Articles | Volume 5, issue 2
https://doi.org/10.5194/wcd-5-463-2024
© Author(s) 2024. 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-5-463-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
03 Apr 2024
Research article |
| 03 Apr 2024
| 03 Apr 2024
A Lagrangian framework for detecting and characterizing the descent of foehn from Alpine to local scales
Institute for Atmospheric and Climate Science, ETH Zürich, Zurich, Switzerland
Federal Office of Meteorology and Climatology MeteoSwiss, Zurich, Switzerland
Lukas Papritz
Institute for Atmospheric and Climate Science, ETH Zürich, Zurich, Switzerland
Michael Sprenger
Institute for Atmospheric and Climate Science, ETH Zürich, Zurich, Switzerland
Related authors
Lukas Jansing, Lukas Papritz, Bruno Dürr, Daniel Gerstgrasser, and Michael Sprenger
Weather Clim. Dynam., 3, 1113–1138, https://doi.org/10.5194/wcd-3-1113-2022, https://doi.org/10.5194/wcd-3-1113-2022, 2022
Short summary
Short summary
This study presents a 5-year climatology of three main foehn types and three deep-foehn subtypes. The main types differ in their large-scale and Alpine-scale weather conditions and the subtypes in terms of the amount and extent of precipitation on the Alpine south side. The different types of foehn are found to strongly affect the local meteorological conditions at Altdorf. The study concludes by setting the new classification into a historic context.
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
Short summary
Short summary
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.
Jacopo Riboldi, Robin Noyelle, Ellina Agayar, Hanin Binder, Marc Federer, Katharina Hartmuth, Michael Sprenger, Iris Thurnherr, and Selvakumar Vishnupriya
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).
Short summary
Short summary
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
Short summary
Short summary
The Stratospheric Polar Vortex (SPV) with its accompanying strong circumpolar jet is a dominant feature of the wintertime stratosphere. Evidence is presented that the SPV’s periphery often possesses distinctive sub-planetary scale features. The scale and dynamics of the features are linked to the break-up of an annular band of strong vorticity at the SPV’s periphery, and the latter’s aggregation into one or two vortices due to forcing from below bears comparison to Sudden Stratospheric Warming.
Killian P. Brennan, Michael Sprenger, André Walser, Marco Arpagaus, and Heini Wernli
Weather Clim. Dynam., 6, 645–668, https://doi.org/10.5194/wcd-6-645-2025, https://doi.org/10.5194/wcd-6-645-2025, 2025
Short summary
Short summary
We studied severe hailstorms that occurred in Switzerland on 28 June 2021 using a weather prediction model to understand how they evolved. We found that the storms moved toward areas with more storm energy. Hailfall was quickly followed by heavy rain. Just before the storms died out, the air feeding them stopped coming from near the ground. We also observed a delay between different types of precipitation forming in the incoming air.
Ming Hon Franco Lee and Michael Sprenger
EGUsphere, https://doi.org/10.5194/egusphere-2025-1949, https://doi.org/10.5194/egusphere-2025-1949, 2025
Short summary
Short summary
Turbulence can occur in clear-air conditions at cruising altitude. From around 5000 clear-air turbulence events identified using aircraft measurements, nonlinear breaking of large-scale waves and rapidly ascending airstreams associated with cyclones are found concurrent with 40 % and 30 % of them respectively. The results further show that these weather systems may trigger turbulence by generating highly deformed flow or flow instability, improving our understanding of clear-air turbulence.
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
Short summary
Short summary
In this study, we use large-ensemble climate model simulations to analyze extreme winters in the Barents Sea in a changing climate. We find that variability in both atmospheric processes and sea ice conditions determines the formation of such seasons in the present-day climate. The reduction in sea ice variability results in a decreasing importance of surface boundary conditions in a warmer climate, while the robust link shown for surface weather systems persists.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
This study investigates the Laseyer, a local windstorm in a narrow Swiss valley characterized by strong southeasterly winds during northwesterly ambient flow. Using large-eddy simulations (LESs) with 30 m grid spacing, this is the first study to reveal that the extreme gusts in the valley are caused by an amplifying interplay of two recirculation regions. Modifying terrain and ambient wind conditions affects the windstorm's intensity and highlights the importance of topographic details in LES.
Alexander Pietak, Langwen Huang, Luigi Fusco, Michael Sprenger, Sebastian Schemm, and Torsten Hoefler
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).
Short summary
Short summary
As meteorological models grow in complexity, the volume of output data increases, making compression increasingly desirable. However, no specialized methods currently exist for compressing data in the Lagrangian frame. To address this gap, we developed psit, a pipeline for the lossy compression of Lagrangian flow data. In most cases, psit achieves performance that is equivalent or superior to non specialized alternatives, with compression errors behaving similar to measurement inaccuracies.
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
Short summary
Short summary
Hailstorms can cause severe damage to homes, crops, and infrastructure. Using high-resolution climate simulations, we tracked thousands of hailstorms across Europe to study future changes. Large hail will become more frequent, hail-covered areas will expand, and 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
Short summary
Short summary
Although extratropical cyclones in the North Atlantic are among the most impactful midlatitude weather systems, their intensification is not entirely understood. Here, we explore how individual cyclones convert available potential energy (APE) into kinetic energy and relate these conversions to the synoptic development of the cyclones. By combining potential vorticity thinking with a local APE framework, we offer a novel perspective on established concepts in dynamic meteorology.
Philip Rupp, Jonas Spaeth, Hilla Afargan-Gerstman, Dominik Büeler, Michael Sprenger, and Thomas Birner
Weather Clim. Dynam., 5, 1287–1298, https://doi.org/10.5194/wcd-5-1287-2024, https://doi.org/10.5194/wcd-5-1287-2024, 2024
Short summary
Short summary
We quantify the occurrence of strong synoptic storms as contributing about 20 % to the uncertainty of subseasonal geopotential height forecasts over northern Europe. We further show that North Atlantic storms are less frequent, weaker and shifted southward following sudden stratospheric warming events, leading to a reduction in northern European forecast uncertainty.
Emmanouil Flaounas, Stavros Dafis, Silvio Davolio, Davide Faranda, Christian Ferrarin, Katharina Hartmuth, Assaf Hochman, Aristeidis Koutroulis, Samira Khodayar, Mario Marcello Miglietta, Florian Pantillon, Platon Patlakas, Michael Sprenger, and Iris Thurnherr
EGUsphere, https://doi.org/10.5194/egusphere-2024-2809, https://doi.org/10.5194/egusphere-2024-2809, 2024
Short summary
Short summary
Storm Daniel (2023) is one of the most catastrophic ones ever documented in the Mediterranean. Our results highlight the different dynamics and therefore the different predictability skill of precipitation, its extremes and impacts that have been produced in Greece and Libya, the two most affected countries. Our approach concerns a holistic analysis of the storm by articulating dynamics, weather prediction, hydrological and oceanographic implications, climate extremes and attribution theory.
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.
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.
Hilla Afargan-Gerstman, Dominik Büeler, C. Ole Wulff, Michael Sprenger, and Daniela I. V. Domeisen
Weather Clim. Dynam., 5, 231–249, https://doi.org/10.5194/wcd-5-231-2024, https://doi.org/10.5194/wcd-5-231-2024, 2024
Short summary
Short summary
The stratosphere is a layer of Earth's atmosphere found above the weather systems. Changes in the stratosphere can affect the winds and the storm tracks in the North Atlantic region for a relatively long time, lasting for several weeks and even months. We show that the stratosphere can be important for weather forecasts beyond 1 week, but more work is needed to improve the accuracy of these forecasts for 3–4 weeks.
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.
Stefania Gilardoni, Dominic Heslin-Rees, Mauro Mazzola, Vito Vitale, Michael Sprenger, and Radovan Krejci
Atmos. Chem. Phys., 23, 15589–15607, https://doi.org/10.5194/acp-23-15589-2023, https://doi.org/10.5194/acp-23-15589-2023, 2023
Short summary
Short summary
Models still fail in reproducing black carbon (BC) temporal variability in the Arctic. Analysis of equivalent BC concentrations in the European Arctic shows that BC seasonal variability is modulated by the efficiency of removal by precipitation during transport towards high latitudes. Short-term variability is controlled by synoptic-scale circulation patterns. The advection of warm air from lower latitudes is an effective pollution transport pathway during summer.
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.
Thomas Trickl, Martin Adelwart, Dina Khordakova, Ludwig Ries, Christian Rolf, Michael Sprenger, Wolfgang Steinbrecht, and Hannes Vogelmann
Atmos. Meas. Tech., 16, 5145–5165, https://doi.org/10.5194/amt-16-5145-2023, https://doi.org/10.5194/amt-16-5145-2023, 2023
Short summary
Short summary
Tropospheric ozone have been measured for more than a century. Highly quantitative ozone measurements have been made at monitoring stations. However, deficits have been reported for vertical sounding systems. Here, we report a thorough intercomparison effort between a differential-absorption lidar system and two types of balloon-borne ozone sondes, also using ozone sensors at nearby mountain sites as references. The sondes agree very well with the lidar after offset corrections.
Melanie Lauer, Annette Rinke, Irina Gorodetskaya, Michael Sprenger, Mario Mech, and Susanne Crewell
Atmos. Chem. Phys., 23, 8705–8726, https://doi.org/10.5194/acp-23-8705-2023, https://doi.org/10.5194/acp-23-8705-2023, 2023
Short summary
Short summary
We present a new method to analyse the influence of atmospheric rivers (ARs), cyclones, and fronts on the precipitation in the Arctic, based on two campaigns: ACLOUD (early summer 2017) and AFLUX (early spring 2019). There are differences between both campaign periods: in early summer, the precipitation is mostly related to ARs and fronts, especially when they are co-located, while in early spring, cyclones isolated from ARs and fronts contributed most to the precipitation.
Emmanouil Flaounas, Leonardo Aragão, Lisa Bernini, Stavros Dafis, Benjamin Doiteau, Helena Flocas, Suzanne L. Gray, Alexia Karwat, John Kouroutzoglou, Piero Lionello, Mario Marcello Miglietta, Florian Pantillon, Claudia Pasquero, Platon Patlakas, María Ángeles Picornell, Federico Porcù, Matthew D. K. Priestley, Marco Reale, Malcolm J. Roberts, Hadas Saaroni, Dor Sandler, Enrico Scoccimarro, Michael Sprenger, and Baruch Ziv
Weather Clim. Dynam., 4, 639–661, https://doi.org/10.5194/wcd-4-639-2023, https://doi.org/10.5194/wcd-4-639-2023, 2023
Short summary
Short summary
Cyclone detection and tracking methods (CDTMs) have different approaches in defining and tracking cyclone centers. This leads to disagreements on extratropical cyclone climatologies. We present a new approach that combines tracks from individual CDTMs to produce new composite tracks. These new tracks are shown to correspond to physically meaningful systems with distinctive life stages.
Hanna Joos, Michael Sprenger, Hanin Binder, Urs Beyerle, and Heini Wernli
Weather Clim. Dynam., 4, 133–155, https://doi.org/10.5194/wcd-4-133-2023, https://doi.org/10.5194/wcd-4-133-2023, 2023
Short summary
Short summary
Warm conveyor belts (WCBs) are strongly ascending, cloud- and precipitation-forming airstreams in extratropical cyclones. In this study we assess their representation in a climate simulation and their changes under global warming. They become moister, become more intense, and reach higher altitudes in a future climate, implying that they potentially have an increased impact on the mid-latitude flow.
Andreas Schäfler, Michael Sprenger, Heini Wernli, Andreas Fix, and Martin Wirth
Atmos. Chem. Phys., 23, 999–1018, https://doi.org/10.5194/acp-23-999-2023, https://doi.org/10.5194/acp-23-999-2023, 2023
Short summary
Short summary
In this study, airborne lidar profile measurements of H2O and O3 across a midlatitude jet stream are combined with analyses in tracer–trace space and backward trajectories. We highlight that transport and mixing processes in the history of the observed air masses are governed by interacting tropospheric weather systems on synoptic timescales. We show that these weather systems play a key role in the high variability of the paired H2O and O3 distributions near the tropopause.
Hanin Binder, Hanna Joos, Michael Sprenger, and Heini Wernli
Weather Clim. Dynam., 4, 19–37, https://doi.org/10.5194/wcd-4-19-2023, https://doi.org/10.5194/wcd-4-19-2023, 2023
Short summary
Short summary
Warm conveyor belts (WCBs) are the main cloud- and precipitation-producing airstreams in extratropical cyclones. The latent heat release that occurs during cloud formation often contributes to the intensification of the associated cyclone. Based on the Community Earth System Model Large Ensemble coupled climate simulations, we show that WCBs and associated latent heating will become stronger in a future climate and be even more important for explosive cyclone intensification than in the present.
Michael A. Barnes, Thando Ndarana, Michael Sprenger, and Willem A. Landman
Weather Clim. Dynam., 3, 1291–1309, https://doi.org/10.5194/wcd-3-1291-2022, https://doi.org/10.5194/wcd-3-1291-2022, 2022
Short summary
Short summary
Stratospheric air can intrude into the troposphere and is associated with cyclonic development throughout the atmosphere. Through a highly idealized systematic approach, the effect that different intrusion characteristics have on surface cyclogenetic forcing is investigated. The proximity of stratospheric intrusions to the surface is shown to be the main factor in surface cyclogenetic forcing, whilst its width is an additional contributing factor.
Lukas Jansing, Lukas Papritz, Bruno Dürr, Daniel Gerstgrasser, and Michael Sprenger
Weather Clim. Dynam., 3, 1113–1138, https://doi.org/10.5194/wcd-3-1113-2022, https://doi.org/10.5194/wcd-3-1113-2022, 2022
Short summary
Short summary
This study presents a 5-year climatology of three main foehn types and three deep-foehn subtypes. The main types differ in their large-scale and Alpine-scale weather conditions and the subtypes in terms of the amount and extent of precipitation on the Alpine south side. The different types of foehn are found to strongly affect the local meteorological conditions at Altdorf. The study concludes by setting the new classification into a historic context.
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
Short summary
Short summary
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
Short summary
Short summary
Highly polluted air flows from the surface to higher levels of the atmosphere during the Asian summer monsoon. At high levels, the air is trapped within eddies. Here, we study how air masses can leave the eddy within its cutoff, how they distribute, and how their chemical composition changes. We found evidence for transport from the eddy to higher latitudes over the North Pacific and even Alaska. During transport, trace gas concentrations within cutoffs changed gradually, showing steady mixing.
Jörg Wieder, Claudia Mignani, Mario Schär, Lucie Roth, Michael Sprenger, Jan Henneberger, Ulrike Lohmann, Cyril Brunner, and Zamin A. Kanji
Atmos. Chem. Phys., 22, 3111–3130, https://doi.org/10.5194/acp-22-3111-2022, https://doi.org/10.5194/acp-22-3111-2022, 2022
Short summary
Short summary
We investigate the variation in ice-nucleating particles (INPs) relevant for primary ice formation in mixed-phased clouds over the Alps based on simultaneous in situ observations at a mountaintop and a nearby high valley (1060 m height difference). In most cases, advection from the surrounding lower regions was responsible for changes in INP concentration, causing a diurnal cycle at the mountaintop. Our study underlines the importance of the planetary boundary layer as an INP reserve.
Lukas Bösiger, Michael Sprenger, Maxi Boettcher, Hanna Joos, and Tobias Günther
Geosci. Model Dev., 15, 1079–1096, https://doi.org/10.5194/gmd-15-1079-2022, https://doi.org/10.5194/gmd-15-1079-2022, 2022
Short summary
Short summary
Jet streams are coherent air flows that interact with atmospheric structures such as warm conveyor belts (WCBs) and the tropopause. Individually, these structures have a significant impact on the weather evolution. A first step towards a deeper understanding of the meteorological processes is to extract jet stream core lines, for which we develop a novel feature extraction algorithm. Based on the line geometry, we automatically detect and visualize potential interactions between WCBs and jets.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
The strongest cyclone intensification is associated with a strong dry-dynamical forcing. Moreover, strong forcing and strong intensification correspond to a tendency for poleward cyclone propagation, which occurs in distinct regions in the Northern Hemisphere. There is a clear spatial pattern in the occurrence of certain forcing combinations. This implies a fundamental relationship between dry-dynamical processes and the intensification as well as the propagation of extratropical cyclones.
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.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
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.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Armi, L. and Mayr, G. J.: Continuously stratified flows across an Alpine crest with a pass: Shallow and deep föhn, Q. J. Roy. Meteor. Soc., 133, 459–477, https://doi.org/10.1002/qj.22, 2007. a, b
Armi, L. and Mayr, G. J.: The descending stratified flow and internal hydraulic jump in the lee of the Sierras, J. Appl. Meteorol. Clim., 50, 1995–2011, https://doi.org/10.1175/JAMC-D-10-05005.1, 2011. a, b, c, d
Baldauf, M. and Zängl, G.: Horizontal nonlinear Smagorinsky diffusion, COSMO Newsletter 12, Deutscher Wetterdienst, http://www.cosmo-model.org/content/model/documentation/newsLetters/newsLetter12/1-baldauf.pdf (last access: 21 March 2024), 2012. a
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
Baumann, K., Maurer, H., Rau, G., Piringer, M., Pechinger, U., Prévôt, A., Furger, M., Neininger, B., and Pellegrini, U.: The influence of south Foehn on the ozone distribution in the Alpine Rhine Valley–results from the MAP field phase, Atmos. Environ., 35, 6379–6390, https://doi.org/10.1016/S1352-2310(01)00364-8, 2001. a
Billwiller, R.: Besprechung von M. F. F. Hébert's “Etude sur les grands mouvements de l'atmosphère et sur le Foehn et le Scirocco pendant l'hiver 1876/77”, Z. Oester. Ges. Meteorol., 13, 317–320, 1878. a
Blumen, W.: Mountain meteorology, in: Atmospheric processes over complex terrain, edited by: Blumen, W., American Meteorological Society, Boston, MA, https://doi.org/10.1007/978-1-935704-25-6_1, pp. 1–4, 1990. 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
Bukenberger, M., Rüdisühli, S., and Schemm, S.: Jet stream dynamics from a PV gradient perspective: The method and its application to a km-scale simulation, Q. J. Roy. Meteor. Soc., 149, 2409–2432, https://doi.org/10.1002/qj.4513, 2023. a
Clark, T. L. and Peltier, W.: On the evolution and stability of finite-amplitude mountain waves, J. Atmos. Sci., 34, 1715–1730, https://doi.org/10.1175/1520-0469(1977)034<1715:OTEASO>2.0.CO;2, 1977. a
Doms, G. and Baldauf, M.: A description of the nonhydrostatic regional COSMO-model – Part I: Dynamics and Numerics, Tech. rep., Deutscher Wetterdienst, https://doi.org/10.5676/DWD_pub/nwv/cosmo-doc_6.00_I, 2021. a, b
Drobinski, P., Haeberli, C., Richard, E., Lothon, M., Dabas, A., Flamant, P., Furger, M., and Steinacker, R.: Scale interaction processes during the MAP IOP 12 south föhn event in the Rhine Valley, Q. J. Roy. Meteor. Soc., 129, 729–753, https://doi.org/10.1256/qj.02.35, 2003. a
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. Meteor. Soc., 133, 897–916, https://doi.org/10.1002/qj.70, 2007. a
Dürr, B.: Automatisiertes Verfahren zur Bestimmung von Föhn in Alpentälern, Bundesamt für Meteorologie und Klimatologie, MeteoSchweiz, Arbeitsber. MeteoSchweiz, 223, 22 pp., https://www.meteoschweiz.admin.ch/dam/jcr:3ed2aec8-0901-417a-acc3-8be11cce440a/Foehnindex_Arbeitsbericht_223_Automatisiertes_Verfahren_zur_Bestimmung_von_Foehn_in_Alpentaelern_de.pdf (last access: 21 March 2024, 2008. a, b
Durran, D. R.: Mountain waves and downslope winds, in: Atmospheric processes over complex terrain, edited by: Blumen, W., American Meteorological Society, Boston, MA, 59–81, https://doi.org/10.1007/978-1-935704-25-6_4, 1990. a, b, c
Durran, D. R.: Mountain Meteorology | Lee Waves and Mountain Waves, in: Encyclopedia of Atmospheric Sciences, second edition, edited by: North, G. R., Pyle, J., and Zhang, F., Academic Press, Oxford, 95–102, https://doi.org/10.1016/B978-0-12-382225-3.00202-4, 2015. a
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, b
Elvidge, A. D., Renfrew, I. A., King, J. C., Orr, A., and Lachlan-Cope, T. A.: Foehn warming distributions in nonlinear and linear flow regimes: A focus on the Antarctic Peninsula, Q. J. Roy. Meteor. Soc., 142, 618–631, https://doi.org/10.1002/qj.2489, 2014. a
Elvidge, A. D., Kuipers Munneke, P., King, J. C., Renfrew, I. A., and Gilbert, E.: Atmospheric drivers of melt on Larsen C Ice Shelf: Surface energy budget regimes and the impact of foehn, J. Geophys. Res.-Atmos., 125, e2020JD032463, https://doi.org/10.1029/2020JD032463, 2020. a, b
Ficker, H.: Warum steigt der Föhn in die Täler herab?, Meteorol. Z., 48, 227–229, 1931. a
Flamant, C., Drobinski, P., Nance, L., Banta, R., Darby, L., Dusek, J., Hardesty, M., Pelon, J., and Richard, E.: Gap flow in an Alpine valley during a shallow south föhn event: Observations, numerical simulations and hydraulic analogue, Q. J. Roy. Meteor. Soc., 128, 1173–1210, https://doi.org/10.1256/003590002320373256, 2002. a
Flamant, C., Drobinski, P., Furger, M., Chimani, B., Tschannett, S., Steinacker, R., Protat, A., Richner, H., Gubser, S., and Häberli, C.: Föohn/cold-pool interactions in the Rhine valley during MAP IOP 15, Q. J. Roy. Meteor. Soc., 132, 3035–3058, https://doi.org/10.1256/qj.06.36, 2006. a
Frey, K.: Beiträge zur Entwicklung des Föhns und Untersuchungen über Hochnebel, PhD thesis, Rentsch Söhne, Trimbach Olten, 1945. a
Fuhrer, O., Osuna, C., Lapillonne, X., Gysi, T., Cumming, B., Bianco, M., Arteaga, A., and Schulthess, T. C.: Towards a performance portable, architecture agnostic implementation strategy for weather and climate models, Supercomp. Front. Innov., 1, 45–62, https://doi.org/10.14529/jsfi140103, 2014. a
Gohm, A. and Mayr, G.: Hydraulic aspects of föhn winds in an Alpine valley, Q. J. Roy. Meteor. Soc., 130, 449–480, https://doi.org/10.1256/qj.03.28, 2004. a
Gubser, S.: Wechselwirkung zwischen Föhn und planetarer Grenzschicht, PhD thesis, ETH Zurich, https://doi.org/10.3929/ethz-a-005207902, 2006. a
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., Bundesamt für Meteorologie und Klimatologie, MeteoSchweiz, https://doi.org/10.3929/ethz-a-007583529, 2012. a, b, c
Haid, M., Gohm, A., Umek, L., Ward, H. C., Muschinski, T., Lehner, L., and Rotach, M. W.: Foehn–cold pool interactions in the Inn Valley during PIANO IOP2, Q. J. Roy. Meteor. Soc., 146, 1232–1263, https://doi.org/10.1002/qj.3735, 2020. a, b, c
Haid, M., Gohm, A., Umek, L., Ward, H. C., and Rotach, M. W.: Cold-air pool processes in the Inn Valley during föhn: A comparison of four cases during the PIANO campaign, Bound.-Lay. Meteorol., 182, 335–362, https://doi.org/10.1007/s10546-021-00663-9, 2022. a
Hann, J.: Zur Frage über den Ursprung des Föhn, Z. Oester. Ges. Meteorol., 1, 257–263, 1866. a
Heise, E., Ritter, B., and Schrodin, R.: Operational implementation of the multilayer soil model, COSMO tech. rep., Deutscher Wetterdienst, https://doi.org/10.5676/DWD_pub/nwv/cosmo-tr_9, 2006. a
Jackson, P., Mayr, G., and Vosper, S.: Dynamically-driven winds, chap. 3, in: Mountain Weather Research and Forecasting, edited by: Chow, F. K., De Wekker, S. F., and Snyder, B. J., Springer Atmospheric Sciences, 121–218, https://doi.org/10.1007/978-94-007-4098-3_3, 2013. a
Jansing, L.: A Lagrangian perspective on the Alpine Foehn, PhD thesis, ETH Zurich, https://doi.org/10.3929/ethz-b-000619589, 2023. a, b, c, d
Jiang, Q., Doyle, J. D., and Smith, R. B.: Interaction between trapped waves and boundary layers, J. Atmos. Sci., 63, 617–633, https://doi.org/10.1175/JAS3640.1, 2006. a, b
Klemp, J. and Lilly, D.: The dynamics of wave-induced downslope winds, J. Atmos. Sci., 32, 320–339, https://doi.org/10.1175/1520-0469(1975)032<0320:TDOWID>2.0.CO;2, 1975. a
Kruse, C. G. and Smith, R. B.: Gravity wave diagnostics and characteristics in mesoscale fields, J. Atmos. Sci., 72, 4372–4392, https://doi.org/10.1175/JAS-D-15-0079.1, 2015. 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, c
Lehmann, O.: Zur Geschichte der Föhntheorie, Vierteljahresschr. Naturforsch. Ges. Zürich, 82, 45–76, 1937. a
Lehner, M. and Rotach, M. W.: Current challenges in understanding and predicting transport and exchange in the atmosphere over mountainous terrain, Atmosphere, 9, 276, https://doi.org/10.3390/atmos9070276, 2018. a
Leuenberger, D., Koller, M., Fuhrer, O., and Schär, C.: A generalization of the SLEVE vertical coordinate, Mon. Weather Rev., 138, 3683–3689, https://doi.org/10.1175/2010MWR3307.1, 2010. a
Leutwyler, D., Fuhrer, O., Lapillonne, X., Lüthi, D., and Schär, C.: Towards European-scale convection-resolving climate simulations with GPUs: a study with COSMO 4.19, Geosci. Model Dev., 9, 3393–3412, https://doi.org/10.5194/gmd-9-3393-2016, 2016. a
Lezuo, T., Jansing, L., Rostkier-Edelstein, D., and Sprenger, M.: Is it foehn or sea breeze? Eulerian and Lagrangian analysis of the flow in the Jordan Valley, Meteorol. Z., 32, 367–381, https://doi.org/10.1127/metz/2023/1167, 2023. a
Mattingly, K. S., Mote, T. L., Fettweis, X., Van As, D., Van Tricht, K., Lhermitte, S., Pettersen, C., and Fausto, R. S.: Strong summer atmospheric rivers trigger Greenland Ice Sheet melt through spatially varying surface energy balance and cloud regimes, J. Climate, 33, 6809–6832, https://doi.org/10.1175/JCLI-D-19-0835.1, 2020. a
Mattingly, K. S., Turton, J. V., Wille, J. D., Noël, B., Fettweis, X., Rennermalm, Å. K., and Mote, T. L.: Increasing extreme melt in northeast Greenland linked to foehn winds and atmospheric rivers, Nat. Commun., 14, 1743, https://doi.org/10.1038/s41467-023-37434-8, 2023. a
Mayr, G. J. and Armi, L.: The influence of downstream diurnal heating on the descent of flow across the Sierras, J. Appl. Meteorol. Clim., 49, 1906–1912, https://doi.org/10.1175/2010JAMC2516.1, 2010. a, b, c
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. Meteor. Soc., 133, 881–896, https://doi.org/10.1002/qj.66, 2007. a, b, c, d
Mellor, G. L. and Yamada, T.: Development of a turbulence closure model for geophysical fluid problems, Rev. Geophys., 20, 851–875, https://doi.org/10.1029/RG020i004p00851, 1982. 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, b
Miltenberger, A. K., Reynolds, S., and Sprenger, M.: Revisiting the latent heating contribution to foehn warming: Lagrangian analysis of two foehn events over the Swiss Alps, Q. J. Roy. Meteor. Soc., 142, 2194–2204, https://doi.org/10.1002/qj.2816, 2016. a, b
Mony, C.: Evaluating foehn development in a changing climate using machine learning and investigating the impact of foehn on forest fire occurrence and severity, Master's thesis, ETH Zurich, https://doi.org/10.3929/ethz-b-000594509, 2020. a
Muñoz, R. C., Armi, L., Rutllant, J. A., Falvey, M., Whiteman, C. D., Garreaud, R., Arriagada, A., Flores, F., and Donoso, N.: Raco wind at the exit of the Maipo Canyon in central Chile: climatology, special observations, and possible mechanisms, J. Appl. Meteorol. Clim., 59, 725–749, https://doi.org/10.1175/JAMC-D-19-0188.1, 2020. a
Pezzatti, G. B., De Angelis, A., and Conedera, M.: Potenzielle Entwicklung der Waldbrandgefahr im Klimawandel, chap. 3.8, in: Wald im Klimawandel. Grundlagen für Adaptationsstrategien, edited by: Pluess, A. R., Augustin, S., and Brang, P., Haupt, Bern, https://www.dora.lib4ri.ch/wsl/islandora/object/wsl:10619 (last access: 21 March 2024), pp. 223–246, 2016. a
Queney, P.: The problem of air flow over mountains: A summary of theoretical studies, B. Am. Meteorol. Soc., 29, 16–26, https://doi.org/10.1175/1520-0477-29.1.16, 1948. a
Raphael, M.: The Santa Ana winds of California, Earth Interact., 7, 1–13, https://doi.org/10.1175/1087-3562(2003)007<0001:TSAWOC>2.0.CO;2, 2003. a
Raschendorfer, M.: The new turbulence parameterization of LM, COSMO Newsletter 1, Deutscher Wetterdienst, https://www.cosmo-model.org/content/model/documentation/newsLetters/newsLetter01/newsLetter_01.pdf (last access: 21 March 2024), 2001. a
Reinhardt, T. and Seifert, A.: A three-category ice scheme for LMK, COSMO Newsletter 6, Deutscher Wetterdienst, https://www.cosmo-model.org/content/model/documentation/newsLetters/newsLetter06/cnl6_reinhardt.pdf (last access: 21 March 2024), 2006. a
Richner, H. and Hächler, P.: Understanding and forecasting Alpine foehn, chap. 4, in: Mountain Weather Research and Forecasting, edited by: Chow, F. K., De Wekker, S. F., and Snyder, B. J., Springer Atmospheric Sciences, 219–260, https://doi.org/10.1007/978-94-007-4098-3_4, 2013. a, b, c, d
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
Ritter, B. and Geleyn, J.-F.: A comprehensive radiation scheme for numerical weather prediction models with potential applications in climate simulations, Mon. Weather Rev., 120, 303–325, https://doi.org/10.1175/1520-0493(1992)120<0303:ACRSFN>2.0.CO;2, 1992. a
Rossmann, F.: Über das Absteigen des Föhns in die Täler, Ber. deutsch. Wetterd. US-Zone, 12, 94–98, 1950. a
Rotach, M. W., Wohlfahrt, G., Hansel, A., Reif, M., Wagner, J., and Gohm, A.: The world is not flat: Implications for the global carbon balance, B. Am. Meteorol. Soc., 95, 1021–1028, https://doi.org/10.1175/BAMS-D-13-00109.1, 2014. 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
Schär, C., Leuenberger, D., Fuhrer, O., Lüthi, D., and Girard, C.: A new terrain-following vertical coordinate formulation for atmospheric prediction models, Mon. Weather Rev., 130, 2459–2480, https://doi.org/10.1175/1520-0493(2002)130<2459:ANTFVC>2.0.CO;2, 2002. a
Schättler, U., Doms, G., and Schraff, C.: A description of the nonhydrostatic regional COSMO-model – Part VII: User's Guide, Tech. rep., Deutscher Wetterdienst, https://doi.org/10.5676/DWD_pub/nwv/cosmo-doc_6.00_VII, 2021. a
Schweitzer, H.: Versuch einer Erklärung des Föhns als Luftströmung mit überkritischer Geschwindigkeit, Arch. Meteorol. Geophys. Bioklim., 5, 350–371, https://doi.org/10.1007/BF02247776, 1952. a
Schüepp, W.: Die qualitative und quantitative Bedeutung der Föhnmauer, Meteorol. Rundsch., 5, 136–138, 1952. a
Seibert, P., Feldmann, H., Neininger, B., Bäumle, M., and Trickl, T.: South foehn and ozone in the Eastern Alps – case study and climatological aspects, Atmos. Environ., 34, 1379–1394, https://doi.org/10.1016/S1352-2310(99)00439-2, 2000. 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., Dürr, B., and Richner, H.: Foehn studies in Switzerland, chap. 11, in: From weather observations to atmospheric and climate sciences in Switzerland, edited by: Willemse, S. and Furger, M., vdf Hochschulverlag AG, Zurich, 215–248, https://doi.org/10.3218/3746-3, 2016. a, b, c
Steinacker, R., Spatzierer, M., Dorninger, M., and Häberli, C.: Selected results of the FORMAT field measurements, Österr. Beitr. Meteorol. Geophys., 29, 55–70, 2003. a
Steppeler, J., Doms, G., Schättler, U., Bitzer, H. W., 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
Strauss, S.: An ill wind: the Foehn in Leukerbad and beyond, J. Roy. Anthropol. Inst., 13, S165–S181, https://doi.org/10.1111/j.1467-9655.2007.00406.x, 2007. a
Stucki, P., Brönnimann, S., Martius, O., Welker, C., Rickli, R., Dierer, S., Bresch, D. N., Compo, G. P., and Sardeshmukh, P. D.: Dynamical downscaling and loss modeling for the reconstruction of historical weather extremes and their impacts: A severe foehn storm in 1925, B. Am. Meteorol. Soc., 96, 1233–1241, https://doi.org/10.1175/BAMS-D-14-00041.1, 2015. a
Umek, L., Gohm, A., Haid, M., Ward, H. C., and Rotach, M. W.: Large-eddy simulation of foehn–cold pool interactions in the Inn Valley during PIANO IOP 2, Q. J. Roy. Meteor. Soc., 147, 944–982, https://doi.org/10.1002/qj.3954, 2021. a, b
Umek, L., Gohm, A., Haid, M., Ward, H. C., and Rotach, M. W.: Influence of grid resolution of large-eddy simulations on foehn-cold pool interaction, Q. J. Roy. Meteor. Soc., 148, 1840–1863, https://doi.org/10.1002/qj.4281, 2022. a
Vergara-Temprado, J., Ban, N., Panosetti, D., Schlemmer, L., and Schär, C.: Climate models permit convection at much coarser resolutions than previously considered, J. Climate, 33, 1915–1933, https://doi.org/10.1175/JCLI-D-19-0286.1, 2020. a
Vosper, S. B., Ross, A. N., Renfrew, I. A., Sheridan, P., Elvidge, A. D., and Grubišić, V.: Current challenges in orographic flow dynamics: turbulent exchange due to low-level gravity-wave processes, Atmosphere, 9, 361, https://doi.org/10.3390/atmos9090361, 2018. 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
Wicker, L. J. and Skamarock, W. C.: Time-splitting methods for elastic models using forward time schemes, Mon. Weather Rev., 130, 2088–2097, https://doi.org/10.1175/1520-0493(2002)130<2088:TSMFEM>2.0.CO;2, 2002. a
Wild, H.: Über Föhn und Eiszeit. Mit Nachtrag: Der Schweizer-Föhn, Jent & Reinert, 1868. a
Xue, M.: High-order monotonic numerical diffusion and smoothing, Mon. Weather Rev., 128, 2853–2864, https://doi.org/10.1175/1520-0493(2000)128<2853:HOMNDA>2.0.CO;2, 2000. a
Zängl, G.: Deep and shallow south foehn in the region of Innsbruck: Typical features and semi-idealized numerical simulations, Meteorol. Atmos. Phys., 83, 237–261, https://doi.org/10.1007/s00703-002-0565-7, 2003. 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, b
Zängl, G. and Hornsteiner, M.: Can trapped gravity waves be relevant for severe foehn windstorms? A case study, Meteorol. Z., 16, 203–212, https://doi.org/10.1127/0941-2948/2007/0199, 2007. a, b
Zou, X., Bromwich, D. H., Montenegro, A., Wang, S.-H., and Bai, L.: Major surface melting over the Ross Ice Shelf part I: Foehn effect, Q. J. Roy. Meteor. Soc., 147, 2874–2894, https://doi.org/10.1002/qj.4104, 2021. 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
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.
Using an innovative approach, the descent of foehn is diagnosed from a Lagrangian perspective...
