Articles | Volume 1, issue 2
https://doi.org/10.5194/wcd-1-325-2020
© Author(s) 2020. 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-1-325-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
17 Jul 2020
Research article |
| 17 Jul 2020
| 17 Jul 2020
The role of large-scale dynamics in an exceptional sequence of severe thunderstorms in Europe May–June 2018
Institute of Meteorology and Climate Research (IMK), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
Jannik Wilhelm
Institute of Meteorology and Climate Research (IMK), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
Jan Wandel
Institute of Meteorology and Climate Research (IMK), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
Michael Kunz
Institute of Meteorology and Climate Research (IMK), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
Center for Disaster Management and Risk Reduction Technology (CEDIM), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
Raphael Portmann
Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland
Heinz Jürgen Punge
Institute of Meteorology and Climate Research (IMK), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
Manuel Schmidberger
Institute of Meteorology and Climate Research (IMK), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
Julian F. Quinting
Institute of Meteorology and Climate Research (IMK), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
Christian M. Grams
Institute of Meteorology and Climate Research (IMK), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
Related authors
Markus Augenstein, Susanna Mohr, and Michael Kunz
EGUsphere, https://doi.org/10.5194/egusphere-2024-2804, https://doi.org/10.5194/egusphere-2024-2804, 2024
Short summary
Short summary
A grid-based analysis of lightning in Europe shows a reduction in thunderstorm activity in many regions. Moving away from a grid-based analysis, a spatio-temporal clustering algorithm was used. The results show a slight trend towards the occurrence of smaller, more separated convective clustered events, suggesting changes in the organization of convective systems. One reason for this could be the increased occurrence of the negative phase of the North Atlantic Oscillation in the last decade.
Elena Xoplaki, Florian Ellsäßer, Jens Grieger, Katrin M. Nissen, Joaquim Pinto, Markus Augenstein, Ting-Chen Chen, Hendrik Feldmann, Petra Friederichs, Daniel Gliksman, Laura Goulier, Karsten Haustein, Jens Heinke, Lisa Jach, Florian Knutzen, Stefan Kollet, Jürg Luterbacher, Niklas Luther, Susanna Mohr, Christoph Mudersbach, Christoph Müller, Efi Rousi, Felix Simon, Laura Suarez-Gutierrez, Svenja Szemkus, Sara M. Vallejo-Bernal, Odysseas Vlachopoulos, and Frederik Wolf
EGUsphere, https://doi.org/10.5194/egusphere-2023-1460, https://doi.org/10.5194/egusphere-2023-1460, 2023
Short summary
Short summary
Europe is regularly affected by compound events and natural hazards that occur simultaneously or with a temporal lag and are connected with disproportional impacts. Within the interdisciplinary project climXtreme (https://climxtreme.net/) we investigate the interplay of these events, their characteristics and changes, intensity, frequency and uncertainties in the past, present and future, as well as the associated impacts on different socio-economic sectors in Germany and Central Europe.
Patrick Ludwig, Florian Ehmele, Mário J. Franca, Susanna Mohr, Alberto Caldas-Alvarez, James E. Daniell, Uwe Ehret, Hendrik Feldmann, Marie Hundhausen, Peter Knippertz, Katharina Küpfer, Michael Kunz, Bernhard Mühr, Joaquim G. Pinto, Julian Quinting, Andreas M. Schäfer, Frank Seidel, and Christina Wisotzky
Nat. Hazards Earth Syst. Sci., 23, 1287–1311, https://doi.org/10.5194/nhess-23-1287-2023, https://doi.org/10.5194/nhess-23-1287-2023, 2023
Short summary
Short summary
Heavy precipitation in July 2021 led to widespread floods in western Germany and neighboring countries. The event was among the five heaviest precipitation events of the past 70 years in Germany, and the river discharges exceeded by far the statistical 100-year return values. Simulations of the event under future climate conditions revealed a strong and non-linear effect on flood peaks: for +2 K global warming, an 18 % increase in rainfall led to a 39 % increase of the flood peak in the Ahr river.
Susanna Mohr, Uwe Ehret, Michael Kunz, Patrick Ludwig, Alberto Caldas-Alvarez, James E. Daniell, Florian Ehmele, Hendrik Feldmann, Mário J. Franca, Christian Gattke, Marie Hundhausen, Peter Knippertz, Katharina Küpfer, Bernhard Mühr, Joaquim G. Pinto, Julian Quinting, Andreas M. Schäfer, Marc Scheibel, Frank Seidel, and Christina Wisotzky
Nat. Hazards Earth Syst. Sci., 23, 525–551, https://doi.org/10.5194/nhess-23-525-2023, https://doi.org/10.5194/nhess-23-525-2023, 2023
Short summary
Short summary
The flood event in July 2021 was one of the most severe disasters in Europe in the last half century. The objective of this two-part study is a multi-disciplinary assessment that examines the complex process interactions in different compartments, from meteorology to hydrological conditions to hydro-morphological processes to impacts on assets and environment. In addition, we address the question of what measures are possible to generate added value to early response management.
Alberto Caldas-Alvarez, Markus Augenstein, Georgy Ayzel, Klemens Barfus, Ribu Cherian, Lisa Dillenardt, Felix Fauer, Hendrik Feldmann, Maik Heistermann, Alexia Karwat, Frank Kaspar, Heidi Kreibich, Etor Emanuel Lucio-Eceiza, Edmund P. Meredith, Susanna Mohr, Deborah Niermann, Stephan Pfahl, Florian Ruff, Henning W. Rust, Lukas Schoppa, Thomas Schwitalla, Stella Steidl, Annegret H. Thieken, Jordis S. Tradowsky, Volker Wulfmeyer, and Johannes Quaas
Nat. Hazards Earth Syst. Sci., 22, 3701–3724, https://doi.org/10.5194/nhess-22-3701-2022, https://doi.org/10.5194/nhess-22-3701-2022, 2022
Short summary
Short summary
In a warming climate, extreme precipitation events are becoming more frequent. To advance our knowledge on such phenomena, we present a multidisciplinary analysis of a selected case study that took place on 29 June 2017 in the Berlin metropolitan area. Our analysis provides evidence of the extremeness of the case from the atmospheric and the impacts perspectives as well as new insights on the physical mechanisms of the event at the meteorological and climate scales.
Michael Kunz, Jan Wandel, Elody Fluck, Sven Baumstark, Susanna Mohr, and Sebastian Schemm
Nat. Hazards Earth Syst. Sci., 20, 1867–1887, https://doi.org/10.5194/nhess-20-1867-2020, https://doi.org/10.5194/nhess-20-1867-2020, 2020
Short summary
Short summary
Severe convective storms are major loss drivers across Europe. We reconstructed several thousand storm tracks from radar reflectivity over a 10-year period for parts of Europe. The tracks were additionally combined with hail reports, reanalysis data, and front detections based on ERA-Interim (ECMWF Reanalysis). It is found that frontal hailstorms on average produce larger hailstones and have longer tracks and that wind shear is important not only for the hail diameter but also for track length.
Philip J. Ward, Veit Blauhut, Nadia Bloemendaal, James E. Daniell, Marleen C. de Ruiter, Melanie J. Duncan, Robert Emberson, Susanna F. Jenkins, Dalia Kirschbaum, Michael Kunz, Susanna Mohr, Sanne Muis, Graeme A. Riddell, Andreas Schäfer, Thomas Stanley, Ted I. E. Veldkamp, and Hessel C. Winsemius
Nat. Hazards Earth Syst. Sci., 20, 1069–1096, https://doi.org/10.5194/nhess-20-1069-2020, https://doi.org/10.5194/nhess-20-1069-2020, 2020
Short summary
Short summary
We review the scientific literature on natural hazard risk assessments at the global scale. In doing so, we examine similarities and differences between the approaches taken across the different hazards and identify potential ways in which different hazard communities can learn from each other. Finally, we discuss opportunities for learning from methods and approaches being developed and applied to assess natural hazard risks at more continental or regional scales.
Susanna Mohr, Michael Kunz, Alexandra Richter, and Bodo Ruck
Nat. Hazards Earth Syst. Sci., 17, 957–969, https://doi.org/10.5194/nhess-17-957-2017, https://doi.org/10.5194/nhess-17-957-2017, 2017
Short summary
Short summary
Due to the small-scale and non-stationary nature of the convective wind gusts usually associated with thunderstorms, there is a considerable lack of knowledge regarding their characteristics and statistics. Thus, we investigated the temporal and spatial distribution, intensity, and return values of those wind events in Germany. The study constitutes a fundamental addition to an improved understanding of convective wind gusts and serves as basis for further risk assessments.
David Piper, Michael Kunz, Florian Ehmele, Susanna Mohr, Bernhard Mühr, Andreas Kron, and James Daniell
Nat. Hazards Earth Syst. Sci., 16, 2835–2850, https://doi.org/10.5194/nhess-16-2835-2016, https://doi.org/10.5194/nhess-16-2835-2016, 2016
Markus Augenstein, Susanna Mohr, and Michael Kunz
EGUsphere, https://doi.org/10.5194/egusphere-2024-2804, https://doi.org/10.5194/egusphere-2024-2804, 2024
Short summary
Short summary
A grid-based analysis of lightning in Europe shows a reduction in thunderstorm activity in many regions. Moving away from a grid-based analysis, a spatio-temporal clustering algorithm was used. The results show a slight trend towards the occurrence of smaller, more separated convective clustered events, suggesting changes in the organization of convective systems. One reason for this could be the increased occurrence of the negative phase of the North Atlantic Oscillation in the last decade.
Edgar Dolores-Tesillos, Olivia Martius, and Julian Quinting
EGUsphere, https://doi.org/10.5194/egusphere-2024-2878, https://doi.org/10.5194/egusphere-2024-2878, 2024
Short summary
Short summary
An accurate representation of synoptic weather systems in climate models is required to estimate their societal and economic impacts under climate warming. Current climate models poorly represent the frequency of atmospheric blocking. Few studies have analysed the role of moist processes as a source of bias of blocks. Here, we implement ELIAS2.0, a deep learning tool, to validate the representation of moist processes in CMIP6 models and their link to the Euro-Atlantic blocking biases.
Katharina Küpfer, Alexandre Tuel, and Michael Kunz
EGUsphere, https://doi.org/10.5194/egusphere-2024-2803, https://doi.org/10.5194/egusphere-2024-2803, 2024
Short summary
Short summary
Using loss data, we assess when and how single and multiple types of meteorological extremes (river floods and heavy rainfall events, windstorms and convective gusts, and hail). We find that the combination of several types of hazards clusters robustly on a seasonal scale, whereas only some single hazard types occur in clusters. This can be associated with higher losses compared to isolated events. We argue for the relevance of jointly considering multiple types of hazards.
Joshua Dorrington, Marta Wenta, Federico Grazzini, Linus Magnusson, Frederic Vitart, and Christian M. Grams
Nat. Hazards Earth Syst. Sci., 24, 2995–3012, https://doi.org/10.5194/nhess-24-2995-2024, https://doi.org/10.5194/nhess-24-2995-2024, 2024
Short summary
Short summary
Extreme rainfall is the leading weather-related source of damages in Europe, but it is still difficult to predict on long timescales. A recent example of this was the devastating floods in the Italian region of Emiglia Romagna in May 2023. We present perspectives based on large-scale dynamical information that allows us to better understand and predict such events.
Svenja Christ, Marta Wenta, Christian M. Grams, and Annika Oertel
EGUsphere, https://doi.org/10.5194/egusphere-2024-2403, https://doi.org/10.5194/egusphere-2024-2403, 2024
Short summary
Short summary
The detailed representation of sea surface temperature (SST) in numerical models is important for the prediction of atmospheric blocking in the North Atlantic. Yet, the underlying physical processes are not fully understood. Using SST sensitivity experiments for a case study, we identify a physical pathway through which SST in the Gulf Stream region is linked to the downstream upper-level flow evolution in the North Atlantic.
Raphael Portmann, Timo Schmid, Leonie Villiger, David N. Bresch, and Pierluigi Calanca
Nat. Hazards Earth Syst. Sci., 24, 2541–2558, https://doi.org/10.5194/nhess-24-2541-2024, https://doi.org/10.5194/nhess-24-2541-2024, 2024
Short summary
Short summary
The study presents an open-source model to determine the occurrence of hail damage to field crops and grapevines after hailstorms in Switzerland based on radar, agricultural land use data, and insurance damage reports. The model performs best at 8 km resolution for field crops and 1 km for grapevine and in the main production areas. Highlighting performance trade-offs and the relevance of user needs, the study is a first step towards the assessment of risk and damage for crops in Switzerland.
Alexandre Mass, Hendrik Andersen, Jan Cermak, Paola Formenti, Eva Pauli, and Julian Quinting
EGUsphere, https://doi.org/10.5194/egusphere-2024-1627, https://doi.org/10.5194/egusphere-2024-1627, 2024
Short summary
Short summary
This study investigates the interaction between smoke aerosols and fog and low clouds (FLCs) in the Namib desert between June and October. Here, a satellite-based dataset of FLCs, reanalysis data and machine learning are used to systematically analyze FLCs persistence under different aerosol loadings. Aerosol plumes are shown to modify local thermodynamics which increases FLC persistence. But fully disentangling aerosol effects from meteorological ones remains a challenge.
Moritz Deinhard and Christian M. Grams
Weather Clim. Dynam., 5, 927–942, https://doi.org/10.5194/wcd-5-927-2024, https://doi.org/10.5194/wcd-5-927-2024, 2024
Short summary
Short summary
Stochastic perturbations are an established technique to represent model uncertainties in numerical weather prediction. While such schemes are beneficial for the forecast skill, they can also change the mean state of the model. We analyse how different schemes modulate rapidly ascending airstreams and whether the changes to such weather systems are projected onto larger scales. We thereby provide a process-oriented perspective on how perturbations affect the model climate.
Marc Federer, Lukas Papritz, Michael Sprenger, and Christian M. Grams
EGUsphere, https://doi.org/10.5194/egusphere-2024-2112, https://doi.org/10.5194/egusphere-2024-2112, 2024
Short summary
Short summary
Although extratropical cyclones in the North Atlantic are among the most impactful midlatitude weather systems, the potential for their growth on synoptic scales is not well understood. Here we show how they convert potential into kinetic energy through the descent of cold upper-tropospheric air from high latitudes. Surface processes, such as ocean heat exchange, have a smaller effect. Understanding these dynamics helps to explain the processes that maintain storm tracks.
Antonio Giordani, Michael Kunz, Kristopher M. Bedka, Heinz Jürgen Punge, Tiziana Paccagnella, Valentina Pavan, Ines M. L. Cerenzia, and Silvana Di Sabatino
Nat. Hazards Earth Syst. Sci., 24, 2331–2357, https://doi.org/10.5194/nhess-24-2331-2024, https://doi.org/10.5194/nhess-24-2331-2024, 2024
Short summary
Short summary
To improve the challenging representation of hazardous hailstorms, a proxy for hail frequency based on satellite detections, convective parameters from high-resolution reanalysis, and crowd-sourced reports is tested and presented. Hail likelihood peaks in mid-summer at 15:00 UTC over northern Italy and shows improved agreement with observations compared to previous estimates. By separating ambient signatures based on hail severity, enhanced appropriateness for large-hail occurrence is found.
Deifilia Aurora To, Julian Quinting, Gholam Ali Hoshyaripour, Markus Götz, Achim Streit, and Charlotte Debus
EGUsphere, https://doi.org/10.5194/egusphere-2024-1714, https://doi.org/10.5194/egusphere-2024-1714, 2024
Short summary
Short summary
Pangu-Weather is a breakthrough machine learning model in medium-range weather forecasting that considers three-dimensional atmospheric information. We show that using a simpler 2D framework improves robustness, speeds up training, and reduces computational needs by 20–30%. We introduce a training procedure that varies the importance of atmospheric variables over time to speed up training convergence. Decreasing computational demand increases accessibility of training and working with the model.
Luise J. Fischer, David N. Bresch, Dominik Büeler, Christian M. Grams, Matthias Röthlisberger, and Heini Wernli
EGUsphere, https://doi.org/10.5194/egusphere-2024-1253, https://doi.org/10.5194/egusphere-2024-1253, 2024
Short summary
Short summary
Atmospheric flows over the North Atlantic can be meaningfully classified into weather regimes, and climate simulations suggest that the regime frequencies might change in the future. We provide a quantitative framework that helps assessing whether these regime frequency changes are relevant for understanding climate change signals in precipitation. At least in our example application, this is not the case, i.e., regime frequency changes explain little of the projected precipitation changes.
Seraphine Hauser, Franziska Teubler, Michael Riemer, Peter Knippertz, and Christian M. Grams
Weather Clim. Dynam., 5, 633–658, https://doi.org/10.5194/wcd-5-633-2024, https://doi.org/10.5194/wcd-5-633-2024, 2024
Short summary
Short summary
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.
Steven J. De Hertog, Carmen E. Lopez-Fabara, Ruud van der Ent, Jessica Keune, Diego G. Miralles, Raphael Portmann, Sebastian Schemm, Felix Havermann, Suqi Guo, Fei Luo, Iris Manola, Quentin Lejeune, Julia Pongratz, Carl-Friedrich Schleussner, Sonia I. Seneviratne, and Wim Thiery
Earth Syst. Dynam., 15, 265–291, https://doi.org/10.5194/esd-15-265-2024, https://doi.org/10.5194/esd-15-265-2024, 2024
Short summary
Short summary
Changes in land use are crucial to achieve lower global warming. However, despite their importance, the effects of these changes on moisture fluxes are poorly understood. We analyse land cover and management scenarios in three climate models involving cropland expansion, afforestation, and irrigation. Results show largely consistent influences on moisture fluxes, with cropland expansion causing a drying and reduced local moisture recycling, while afforestation and irrigation show the opposite.
Timo Schmid, Raphael Portmann, Leonie Villiger, Katharina Schröer, and David N. Bresch
Nat. Hazards Earth Syst. Sci., 24, 847–872, https://doi.org/10.5194/nhess-24-847-2024, https://doi.org/10.5194/nhess-24-847-2024, 2024
Short summary
Short summary
Hailstorms cause severe damage to buildings and cars, which motivates a detailed risk assessment. Here, we present a new open-source hail damage model based on radar data in Switzerland. The model successfully estimates the correct order of magnitude of car and building damages for most large hail events over 20 years. However, large uncertainty remains in the geographical distribution of modelled damages, which can be improved for individual events by using crowdsourced hail reports.
Marta Wenta, Christian M. Grams, Lukas Papritz, and Marc Federer
Weather Clim. Dynam., 5, 181–209, https://doi.org/10.5194/wcd-5-181-2024, https://doi.org/10.5194/wcd-5-181-2024, 2024
Short summary
Short summary
Our study links air–sea interactions over the Gulf Stream to an atmospheric block in February 2019. We found that over 23 % of air masses that were lifted into the block by cyclones interacted with the Gulf Stream. As cyclones pass over the Gulf Stream, they cause intense surface evaporation events, preconditioning the environment for the development of cyclones. This implies that air–sea interactions over the Gulf Stream affect the large-scale dynamics in the North Atlantic–European region.
Julian F. Quinting, Christian M. Grams, Edmund Kar-Man Chang, Stephan Pfahl, and Heini Wernli
Weather Clim. Dynam., 5, 65–85, https://doi.org/10.5194/wcd-5-65-2024, https://doi.org/10.5194/wcd-5-65-2024, 2024
Short summary
Short summary
Research in the last few decades has revealed that rapidly ascending airstreams in extratropical cyclones have an important effect on the evolution of downstream weather and predictability. In this study, we show that the occurrence of these airstreams over the North Pacific is modulated by tropical convection. Depending on the modulation, known atmospheric circulation patterns evolve quite differently, which may affect extended-range predictions in the Atlantic–European region.
Elena Xoplaki, Florian Ellsäßer, Jens Grieger, Katrin M. Nissen, Joaquim Pinto, Markus Augenstein, Ting-Chen Chen, Hendrik Feldmann, Petra Friederichs, Daniel Gliksman, Laura Goulier, Karsten Haustein, Jens Heinke, Lisa Jach, Florian Knutzen, Stefan Kollet, Jürg Luterbacher, Niklas Luther, Susanna Mohr, Christoph Mudersbach, Christoph Müller, Efi Rousi, Felix Simon, Laura Suarez-Gutierrez, Svenja Szemkus, Sara M. Vallejo-Bernal, Odysseas Vlachopoulos, and Frederik Wolf
EGUsphere, https://doi.org/10.5194/egusphere-2023-1460, https://doi.org/10.5194/egusphere-2023-1460, 2023
Short summary
Short summary
Europe is regularly affected by compound events and natural hazards that occur simultaneously or with a temporal lag and are connected with disproportional impacts. Within the interdisciplinary project climXtreme (https://climxtreme.net/) we investigate the interplay of these events, their characteristics and changes, intensity, frequency and uncertainties in the past, present and future, as well as the associated impacts on different socio-economic sectors in Germany and Central Europe.
Annika Oertel, Annette K. Miltenberger, Christian M. Grams, and Corinna Hoose
Atmos. Chem. Phys., 23, 8553–8581, https://doi.org/10.5194/acp-23-8553-2023, https://doi.org/10.5194/acp-23-8553-2023, 2023
Short summary
Short summary
Warm conveyor belts (WCBs) are cloud- and precipitation-producing airstreams in extratropical cyclones that are important for the large-scale flow and cloud radiative forcing. We analyze cloud formation processes during WCB ascent in a two-moment microphysics scheme. Quantification of individual diabatic heating rates shows the importance of condensation, vapor deposition, rain evaporation, melting, and cloud-top radiative cooling for total heating and WCB-related potential vorticity structure.
Axel Seifert, Vanessa Bachmann, Florian Filipitsch, Jochen Förstner, Christian M. Grams, Gholam Ali Hoshyaripour, Julian Quinting, Anika Rohde, Heike Vogel, Annette Wagner, and Bernhard Vogel
Atmos. Chem. Phys., 23, 6409–6430, https://doi.org/10.5194/acp-23-6409-2023, https://doi.org/10.5194/acp-23-6409-2023, 2023
Short summary
Short summary
We investigate how mineral dust can lead to the formation of cirrus clouds. Dusty cirrus clouds lead to a reduction in solar radiation at the surface and, hence, a reduced photovoltaic power generation. Current weather prediction systems are not able to predict this interaction between mineral dust and cirrus clouds. We have developed a new physical description of the formation of dusty cirrus clouds. Overall we can show a considerable improvement in the forecast quality of clouds and radiation.
Steven J. De Hertog, Carmen E. Lopez-Fabara, Ruud van der Ent, Jessica Keune, Diego G. Miralles, Raphael Portmann, Sebastian Schemm, Felix Havermann, Suqi Guo, Fei Luo, Iris Manola, Quentin Lejeune, Julia Pongratz, Carl-Friedrich Schleussner, Sonia I. Seneviratne, and Wim Thiery
EGUsphere, https://doi.org/10.5194/egusphere-2023-953, https://doi.org/10.5194/egusphere-2023-953, 2023
Preprint archived
Short summary
Short summary
Land cover and management changes can affect the climate and water availability. In this study we use climate model simulations of extreme global land cover changes (afforestation, deforestation) and land management changes (irrigation) to understand the effects on the global water cycle and local to continental water availability. We show that cropland expansion generally leads to higher evaporation and lower amounts of precipitation and afforestation and irrigation expansion to the opposite.
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
Short summary
Short summary
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.
Heinz Jürgen Punge, Kristopher M. Bedka, Michael Kunz, Sarah D. Bang, and Kyle F. Itterly
Nat. Hazards Earth Syst. Sci., 23, 1549–1576, https://doi.org/10.5194/nhess-23-1549-2023, https://doi.org/10.5194/nhess-23-1549-2023, 2023
Short summary
Short summary
We have estimated the probability of hail events in South Africa using a combination of satellite observations, reanalysis, and insurance claims data. It is found that hail is mainly concentrated in the southeast. Multivariate stochastic modeling of event characteristics, such as multiple events per day or track dimensions, provides an event catalogue for 25 000 years. This can be used to estimate hail risk for return periods of 200 years, as required by insurance companies.
Patrick Ludwig, Florian Ehmele, Mário J. Franca, Susanna Mohr, Alberto Caldas-Alvarez, James E. Daniell, Uwe Ehret, Hendrik Feldmann, Marie Hundhausen, Peter Knippertz, Katharina Küpfer, Michael Kunz, Bernhard Mühr, Joaquim G. Pinto, Julian Quinting, Andreas M. Schäfer, Frank Seidel, and Christina Wisotzky
Nat. Hazards Earth Syst. Sci., 23, 1287–1311, https://doi.org/10.5194/nhess-23-1287-2023, https://doi.org/10.5194/nhess-23-1287-2023, 2023
Short summary
Short summary
Heavy precipitation in July 2021 led to widespread floods in western Germany and neighboring countries. The event was among the five heaviest precipitation events of the past 70 years in Germany, and the river discharges exceeded by far the statistical 100-year return values. Simulations of the event under future climate conditions revealed a strong and non-linear effect on flood peaks: for +2 K global warming, an 18 % increase in rainfall led to a 39 % increase of the flood peak in the Ahr river.
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
Short summary
Short summary
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.
Susanna Mohr, Uwe Ehret, Michael Kunz, Patrick Ludwig, Alberto Caldas-Alvarez, James E. Daniell, Florian Ehmele, Hendrik Feldmann, Mário J. Franca, Christian Gattke, Marie Hundhausen, Peter Knippertz, Katharina Küpfer, Bernhard Mühr, Joaquim G. Pinto, Julian Quinting, Andreas M. Schäfer, Marc Scheibel, Frank Seidel, and Christina Wisotzky
Nat. Hazards Earth Syst. Sci., 23, 525–551, https://doi.org/10.5194/nhess-23-525-2023, https://doi.org/10.5194/nhess-23-525-2023, 2023
Short summary
Short summary
The flood event in July 2021 was one of the most severe disasters in Europe in the last half century. The objective of this two-part study is a multi-disciplinary assessment that examines the complex process interactions in different compartments, from meteorology to hydrological conditions to hydro-morphological processes to impacts on assets and environment. In addition, we address the question of what measures are possible to generate added value to early response management.
Alberto Caldas-Alvarez, Markus Augenstein, Georgy Ayzel, Klemens Barfus, Ribu Cherian, Lisa Dillenardt, Felix Fauer, Hendrik Feldmann, Maik Heistermann, Alexia Karwat, Frank Kaspar, Heidi Kreibich, Etor Emanuel Lucio-Eceiza, Edmund P. Meredith, Susanna Mohr, Deborah Niermann, Stephan Pfahl, Florian Ruff, Henning W. Rust, Lukas Schoppa, Thomas Schwitalla, Stella Steidl, Annegret H. Thieken, Jordis S. Tradowsky, Volker Wulfmeyer, and Johannes Quaas
Nat. Hazards Earth Syst. Sci., 22, 3701–3724, https://doi.org/10.5194/nhess-22-3701-2022, https://doi.org/10.5194/nhess-22-3701-2022, 2022
Short summary
Short summary
In a warming climate, extreme precipitation events are becoming more frequent. To advance our knowledge on such phenomena, we present a multidisciplinary analysis of a selected case study that took place on 29 June 2017 in the Berlin metropolitan area. Our analysis provides evidence of the extremeness of the case from the atmospheric and the impacts perspectives as well as new insights on the physical mechanisms of the event at the meteorological and climate scales.
Matthias Röthlisberger, Barbara Scherrer, Andries Jan de Vries, and Raphael Portmann
Weather Clim. Dynam., 3, 733–754, https://doi.org/10.5194/wcd-3-733-2022, https://doi.org/10.5194/wcd-3-733-2022, 2022
Short summary
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.
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.
Julian F. Quinting and Christian M. Grams
Geosci. Model Dev., 15, 715–730, https://doi.org/10.5194/gmd-15-715-2022, https://doi.org/10.5194/gmd-15-715-2022, 2022
Short summary
Short summary
Physical processes in weather systems importantly affect the midlatitude large-scale circulation. This study introduces an artificial-intelligence-based framework which allows the identification of an important weather system – the so-called warm conveyor belt (WCB) – at comparably low computational costs and from data at low spatial and temporal resolution. The framework thus newly enables the systematic investigation of WCBs in large data sets such as climate model projections.
Julian F. Quinting, Christian M. Grams, Annika Oertel, and Moritz Pickl
Geosci. Model Dev., 15, 731–744, https://doi.org/10.5194/gmd-15-731-2022, https://doi.org/10.5194/gmd-15-731-2022, 2022
Short summary
Short summary
This study applies novel artificial-intelligence-based models that allow the identification of one specific weather system which affects the midlatitude circulation. We show that the models yield similar results as their trajectory-based counterpart, which requires data at higher spatiotemporal resolution and is computationally more expensive. Overall, we aim to show how deep learning methods can be used efficiently to support process understanding of biases in weather prediction models.
Raphael Portmann, Michael Sprenger, and Heini Wernli
Weather Clim. Dynam., 2, 507–534, https://doi.org/10.5194/wcd-2-507-2021, https://doi.org/10.5194/wcd-2-507-2021, 2021
Short summary
Short summary
We explore the three-dimensional life cycle of cyclonic structures
(so-called PV cutoffs) near the tropopause. PV cutoffs are frequent weather systems in the extratropics that lead to high-impact weather. However, many unknowns exist regarding their evolution. We present a new method to track PV cutoffs as 3D objects in reanalysis data by following air parcels along the flow. We study the climatological life cycles of PV cutoffs in detail and propose a classification into three types.
Elody Fluck, Michael Kunz, Peter Geissbuehler, and Stefan P. Ritz
Nat. Hazards Earth Syst. Sci., 21, 683–701, https://doi.org/10.5194/nhess-21-683-2021, https://doi.org/10.5194/nhess-21-683-2021, 2021
Short summary
Short summary
Severe convective storms (SCSs) and the related hail events constitute major atmospheric hazards in parts of Europe. In our study, we identified the regions of France, Germany, Belgium and Luxembourg that were most affected by hail over a 10 year period (2005 to 2014). A cell-tracking algorithm was computed on remote-sensing data to enable the reconstruction of several thousand SCS tracks. The location of hail hotspots will help us understand hail formation and improve hail forecasting.
Assaf Hochman, Sebastian Scher, Julian Quinting, Joaquim G. Pinto, and Gabriele Messori
Earth Syst. Dynam., 12, 133–149, https://doi.org/10.5194/esd-12-133-2021, https://doi.org/10.5194/esd-12-133-2021, 2021
Short summary
Short summary
Skillful forecasts of extreme weather events have a major socioeconomic relevance. Here, we compare two approaches to diagnose the predictability of eastern Mediterranean heat waves: one based on recent developments in dynamical systems theory and one leveraging numerical ensemble weather forecasts. We conclude that the former can be a useful and cost-efficient complement to conventional numerical forecasts for understanding the dynamics of eastern Mediterranean heat waves.
Raphael Portmann, Juan Jesús González-Alemán, Michael Sprenger, and Heini Wernli
Weather Clim. Dynam., 1, 597–615, https://doi.org/10.5194/wcd-1-597-2020, https://doi.org/10.5194/wcd-1-597-2020, 2020
Short summary
Short summary
In September 2018 an intense Mediterranean cyclone with structural similarities to a hurricane, a so-called medicane, caused severe damage in Greece. Its development was uncertain, even just a few days in advance. The reason for this was uncertainties in the jet stream over the North Atlantic 3 d prior to cyclogenesis that propagated into the Mediterranean. They led to an uncertain position of the upper-level disturbance and, as a result, of the position and thermal structure of the cyclone.
Daniela I. V. Domeisen, Christian M. Grams, and Lukas Papritz
Weather Clim. Dynam., 1, 373–388, https://doi.org/10.5194/wcd-1-373-2020, https://doi.org/10.5194/wcd-1-373-2020, 2020
Short summary
Short summary
We cannot currently predict the weather over Europe beyond 2 weeks. The stratosphere provides a promising opportunity to go beyond that limit by providing a change in probability of certain weather regimes at the surface. However, not all stratospheric extreme events are followed by the same surface weather evolution. We show that this weather evolution is related to the tropospheric weather regime around the onset of the stratospheric extreme event for many stratospheric events.
Michael Kunz, Jan Wandel, Elody Fluck, Sven Baumstark, Susanna Mohr, and Sebastian Schemm
Nat. Hazards Earth Syst. Sci., 20, 1867–1887, https://doi.org/10.5194/nhess-20-1867-2020, https://doi.org/10.5194/nhess-20-1867-2020, 2020
Short summary
Short summary
Severe convective storms are major loss drivers across Europe. We reconstructed several thousand storm tracks from radar reflectivity over a 10-year period for parts of Europe. The tracks were additionally combined with hail reports, reanalysis data, and front detections based on ERA-Interim (ECMWF Reanalysis). It is found that frontal hailstorms on average produce larger hailstones and have longer tracks and that wind shear is important not only for the hail diameter but also for track length.
Philip J. Ward, Veit Blauhut, Nadia Bloemendaal, James E. Daniell, Marleen C. de Ruiter, Melanie J. Duncan, Robert Emberson, Susanna F. Jenkins, Dalia Kirschbaum, Michael Kunz, Susanna Mohr, Sanne Muis, Graeme A. Riddell, Andreas Schäfer, Thomas Stanley, Ted I. E. Veldkamp, and Hessel C. Winsemius
Nat. Hazards Earth Syst. Sci., 20, 1069–1096, https://doi.org/10.5194/nhess-20-1069-2020, https://doi.org/10.5194/nhess-20-1069-2020, 2020
Short summary
Short summary
We review the scientific literature on natural hazard risk assessments at the global scale. In doing so, we examine similarities and differences between the approaches taken across the different hazards and identify potential ways in which different hazard communities can learn from each other. Finally, we discuss opportunities for learning from methods and approaches being developed and applied to assess natural hazard risks at more continental or regional scales.
Hendrik Andersen, Jan Cermak, Julia Fuchs, Peter Knippertz, Marco Gaetani, Julian Quinting, Sebastian Sippel, and Roland Vogt
Atmos. Chem. Phys., 20, 3415–3438, https://doi.org/10.5194/acp-20-3415-2020, https://doi.org/10.5194/acp-20-3415-2020, 2020
Short summary
Short summary
Fog and low clouds (FLCs) are an essential but poorly understood element of Namib regional climate. Here, a satellite-based data set of FLCs in central Namib, reanalysis data, and back trajectories are used to systematically analyze conditions when FLCs occur. Synoptic-scale mechanisms are identified that influence the formation of FLCs and the onshore advection of marine boundary-layer air masses. The findings lead to a new conceptual model of mechanisms that drive FLC variability in the Namib.
Constanze Wellmann, Andrew I. Barrett, Jill S. Johnson, Michael Kunz, Bernhard Vogel, Ken S. Carslaw, and Corinna Hoose
Atmos. Chem. Phys., 20, 2201–2219, https://doi.org/10.5194/acp-20-2201-2020, https://doi.org/10.5194/acp-20-2201-2020, 2020
Short summary
Short summary
Severe hailstorms may cause damage to buildings and crops. Thus, the forecast of numerical weather prediction (NWP) models should be as reliable as possible.
Using statistical emulation, we identify those model input parameters describing environmental conditions and cloud microphysics which lead to large uncertainties in the prediction of deep convection. We find that the impact of the input parameters on the uncertainty depends on the considered output variable.
Karmen Babić, Norbert Kalthoff, Bianca Adler, Julian F. Quinting, Fabienne Lohou, Cheikh Dione, and Marie Lothon
Atmos. Chem. Phys., 19, 13489–13506, https://doi.org/10.5194/acp-19-13489-2019, https://doi.org/10.5194/acp-19-13489-2019, 2019
Short summary
Short summary
This study investigates differences in atmospheric conditions between nights with and without low-level stratus clouds (LLCs) over southern West Africa. We use high-quality observations collected during 2016 summer monsoon season and the ERA5 reanalysis data set. Our results show that the formation of LLCs depends on the interplay between the onset time and strength of the nocturnal low-level jet, horizontal cold-air advection, and the overall moisture level in the whole region.
Florian Ehmele and Michael Kunz
Hydrol. Earth Syst. Sci., 23, 1083–1102, https://doi.org/10.5194/hess-23-1083-2019, https://doi.org/10.5194/hess-23-1083-2019, 2019
Short summary
Short summary
The risk estimation of precipitation events with high recurrence periods is difficult due to the limited timescale with meteorological observations and an inhomogeneous distribution of rain gauges, especially in mountainous terrains. In this study a spatially high resolved analytical model, designed for stochastic simulations of flood-related precipitation, is developed and applied to an investigation area in Germany but is transferable to other areas. High conformity with observations is found.
Kai Schröter, Daniela Molinari, Michael Kunz, and Heidi Kreibich
Nat. Hazards Earth Syst. Sci., 18, 963–968, https://doi.org/10.5194/nhess-18-963-2018, https://doi.org/10.5194/nhess-18-963-2018, 2018
David Piper and Michael Kunz
Nat. Hazards Earth Syst. Sci., 17, 1319–1336, https://doi.org/10.5194/nhess-17-1319-2017, https://doi.org/10.5194/nhess-17-1319-2017, 2017
Susanna Mohr, Michael Kunz, Alexandra Richter, and Bodo Ruck
Nat. Hazards Earth Syst. Sci., 17, 957–969, https://doi.org/10.5194/nhess-17-957-2017, https://doi.org/10.5194/nhess-17-957-2017, 2017
Short summary
Short summary
Due to the small-scale and non-stationary nature of the convective wind gusts usually associated with thunderstorms, there is a considerable lack of knowledge regarding their characteristics and statistics. Thus, we investigated the temporal and spatial distribution, intensity, and return values of those wind events in Germany. The study constitutes a fundamental addition to an improved understanding of convective wind gusts and serves as basis for further risk assessments.
David Piper, Michael Kunz, Florian Ehmele, Susanna Mohr, Bernhard Mühr, Andreas Kron, and James Daniell
Nat. Hazards Earth Syst. Sci., 16, 2835–2850, https://doi.org/10.5194/nhess-16-2835-2016, https://doi.org/10.5194/nhess-16-2835-2016, 2016
Y. Brugnara, R. Auchmann, S. Brönnimann, R. J. Allan, I. Auer, M. Barriendos, H. Bergström, J. Bhend, R. Brázdil, G. P. Compo, R. C. Cornes, F. Dominguez-Castro, A. F. V. van Engelen, J. Filipiak, J. Holopainen, S. Jourdain, M. Kunz, J. Luterbacher, M. Maugeri, L. Mercalli, A. Moberg, C. J. Mock, G. Pichard, L. Řezníčková, G. van der Schrier, V. Slonosky, Z. Ustrnul, M. A. Valente, A. Wypych, and X. Yin
Clim. Past, 11, 1027–1047, https://doi.org/10.5194/cp-11-1027-2015, https://doi.org/10.5194/cp-11-1027-2015, 2015
Short summary
Short summary
A data set of instrumental pressure and temperature observations for the early instrumental period (before ca. 1850) is described. This is the result of a digitisation effort involving the period immediately after the eruption of Mount Tambora in 1815, combined with the collection of already available sub-daily time series. The highest data availability is therefore for the years 1815 to 1817. An analysis of pressure variability and of case studies in Europe is performed for that period.
M. Rautenhaus, C. M. Grams, A. Schäfler, and R. Westermann
Geosci. Model Dev., 8, 2355–2377, https://doi.org/10.5194/gmd-8-2355-2015, https://doi.org/10.5194/gmd-8-2355-2015, 2015
Short summary
Short summary
This article presents the application of interactive 3D visualization of ensemble
weather predictions to forecasting warm conveyor belt situations during aircraft-based atmospheric research campaigns. A method to predict 3D probabilities of the spatial occurrence of WCBs is developed and integrated into the 3D visualization tool "Met.3D", introduced in the first part of this two-paper study. A case study demonstrates the use of 3D and uncertainty visualization for weather forecasting.
K. Schröter, M. Kunz, F. Elmer, B. Mühr, and B. Merz
Hydrol. Earth Syst. Sci., 19, 309–327, https://doi.org/10.5194/hess-19-309-2015, https://doi.org/10.5194/hess-19-309-2015, 2015
Short summary
Short summary
Extreme antecedent precipitation, increased initial hydraulic load in the river network and strong but not extraordinary event precipitation were key drivers for the flood in June 2013 in Germany. Our results are based on extreme value statistics and aggregated severity indices which we evaluated for a set of 74 historic large-scale floods. This flood database and the methodological framework enable the rapid assessment of future floods using precipitation and discharge observations.
C. M. Grams, H. Binder, S. Pfahl, N. Piaget, and H. Wernli
Nat. Hazards Earth Syst. Sci., 14, 1691–1702, https://doi.org/10.5194/nhess-14-1691-2014, https://doi.org/10.5194/nhess-14-1691-2014, 2014
M. Kunz, B. Mühr, T. Kunz-Plapp, J. E. Daniell, B. Khazai, F. Wenzel, M. Vannieuwenhuyse, T. Comes, F. Elmer, K. Schröter, J. Fohringer, T. Münzberg, C. Lucas, and J. Zschau
Nat. Hazards Earth Syst. Sci., 13, 2579–2598, https://doi.org/10.5194/nhess-13-2579-2013, https://doi.org/10.5194/nhess-13-2579-2013, 2013
Related subject area
Dynamical processes in midlatitudes
The impact of preceding convection on the development of Medicane Ianos and the sensitivity to sea surface temperature
The importance of diabatic processes for the dynamics of synoptic-scale extratropical weather systems – a review
The impact of synoptic storm likelihood on European subseasonal forecast uncertainty and their modulation by the stratosphere
Spatio-temporal averaging of jets obscures the reinforcement of baroclinicity by latent heating
Impact of stochastic physics on the representation of atmospheric blocking in EC-Earth3
The crucial representation of deep convection for the cyclogenesis of Medicane Ianos
The connection between North Atlantic storm track regimes and eastern Mediterranean cyclonic activity
A storm-relative climatology of compound hazards in Mediterranean cyclones
A new characterisation of the North Atlantic eddy-driven jet using two-dimensional moment analysis
Linking compound weather extremes to Mediterranean cyclones, fronts, and airstreams
From Sea to Sky: Understanding the sea surface temperature impact on an atmospheric blocking event using sensitivity experiments with the ICOsahedral Nonhydrostatic (ICON) model
A linear assessment of barotropic Rossby wave propagation in different background flow configurations
Towards a process-oriented understanding of the impact of stochastic perturbations on the model climate
Atmospheric Deserts: Detection and Consequences
Lagrangian characterization of heat waves: The perspective matters
Deepening mechanisms of cut-off lows in the Southern Hemisphere and the role of jet streams: insights from eddy kinetic energy analysis
Large-scale perspective on extreme near-surface winds in the central North Atlantic
Divergent convective outflow in ICON deep-convection-permitting and parameterised deep convection simulations
A global climatology of sting-jet extratropical cyclones
Changes in the North Atlantic Oscillation over the 20th century
Life cycle dynamics of Greenland blocking from a potential vorticity perspective
Warm conveyor belt characteristics and impacts along the life cycle of extratropical cyclones: case studies and climatological analysis based on ERA5
Influence of radiosonde observations on the sharpness and altitude of the midlatitude tropopause in the ECMWF IFS
Analysing 23 years of warm-season derechos in France: a climatology and investigation of synoptic and environmental changes
A Lagrangian framework for detecting and characterizing the descent of foehn from Alpine to local scales
The upstream–downstream connection of North Atlantic and Mediterranean cyclones in semi-idealized simulations
Simulating record-shattering cold winters of the beginning of the 21st century in France
Understanding the vertical temperature structure of recent record-shattering heatwaves
Persistent warm and cold spells in the Northern Hemisphere extratropics: regionalisation, synoptic-scale dynamics and temperature budget
Linking Gulf Stream air–sea interactions to the exceptional blocking episode in February 2019: a Lagrangian perspective
Process-based classification of Mediterranean cyclones using potential vorticity
The relation between Rossby wave-breaking events and low-level weather systems
Aquaplanet simulations with winter and summer hemispheres: model setup and circulation response to warming
Seasonally dependent increases in subweekly temperature variability over Southern Hemisphere landmasses detected in multiple reanalyses
Identification of high-wind features within extratropical cyclones using a probabilistic random forest – Part 2: Climatology over Europe
Cold wintertime air masses over Europe: where do they come from and how do they form?
Diabatic effects on the evolution of storm tracks
Atmospheric response to cold wintertime Tibetan Plateau conditions over eastern Asia in climate models
Transient anticyclonic eddies and their relationship to atmospheric block persistence
A composite approach to produce reference datasets for extratropical cyclone tracks: application to Mediterranean cyclones
Thunderstorm environments in Europe
What distinguishes 100-year precipitation extremes over central European river catchments from more moderate extreme events?
Towards a holistic understanding of blocked regime dynamics through a combination of complementary diagnostic perspectives
Moist available potential energy of the mean state of the atmosphere and the thermodynamic potential for warm conveyor belts and convection
Large spread in the representation of compound long-duration dry and hot spells over Europe in CMIP5
Similarity and variability of blocked weather-regime dynamics in the Atlantic–European region
Anomalous subtropical zonal winds drive decreases in southern Australian frontal rain
Origin of low-tropospheric potential vorticity in Mediterranean cyclones
Robust poleward jet shifts in idealised baroclinic-wave life-cycle experiments with noisy initial conditions
Revisiting the wintertime emergent constraint of the southern hemispheric midlatitude jet response to global warming
Claudio Sánchez, Suzanne Gray, Ambrogio Volonté, Florian Pantillon, Ségolène Berthou, and Silvio Davolio
Weather Clim. Dynam., 5, 1429–1455, https://doi.org/10.5194/wcd-5-1429-2024, https://doi.org/10.5194/wcd-5-1429-2024, 2024
Short summary
Short summary
Medicane Ianos was a very intense cyclone that led to harmful impacts over Greece. We explore what processes are important for the forecasting of Medicane Ianos, with the use of the Met Office weather model. There was a preceding precipitation event before Ianos’s birth, whose energetics generated a bubble in the tropopause. This bubble created the necessary conditions for Ianos to emerge and strengthen, and the processes are enhanced in simulations with a warmer Mediterranean Sea.
Heini Wernli and Suzanne L. Gray
Weather Clim. Dynam., 5, 1299–1408, https://doi.org/10.5194/wcd-5-1299-2024, https://doi.org/10.5194/wcd-5-1299-2024, 2024
Short summary
Short summary
The science of extratropical dynamics has reached a new level where the interplay of dry dynamics with effects of latent heating in clouds and other diabatic processes is considered central to the field. This review documents how research about the role of diabatic processes evolved over more than a century; it highlights that progress relied essentially on the integration of theory, field campaigns, novel diagnostics, and numerical modelling, and it outlines avenues for future research.
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.
Henrik Auestad, Clemens Spensberger, Andrea Marcheggiani, Paulo Ceppi, Thomas Spengler, and Tim Woollings
Weather Clim. Dynam., 5, 1269–1286, https://doi.org/10.5194/wcd-5-1269-2024, https://doi.org/10.5194/wcd-5-1269-2024, 2024
Short summary
Short summary
Latent heating due to condensation can influence atmospheric circulation by strengthening or weakening horizontal temperature contrasts. Strong temperature contrasts intensify storms and imply the existence of strong upper tropospheric winds called jets. It remains unclear whether latent heating preferentially reinforces or abates the existing jet. We show that this disagreement is attributable to how the jet is defined, confirming that latent heating reinforces the jet.
Michele Filippucci, Simona Bordoni, and Paolo Davini
Weather Clim. Dynam., 5, 1207–1222, https://doi.org/10.5194/wcd-5-1207-2024, https://doi.org/10.5194/wcd-5-1207-2024, 2024
Short summary
Short summary
Atmospheric blocking is a recurring phenomenon in midlatitudes, causing winter cold spells and summer heat waves. Current models underestimate it, hindering understanding of global warming's impact on extremes. In this paper, we investigate whether stochastic parameterizations can improve blocking representation. We find that blocking frequency representation slightly deteriorates, following a change in midlatitude winds. We conclude by suggesting a direction for future model development.
Florian Pantillon, Silvio Davolio, Elenio Avolio, Carlos Calvo-Sancho, Diego Saul Carrió, Stavros Dafis, Emanuele Silvio Gentile, Juan Jesus Gonzalez-Aleman, Suzanne Gray, Mario Marcello Miglietta, Platon Patlakas, Ioannis Pytharoulis, Didier Ricard, Antonio Ricchi, Claudio Sanchez, and Emmanouil Flaounas
Weather Clim. Dynam., 5, 1187–1205, https://doi.org/10.5194/wcd-5-1187-2024, https://doi.org/10.5194/wcd-5-1187-2024, 2024
Short summary
Short summary
Cyclone Ianos of September 2020 was a high-impact but poorly predicted medicane (Mediterranean hurricane). A community effort of numerical modelling provides robust results to improve prediction. It is found that the representation of local thunderstorms controlled the interaction of Ianos with a jet stream at larger scales and its subsequent evolution. The results help us understand the peculiar dynamics of medicanes and provide guidance for the next generation of weather and climate models.
Dor Sandler, Hadas Saaroni, Baruch Ziv, Talia Tamarin-Brodsky, and Nili Harnik
Weather Clim. Dynam., 5, 1103–1116, https://doi.org/10.5194/wcd-5-1103-2024, https://doi.org/10.5194/wcd-5-1103-2024, 2024
Short summary
Short summary
The North Atlantic region serves as a source of moisture and energy for Mediterranean storms. Its impact over the Levant region remains an open question due to its smaller weather systems and their longer distance from the ocean. We find an optimal circulation pattern which allows North Atlantic influence to reach farther into the eastern Mediterranean, thus making storms stronger and rainier. This may be relevant for future Mediterranean climate, which is projected to become much drier.
Raphaël Rousseau-Rizzi, Shira Raveh-Rubin, Jennifer L. Catto, Alice Portal, Yonatan Givon, and Olivia Martius
Weather Clim. Dynam., 5, 1079–1101, https://doi.org/10.5194/wcd-5-1079-2024, https://doi.org/10.5194/wcd-5-1079-2024, 2024
Short summary
Short summary
We identify situations when rain and wind, rain and wave, or heat and dust hazards co-occur within Mediterranean cyclones. These hazard combinations are associated with risk to infrastructure, risk of coastal flooding and risk of respiratory issues. The presence of Mediterranean cyclones is associated with increased probability of all three hazard combinations. We identify weather configurations and cyclone structures, particularly those associated with specific co-occurrence combinations.
Jacob Perez, Amanda C. Maycock, Stephen D. Griffiths, Steven C. Hardiman, and Christine M. McKenna
Weather Clim. Dynam., 5, 1061–1078, https://doi.org/10.5194/wcd-5-1061-2024, https://doi.org/10.5194/wcd-5-1061-2024, 2024
Short summary
Short summary
This study assesses existing methods for identifying the position and tilt of the North Atlantic eddy-driven jet, proposing a new feature-based approach. The new method overcomes limitations of other methods, offering a more robust characterisation. Contrary to prior findings, the distribution of daily latitudes shows no distinct multi-modal structure, challenging the notion of preferred jet stream latitudes or regimes. This research enhances our understanding of North Atlantic dynamics.
Alice Portal, Shira Raveh-Rubin, Jennifer L. Catto, Yonatan Givon, and Olivia Martius
Weather Clim. Dynam., 5, 1043–1060, https://doi.org/10.5194/wcd-5-1043-2024, https://doi.org/10.5194/wcd-5-1043-2024, 2024
Short summary
Short summary
Mediterranean cyclones are associated with extended rain, wind, and wave impacts. Although beneficial for regional water resources, their passage may induce extreme weather, which is especially impactful when multiple hazards combine together. Here we show how the passage of Mediterranean cyclones increases the likelihood of rain–wind and wave–wind compounding and how compound–cyclone statistics vary by region and season, depending on the presence of specific airflows around the cyclone.
Svenja Christ, Marta Wenta, Christian M. Grams, and Annika Oertel
EGUsphere, https://doi.org/10.5194/egusphere-2024-2403, https://doi.org/10.5194/egusphere-2024-2403, 2024
Short summary
Short summary
The detailed representation of sea surface temperature (SST) in numerical models is important for the prediction of atmospheric blocking in the North Atlantic. Yet, the underlying physical processes are not fully understood. Using SST sensitivity experiments for a case study, we identify a physical pathway through which SST in the Gulf Stream region is linked to the downstream upper-level flow evolution in the North Atlantic.
Antonio Segalini, Jacopo Riboldi, Volkmar Wirth, and Gabriele Messori
Weather Clim. Dynam., 5, 997–1012, https://doi.org/10.5194/wcd-5-997-2024, https://doi.org/10.5194/wcd-5-997-2024, 2024
Short summary
Short summary
Planetary Rossby waves are created by topography and evolve in time. In this work, an analytical solution of this classical problem is proposed under the approximation of linear wave dynamics. The theory is able to describe reasonably well the evolution of the perturbation and compares well with full nonlinear simulations. Several relevant cases with single and double zonal jets are assessed with the theoretical framework
Moritz Deinhard and Christian M. Grams
Weather Clim. Dynam., 5, 927–942, https://doi.org/10.5194/wcd-5-927-2024, https://doi.org/10.5194/wcd-5-927-2024, 2024
Short summary
Short summary
Stochastic perturbations are an established technique to represent model uncertainties in numerical weather prediction. While such schemes are beneficial for the forecast skill, they can also change the mean state of the model. We analyse how different schemes modulate rapidly ascending airstreams and whether the changes to such weather systems are projected onto larger scales. We thereby provide a process-oriented perspective on how perturbations affect the model climate.
Fiona Fix, Georg Johann Mayr, Achim Zeileis, Isabell Kathrin Stucke, and Reto Stauffer
EGUsphere, https://doi.org/10.5194/egusphere-2024-2143, https://doi.org/10.5194/egusphere-2024-2143, 2024
Short summary
Short summary
“Atmospheric deserts” (ADs) are air masses that are transported away from hot, dry regions. Our study introduces this new concept. ADs can suppress or boost thunderstorms, and potentially contribute to the formation of heat waves, which makes them relevant for forecasting extreme events. Using a novel detection method, we follow the AD directly from North Africa to Europe for a case in June 2022, allowing us to analyze the air mass at any time and investigate how it is modified along the way.
Amelie Mayer and Volkmar Wirth
EGUsphere, https://doi.org/10.5194/egusphere-2024-2018, https://doi.org/10.5194/egusphere-2024-2018, 2024
Short summary
Short summary
Although heatwaves are among the most dangerous weather-related hazards, their underlying mechanisms are not fully understood. Here, we investigate the formation of heat waves in an air-parcel based framework and distinguish the contributions from horizontal transport, vertical transport, and diabatic heating. We show that the obtained results depend profoundly on whether one compares the absolute contributions of the individual terms or, instead, their anomalies relative to climatology.
Henri Rossi Pinheiro, Kevin Ivan Hodges, and Manoel Alonso Gan
Weather Clim. Dynam., 5, 881–894, https://doi.org/10.5194/wcd-5-881-2024, https://doi.org/10.5194/wcd-5-881-2024, 2024
Short summary
Short summary
Cut-off lows (COLs) are weather systems with varied structures and lifecycles, from upper atmospheric to deep vortices. Deep, strong COLs are common around Australia and the southwestern Pacific in autumn and spring, while shallow, weak COLs occur more in summer near the Equator. Jet streams play a crucial role in COL development, with different jets influencing its depth and strength. The study also emphasizes the need for better representation of diabatic processes in reanalysis data.
Aleksa Stanković, Gabriele Messori, Joaquim G. Pinto, and Rodrigo Caballero
Weather Clim. Dynam., 5, 821–837, https://doi.org/10.5194/wcd-5-821-2024, https://doi.org/10.5194/wcd-5-821-2024, 2024
Short summary
Short summary
The article studies extreme winds near the surface over the North Atlantic Ocean. These winds are caused by storms that pass through this region. The strongest storms that have occurred in the winters from 1950–2020 are studied in detail and compared to weaker but still strong storms. The analysis shows that the storms associated with the strongest winds are preceded by another older storm that travelled through the same region and made the conditions suitable for development of extreme winds.
Edward Groot, Patrick Kuntze, Annette Miltenberger, and Holger Tost
Weather Clim. Dynam., 5, 779–803, https://doi.org/10.5194/wcd-5-779-2024, https://doi.org/10.5194/wcd-5-779-2024, 2024
Short summary
Short summary
Deep convective clouds (thunderstorms), which may cause severe weather, tend to coherently organise into structured cloud systems. Accurate representation of these systems in models is difficult due to their complex dynamics and, in numerical simulations, the dependence of their dynamics on resolution. Here, the effect of convective organisation and geometry on their outflow winds (altitudes of 7–14 km) is investigated. Representation of their dynamics and outflows improves at higher resolution.
Suzanne Louise Gray, Ambrogio Volonté, Oscar Martínez-Alvarado, and Ben J. Harvey
EGUsphere, https://doi.org/10.5194/egusphere-2024-1413, https://doi.org/10.5194/egusphere-2024-1413, 2024
Short summary
Short summary
Sting jets occur in some of the most damaging extratropical cyclones impacting Europe. We present the first climatology of sting-jet cyclones over the major ocean basins. Cyclones with sting-jet precursors occur over the North Atlantic, North Pacific and Southern Oceans, with implications for wind warnings. Precursor cyclones have distinct characteristics, even in reanalyses which are too coarse to resolve sting jets, evidencing the climatological consequences of strong diabatic cloud processes.
Stephen Outten and Richard Davy
Weather Clim. Dynam., 5, 753–762, https://doi.org/10.5194/wcd-5-753-2024, https://doi.org/10.5194/wcd-5-753-2024, 2024
Short summary
Short summary
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.
Seraphine Hauser, Franziska Teubler, Michael Riemer, Peter Knippertz, and Christian M. Grams
Weather Clim. Dynam., 5, 633–658, https://doi.org/10.5194/wcd-5-633-2024, https://doi.org/10.5194/wcd-5-633-2024, 2024
Short summary
Short summary
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.
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.
Konstantin Krüger, Andreas Schäfler, Martin Weissmann, and George C. Craig
Weather Clim. Dynam., 5, 491–509, https://doi.org/10.5194/wcd-5-491-2024, https://doi.org/10.5194/wcd-5-491-2024, 2024
Short summary
Short summary
Initial conditions of current numerical weather prediction models insufficiently represent the sharp vertical gradients across the midlatitude tropopause. Observation-space data assimilation output is used to study the influence of assimilated radiosondes on the tropopause. The radiosondes reduce systematic biases of the model background and sharpen temperature and wind gradients in the analysis. Tropopause sharpness is still underestimated in the analysis, which may impact weather forecasts.
Lucas Fery and Davide Faranda
Weather Clim. Dynam., 5, 439–461, https://doi.org/10.5194/wcd-5-439-2024, https://doi.org/10.5194/wcd-5-439-2024, 2024
Short summary
Short summary
In this study, we analyse warm-season derechos – a type of severe convective windstorm – in France between 2000 and 2022, identifying 38 events. We compare their frequency and features with other countries. We also examine changes in the associated large-scale patterns. We find that convective instability has increased in southern Europe. However, the attribution of these changes to natural climate variability, human-induced climate change or a combination of both remains unclear.
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.
Alexander Scherrmann, Heini Wernli, and Emmanouil Flaounas
Weather Clim. Dynam., 5, 419–438, https://doi.org/10.5194/wcd-5-419-2024, https://doi.org/10.5194/wcd-5-419-2024, 2024
Short summary
Short summary
We show that the formation of Mediterranean cyclones follows the presence of cyclones over the North Atlantic. The distinct regions of cyclone activity in the Mediterranean in the different seasons can be linked to the atmospheric state, in particular the position of the polar jet over the North Atlantic. With this we now better understand the processes that lead to the formation of Mediterranean cyclones. We used a novel simulation framework in which we directly show and probe this connection.
Camille Cadiou and Pascal Yiou
EGUsphere, https://doi.org/10.5194/egusphere-2024-612, https://doi.org/10.5194/egusphere-2024-612, 2024
Short summary
Short summary
Extreme winter cold temperatures in Europe have huge societal impacts. This study focuses on very extreme cold events, such as the record of winter 1963 in France, expected to become rarer due to climate change. We use a light and efficient rare event algorithm to simulate a large number of extreme cold winters over France, to analyse their characteristics. We find that despite fewer occurrences, their intensity remains steady. We analyse prevailing atmospheric circulation during these events.
Belinda Hotz, Lukas Papritz, and Matthias Röthlisberger
Weather Clim. Dynam., 5, 323–343, https://doi.org/10.5194/wcd-5-323-2024, https://doi.org/10.5194/wcd-5-323-2024, 2024
Short summary
Short summary
Analysing the vertical structure of temperature anomalies of recent record-breaking heatwaves reveals a complex four-dimensional interplay of anticyclone–heatwave interactions, with vertically strongly varying advective, adiabatic, and diabatic contributions to the respective temperature anomalies. The heatwaves featured bottom-heavy positive temperature anomalies, extending throughout the troposphere.
Alexandre Tuel and Olivia Martius
Weather Clim. Dynam., 5, 263–292, https://doi.org/10.5194/wcd-5-263-2024, https://doi.org/10.5194/wcd-5-263-2024, 2024
Short summary
Short summary
Warm and cold spells often have damaging consequences for agriculture, power demand, human health and infrastructure, especially when they occur over large areas and persist for a week or more. Here, we split the Northern Hemisphere extratropics into coherent regions where 3-week warm and cold spells in winter and summer are associated with the same large-scale circulation patterns. To understand their physical drivers, we analyse the associated circulation and temperature budget anomalies.
Marta Wenta, Christian M. Grams, Lukas Papritz, and Marc Federer
Weather Clim. Dynam., 5, 181–209, https://doi.org/10.5194/wcd-5-181-2024, https://doi.org/10.5194/wcd-5-181-2024, 2024
Short summary
Short summary
Our study links air–sea interactions over the Gulf Stream to an atmospheric block in February 2019. We found that over 23 % of air masses that were lifted into the block by cyclones interacted with the Gulf Stream. As cyclones pass over the Gulf Stream, they cause intense surface evaporation events, preconditioning the environment for the development of cyclones. This implies that air–sea interactions over the Gulf Stream affect the large-scale dynamics in the North Atlantic–European region.
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.
Talia Tamarin-Brodsky and Nili Harnik
Weather Clim. Dynam., 5, 87–108, https://doi.org/10.5194/wcd-5-87-2024, https://doi.org/10.5194/wcd-5-87-2024, 2024
Short summary
Short summary
Synoptic waves in the atmosphere tend to follow a typical Rossby wave lifecycle, involving a linear growth stage followed by nonlinear and irreversible Rossby wave breaking (RWB). Here we take a new approach to study RWB events and their fundamental relation to weather systems by combining a storm-tracking technique and an RWB detection algorithm. The synoptic-scale dynamics leading to RWB is then examined by analyzing time evolution composites of cyclones and anticyclones during RWB events.
Sebastian Schemm and Matthias Röthlisberger
Weather Clim. Dynam., 5, 43–63, https://doi.org/10.5194/wcd-5-43-2024, https://doi.org/10.5194/wcd-5-43-2024, 2024
Short summary
Short summary
Climate change has started to weaken atmospheric circulation during summer in the Northern Hemisphere. However, there is low agreement on the processes underlying changes in, for example, the stationarity of weather patterns or the seasonality of the jet response to warming. This study examines changes during summertime in an idealised setting and confirms some important changes in hemisphere-wide wave and jet characteristics under warming.
Patrick Martineau, Swadhin K. Behera, Masami Nonaka, Hisashi Nakamura, and Yu Kosaka
Weather Clim. Dynam., 5, 1–15, https://doi.org/10.5194/wcd-5-1-2024, https://doi.org/10.5194/wcd-5-1-2024, 2024
Short summary
Short summary
The representation of subweekly near-surface temperature variability trends over the Southern Hemisphere landmasses is compared across multiple atmospheric reanalyses. It is found that there is generally a good agreement concerning the positive trends affecting South Africa and Australia in the spring, and South America in the summer. A more efficient generation of subweekly temperature variance by horizontal temperature fluxes contributes to the observed rise.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
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.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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.
Cited articles
Attinger, R., Keller, J. H., Köhler, M., Riboldi, J., and Grams, C. M.:
Representation of atmospheric blocking in the new global non-hydrostatic
weather prediction model ICON, Meteorol. Z., 28, 429–446,
https://doi.org/10.1127/metz/2019/0967, 2019. a
Barriopedro, D., García-Herrera, R., Lupo, A. R., and Hernández, E.:
A climatology of Northern Hemisphere blocking, J. Climate, 19, 1042–1063,
https://doi.org/10.1175/JCLI3678.1, 2006. a
Barthlott, C., Schipper, J. W., Kalthoff, N., Adler, B., Kottmeier, C., Blyth,
A., and Mobbs, S.: Model representation of boundary-layer convergence
triggering deep convection over complex terrain: A case study from COPS,
Atmos. Res., 95, 172–185, https://doi.org/10.1016/j.atmosres.2009.09.010, 2010. a
Bennett, L. J., Browning, K. A., Blyth, A. M., Parker, D. J., and Clark, P. A.:
A review of the initiation of precipitating convection in the United
Kingdom, Q. J. Roy. Meteor. Soc., 132, 1001–1020, https://doi.org/10.1256/qj.05.54,
2006. a
Bieli, M., Pfahl, S., and Wernli, H.: A Lagrangian investigation of hot and
cold temperature extremes in Europe, Q. J. Roy. Meteor. Soc., 141, 98–108,
https://doi.org/10.1002/qj.2339, 2015. a
Bronstert, A., Agarwal, A., Boessenkool, B., Crisologo, I., Fischer, M.,
Heistermann, M., Köhn-Reich, L., López-Tarazón, J. A., Moran, T., Ozturk, U., Reinhardt-Imjela, C., and Wendi, D.: Forensic
hydro-meteorological analysis of an extreme flash flood: The 2016-05-29 event
in Braunsbach, SW Germany, Sci. Total Environ., 630, 977–991,
https://doi.org/10.1016/j.scitotenv.2018.02.241, 2018. a
Browning, K., Blyth, A., Clark, P., Corsmeier, U., Morcrette, C., Agnew, J.,
Bamber, D., Barthlott, C., Bennett, L., Beswick, K., Bitter, M., Bozier, K.,
Brooks, B., Collier, C., Cook, C., Davies, F., Deny, B., Feuerle, T., Forbes,
R., Gaffard, C., Gray, M., Rolf Hankers, R., Hewison, T., Kalthoff, N.,
Khodayar, S., Kohler, M., Kottmeier, C., Kraut, S., Kunz, M., Ladd, D.,
Lenfant, J., Marsham, J., McGregor, J., Nicol, J., Norton, E., Parker, D.,
Perry, F., Ramatschi, M., Ricketts, H., Roberts, N., Russell, A., Schulz, H.,
Slack, E., Vaughan, G., Waight, J., Watson, R., Webb, A., and Wieser, A.:
The Convective Storms Initiation Project, B. Am. Meteorol. Soc., 88,
1939–1955, https://doi.org/10.1175/BAMS-88-12-1939, 2007. a, b
Corfidi, S. F.: Cold pools and MCS propagation: Forecasting the motion of
downwind-developing MCSs, Weather Forecast., 18, 997–1017,
https://doi.org/10.1175/1520-0434(2003)018<0997:CPAMPF>2.0.CO;2, 2003. a
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
Vitartv, 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. a
Dennis, E. J. and Kumjian, M. R.: The impact of vertical wind shear on hail
growth in simulated supercells, J. Atmos. Sci., 74, 641–663,
https://doi.org/10.1175/JAS-D-16-0066.1, 2017. a
Dole, R. M. and Gordon, N. D.: Persistent anomalies of the extratropical
Northern Hemisphere wintertime circulation: Geographical distribution and
regional persistence characteristics, Mon. Weather Rev., 111, 1567–1586,
https://doi.org/10.1175/1520-0493(1983)111<1567:PAOTEN>2.0.CO;2, 1983. a
Doswell, C. A. and Evans, J. S.: Proximity sounding analysis for derechos and
supercells: An assessment of similarities and differences, Atmos. Res., 67,
117–133, https://doi.org/10.1016/S0169-8095(03)00047-4, 2003. a
Doswell, C. A., Brooks, H. E., and Maddox, R. A.: Flash flood forecasting: An
ingredients-based methodology, Weather Forecast., 11, 560–581,
https://doi.org/10.1175/1520-0434(1996)011<0560:FFFAIB>2.0.CO;2, 1996. a
Dotzek, N., Groenemeijer, P., Feuerstein, B., and Holzer, A. M.: Overview of
ESSL's severe convective storms research using the European Severe Weather
Database ESWD, Atmos. Res., 93, 575–586,
https://doi.org/10.1016/j.atmosres.2008.10.020, 2009. a, b
Drüe, C., Hauf, T., Finke, U., Keyn, S., and Kreyer, O.: Comparison of a
SAFIR lightning detection network in northern Germany to the operational
BLIDS network, J. Geophys. Res.-Atmos., 112, D18114,
https://doi.org/10.1029/2006JD007680, 2007. a
Durre, I., Vose, R. S., and Wuertz, D. B.: Overview of the integrated global
radiosonde archive, J. Climate, 1151, 53–68, https://doi.org/10.1175/JCLI3594.1,
2006. a
DWD: Schadensrückblick des Deutschen Wetterdienstes: Gefährliche
Wetterereignisse und Wetterschäden in Deutschland 2018, Deutscher
Wetterdienst (DWD), Offenbach, Germany, available at:
https://www.dwd.de/DE/presse/pressemitteilungen/DE/2018/20181213_schadensrueckblick2018_news.html
(last access: 6 March 2020), 2018a. a, b
DWD: REGNIE: Regionalisierte Niederschläge Verfahrensbeschreibung und
Nutzeranleitung, Deutscher Wetterdienst (DWD), Abteilung Hydrometeorologie,
Offenbach, Germany, available at:
https://www.dwd.de/DE/leistungen/regnie/regnie.html?nn=353366 (last access: 13 December 2019), 2018b. a
DWD: Niederschlagsdaten, CDC – Climate Data Center, Deutsche Wetterdienst (DWD), Offenbach, Germany, available at: https://cdc.dwd.de/portal, last access: 29 November 2018c. a
DWD: RADOLAN/RADVOR: Hoch aufgelöste Niederschlagsanalyse und -vorhersage auf
der Basis quantitativer Radar-und Ombrometerdaten für grenzüberschreitende
Fluss-Einzugsgebiete von Deutschland im Echtzeitbetrieb – Beschreibung des
Kompositformats Version 2.5, Tech. rep., Deutscher Wetterdienst (DWD):
Abteilung Hydrometeorologie, Offenbach, Germany, available at:
https://www.dwd.de/DE/leistungen/radolan/radolan.html (last access: 6 March
2020), 2019. a
ECA&D: European Climate Assessment & Dataset project, ECA&D Project Team, Royal Netherlands Meteorological Institute (KNMI), De Bilt, the Netherlands, available at: https://knmi-ecad-assets-prd.s3.amazonaws.com/download/ECA_blend_rr.zip, last access: 26 October 2018. a
ECMWF: TIGGE Data Retrieval, European Centre for Medium-Range Weather Forecasts (ECMWF), Reading, UK, available at: https://apps.ecmwf.int/datasets/data/tigge, last access: 13 November 2018. a
ECMWF: ERA-Interim reanalysis, European Centre for Medium-Range Weather Forecasts (ECMWF), Reading, UK, available at: https://apps.ecmwf.int/datasets/data/interim-full-daily, last access: 13 September 2019. a
Ehmele, F. and Kunz, M.: Flood-related extreme precipitation in southwestern Germany: development of a two-dimensional stochastic precipitation model, Hydrol. Earth Syst. Sci., 23, 1083–1102, https://doi.org/10.5194/hess-23-1083-2019, 2019. a
Enno, S.-E., Sugier, J., Alber, R., and Seltzer, M.: Lightning flash density
in Europe based on 10 years of ATDnet data, Atmos. Res., 235, 104769,
https://doi.org/10.1016/j.atmosres.2019.104769, 2020. a
ESSL: European Severe Weather Database (ESWD), European Severe Storms Laboratory (ESSL), Wessling, Germany, available at: https://www.eswd.eu, last access: 9 April 2020. a
Ferranti, L., Corti, S., and Janousek, M.: Flow-dependent verification of the
ECMWF ensemble over the Euro-Atlantic sector, Q. J. Roy. Meteor.
Soc., 141, 916–924, https://doi.org/10.1002/qj.2411, 2015. a, b
Galway, J. G.: The lifted index as a predictor of latent instability, B.
Am. Meteorol. Soc., 37, 528–529, https://doi.org/10.1175/1520-0477-37.10.528, 1956. 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., Beerli, R., Pfenninger, S., Staffell, I., and Wernli, H.:
Balancing Europe's wind-power output through spatial deployment informed by
weather regimes, Nat. Clim. Change, 7, 557–562, https://doi.org/10.1038/nclimate3338,
2017. a, b, c
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. Meteor. Soc.,
144, 2577–2591, https://doi.org/10.1002/qj.3353, 2018. a
Groenemeijer, P., Púčik, T., Holzer, A. M., Antonescu, B.,
Riemann-Campe, K., Schultz, D. M., Kühne, T., Feuerstein, B., Brooks,
H. E., Doswell, C. A., Koppert, H.-J., and Sausen, R.: Severe convective
storms in Europe: Ten years of research at the European Severe Storms
Laboratory, B. Am. Meteorol. Soc., 98, 2641–2651,
https://doi.org/10.1175/BAMS-D-16-0067.1, 2017. a, b
Gumbel, E. J.: Statistics of Extremes, Columbia University Press, New York,
USA, 1958. a
Haklander, A. J. and van Delden, A.: Thunderstorm predictors and their
forecast skill for the Netherlands, Atmos. Res., 67–68, 273–299,
https://doi.org/10.1016/S0169-8095(03)00056-5, 2003. a, b
Handwerker, J.: Cell tracking with TRACE3D – A new algorithm, Atmos. Res.,
61, 15–34, https://doi.org/10.1016/S0169-8095(01)00100-4, 2002. a
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. a
Houston, A. L. and Wilhelmson, R. B.: The impact of airmass boundaries on the
propagation of deep convection: A modeling-based study in a high-CAPE,
low-shear environment, Mon. Weather Rev., 140, 167–183,
https://doi.org/10.1175/MWR-D-10-05033.1, 2012. a
Huntrieser, H., Schiesser, H. H., Schmid, W., and Waldvogl, A.: Comparison of traditional and newly developed thunderstorm indices for Switzerland,
Weather Forecast., 12, 108–125,
https://doi.org/10.1175/1520-0434(1997)012<0108:COTAND>2.0.CO;2, 1997. a
Johns, R. H. and Doswell, C. A.: Severe local storms forecasting, Weather
Forecast., 7, 588–612, https://doi.org/10.1175/1520-0434(1992)007<0588:SLSF>2.0.CO;2,
1992. a
Kapsch, M. L., Kunz, M., Vitolo, R., and Economou, T.: Long-term trends of
hail-related weather types in an ensemble of regional climate models using a
Bayesian approach, J. Geophys. Res., 117, D15107,
https://doi.org/10.1029/2011JD017185, 2012. a
Klein Tank, A. M. G., Wijngaard, J. B., Können, G. P., Böhm, R.,
Demarée, G., Gocheva, A., Mileta, M., Pashiardis, S., Hejkrlik, L.,
Kern-Hansen, C., Heino, R., Bessemoulin, P., Müller-Westermeier, G.,
Tzanakou, M., Szalai, S., Pálsdóttir, T., Fitzgerald, D., Rubin, S.,
Capaldo, M., Maugeri, M., Leitass, A., Bukantis, A., Aberfeld, R., van
Engelen, A. F. V., Forland, E., Mietus, M., Coelho, F., Mares, C., Razuvaev,
V., Nieplova, E., Cegnar, T., Antonio López, J. A., Dahlström, B.,
Moberg, A., Kirchhofer, W., Ceylan, A., Pachaliuk, O., Alexander, L. V., and
Petrovic, P.: Daily dataset of 20th-century surface air temperature and
precipitation series for the European climate assessment, Int. J. Climatol.,
22, 1441–1453, https://doi.org/10.1002/joc.773, 2002. a
Kunz, M.: The skill of convective parameters and indices to predict isolated and severe thunderstorms, Nat. Hazards Earth Syst. Sci., 7, 327–342, https://doi.org/10.5194/nhess-7-327-2007, 2007. a, b
Kunz, M., Wandel, J., Fluck, E., Baumstark, S., Mohr, S., and Schemm, S.: Ambient conditions prevailing during hail events in central Europe, Nat. Hazards Earth Syst. Sci., 20, 1867–1887, https://doi.org/10.5194/nhess-20-1867-2020, 2020. a, b
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. a
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, 2018. a
Manzato, A.: A climatology of instability indices derived from Friuli Venezia Giulia soundings, using three different methods, Atmos. Res., 67, 417–454,
https://doi.org/10.1016/S0169-8095(03)00058-9, 2003. a, b
Martius, O., Sodemann, H., Joos, H., Pfahl, S., Winschall, A., Croci-Maspoli,
M., Graf, M., Madonna, E., Mueller, B., Schemm, S., Sedlacek, 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. a
Merino, A., Wu, X., Gascón, E., Berthet, C., García-Ortega, E., and
Dessens, J.: Hailstorms in southwestern France: Incidence and atmospheric
characterization, Atmos. Res., 140–141, 61–75,
https://doi.org/10.1016/j.atmosres.2014.01.015, 2014. a
Météo-France: Observations In situ, Météo-France, Saint-Mandé CEDEX, France, available at: https://donneespubliques.meteofrance.fr/?fond=rubrique&id_rubrique=26, last access: 8 November 2018. a
MeteoSwiss: Bodenstationsdaten der MeteoSchweiz, MeteoSwiss, Zurich-Airport, Switzerland, available at: https://www.meteoswiss.admin.ch/home/services-and-publications/beratung-und-service/datenportal-fuer-lehre-und-forschung.html, last access: 7 November 2018. a
Michel, C. and Rivière, G.: The link between Rossby wave breakings and
weather regime transitions, J. Atmos. Sci., 68, 1730–1748,
https://doi.org/10.1175/2011JAS3635.1, 2011. a
Michelangeli, P.-A., Vautard, R., and Legras, B.: Weather regimes: Recurrence
and quasi stationarity, J. Atmos. Sci., 52, 1237–1256,
https://doi.org/10.1175/1520-0469(1995)052<1237:WRRAQS>2.0.CO;2, 1995. a
Mohr, S.: Änderung des Gewitter- und Hagelpotentials im Klimawandel, PhD
thesis, Wiss. Berichte d. Instituts für Meteorologie und Klimaforschung
des Karlsruher Instituts für Technologie, Vol. 58, KIT Scientific
Publishing, Karlsruhe, Germany, https://doi.org/10.5445/KSP/1000033828, 2013. a
Mohr, S.: Video supplement: Animated 2D radar reflectivity of the German Weather Service (DWD) for 27 May 2018, Repository KITopen, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany, https://doi.org/10.5445/IR/1000118571, 2020a. a
Mohr, S.: Video supplement: Animated 2D radar reflectivity of the German Weather Service (DWD) for 31 May 2018, Repository KITopen, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany, https://doi.org/10.5445/IR/1000118574, 2020b. a
Mohr, S. and Kunz, M.: Recent trends and variabilities of convective
parameters relevant for hail events in Germany and Europe, Atmos. Res., 123,
211–228, https://doi.org/10.1016/j.atmosres.2012.05.016, 2013. a, b, c
Morcrette, C., Lean, H., Browning, K., Nicol, J., Roberts, N., Clark, P.,
Russell, A., and Blyth, A.: Combination of mesoscale and synoptic mechanisms
for triggering an isolated thunderstorm: Observational case study of
CSIP IOP 1, Mon. Weather Rev., 135, 3728–3749,
https://doi.org/10.1175/2007MWR2067.1, 2007. a
Munich Re: Natural catastrophe statistics online – the new NatCatSERVICE
analysis tool, Munich Re, Munich, Germany, available at:
https://www.munichre.com/en/reinsurance/business/non-life/natcatservice/index.html, last access: 13 December 2019. a
Nachtnebel, H.-P.: New strategies for flood risk management after the
catastrophic flood in 2002 in Europe, Third DPRI-IIASA International
Symposium on Integrated Disaster Risk Management: Coping with Regional
Vulnerability, Full Conference Proceedings; 3–5 July 2003, Kyoto, Japan, 2003. a
Nieto, R., Gimeno, L., Añel, J. A., De la Torre, L., Gallego, D.,
Barriopedro, D., Gallego, M., Gordillo, A., Redaño, A., and Delgado, G.:
Analysis of the precipitation and cloudiness associated with COLs occurrence
in the Iberian Peninsula, Meteorol. Atmos. Phys., 96, 103–119,
https://doi.org/10.1007/s00703-006-0223-6, 2007a. a
Nieto, R., Gimeno, L., De la Torre, L., Ribera, P., Barriopedro, D.,
García-Herrera, R., Serrano, A., Gordillo, A., Redano, A., and Lorente,
J.: Interannual variability of cut-off low systems over the European sector:
The role of blocking and the Northern Hemisphere circulation modes,
Meteorol. Atmos. Phys., 96, 85–101, https://doi.org/10.1007/s00703-006-0222-7,
2007b. a
Nieto, R., Sprenger, M., Wernli, H., Trigo, R. M., and Gimeno, L.:
Identification and climatology of cut-off lows near the tropopause, Ann. NY
Acad. Sci., 1146, 256–290, https://doi.org/10.1196/annals.1446.016, 2008. a
Nisi, L., Martius, O., Hering, A., Kunz, M., and Germann, U.: Spatial and
temporal distribution of hailstorms in the Alpine region: A long-term, high
resolution, radar-based analysis, Q. J. Roy. Meteor. Soc., 142, 1590–1604,
https://doi.org/10.1002/qj.2771, 2016. a
NOAA: Integrated Global Radiosonde Archive (IGRA), National Centers for Environmental Information (NCEI), National Oceanic and Atmospheric Administration (NOAA), Asheville, USA, available at: https://www.ncdc.noaa.gov/data-access/weather-balloon/integrated-global-radiosonde-archive, last access: 8 October 2018. a
Ozturk, U., Wendi, D., Crisologo, I., Riemer, A., Agarwal, A., Vogel, K.,
López-Tarazón, J. A., and Korup, O.: Rare flash floods and debris
flows in southern Germany, Sci. Total Environ., 626, 941–952,
https://doi.org/10.1016/j.scitotenv.2018.01.172, 2018. a
Pfahl, S. and Wernli, H.: Quantifying the relevance of atmospheric blocking for co-located temperature extremes in the Northern Hemisphere on (sub-)daily time scales, Geophys. Res. Lett., 39, L12807, https://doi.org/10.1029/2012GL052261,
2012a. a, b
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, 2012b. a
Piaget, N., Froidevaux, P., Giannakaki, P., Gierth, F., Martius, O., Riemer,
M., Wolf, G., and Grams, C. M.: Dynamics of a local Alpine flooding event
in October 2011: Moisture source and large-scale circulation, Q. J. Roy.
Meteor. Soc., 141, 1922–1937, https://doi.org/10.1002/qj.2496, 2015. a
Piper, D. and Kunz, M.: Spatiotemporal variability of lightning activity in Europe and the relation to the North Atlantic Oscillation teleconnection pattern, Nat. Hazards Earth Syst. Sci., 17, 1319–1336, https://doi.org/10.5194/nhess-17-1319-2017, 2017. a
Piper, D., Kunz, M., Ehmele, F., Mohr, S., Mühr, B., Kron, A., and Daniell, J.: Exceptional sequence of severe thunderstorms and related flash floods in May and June 2016 in Germany – Part 1: Meteorological background, Nat. Hazards Earth Syst. Sci., 16, 2835–2850, https://doi.org/10.5194/nhess-16-2835-2016, 2016. a, b
Piper, D. A., Kunz, M., Allen, J. T., and Mohr, S.: Investigation of the
temporal variability of thunderstorms in Central and Western Europe and the
relation to large-scale flow and teleconnection patterns, Q. J. Roy. Meteor.
Soc., 145, 3644–3666, https://doi.org/10.1002/qj.3647, 2019. a
Poelman, D. R., Schulz, W., Diendorfer, G., and Bernardi, M.: The European lightning location system EUCLID – Part 2: Observations, Nat. Hazards Earth Syst. Sci., 16, 607–616, https://doi.org/10.5194/nhess-16-607-2016, 2016. a
Portmann, R., Crezee, B., Quinting, J., and Wernli, H.: The complex life cycles
of two long-lived potential vorticity cut-offs over Europe, Q. J. Roy.
Meteor. Soc., 144, 701–719, https://doi.org/10.1002/qj.3239, 2018. a
Puskeiler, M., Kunz, M., and Schmidberger, M.: Hail statistics for Germany
derived from single-polarization radar data, Atmos. Res., 178–179,
459–470, https://doi.org/10.1016/j.atmosres.2016.04.014, 2016. a
Quinting, J. F. and Vitart, F.: Representation of synoptic-scale Rossby wave
packets and blocking in the S2S Prediction Project Database, Geophys. Res.
Lett., 46, 1070–1078, https://doi.org/10.1029/2018GL081381, 2019. a
Rädler, A. T., Groenemeijer, P., Faust, E., and Sausen, R.: Detecting
severe weather trends using an Additive Regressive Convective Hazard Model
(AR-CHaMo), J. Appl. Meteorl. Clim., 57, 569–587,
https://doi.org/10.1175/JAMC-D-17-0132.1, 2018. a
Rasmussen, P. F. and Gautam, N.: Alternative PWM-estimators of the Gumbel
distribution, J. Hydrol., 280, 265–271,
https://doi.org/10.1016/S0022-1694(03)00241-5, 2003. a
Rauthe, M., Steiner, H., Riediger, U., A., M., and Gratzki, A.: A Central
European precipitation climatology – Part I: Generation and validation of a
high-resolution gridded daily data set (HYRAS), Meteorol. Z., 22, 235–256,
https://doi.org/10.1127/0941-2948/2013/0436, 2013. a, b, c
Rex, D. F.: Blocking action in the middle troposphere and its effect upon
regional climate: I. An aerological study of blocking action, Tellus, 2,
196–211, https://doi.org/10.3402/tellusa.v2i3.8546, 1950a. a, b
Rex, D. F.: Blocking action in the middle troposphere and its effect upon
regional climate: II. The climatology of blocking action, Tellus, 2,
275–301, https://doi.org/10.3402/tellusa.v2i4.8603, 1950b. a
Roberts, N. M.: The relationship between water vapour imagery and
thunderstorms, Joint Centre for Mesoscale Meteorology Internal Report No. 110, Met Office, Reading, UK, 2000. a
Röthlisberger, M. and Martius, O.: Quantifying the local effect of Northern
Hemisphere atmospheric blocks on the persistence of summer hot and dry
spells, Geophys. Res. Lett., 43, 10101–10111,
https://doi.org/10.1029/2019GL083745, 2019. a
Röthlisberger, M., Martius, O., and Wernli, H.: Northern Hemisphere Rossby
wave initiation events on the extratropical jet – A climatological
analysis, J. Climate, 31, 743–760, https://doi.org/10.1175/JCLI-D-17-0346.1, 2018. a
Russell, A., Vaughan, G., and Norton, E. G.: Large-scale potential vorticity
anomalies and deep convection, Q. J. Roy. Meteor. Soc., 138, 1627–1639,
https://doi.org/10.1002/qj.1875, 2012. a
Sánchez, J. L., Marcos, J. L., Dessens, J., López, L., Bustos, C., and
García-Ortega, E.: Assessing sounding-derived parameters as storm
predictors in different latitudes, Atmos. Res., 93, 446–456,
https://doi.org/10.1016/j.atmosres.2008.11.006, 2009. a, b
Santos, J. A. and Belo-Pereira, M.: A comprehensive analysis of hail events in Portugal: Climatology and consistency with atmospheric circulation, Int. J. Climatol., 39, 188–205, https://doi.org/10.1002/joc.5794, 2019. a
Schaller, N., Sillmann, J., Anstey, J., Fischer, E. M., Grams, C. M., and
Russo, S.: Influence of blocking on Northern European and Western
Russian heatwaves in large climate model ensembles, Environ. Res. Lett.,
13, 054015, https://doi.org/10.1088/1748-9326/aaba55, 2018. a
Schmidberger, M.: Hagelgefährdung und Hagelrisiko in Deutschland basierend
auf einer Kombination von Radardaten und Versicherungsdaten, PhD thesis,
Wiss. Berichte d. Instituts für Meteorologie und Klimaforschung des
Karlsruher Instituts für Technologie, Vol. 78, KIT Scientific Publishing,
Karlsruhe, Germany, https://doi.org/10.5445/KSP/1000086012, 2018. a
Schulz, W., Diendorfer, G., Pedeboy, S., and Poelman, D. R.: The European lightning location system EUCLID – Part 1: Performance analysis and validation, Nat. Hazards Earth Syst. Sci., 16, 595–605, https://doi.org/10.5194/nhess-16-595-2016, 2016. a
Sivapalan, M. and Blöschl, G.: Transformation of point rainfall to areal
rainfall: Intensity-duration-frequency curves, J. Hydrol., 204, 150–167,
https://doi.org/10.1016/S0022-1694(03)00241-5, 1998. a
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. 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
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. a, b
Tarabukina, L. D., Antokhina, O. Y., Kononova, N. K., Kozlov, V. I., and
Innokentiev, D. E.: Formation of intense thunderstorms in Yakutia in periods
of frequent atmospheric blocking in Western Siberia, IOP Conf. Ser.:
Mater. Sci. Eng., 698, 044050, https://doi.org/10.1088/1757-899x/698/4/044050,
2019. a
Thompson, R. L., Mead, C. M., and Edwards, R.: Effective storm-relative
helicity and bulk shear in supercell thunderstorm environments, Weather
Forecast., 22, 102–115, https://doi.org/10.1175/WAF969.1, 2007. a, b
Tibaldi, S. and Molteni, F.: On the operational predictability of blocking,
Tellus A, 42, 343–365, https://doi.org/10.1034/j.1600-0870.1990.t01-2-00003.x, 1990. a
Trapp, R. J.: Mesoscale-convective processes in the atmosphere, Cambridge
University Press, New York, USA, 2013. a
UCAR/NCAR/CISL/VETS: The NCAR Command Language (Version 6.6.2),
Software, Boulder, Colorado, USA, https://doi.org/10.5065/D6WD3XH5, 2019. a
van Delden, A.: The synoptic setting of thunderstorms in Western Europe,
Atmos. Res., 56, 89–110, https://doi.org/10.1016/S0169-8095(00)00092-2, 2001. a
van den Besselaar, E. J. M., Klein Tank, A. M. G., and Buishand, T. A.: Trends
in European precipitation extremes over 1951–2010, Int. J. Climatol., 33,
2682–2689, https://doi.org/10.1002/joc.3619, 2013. a
Vautard, R.: Multiple weather regimes over the North Atlantic: Analysis of
precursors and successors, Mon. Weather Rev., 118, 2056–2081,
https://doi.org/10.1175/1520-0493(1990)118<2056:MWROTN>2.0.CO;2, 1990. a
Wapler, K.: High-resolution climatology of lightning characteristics within
Central Europe, Meteorol. Atmos. Phys., 122, 175–184,
https://doi.org/10.1007/s00703-013-0285-1, 2013. a
Wapler, K. and James, P.: Thunderstorm occurrence and characteristics in
Central Europe under different synoptic conditions, Atmos. Res., 158,
231–244, https://doi.org/10.1016/j.atmosres.2014.07.011, 2015. a
Weisman, M. L. and Klemp, J. B.: The dependence of numerically simulated
convective storms on vertical wind shear and buoyancy, Mon. Weather Rev.,
110, 504–520, https://doi.org/10.1175/1520-0493(1982)110<0504:TDONSC>2.0.CO;2, 1982. a, b
Wernli, H. and Davies, H. C.: A Lagrangian-based analysis of extratropical
cyclones. I: The method and some applications, Q. J. Roy. Meteor. Soc., 123,
467–489, https://doi.org/10.1002/qj.49712353811, 1997. a
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. a, b, c, d
Westermayer, A. T., Groenemeijer, P., Pistotnik, G., Sausen, R., and Faust, E.:
Identification of favorable environments for thunderstorms in reanalysis
data, Meteorol. Z., 26, 59–70, https://doi.org/10.1127/metz/2016/0754, 2017. a
WetterOnline: Tornado wütet bei Viersen: Dutzende Häuser stark beschädigt
(17.05.2018), WetterOnline Meteorologische Dienstleistungen GmbH, Bonn,
Germany, available at:
https://www.wetteronline.de/extremwetter/tornado-wuetet-bei-viersen-dutzende-haeuser-stark-beschaedigt-2018-05-17-tv
(last access: 13 March 2020), 2018a. a
WetterOnline: Unwetterserie Ende Mai: Ganze Ortschaften verwüstet,
WetterOnline Meteorologische Dienstleistungen GmbH, Bonn, Germany, available
at: https://www.wetteronline.de/extremwetter/unwetterserie-ende-mai-ganze-ortschaften-verwuestet-2018-05-31-us
(last access: 13 March 2020), 2018b. a, b
WetterOnline: Unwetterserie im Juni: Überflutungen und Hagelmassen
(14.06.2018), WetterOnline Meteorologische Dienstleistungen GmbH, Bonn,
Germany, available at:
https://www.wetteronline.de/extremwetter/unwetterserie-im-juni-ueberflutungen-und-hagelmassen-2018-06-14-js
(last access: 13 March 2020), 2018c. a
Wilson, J. W. and Schreiber, W. E.: Initiation of convective storms at
radar-observed boundary-layer convergence lines, Mon. Weather Rev., 114,
2516–2536, https://doi.org/10.1175/1520-0493(1986)114<2516:IOCSAR>2.0.CO;2, 1986. a
Woollings, T., Barriopedro, D., Methven, J., Son, S.-W., Martius, O., Harvey,
B., Sillmann, J., Lupo, A. R., and Seneviratne, S.: Blocking and its
response to climate change, Curr. Clim. Change Rep., 4, 287–300,
https://doi.org/10.1007/s40641-018-0108-z, 2018. a
Wussow, G.: Untere Grenzwerte dichter Regenfälle, Meteorol. Z., 39,
173–178, 1922. a
ZAMG: Messdaten, Zentralanstalt für Meteorologie und Geodynamik (ZAMG), Vienna, Austria, available at: https://www.zamg.ac.at/cms/de/klima/produkte-und-services/daten-und-statistiken/messdaten, last access: 25 January 2019. a
Short summary
We investigated an exceptional thunderstorm episode in 2018, in which atmospheric blocking provided large-scale environmental conditions favouring convection. Furthermore, blocking was accompanied by a high cut-off frequency on its upstream side, which together with filaments of high PV provided the mesoscale setting for deep moist convection. The exceptional persistence of low stability combined with weak wind speed in the mid-troposphere over more than 3 weeks has never been observed before.
We investigated an exceptional thunderstorm episode in 2018, in which atmospheric blocking...
