C., Müller, C., Merker, C., Leuenberger, D., Leutwyler, D., Alexeev, D., Vollenweider, G., Van Parys, G., Jucker, J., Jansing, L., Arpagaus, M., Induni, M., Jacob, M., Kraushaar, M., Jähn, M., Stellio, M., Fuhrer, O., Baumann, P., Steiner, P., Kaufmann, P., Dietlicher, R., Müller, R., Kosukhin, S., Schulthess, T. C., Schättler, U., Cherkas, V., and Sawyer, W.: Operational numerical weather prediction with ICON on GPUs (version 2024.10), Geosci. Model Dev., 19, 755–772, https://doi.org/10.5194/gmd-19-755-2026, 2026. a
Li, Z., Peng, J., Zhang, L., and Guan, J.: Exploring the Differences in Kinetic Energy Spectra between the NCEP FNL and ERA5 Datasets, J. Atmos. Sci., 81, 363–380, https://doi.org/10.1175/JAS-D-23-0043.1, 2024. a
Lillo, S. P. and Parsons, D. B.: Investigating the dynamics of error growth in ECMWF medium-range forecast busts, Q. J. Roy. Meteorol. Soc., 143, 1211–1226, https://doi.org/10.1002/qj.2938, 2017. a
Lojko, A., Prein, A. F., Ribeiro, B. Z., and Winters, A.: Warm-Conveyor Belt Persistence and Upstream Cyclone Tilt Shape the Predictability of a Rossby Wave Breaking Event, J. Geophys. Res.-Atmos., 131, e2025JD045396, https://doi.org/10.22541/essoar.175821720.04705853/v1, 2025a. a, b
Lojko, A., Winters, A. C., Oertel, A., Jablonowski, C., and Payne, A. E.: An ERA5 climatology of synoptic-scale negative potential vorticity–jet interactions over the western North Atlantic, Weather Clim. Dynam., 6, 387–411, https://doi.org/10.5194/wcd-6-387-2025, 2025b. a
Luo, F., Selten, F., Wehrli, K., Kornhuber, K., Le Sager, P., May, W., Reerink, T., Seneviratne, S. I., Shiogama, H., Tokuda, D., Kim, H., and Coumou, D.: Summertime Rossby waves in climate models: substantial biases in surface imprint associated with small biases in upper-level circulation, Weather Clim. Dynam., 3, 905–935, https://doi.org/10.5194/wcd-3-905-2022, 2022. a
Madonna, E., Limbach, S., Aebi, C., Joos, H., Wernli, H., and Martius, O.: On the Co-Occurrence of Warm Conveyor Belt Outflows and PV Streamers, J. Atmos. Sci., 71, 3668–3673, https://doi.org/10.1175/JAS-D-14-0119.1, 2014a. a, b
Madonna, E., Wernli, H., Joos, H., and Martius, O.: Warm Conveyor Belts in the ERA-Interim Dataset (1979–2010). Part I: Climatology and Potential Vorticity Evolution, J. Climate, 27, 3–26, https://doi.org/10.1175/JCLI-D-12-00720.1, 2014b. a, b
Magnusson, L.: Diagnostic methods for understanding the origin of forecast errors, Q. J. Roy. Meteorol. Soc., 143, 2129–2142, https://doi.org/10.1002/qj.3072, 2017. a, b
Martínez-Alvarado, O., Joos, H., Chagnon, J., Boettcher, M., Gray, S. L., Plant, R. S., Methven, J., and Wernli, H.: The dichotomous structure of the warm conveyor belt, Q. J. Roy. Meteorol. Soc., 140, 1809–1824, https://doi.org/10.1002/qj.2276, 2014. a
Martínez-Alvarado, O., Madonna, E., Gray, S. L., and Joos, H.: A route to systematic error in forecasts of Rossby waves, Q. J. Roy. Meteorol. Soc., 142, 196–210, https://doi.org/10.1002/qj.2645, 2016. a, b
Oertel, A., Boettcher, M., Joos, H., Sprenger, M., and Wernli, H.: Potential vorticity structure of embedded convection in a warm conveyor belt and its relevance for large-scale dynamics, Weather Clim. Dynam., 1, 127–153, https://doi.org/10.5194/wcd-1-127-2020, 2020. a, b, c
Oertel, A., Pickl, M., Quinting, J. F., Hauser, S., Wandel, J., Magnusson, L., Balmaseda, M., Vitart, F., and Grams, C. M.: Everything Hits at Once: How Remote Rainfall Matters for the Prediction of the 2021 North American Heat Wave, Geophys. Res. Lett., 50, e2022GL100958, https://doi.org/10.1029/2022GL100958, 2023. a, b
Palmer, T. N.: Predicting uncertainty in forecasts of weather and climate, Rep. Prog. Phys., 63, 71, https://doi.org/10.1088/0034-4885/63/2/201, 2000. a
Panosetti, D., Schlemmer, L., and Schär, C.: Bulk and structural convergence at convection-resolving scales in real-case simulations of summertime moist convection over land, Q. J. Roy. Meteorol. Soc., 145, 1427–1443, https://doi.org/10.1002/qj.3502, 2019. a, b
Panosetti, D., Schlemmer, L., and Schär, C.: Convergence behavior of idealized convection-resolving simulations of summertime deep moist convection over land, Clim. Dynam., 55, 215–234, https://doi.org/10.1007/s00382-018-4229-9, 2020. a, b
Park, H., Hwang, J., Cha, D.-H., Lee, M.-I., Song, C.-K., Kim, J., Park, S.-H., and Lee, D.-K.: Does a Scale-Aware Convective Parameterization Scheme Improve the Simulation of Heavy Rainfall Events?, J. Geophys. Res.-Atmos., 129, e2023JD039407, https://doi.org/10.1029/2023JD039407, 2024. a
Parsons, D. B., Lillo, S. P., Rattray, C. P., Bechtold, P., Rodwell, M. J., and Bruce, C. M.: The Role of Continental Mesoscale Convective Systems in Forecast Busts within Global Weather Prediction Systems, Atmosphere, 10, 681, https://doi.org/10.3390/atmos10110681, 2019. a, b, c
Pickl, M., Quinting, J. F., and Grams, C. M.: Warm conveyor belts as amplifiers of forecast uncertainty, Q. J. Roy. Meteorol. Soc., 149, 3064–3085, https://doi.org/10.1002/qj.4546, 2023. a
Portmann, R., González-Alemán, J. J., Sprenger, M., and Wernli, H.: How an uncertain short-wave perturbation on the North Atlantic wave guide affects the forecast of an intense Mediterranean cyclone (Medicane Zorbas), Weather Clim. Dynam., 1, 597–615, https://doi.org/10.5194/wcd-1-597-2020, 2020. a, b
Pothapakula, P. K., Prein, A. F., Sunkisala, A., and Dipankar, A.: Global Monsoon in ICON: The Scale-Dependent Response of Northern Hemisphere Monsoons, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2026-782, 2026. a
Prein, A. F., Langhans, W., Fosser, G., Ferrone, A., Ban, N., Goergen, K., Keller, M., Tölle, M., Gutjahr, O., Feser, F., Brisson, E., Kollet, S., Schmidli, J., Lipzig, N. P. M. v., and Leung, R.: A review on regional convection-permitting climate modeling: Demonstrations, prospects, and challenges, Rev. Geophys., 53, 323–361, https://doi.org/10.1002/2014RG000475, 2015. a
Prein, A. F., Rasmussen, R. M., Ikeda, K., Liu, C., Clark, M. P., and Holland, G. J.: The future intensification of hourly precipitation extremes, Nat. Clim. Change, 7, 48–52, 2017. a
Prein, A. F., Liu, C., Ikeda, K., Bullock, R., Rasmussen, R. M., Holland, G. J., and Clark, M.: Simulating North American mesoscale convective systems with a convection-permitting climate model, Clim. Dynam., 55, 95–110, https://doi.org/10.1007/s00382-017-3993-2, 2020. a, b
Prein, A. F., Mooney, P. A., and Done, J. M.: The Multi-Scale Interactions of Atmospheric Phenomenon in Mean and Extreme Precipitation, Earth's Future, 11, e2023EF003534, https://doi.org/10.1029/2023EF003534, 2023 (data available at: https://github.com/andreas-prein/MOAAP, last access: 16 October 2026). a, b
Prein, A. F., Wang, D., Ge, M., Ramos Valle, A., and Chasteen, M. B.: Resolving Mesoscale Convective Systems: Grid Spacing Sensitivity in the Tropics and Midlatitudes, J. Geophys. Res.-Atmos., 130, e2024JD042530, https://doi.org/10.1029/2024JD042530, 2025. a, b
Prein, A. F., Pothapakula, P. K., Zeman, C., Lalonde, M., Rixen, M., Dipankar, A., Leclair, M., and Jocksch, A.: From single storms to large-scale waves: a multi-year kilometer-scale global simulation, Geosci. Model Dev., 19, 5277–5303, https://doi.org/10.5194/gmd-19-5277-2026, 2026. a, b
Riemer, M. and Jones, S. C.: The downstream impact of tropical cyclones on a developing baroclinic wave in idealized scenarios of extratropical transition, Q. J. Roy. Meteorol. Soc., 136, 617–637, https://doi.org/10.1002/qj.605, 2010. a
Rixen, M.: mariusrixen/Rixen_et_al_2026_Grid_spacing_RWB: Grid-Spacing Sensitivity of Rossby Wave Breaking to Mesoscale Diabatic Processes, Zenodo [code], https://doi.org/10.5281/zenodo.19347928, 2026. a
Rodwell, M. J., Magnusson, L., Bauer, P., Bechtold, P., Bonavita, M., Cardinali, C., Diamantakis, M., Earnshaw, P., Garcia-Mendez, A., Isaksen, L., Källén, E., Klocke, D., Lopez, P., McNally, T., Persson, A., Prates, F., and Wedi, N.: Characteristics of Occasional Poor Medium-Range Weather Forecasts for Europe, B. Am. Meteorol. Soc., https://doi.org/10.1175/BAMS-D-12-00099.1, 2013. a, b, c, d, e
Schär, C., Leuenberger, D., Fuhrer, O., Lüthi, D., and Girard, C.: A New Terrain-Following Vertical Coordinate Formulation for Atmospheric Prediction Models, Mon. Weather Rev., 130, 2459–2480, https://doi.org/10.1175/1520-0493(2002)130<2459:ANTFVC>2.0.CO;2, 2002. a
Schulz, J.-P. and Vogel, G.: Improving the Processes in the Land Surface Scheme TERRA: Bare Soil Evaporation and Skin Temperature, Atmosphere, 11, 513, https://doi.org/10.3390/atmos11050513, 2020. a
Seifert, A.: A revised cloud microphysical parameterization for COSMO-LME, COSMO Newsletter 7, Consortium for SmallScale Modelling, proceedings from the 8th COSMO General Meeting, Bucharest, 2006, http://www.cosmo-model.org (last access: 16 October 2026), 2008. a
Soci, C., Hersbach, H., Simmons, A., Poli, P., Bell, B., Berrisford, P., Horányi, A., Muñoz-Sabater, J., Nicolas, J., Radu, R., Schepers, D., Villaume, S., Haimberger, L., Woollen, J., Buontempo, C., and Thépaut, J.-N.: The ERA5 global reanalysis from 1940 to 2022, Q. J. Roy. Meteorol. Soc., 150, 4014–4048, https://doi.org/10.1002/qj.4803, 2024. a
Sprenger, M. and Wernli, H.: The LAGRANTO Lagrangian analysis tool – version 2.0, Geosci. Model Dev., 8, 2569–2586, https://doi.org/10.5194/gmd-8-2569-2015, 2015. a
Tiedtke, M.: A Comprehensive Mass Flux Scheme for Cumulus Parameterization in Large-Scale Models, Mon. Weather Rev., 117, 1779–1800, https://doi.org/10.1175/1520-0493(1989)117<1779:ACMFSF>2.0.CO;2, 1989. a
Tomassini, L., Willett, M., Sellar, A., Lock, A., Walters, D., Whitall, M., Sanchez, C., Heming, J., Earnshaw, P., Rodriguez, J. M., Ackerley, D., Xavier, P., Franklin, C., and Senior, C. A.: Confronting the Convective Gray Zone in the Global Configuration of the Met Office Unified Model, J. Adv. Model. Earth Syst., 15, e2022MS003418, https://doi.org/10.1029/2022MS003418, 2023. a, b
Uma, K. N., Das, S. S., Ratnam, M. V., and Suneeth, K. V.: Assessment of vertical air motion among reanalyses and qualitative comparison with very-high-frequency radar measurements over two tropical stations, Atmos. Chem. Phys., 21, 2083–2103, https://doi.org/10.5194/acp-21-2083-2021, 2021. a
UNHCR: Libya: Floods Emergency - Six-Month Impact Report, World Bank, https://doi.org/10.1596/41039, 2024. a
Vergara-Temprado, J., Ban, N., Panosetti, D., Schlemmer, L., and Schär, C.: Climate Models Permit Convection at Much Coarser Resolutions Than Previously Considered, J. Climate, 33, 1915–1933, https://doi.org/10.1175/JCLI-D-19-0286.1, 2020. a, b
Vishnupriya, S., Sprenger, M., Joos, H., and Wernli, H.: The interaction of warm conveyor belt outflows with the upper-level waveguide: a four-type climatological classification, Weather Clim. Dynam., 6, 1195–1219, https://doi.org/10.5194/wcd-6-1195-2025, 2025. a, b
Wang, W.: Forecasting Convection with a “Scale-Aware” Tiedtke Cumulus Parameterization Scheme at Kilometer Scales, Weather Forecast., 37, 1491–1507, https://doi.org/10.1175/WAF-D-21-0179.1, 2022. a
Wernli, H. and Davies, H. C.: A Lagrangian-based analysis of extratropical cyclones. I: The method and some applications, Q. J. Roy. Meteorol. Soc., 123, 467–489, https://doi.org/10.1002/qj.49712353811, 1997. a, b
Wernli, H. and Gray, S. L.: The importance of diabatic processes for the dynamics of synoptic-scale extratropical weather systems – a review, Weather Clim. Dynam., 5, 1299–1408, https://doi.org/10.5194/wcd-5-1299-2024, 2024. a
Willison, J., Robinson, W. A., and Lackmann, G. M.: The Importance of Resolving Mesoscale Latent Heating in the North Atlantic Storm Track, J. Atmos. Sci., 70, 2234–2250, https://doi.org/10.1175/JAS-D-12-0226.1, 2013. a, b
Zeman, C., Wedi, N. P., Dueben, P. D., Ban, N., and Schär, C.: Model intercomparison of COSMO 5.0 and IFS 45r1 at kilometer-scale grid spacing, Geosci. Model Dev., 14, 4617–4639, https://doi.org/10.5194/gmd-14-4617-2021, 2021. a, b
Zängl, G., Reinert, D., Rípodas, P., and Baldauf, M.: The ICON (ICOsahedral Non-hydrostatic) modelling framework of DWD and MPI-M: Description of the non-hydrostatic dynamical core, Q. J. Roy. Meteorol. Soc., 141, 563–579, https://doi.org/10.1002/qj.2378, 2015. a
Short summary
Despite steady improvements in forecasting skill, episodes of low forecast skill, called forecast busts, still persist. Using global ensemble simulations at different grid spacings, we show that coarse-grid simulations fail to resolve key mesoscale diabatic processes, and that errors upscale and propagate downstream, leading to large forecast errors. Fine grid spacing simulations better capture scale interactions in strongly diabatic flow, highlighting the potential of kilometer-scale models.
Despite steady improvements in forecasting skill, episodes of low forecast skill, called...
