Articles | Volume 3, issue 3
https://doi.org/10.5194/wcd-3-1113-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/wcd-3-1113-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Classification of Alpine south foehn based on 5 years of kilometre-scale analysis data
Institute for Atmospheric and Climate Science, ETH Zürich, Zurich, Switzerland
Lukas Papritz
Institute for Atmospheric and Climate Science, ETH Zürich, Zurich, Switzerland
Bruno Dürr
Sunergy GmbH, Degersheim, Switzerland
Daniel Gerstgrasser
MeteoSwiss, Zurich, Switzerland
Michael Sprenger
Institute for Atmospheric and Climate Science, ETH Zürich, Zurich, Switzerland
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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
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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.
Iris Thurnherr, Katharina Hartmuth, Lukas Jansing, Josué Gehring, Maxi Boettcher, Irina Gorodetskaya, Martin Werner, Heini Wernli, and Franziska Aemisegger
Weather Clim. Dynam., 2, 331–357, https://doi.org/10.5194/wcd-2-331-2021, https://doi.org/10.5194/wcd-2-331-2021, 2021
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Extratropical cyclones are important for the transport of moisture from low to high latitudes. In this study, we investigate how the isotopic composition of water vapour is affected by horizontal temperature advection associated with extratropical cyclones using measurements and modelling. It is shown that air–sea moisture fluxes induced by this horizontal temperature advection lead to the strong variability observed in the isotopic composition of water vapour in the marine boundary layer.
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EGUsphere, https://doi.org/10.5194/egusphere-2025-3599, https://doi.org/10.5194/egusphere-2025-3599, 2025
This preprint is open for discussion and under review for Weather and Climate Dynamics (WCD).
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Storm Boris hit central Europe in September 2024 with extreme precipitation and impacts: this work introduces a methodology to strengthen our comprehension of how global warming affects similar events, based on the incorporation of event-specific meteorological information. Furthermore, it contextualizes how the answer to the question "How will Boris-like storms change in a warmer climate?" depends on explicit and implicit methodological choices, with the aim to inform future research.
Huw Davies and Michael Sprenger
EGUsphere, https://doi.org/10.5194/egusphere-2025-3017, https://doi.org/10.5194/egusphere-2025-3017, 2025
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Killian P. Brennan, Michael Sprenger, André Walser, Marco Arpagaus, and Heini Wernli
Weather Clim. Dynam., 6, 645–668, https://doi.org/10.5194/wcd-6-645-2025, https://doi.org/10.5194/wcd-6-645-2025, 2025
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We studied severe hailstorms that occurred in Switzerland on 28 June 2021 using a weather prediction model to understand how they evolved. We found that the storms moved toward areas with more storm energy. Hailfall was quickly followed by heavy rain. Just before the storms died out, the air feeding them stopped coming from near the ground. We also observed a delay between different types of precipitation forming in the incoming air.
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EGUsphere, https://doi.org/10.5194/egusphere-2025-1949, https://doi.org/10.5194/egusphere-2025-1949, 2025
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Katharina Hartmuth, Heini Wernli, and Lukas Papritz
Weather Clim. Dynam., 6, 505–520, https://doi.org/10.5194/wcd-6-505-2025, https://doi.org/10.5194/wcd-6-505-2025, 2025
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Selvakumar Vishnupriya, Michael Sprenger, Hanna Joos, and Heini Wernli
EGUsphere, https://doi.org/10.5194/egusphere-2025-1731, https://doi.org/10.5194/egusphere-2025-1731, 2025
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Extratropical cyclones feature rapidly ascending airstreams known as warm conveyor belts, which influence upper-level flow dynamics. This study classifies interactions of warm conveyor belts with the jet stream into four types: no interactions, ridges, blocks, and tropospheric cutoffs. We use reanalysis data to show that the interaction type depends more on the structure of the ambient flow than on the WCB properties, which improves the understanding of extratropical flow variability.
Rikke Stoffels, Imme Benedict, Lukas Papritz, Frank Selten, and Chris Weijenborg
EGUsphere, https://doi.org/10.5194/egusphere-2025-1752, https://doi.org/10.5194/egusphere-2025-1752, 2025
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Summertime North Atlantic storms bring heavy rainfall, especially near their centers and along their fronts. By tracking precipitating air parcels back in time we find that the moisture comes from areas of strong ocean evaporation, with hotspots in the Gulf Stream region. We also find that sometimes evaporation in a previous storm can contribute to rainfall in the next. Unlike in winter, summer storms also draw moisture from land, and their properties are partly shaped by former tropical storms.
Nicolai Krieger, Heini Wernli, Michael Sprenger, and Christian Kühnlein
Weather Clim. Dynam., 6, 447–469, https://doi.org/10.5194/wcd-6-447-2025, https://doi.org/10.5194/wcd-6-447-2025, 2025
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This study investigates the Laseyer, a local windstorm in a narrow Swiss valley characterized by strong southeasterly winds during northwesterly ambient flow. Using large-eddy simulations (LESs) with 30 m grid spacing, this is the first study to reveal that the extreme gusts in the valley are caused by an amplifying interplay of two recirculation regions. Modifying terrain and ambient wind conditions affects the windstorm's intensity and highlights the importance of topographic details in LES.
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EGUsphere, https://doi.org/10.5194/egusphere-2025-793, https://doi.org/10.5194/egusphere-2025-793, 2025
This preprint is open for discussion and under review for Geoscientific Model Development (GMD).
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As meteorological models grow in complexity, the volume of output data increases, making compression increasingly desirable. However, no specialized methods currently exist for compressing data in the Lagrangian frame. To address this gap, we developed psit, a pipeline for the lossy compression of Lagrangian flow data. In most cases, psit achieves performance that is equivalent or superior to non specialized alternatives, with compression errors behaving similar to measurement inaccuracies.
Killian P. Brennan, Iris Thurnherr, Michael Sprenger, and Heini Wernli
EGUsphere, https://doi.org/10.5194/egusphere-2025-918, https://doi.org/10.5194/egusphere-2025-918, 2025
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Hailstorms can cause severe damage to homes, crops, and infrastructure. Using high-resolution climate simulations, we tracked thousands of hailstorms across Europe to study future changes. Large hail will become more frequent, hail-covered areas will expand, and extreme hail combined with heavy rain will double. These shifts could increase risks for communities and businesses, highlighting the need for better preparedness and adaptation.
Marc Federer, Lukas Papritz, Michael Sprenger, and Christian M. Grams
Weather Clim. Dynam., 6, 211–230, https://doi.org/10.5194/wcd-6-211-2025, https://doi.org/10.5194/wcd-6-211-2025, 2025
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Although extratropical cyclones in the North Atlantic are among the most impactful midlatitude weather systems, their intensification is not entirely understood. Here, we explore how individual cyclones convert available potential energy (APE) into kinetic energy and relate these conversions to the synoptic development of the cyclones. By combining potential vorticity thinking with a local APE framework, we offer a novel perspective on established concepts in dynamic meteorology.
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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
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Warm conveyor belts (WCBs) are coherently ascending air streams that occur in extratropical cyclones where they form precipitation and often affect the large-scale flow. We quantified the key characteristics and impacts of WCBs and linked them to different phases in the cyclone life cycle and to different WCB branches. A climatology of these metrics revealed that WCBs are most intense during cyclone intensification and that the cyclonic and anticyclonic WCB branches show distinct differences.
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
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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.
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
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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.
Hilla Afargan-Gerstman, Dominik Büeler, C. Ole Wulff, Michael Sprenger, and Daniela I. V. Domeisen
Weather Clim. Dynam., 5, 231–249, https://doi.org/10.5194/wcd-5-231-2024, https://doi.org/10.5194/wcd-5-231-2024, 2024
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The stratosphere is a layer of Earth's atmosphere found above the weather systems. Changes in the stratosphere can affect the winds and the storm tracks in the North Atlantic region for a relatively long time, lasting for several weeks and even months. We show that the stratosphere can be important for weather forecasts beyond 1 week, but more work is needed to improve the accuracy of these forecasts for 3–4 weeks.
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
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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
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A novel classification of Mediterranean cyclones is presented, enabling a separation between storms driven by different atmospheric processes. The surface impact of each cyclone class differs greatly by precipitation, winds, and temperatures, providing an invaluable tool to study the climatology of different types of Mediterranean storms and enhancing the understanding of their predictability, on both weather and climate scales.
Stefania Gilardoni, Dominic Heslin-Rees, Mauro Mazzola, Vito Vitale, Michael Sprenger, and Radovan Krejci
Atmos. Chem. Phys., 23, 15589–15607, https://doi.org/10.5194/acp-23-15589-2023, https://doi.org/10.5194/acp-23-15589-2023, 2023
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Models still fail in reproducing black carbon (BC) temporal variability in the Arctic. Analysis of equivalent BC concentrations in the European Arctic shows that BC seasonal variability is modulated by the efficiency of removal by precipitation during transport towards high latitudes. Short-term variability is controlled by synoptic-scale circulation patterns. The advection of warm air from lower latitudes is an effective pollution transport pathway during summer.
Tiina Nygård, Lukas Papritz, Tuomas Naakka, and Timo Vihma
Weather Clim. Dynam., 4, 943–961, https://doi.org/10.5194/wcd-4-943-2023, https://doi.org/10.5194/wcd-4-943-2023, 2023
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Despite the general warming trend, wintertime cold-air outbreaks in Europe have remained nearly as extreme and as common as decades ago. In this study, we identify six principal cold anomaly types over Europe in 1979–2020. We show the origins of various physical processes and their contributions to the formation of cold wintertime air masses.
Thomas Trickl, Martin Adelwart, Dina Khordakova, Ludwig Ries, Christian Rolf, Michael Sprenger, Wolfgang Steinbrecht, and Hannes Vogelmann
Atmos. Meas. Tech., 16, 5145–5165, https://doi.org/10.5194/amt-16-5145-2023, https://doi.org/10.5194/amt-16-5145-2023, 2023
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Tropospheric ozone have been measured for more than a century. Highly quantitative ozone measurements have been made at monitoring stations. However, deficits have been reported for vertical sounding systems. Here, we report a thorough intercomparison effort between a differential-absorption lidar system and two types of balloon-borne ozone sondes, also using ozone sensors at nearby mountain sites as references. The sondes agree very well with the lidar after offset corrections.
Melanie Lauer, Annette Rinke, Irina Gorodetskaya, Michael Sprenger, Mario Mech, and Susanne Crewell
Atmos. Chem. Phys., 23, 8705–8726, https://doi.org/10.5194/acp-23-8705-2023, https://doi.org/10.5194/acp-23-8705-2023, 2023
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We present a new method to analyse the influence of atmospheric rivers (ARs), cyclones, and fronts on the precipitation in the Arctic, based on two campaigns: ACLOUD (early summer 2017) and AFLUX (early spring 2019). There are differences between both campaign periods: in early summer, the precipitation is mostly related to ARs and fronts, especially when they are co-located, while in early spring, cyclones isolated from ARs and fronts contributed most to the precipitation.
Emmanouil Flaounas, Leonardo Aragão, Lisa Bernini, Stavros Dafis, Benjamin Doiteau, Helena Flocas, Suzanne L. Gray, Alexia Karwat, John Kouroutzoglou, Piero Lionello, Mario Marcello Miglietta, Florian Pantillon, Claudia Pasquero, Platon Patlakas, María Ángeles Picornell, Federico Porcù, Matthew D. K. Priestley, Marco Reale, Malcolm J. Roberts, Hadas Saaroni, Dor Sandler, Enrico Scoccimarro, Michael Sprenger, and Baruch Ziv
Weather Clim. Dynam., 4, 639–661, https://doi.org/10.5194/wcd-4-639-2023, https://doi.org/10.5194/wcd-4-639-2023, 2023
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Cyclone detection and tracking methods (CDTMs) have different approaches in defining and tracking cyclone centers. This leads to disagreements on extratropical cyclone climatologies. We present a new approach that combines tracks from individual CDTMs to produce new composite tracks. These new tracks are shown to correspond to physically meaningful systems with distinctive life stages.
Hanna Joos, Michael Sprenger, Hanin Binder, Urs Beyerle, and Heini Wernli
Weather Clim. Dynam., 4, 133–155, https://doi.org/10.5194/wcd-4-133-2023, https://doi.org/10.5194/wcd-4-133-2023, 2023
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Warm conveyor belts (WCBs) are strongly ascending, cloud- and precipitation-forming airstreams in extratropical cyclones. In this study we assess their representation in a climate simulation and their changes under global warming. They become moister, become more intense, and reach higher altitudes in a future climate, implying that they potentially have an increased impact on the mid-latitude flow.
Andreas Schäfler, Michael Sprenger, Heini Wernli, Andreas Fix, and Martin Wirth
Atmos. Chem. Phys., 23, 999–1018, https://doi.org/10.5194/acp-23-999-2023, https://doi.org/10.5194/acp-23-999-2023, 2023
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In this study, airborne lidar profile measurements of H2O and O3 across a midlatitude jet stream are combined with analyses in tracer–trace space and backward trajectories. We highlight that transport and mixing processes in the history of the observed air masses are governed by interacting tropospheric weather systems on synoptic timescales. We show that these weather systems play a key role in the high variability of the paired H2O and O3 distributions near the tropopause.
Hanin Binder, Hanna Joos, Michael Sprenger, and Heini Wernli
Weather Clim. Dynam., 4, 19–37, https://doi.org/10.5194/wcd-4-19-2023, https://doi.org/10.5194/wcd-4-19-2023, 2023
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Warm conveyor belts (WCBs) are the main cloud- and precipitation-producing airstreams in extratropical cyclones. The latent heat release that occurs during cloud formation often contributes to the intensification of the associated cyclone. Based on the Community Earth System Model Large Ensemble coupled climate simulations, we show that WCBs and associated latent heating will become stronger in a future climate and be even more important for explosive cyclone intensification than in the present.
Michael A. Barnes, Thando Ndarana, Michael Sprenger, and Willem A. Landman
Weather Clim. Dynam., 3, 1291–1309, https://doi.org/10.5194/wcd-3-1291-2022, https://doi.org/10.5194/wcd-3-1291-2022, 2022
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Stratospheric air can intrude into the troposphere and is associated with cyclonic development throughout the atmosphere. Through a highly idealized systematic approach, the effect that different intrusion characteristics have on surface cyclogenetic forcing is investigated. The proximity of stratospheric intrusions to the surface is shown to be the main factor in surface cyclogenetic forcing, whilst its width is an additional contributing factor.
Sebastian Schemm, Lukas Papritz, and Gwendal Rivière
Weather Clim. Dynam., 3, 601–623, https://doi.org/10.5194/wcd-3-601-2022, https://doi.org/10.5194/wcd-3-601-2022, 2022
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Much of the change in our daily weather patterns is due to the development and intensification of extratropical cyclones. The response of these systems to climate change is an important topic of ongoing research. This study is the first to reproduce the changes in the North Atlantic circulation and extratropical cyclone characteristics found in fully coupled Earth system models under high-CO2 scenarios, but in an idealized, reduced-complexity simulation with uniform warming.
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
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Highly polluted air flows from the surface to higher levels of the atmosphere during the Asian summer monsoon. At high levels, the air is trapped within eddies. Here, we study how air masses can leave the eddy within its cutoff, how they distribute, and how their chemical composition changes. We found evidence for transport from the eddy to higher latitudes over the North Pacific and even Alaska. During transport, trace gas concentrations within cutoffs changed gradually, showing steady mixing.
Jörg Wieder, Claudia Mignani, Mario Schär, Lucie Roth, Michael Sprenger, Jan Henneberger, Ulrike Lohmann, Cyril Brunner, and Zamin A. Kanji
Atmos. Chem. Phys., 22, 3111–3130, https://doi.org/10.5194/acp-22-3111-2022, https://doi.org/10.5194/acp-22-3111-2022, 2022
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We investigate the variation in ice-nucleating particles (INPs) relevant for primary ice formation in mixed-phased clouds over the Alps based on simultaneous in situ observations at a mountaintop and a nearby high valley (1060 m height difference). In most cases, advection from the surrounding lower regions was responsible for changes in INP concentration, causing a diurnal cycle at the mountaintop. Our study underlines the importance of the planetary boundary layer as an INP reserve.
Lukas Bösiger, Michael Sprenger, Maxi Boettcher, Hanna Joos, and Tobias Günther
Geosci. Model Dev., 15, 1079–1096, https://doi.org/10.5194/gmd-15-1079-2022, https://doi.org/10.5194/gmd-15-1079-2022, 2022
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Jet streams are coherent air flows that interact with atmospheric structures such as warm conveyor belts (WCBs) and the tropopause. Individually, these structures have a significant impact on the weather evolution. A first step towards a deeper understanding of the meteorological processes is to extract jet stream core lines, for which we develop a novel feature extraction algorithm. Based on the line geometry, we automatically detect and visualize potential interactions between WCBs and jets.
Katharina Hartmuth, Maxi Boettcher, Heini Wernli, and Lukas Papritz
Weather Clim. Dynam., 3, 89–111, https://doi.org/10.5194/wcd-3-89-2022, https://doi.org/10.5194/wcd-3-89-2022, 2022
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In this study, we introduce a novel method to objectively define and identify extreme Arctic seasons based on different surface variables. We find that such seasons are resulting from various combinations of unusual seasonal conditions. The occurrence or absence of different atmospheric processes strongly affects the character of extreme Arctic seasons. Further, changes in sea ice and sea surface temperature can strongly influence the formation of such a season in distinct regions.
Sonja Murto, Rodrigo Caballero, Gunilla Svensson, and Lukas Papritz
Weather Clim. Dynam., 3, 21–44, https://doi.org/10.5194/wcd-3-21-2022, https://doi.org/10.5194/wcd-3-21-2022, 2022
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This study uses reanalysis data to investigate the role of atmospheric blocking, prevailing high-pressure systems and mid-latitude cyclones in driving high-Arctic wintertime warm extreme events. These events are mainly preceded by Ural and Scandinavian blocks, which are shown to be significantly influenced and amplified by cyclones in the North Atlantic. It also highlights processes that need to be well captured in climate models for improving their representation of Arctic wintertime climate.
Lukas Papritz, David Hauswirth, and Katharina Hartmuth
Weather Clim. Dynam., 3, 1–20, https://doi.org/10.5194/wcd-3-1-2022, https://doi.org/10.5194/wcd-3-1-2022, 2022
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Water vapor profoundly impacts the Arctic, for example by contributing to sea ice melt. A substantial portion of water vapor in the Arctic originates at mid-latitudes and is transported poleward in a few episodic and intense events. This transport is accomplished by low- and high-pressure systems occurring in specific regions or following particular tracks. Here, we explore how the type of weather system impacts where the water vapor is coming from and how it is transported poleward.
Philippe Besson, Luise J. Fischer, Sebastian Schemm, and Michael Sprenger
Weather Clim. Dynam., 2, 991–1009, https://doi.org/10.5194/wcd-2-991-2021, https://doi.org/10.5194/wcd-2-991-2021, 2021
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The strongest cyclone intensification is associated with a strong dry-dynamical forcing. Moreover, strong forcing and strong intensification correspond to a tendency for poleward cyclone propagation, which occurs in distinct regions in the Northern Hemisphere. There is a clear spatial pattern in the occurrence of certain forcing combinations. This implies a fundamental relationship between dry-dynamical processes and the intensification as well as the propagation of extratropical cyclones.
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
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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.
Iris Thurnherr, Katharina Hartmuth, Lukas Jansing, Josué Gehring, Maxi Boettcher, Irina Gorodetskaya, Martin Werner, Heini Wernli, and Franziska Aemisegger
Weather Clim. Dynam., 2, 331–357, https://doi.org/10.5194/wcd-2-331-2021, https://doi.org/10.5194/wcd-2-331-2021, 2021
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Extratropical cyclones are important for the transport of moisture from low to high latitudes. In this study, we investigate how the isotopic composition of water vapour is affected by horizontal temperature advection associated with extratropical cyclones using measurements and modelling. It is shown that air–sea moisture fluxes induced by this horizontal temperature advection lead to the strong variability observed in the isotopic composition of water vapour in the marine boundary layer.
Maxi Boettcher, Andreas Schäfler, Michael Sprenger, Harald Sodemann, Stefan Kaufmann, Christiane Voigt, Hans Schlager, Donato Summa, Paolo Di Girolamo, Daniele Nerini, Urs Germann, and Heini Wernli
Atmos. Chem. Phys., 21, 5477–5498, https://doi.org/10.5194/acp-21-5477-2021, https://doi.org/10.5194/acp-21-5477-2021, 2021
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Warm conveyor belts (WCBs) are important airstreams in extratropical cyclones, often leading to the formation of intense precipitation. We present a case study that involves aircraft, lidar and radar observations of water and clouds in a WCB ascending from western Europe across the Alps towards the Baltic Sea during the field campaigns HyMeX and T-NAWDEX-Falcon in October 2012. A probabilistic trajectory measure and an airborne tracer experiment were used to confirm the long pathway of the WCB.
Melissa L. Breeden, Amy H. Butler, John R. Albers, Michael Sprenger, and Andrew O'Neil Langford
Atmos. Chem. Phys., 21, 2781–2794, https://doi.org/10.5194/acp-21-2781-2021, https://doi.org/10.5194/acp-21-2781-2021, 2021
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Prior research has found a maximum in deep stratosphere-to-troposphere mass/ozone transport over the western United States in boreal spring, which can enhance surface ozone concentrations, reducing air quality. We find that the winter-to-summer evolution of the north Pacific jet increases the frequency of stratospheric intrusions that drive transport, helping explain the observed maximum. The El Niño–Southern Oscillation affects the timing of the spring jet transition and therefore transport.
Annika Oertel, Michael Sprenger, Hanna Joos, Maxi Boettcher, Heike Konow, Martin Hagen, and Heini Wernli
Weather Clim. Dynam., 2, 89–110, https://doi.org/10.5194/wcd-2-89-2021, https://doi.org/10.5194/wcd-2-89-2021, 2021
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Convection embedded in the stratiform cloud band of strongly ascending airstreams in extratropical cyclones (so-called warm conveyor belts) can influence not only surface precipitation but also the
upper-tropospheric potential vorticity (PV) and waveguide. The comparison of intense vs. moderate embedded convection shows that its strength alone is not a reliable measure for upper-tropospheric PV modification. Instead, characteristics of the ambient flow co-determine its dynamical significance.
Emmanouil Flaounas, Matthias Röthlisberger, Maxi Boettcher, Michael Sprenger, and Heini Wernli
Weather Clim. Dynam., 2, 71–88, https://doi.org/10.5194/wcd-2-71-2021, https://doi.org/10.5194/wcd-2-71-2021, 2021
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In this study we identify the wettest seasons globally and address their meteorological characteristics. We show that in different regions the wettest seasons occur in different times of the year and result from either unusually high frequencies of wet days and/or daily extremes. These high frequencies can be largely attributed to four specific weather systems, especially cyclones. Our analysis uses a thoroughly explained, novel methodology that could also be applied to climate models.
Claudia Mignani, Jörg Wieder, Michael A. Sprenger, Zamin A. Kanji, Jan Henneberger, Christine Alewell, and Franz Conen
Atmos. Chem. Phys., 21, 657–664, https://doi.org/10.5194/acp-21-657-2021, https://doi.org/10.5194/acp-21-657-2021, 2021
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Most precipitation above land starts with ice in clouds. It is promoted by extremely rare particles. Some ice-nucleating particles (INPs) cause cloud droplets to already freeze above −15°C, a temperature at which many clouds begin to snow. We found that the abundance of such INPs among other particles of similar size is highest in precipitating air masses and lowest when air carries desert dust. This brings us closer to understanding the interactions between land, clouds, and precipitation.
Stefan Rüdisühli, Michael Sprenger, David Leutwyler, Christoph Schär, and Heini Wernli
Weather Clim. Dynam., 1, 675–699, https://doi.org/10.5194/wcd-1-675-2020, https://doi.org/10.5194/wcd-1-675-2020, 2020
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Most precipitation over Europe is linked to low-pressure systems, cold fronts, warm fronts, or high-pressure systems. Based on a massive computer simulation able to resolve thunderstorms, we quantify in detail how much precipitation these weather systems produced during 2000–2008. We find distinct seasonal and regional differences, such as fronts precipitating a lot in fall and winter over the North Atlantic but high-pressure systems mostly in summer over the continent by way of thunderstorms.
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
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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.
Hanin Binder, Maxi Boettcher, Hanna Joos, Michael Sprenger, and Heini Wernli
Weather Clim. Dynam., 1, 577–595, https://doi.org/10.5194/wcd-1-577-2020, https://doi.org/10.5194/wcd-1-577-2020, 2020
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Warm conveyor belts (WCBs) are important cloud- and
precipitation-producing airstreams in extratropical cyclones. By combining satellite observations with model data from a new reanalysis dataset, this study provides detailed observational insight into the vertical cloud structure of WCBs. We find that the reanalyses essentially capture the observed cloud pattern, but the observations reveal mesoscale structures not resolved by the temporally and spatially much coarser-resolution model data.
Hilla Afargan-Gerstman, Iuliia Polkova, Lukas Papritz, Paolo Ruggieri, Martin P. King, Panos J. Athanasiadis, Johanna Baehr, and Daniela I. V. Domeisen
Weather Clim. Dynam., 1, 541–553, https://doi.org/10.5194/wcd-1-541-2020, https://doi.org/10.5194/wcd-1-541-2020, 2020
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We investigate the stratospheric influence on marine cold air outbreaks (MCAOs) in the North Atlantic using ERA-Interim reanalysis data. MCAOs are associated with severe Arctic weather, such as polar lows and strong surface winds. Sudden stratospheric events are found to be associated with more frequent MCAOs in the Barents and the Norwegian seas, affected by the anomalous circulation over Greenland and Scandinavia. Identification of MCAO precursors is crucial for improved long-range prediction.
Mauro Hermann, Lukas Papritz, and Heini Wernli
Weather Clim. Dynam., 1, 497–518, https://doi.org/10.5194/wcd-1-497-2020, https://doi.org/10.5194/wcd-1-497-2020, 2020
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We find, by tracing backward in time, that air masses causing extensive melt of the Greenland Ice Sheet originate from further south and lower altitudes than usual. Their exceptional warmth further arises due to ascent and cloud formation, which is special compared to near-surface heat waves in the midlatitudes or the central Arctic. The atmospheric systems and transport pathways identified here are crucial in understanding and simulating the atmospheric control of the ice sheet in the future.
Cited articles
Baldauf, M., Seifert, A., Förstner, J., Majewski, D., Raschendorfer, M., and Reinhardt, T.: Operational convective-scale numerical weather prediction with the COSMO model: Description and sensitivities, Mon. Weather Rev., 139, 3887–3905, https://doi.org/10.1175/MWR-D-10-05013.1, 2011. a
Bougeault, P., Binder, P., Buzzi, A., Dirks, R., Houze, R., Kuettner, J.,
Smith, R. B., Steinacker, R., and Volkert, H.: The MAP special observing
period, B. Am. Meteorol. Soc., 82, 433–462, https://doi.org/10.1175/1520-0477(2001)082<0433:TMSOP>2.3.CO;2, 2001. a
Burri, K., Hächler, P., Schüepp, M., and Werner, R.: Der Föhnfall von April 1993, Arbeitsber. MeteoSchweiz, 196, 89 pp., https://www.meteoschweiz.admin.ch/content/dam/meteoswiss/de/Ungebundene-Seiten/Publikationen/Fachberichte/doc/arbeitsbericht196.pdf (last access: 22 September 2022), 1999. a, b, c, d, e, f, g, h, i, j
Drobinski, P., Steinacker, R., Richner, H., Baumann-Stanzer, K., Beffrey, G., Benech, B., Berger, H., Chimani, B., Dabas, A., Dorninger, M., Dürr, B., Flamant, C., Frioud, M., Furger, M., Gröhn, I., Gubser, S., Gutermann, T., Häberli, C., Häller-Scharnhost, E., Jaubert, G., Lothon, M., Mitev, V., Pechinger, U., Piringer, M., Ratheiser, M., Ruffieux, D., Seiz, G., Spatzierer, M., Tschannett, S., Vogt, S., Werner, R., and Zängl, G.: Föhn in the Rhine Valley during MAP: A review of its multiscale dynamics
in complex valley geometry, Q. J. Roy. Meteorol. Soc., 133, 897–916,
https://doi.org/10.1002/qj.70, 2007. a, b
Elvidge, A. D. and Renfrew, I. A.: The causes of foehn warming in the lee of
mountains, B. Am. Meteorol. Soc., 97, 455–466,
https://doi.org/10.1175/BAMS-D-14-00194.1, 2016. a
Elvidge, A. D., Renfrew, I. A., King, J. C., Orr, A., Lachlan-Cope, T. A.,
Weeks, M., and Gray, S. L.: Foehn jets over the Larsen C ice shelf,
Antarctica, Q. J. Roy. Meteorol. Soc., 141, 698–713, https://doi.org/10.1002/qj.2382, 2015. a
Ficker, H.: Über die Entstehung der Föhnwinde auf der Nordseite der Alpen (On the formation of foehn winds on the northern side of the Alps), Meteorol. Z., 27, 439–451, https://doi.org/10.1127/0941-2948/2012/0532, 1910 (translated and edited by: Volken, E. and Brönnimann, S., Meteorol. Z., 21, 597–605, 2012). a, b, c
Ficker, H.: Warum steigt der Föhn in die Täler herab, Meteorol. Z, 48, 227–229, 1931. a
Frey, K.: Der “Jahrhundertföhn” vom 8. November 1982, Meteorol. Rundsch., 37, 209–220, 1984. a
Frey, K.: Entwicklung und Eigenschaften des Südföhns: Beitrag für ein modifiziertes Föhnmodell, Geogr. Helv., 47, 57–63, https://doi.org/10.5194/gh-47-57-1992, 1992. a
Frey, K.: Geheimnisvoller Föhn: Beschreibungen – Wissenschaftliches – Merkwürdiges, Mitt. Naturforsch. Ges. Kt. Solothurn, 40, 65–88, 2007. a
Gohm, A. and Mayr, G.: Hydraulic aspects of föhn winds in an Alpine valley, Q. J. Roy. Meteorol. Soc., 130, 449–480, https://doi.org/10.1256/qj.03.28, 2004. a, b
Gohm, A., Siller, M., and Bär, J.: Nature and climatology of Pfänderwind, Meteorol. Z., 24, 243–259, https://doi.org/10.1127/metz/2015/0648,
2015. a
Gubser, S.: Wechselwirkung zwischen Föhn und planetarer Grenzschicht, PhD thesis, ETH Zurich, https://doi.org/10.3929/ethz-a-005207902, 2006. a, b
Güller, A.: Der aussergewöhnliche Föhnsturm vom 13. Februar 1976 in der Ostschweiz, Arbeitsbericht der Schweiz. Met. Zentralanstalt, 69, 16 pp., https://www.meteoschweiz.admin.ch/content/dam/meteoswiss/de/Ungebundene-Seiten/Publikationen/Fachberichte/doc/arbeitsbericht69.pdf (last access: 22 September 2022), 1977. a, b, c, d, e, f, g
Gutermann, T., Dürr, B., Richner, H., and Bader, S.: Föhnklimatologie
Altdorf: Die lange Reihe (1864–2008) und ihre Weiterführung, Vergleich mit
anderen Stationen, Arbeitsber. MeteoSchweiz, 241, 53 pp.,
https://doi.org/10.3929/ethz-a-007583529, 2012. a, b
Hächler, P., Burri, K., Dürr, B., Gutermann, T., Neururer, A., Richner, H., and Werner, R.: Der Föhnfall vom 8. Dezember 2006 – eine Fallstudie, Arbeitsber. MeteoSchweiz, 234, https://doi.org/10.3929/ethz-a-007319165, 2011. a, b, c
Hann, J.: Zur Frage über den Urpsrung des Föhn, Z. Oester. Ges.
Meteorol., 1, 257–263, 1866. a
Hann, J.: Einige Bemerkungen zur Entwickelungs-Geschichte der Ansichten über den Ursprung des Föhn, Meteorol. Z., 20, 393–399, 1885. a
Hann, J.: Lehrbuch der Meteorologie, VDM Verlag Dr. Müller, ISBN 978-3-8364-2990-0, 1901. a
Kanitscheider, R.: Beiträge zur Mechanik des Föhns, Beitr. Phys. fr.
Atm., 18, 27–49, 1932. a
Krieger, N., Sprenger, M. A., and Müller, E.: Westföhn am Vierwaldstättersee, Fachber. MeteoSchweiz, 269 pp., https://www.meteoschweiz.admin.ch/content/dam/meteoswiss/de/service-und-publikationen/Publikationen/doc/TR_269_BA_NKrieger_final_V1.1.pdf (last access: 22 September 2022), 2018. a
Kusaka, H., Nishi, A., Kakinuma, A., Doan, Q.-V., Onodera, T., and Endo, S.:
Japan's south foehn on the Toyama Plain: Dynamical or thermodynamical
mechanisms?, Int. J. Climatol., 41, 5350–5367, https://doi.org/10.1002/joc.7133, 2021. a, b
Lehmann, O.: Zur Geschichte der Föhntheorie, Vierteljahresschr. Naturforsch.
Ges. Zürich, 82, 45–76, 1937. a
Mayr, G., Armi, L., Arnold, S., Banta, R. M., Darby, L. S., Durran, D., Flamant, C., Gaberšek, S., Gohm, A., Mayr, R., Mobbs, S., Nance, L. B., Vergeiner, I., Vergeiner, J., and Whiteman, C. D.: Gap flow measurements during the Mesoscale Alpine Programme, Meteorol. Atmos. Phys., 86, 99–119, https://doi.org/10.1007/s00703-003-0022-2, 2004. a
Mayr, G. J. and Armi, L.: Föhn as a response to changing upstream and
downstream air masses, Q. J. Roy. Meteorol. Soc., 134, 1357–1369,
https://doi.org/10.1002/qj.295, 2008. a, b, c, d
Mayr, G. J., Armi, L., Gohm, A., Zängl, G., Durran, D. R., Flamant, C., Gaberšek, S., Mobbs, S., Ross, A., and Weissmann, M.: Gap flows: results from the Mesoscale Alpine Programme, Q. J. Roy. Meteorol. Soc., 133,
881–896, https://doi.org/10.1002/qj.66, 2007. a, b, c
Medina, S. and Houze, R. A.: Air motions and precipitation growth in Alpine
storms, Q. J. Roy. Meteorol. Soc., 129, 345–371, https://doi.org/10.1256/qj.02.13,
2003. a
Miltenberger, A. K., Pfahl, S., and Wernli, H.: An online trajectory module (version 1.0) for the nonhydrostatic numerical weather prediction model COSMO, Geosci. Model Dev., 6, 1989–2004, https://doi.org/10.5194/gmd-6-1989-2013, 2013. a
Richner, H. and Dürr, B.: Facts and fallacies related to dimmerfoehn, Tech. rep., ETH Zurich, https://doi.org/10.3929/ethz-a-010439615, 2015. a
Richner, H. and Hächler, P.: Understanding and forecasting Alpine
Foehn, in: Mountain Weather Research and Forecasting, edited by: Chow,
F. K., De Wekker, S. F., and Snyder, B. J., chap. 4, Springer
Atmospheric Sciences, 219–260, https://doi.org/10.1007/978-94-007-4098-3, 2013. a, b, c, d, e, f, g, h
Richner, H., Baumann-Stanzer, K., Benech, B., Berger, H., Chimani, B., Dorninger, M., Drobinski, P., Furger, M., Gubser, S., Gutermann, T., Häberli, C., Häller, E., Lothon, M., Mitev, V., Ruffieux, D., Seiz, G., Steinacker, R., Tschanett, S., Vogt, S., and Werner, R.: Unstationary aspects of foehn in a large valley part I: operational setup,
scientific objectives and analysis of the cases during the special observing period of the MAP subprogramme FORM, Meteorol. Atmos. Phys., 92, 255–284, https://doi.org/10.1007/s00703-005-0134-y, 2006. a, b, c
Richner, H., Dürr, B., Gutermann, T., and Bader, S.: The use of automatic
station data for continuing the long time series (1864 to 2008) of foehn in
Altdorf, Meteorol. Z., 23, 159–166, https://doi.org/10.1127/0941-2948/2014/0528, 2014. a
Rotunno, R. and Houze, R. A.: Lessons on orographic precipitation from the
Mesoscale Alpine Programme, Q. J. Roy. Meteorol. Soc., 133, 811–830,
https://doi.org/10.1002/qj.67, 2007. a, b
Saigger, M.: Is it North or West Foehn? A Lagrangian Analysis of PIANO IOP 1, Master's thesis, University of Innsbruck, https://diglib.uibk.ac.at/urn/urn:nbn:at:at-ubi:1-94032 (last access: 20 September 2022), 2021. a
Saigger, M. and Gohm, A.: Is it north or west foehn? A Lagrangian analysis of Penetration and Interruption of Alpine Foehn intensive observation period 1 (PIANO IOP 1), Weather Clim. Dynam., 3, 279–303, https://doi.org/10.5194/wcd-3-279-2022, 2022. a, b, c, d
Sandner, V.: Verification of COSMO-1 forecasts of foehn breakthrough and interruption in the region of Innsbruck, Master's thesis, University of Innsbruck, https://resolver.obvsg.at/urn:nbn:at:at-ubi:1-65459 (last access: 20 September 2022), 2020. a
Schär, C., Fuhrer, O., Arteaga, A., Ban, N., Charpilloz, C., Di Girolamo, S., Hentgen, L., Hoefler, T., Lapillonne, X., Leutwyler, D., Osterried, K., Panosetti, D., Rüdisühli, S., Schlemmer, L., Schulthess, T. C., Sprenger, M., Ubbiali, S., and Wernli, H.:
Kilometer-scale climate models: Prospects and challenges, B. Am. Meteorol.
Soc., 101, E567–E587, https://doi.org/10.1175/BAMS-D-18-0167.1, 2020. a
Schneidereit, M. and Schär, C.: Idealised numerical experiments of Alpine flow regimes and southside precipitation events, Meteorol. Atmos. Phys., 72,
233–250, https://doi.org/10.1007/s007030050018, 2000. a, b
Schraff, C. H.: Mesoscale data assimilation and prediction of low stratus in
the Alpine region, Meteorol. Atmos. Phys., 64, 21–50,
https://doi.org/10.1007/BF01044128, 1997. a
Seibert, P.: Hann's thermodynamic foehn theory and its presentation in meteorological textbooks in the course of time, From Beaufort to Bjerknes and
Beyond, Algorismus, 52, 169–180, 2005. a
Smith, R. B.: The influence of mountains on the atmosphere, Adv. Geophys., 21, 87–230, https://doi.org/10.1016/S0065-2687(08)60262-9, 1979. a
Sprenger, M. and Schär, C.: Rotational aspects of stratified gap flows and shallow föhn, Q. J. Roy. Meteorol. Soc., 127, 161–187,
https://doi.org/10.1002/qj.49712757110, 2001. 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, b
Sprenger, M., Dürr, B., and Richner, H.: Foehn studies in Switzerland, in:
From weather observations to atmospheric and climate sciences in
Switzerland, edited by: Willemse, S. and Furger, M., chap. 11,
vdf Hochschulverlag AG, Zurich, 215–248, https://doi.org/10.3929/ethz-a-010649833, 2016. a
Stephan, K., Klink, S., and Schraff, C.: Assimilation of radar-derived rain
rates into the convective-scale model COSMO-DE at DWD, Q. J. Roy. Meteorol.
Soc., 134, 1315–1326, https://doi.org/10.1002/qj.269, 2008. a
Steppeler, J., Doms, G., Schättler, U., Bitzer, H., Gassmann, A., Damrath, U., and Gregoric, G.: Meso-gamma scale forecasts using the nonhydrostatic model LM, Meteorol. Atmos. Phys., 82, 75–96,
https://doi.org/10.1007/s00703-001-0592-9, 2003. a
Tian, Y., Schmidli, J., and Quimbayo-Duarte, J.: A station-based evaluation of south foehn forecasting with COSMO-1, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3680, https://doi.org/10.5194/egusphere-egu22-3680, 2022.
a
Walker, A. and Ruffner, H.: Föhnforschung und Traubenreife, Schweiz. Z.
Obst-Weinbau, 9, 245–247, 1998. a
Wastl, C., Schunk, C., Lüpke, M., Cocca, G., Conedera, M., Valese, E., and Menzel, A.: Large-scale weather types, forest fire danger, and wildfire
occurrence in the Alps, Agr. Forest Meteorol., 168, 15–25,
https://doi.org/10.1016/j.agrformet.2012.08.011, 2013. a
Wernli, H. and Davies, H. C.: A Lagrangian-based analysis of extratropical
cyclones. I: The method and some applications, Q. J. Roy. Meteorol. Soc.,
123, 467–489, https://doi.org/10.1002/qj.49712353811, 1997. a, b
Wilhelm, M., Buzzi, M., Sprenger, M., and Hächler, P.: COSMO-2 model performance in forecasting foehn: A systematic process-oriented verification, Master's thesis, Bundesamt für Meteorologie und Klimatologie, MeteoSchweiz, https://www.meteoschweiz.admin.ch/content/dam/meteoswiss/en/Ungebundene-Seiten/Publikationen/Scientific-Reports/doc/Veroeff-89.pdf (last access: 22 September 2022), 2012. a
Zängl, G.: North foehn in the Austrian Inn Valley: A case study and
idealized numerical simulations, Meteorol. Atmos. Phys., 91, 85–105,
https://doi.org/10.1007/s00703-004-0106-7, 2006. a
Zängl, G. and Hornsteiner, M.: The exceptional Alpine south föhn event of 14–16 November 2002: A case study, Meteorol. Atmos. Phys., 98, 217–238, https://doi.org/10.1007/s00703-006-0257-9, 2007. a
Zumbrunnen, T., Bugmann, H., Conedera, M., and Bürgi, M.: Linking forest
fire regimes and climate – a historical analysis in a dry inner Alpine
valley, Ecosystems, 12, 73–86, https://doi.org/10.1007/s10021-008-9207-3, 2009. a
Short summary
This study presents a 5-year climatology of three main foehn types and three deep-foehn subtypes. The main types differ in their large-scale and Alpine-scale weather conditions and the subtypes in terms of the amount and extent of precipitation on the Alpine south side. The different types of foehn are found to strongly affect the local meteorological conditions at Altdorf. The study concludes by setting the new classification into a historic context.
This study presents a 5-year climatology of three main foehn types and three deep-foehn...