Articles | Volume 5, issue 2
https://doi.org/10.5194/wcd-5-491-2024
© 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-5-491-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
05 Apr 2024
Research article |
| 05 Apr 2024
| 05 Apr 2024
Influence of radiosonde observations on the sharpness and altitude of the midlatitude tropopause in the ECMWF IFS
Konstantin Krüger
CORRESPONDING AUTHOR
Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
Andreas Schäfler
Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
Martin Weissmann
Institut für Meteorologie und Geophysik, Universität Wien, Vienna, Austria
George C. Craig
Meteorologisches Institut München, Ludwig-Maximilians-Universität, Munich, Germany
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Benedikt Urbanek, Silke Groß, Andreas Schäfler, and Martin Wirth
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Manuel Gutleben, Silke Gross, Martin Wirth, and Andreas Schäfler
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2016-333, https://doi.org/10.5194/amt-2016-333, 2016
Revised manuscript not accepted
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Shallow marine cumulus convection over the Atlantic ocean is studied with observations by airborne and spaceborne lidar instruments. Cloud top height as well as cloud length and cloud gap length distributions are calculated by use of a newly developed algorithm. The distribution of cloud top heights during wintertime measurements shows a two-layer structure. However, significant differences in cloud top height distributions compared to summertime measurements are found.
Thomas Trickl, Hannes Vogelmann, Andreas Fix, Andreas Schäfler, Martin Wirth, Bertrand Calpini, Gilbert Levrat, Gonzague Romanens, Arnoud Apituley, Keith M. Wilson, Robert Begbie, Jens Reichardt, Holger Vömel, and Michael Sprenger
Atmos. Chem. Phys., 16, 8791–8815, https://doi.org/10.5194/acp-16-8791-2016, https://doi.org/10.5194/acp-16-8791-2016, 2016
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A rather homogeneous deep stratospheric intrusion event was mapped by vertical sounding over central Europe and by model calculations along the transport path. The very low minimum H2O mixing ratios demonstrate almost negligible mixing with tropospheric air during the downward transport. The vertical distributions of O3 and aerosol were transferred from the source region to Europe without major change. A rather shallow outflow from the stratosphere was found.
S. Groß, V. Freudenthaler, K. Schepanski, C. Toledano, A. Schäfler, A. Ansmann, and B. Weinzierl
Atmos. Chem. Phys., 15, 11067–11080, https://doi.org/10.5194/acp-15-11067-2015, https://doi.org/10.5194/acp-15-11067-2015, 2015
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M. Rautenhaus, M. Kern, A. Schäfler, and R. Westermann
Geosci. Model Dev., 8, 2329–2353, https://doi.org/10.5194/gmd-8-2329-2015, https://doi.org/10.5194/gmd-8-2329-2015, 2015
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This article presents "Met.3D", a new open-source tool for the interactive 3D visualization of numerical ensemble weather predictions. Met.3D builds a bridge from proven 2D visualization methods commonly used in meteorology to 3D visualization and implements approaches to using the ensemble to allow the user to assess forecast uncertainty. The article is the first part of a two-paper study discussing how 3D and ensemble visualization can be used in a meaningful way suited to weather forecasting.
M. Rautenhaus, C. M. Grams, A. Schäfler, and R. Westermann
Geosci. Model Dev., 8, 2355–2377, https://doi.org/10.5194/gmd-8-2355-2015, https://doi.org/10.5194/gmd-8-2355-2015, 2015
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This article presents the application of interactive 3D visualization of ensemble
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S. Groß, M. Wirth, A. Schäfler, A. Fix, S. Kaufmann, and C. Voigt
Atmos. Meas. Tech., 7, 2745–2755, https://doi.org/10.5194/amt-7-2745-2014, https://doi.org/10.5194/amt-7-2745-2014, 2014
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Weather Clim. Dynam., 6, 431–446, https://doi.org/10.5194/wcd-6-431-2025, https://doi.org/10.5194/wcd-6-431-2025, 2025
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Jonna van Mourik, Hylke de Vries, and Michiel Baatsen
Weather Clim. Dynam., 6, 413–429, https://doi.org/10.5194/wcd-6-413-2025, https://doi.org/10.5194/wcd-6-413-2025, 2025
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Atmospheric blocking events are quasi-stationary high-pressure areas with large influences on our weather. In this study, we show the wide variety of zonal velocities possible for atmospheric blocking under the most used blocking indices. These include not only stationary blocks, but also eastward- and westward-moving blocks. These respective moving blocks are found to have different characteristics in size and location and have different impacts on our surface temperatures.
Alexander Lojko, Andrew C. Winters, Annika Oertel, Christiane Jablonowski, and Ashley E. Payne
Weather Clim. Dynam., 6, 387–411, https://doi.org/10.5194/wcd-6-387-2025, https://doi.org/10.5194/wcd-6-387-2025, 2025
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Convective storms can produce intense anticyclonically rotating vortices (~10 km) defined by negative potential vorticity (NPV), which can elongate to larger scales (~1000 km). Our composite analysis shows that elongated NPV frequently occurs along the western North Atlantic tropopause, where we observed it enhancing jet stream kinematics. Elongated NPV may impinge on aviation turbulence and weather forecasting despite its small-scale origin.
Verónica Martínez-Andradas, Alvaro de la Cámara, Pablo Zurita-Gotor, François Lott, and Federico Serva
Weather Clim. Dynam., 6, 329–343, https://doi.org/10.5194/wcd-6-329-2025, https://doi.org/10.5194/wcd-6-329-2025, 2025
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Global circulation model biases are present when simulating sudden stratospheric warmings (SSWs). These are important extreme phenomena that occur in the wintertime stratosphere, driven by the breaking of atmospheric waves. The present work shows that there is a large spread of the wave forcing during the development of SSWs in different models. In the mesosphere, gravity waves are found to force advection of the residual circulation, while planetary waves tend to decelerate the wind.
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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Hanin Binder and Heini Wernli
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This study presents a systematic analysis of frequency anomalies and characteristics of extratropical cyclones during extremely wet, dry, windy, and calm winter and summer seasons in the extratropics based on 1050 years of present-day climate simulations. We show that anomalies in cyclone frequency, intensity, and stationarity are crucial to the occurrence of many extreme seasons and that these anomaly patterns exhibit substantial regional and seasonal variability.
Amelie Mayer and Volkmar Wirth
Weather Clim. Dynam., 6, 131–150, https://doi.org/10.5194/wcd-6-131-2025, https://doi.org/10.5194/wcd-6-131-2025, 2025
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Although heatwaves are among the most dangerous weather-related hazards, their underlying mechanisms are not fully understood. Here, we investigate the formation of heatwaves in an air-parcel-based framework and distinguish the contributions from horizontal transport, vertical transport, and diabatic heating. We show that the results obtained depend profoundly on whether one compares the absolute contributions of the individual terms or, instead, their anomalies relative to climatology.
Svenja Christ, Marta Wenta, Christian M. Grams, and Annika Oertel
Weather Clim. Dynam., 6, 17–42, https://doi.org/10.5194/wcd-6-17-2025, https://doi.org/10.5194/wcd-6-17-2025, 2025
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The detailed representation of sea surface temperature (SST) in numerical models is important for the prediction of atmospheric blocking in the North Atlantic. Yet the underlying physical processes are not fully understood. Using SST sensitivity experiments for a case study, we identify a physical pathway through which SST in the Gulf Stream region is linked to the downstream upper-level flow evolution in the North Atlantic.
Camille Cadiou and Pascal Yiou
Weather Clim. Dynam., 6, 1–15, https://doi.org/10.5194/wcd-6-1-2025, https://doi.org/10.5194/wcd-6-1-2025, 2025
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Extreme cold winter temperatures in Europe have huge societal impacts. This study focuses on extreme cold events, such as the winter of 1963 in France, which are expected to become rarer due to climate change. We use a light and efficient rare-event algorithm to simulate a large number of extreme cold winters over France to analyse their characteristics. We find that despite fewer occurrences, their intensity remains steady. We analyse prevailing atmospheric circulation during these events.
Fiona Fix, Georg Mayr, Achim Zeileis, Isabell Stucke, and Reto Stauffer
Weather Clim. Dynam., 5, 1545–1560, https://doi.org/10.5194/wcd-5-1545-2024, https://doi.org/10.5194/wcd-5-1545-2024, 2024
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Atmospheric deserts (ADs) are air masses that are transported away from hot, dry regions. Our study introduces this new concept. ADs can suppress or boost thunderstorms and potentially contribute to the formation of heat waves, which makes them relevant for forecasting extreme events. Using a novel detection method, we follow an AD directly from North Africa to Europe for a case in June 2022, allowing us to analyse the air mass at any time and investigate how it is modified along the way.
Suzanne L. Gray, Ambrogio Volonté, Oscar Martínez-Alvarado, and Ben J. Harvey
Weather Clim. Dynam., 5, 1523–1544, https://doi.org/10.5194/wcd-5-1523-2024, https://doi.org/10.5194/wcd-5-1523-2024, 2024
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Sting jets occur in some of the most damaging cyclones impacting Europe. We present the first climatology of sting-jet cyclones over the major ocean basins. Cyclones with sting-jet precursors occur over the North Atlantic, North Pacific, and Southern Oceans, with implications for wind warnings. Precursor cyclones have distinct characteristics, even in reanalyses that are too coarse to fully resolve sting jets, evidencing the climatological consequences of strong diabatic cloud processes.
Claudio Sánchez, Suzanne Gray, Ambrogio Volonté, Florian Pantillon, Ségolène Berthou, and Silvio Davolio
Weather Clim. Dynam., 5, 1429–1455, https://doi.org/10.5194/wcd-5-1429-2024, https://doi.org/10.5194/wcd-5-1429-2024, 2024
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Medicane Ianos was a very intense cyclone that led to harmful impacts over Greece. We explore what processes are important for the forecasting of Medicane Ianos, with the use of the Met Office weather model. There was a preceding precipitation event before Ianos’s birth, whose energetics generated a bubble in the tropopause. This bubble created the necessary conditions for Ianos to emerge and strengthen, and the processes are enhanced in simulations with a warmer Mediterranean Sea.
Heini Wernli and Suzanne L. Gray
Weather Clim. Dynam., 5, 1299–1408, https://doi.org/10.5194/wcd-5-1299-2024, https://doi.org/10.5194/wcd-5-1299-2024, 2024
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The science of extratropical dynamics has reached a new level where the interplay of dry dynamics with effects of latent heating in clouds and other diabatic processes is considered central to the field. This review documents how research about the role of diabatic processes evolved over more than a century; it highlights that progress relied essentially on the integration of theory, field campaigns, novel diagnostics, and numerical modelling, and it outlines avenues for future research.
Philip Rupp, Jonas Spaeth, Hilla Afargan-Gerstman, Dominik Büeler, Michael Sprenger, and Thomas Birner
Weather Clim. Dynam., 5, 1287–1298, https://doi.org/10.5194/wcd-5-1287-2024, https://doi.org/10.5194/wcd-5-1287-2024, 2024
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We quantify the occurrence of strong synoptic storms as contributing about 20 % to the uncertainty of subseasonal geopotential height forecasts over northern Europe. We further show that North Atlantic storms are less frequent, weaker and shifted southward following sudden stratospheric warming events, leading to a reduction in northern European forecast uncertainty.
Henrik Auestad, Clemens Spensberger, Andrea Marcheggiani, Paulo Ceppi, Thomas Spengler, and Tim Woollings
Weather Clim. Dynam., 5, 1269–1286, https://doi.org/10.5194/wcd-5-1269-2024, https://doi.org/10.5194/wcd-5-1269-2024, 2024
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Latent heating due to condensation can influence atmospheric circulation by strengthening or weakening horizontal temperature contrasts. Strong temperature contrasts intensify storms and imply the existence of strong upper tropospheric winds called jets. It remains unclear whether latent heating preferentially reinforces or abates the existing jet. We show that this disagreement is attributable to how the jet is defined, confirming that latent heating reinforces the jet.
Hugo Banderier, Alexandre Tuel, Tim Woollings, and Olivia Martius
EGUsphere, https://doi.org/10.5194/egusphere-2024-3029, https://doi.org/10.5194/egusphere-2024-3029, 2024
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The jet stream is the main feature of the upper level flow, and drives the weather at the surface. It is stronger and better defined in winter, and has mostly been studied in that season. However, it is very important for (extreme) weather in summer. In this work, we improve and use two existing and complementary methods to study the jet stream(s) in the Euro-Atlantic sector, with a focus on summer. We find that our methods can verify each other and agree on interesting signals and trends.
Michele Filippucci, Simona Bordoni, and Paolo Davini
Weather Clim. Dynam., 5, 1207–1222, https://doi.org/10.5194/wcd-5-1207-2024, https://doi.org/10.5194/wcd-5-1207-2024, 2024
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Atmospheric blocking is a recurring phenomenon in midlatitudes, causing winter cold spells and summer heat waves. Current models underestimate it, hindering understanding of global warming's impact on extremes. In this paper, we investigate whether stochastic parameterizations can improve blocking representation. We find that blocking frequency representation slightly deteriorates, following a change in midlatitude winds. We conclude by suggesting a direction for future model development.
Florian Pantillon, Silvio Davolio, Elenio Avolio, Carlos Calvo-Sancho, Diego Saul Carrió, Stavros Dafis, Emanuele Silvio Gentile, Juan Jesus Gonzalez-Aleman, Suzanne Gray, Mario Marcello Miglietta, Platon Patlakas, Ioannis Pytharoulis, Didier Ricard, Antonio Ricchi, Claudio Sanchez, and Emmanouil Flaounas
Weather Clim. Dynam., 5, 1187–1205, https://doi.org/10.5194/wcd-5-1187-2024, https://doi.org/10.5194/wcd-5-1187-2024, 2024
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Cyclone Ianos of September 2020 was a high-impact but poorly predicted medicane (Mediterranean hurricane). A community effort of numerical modelling provides robust results to improve prediction. It is found that the representation of local thunderstorms controlled the interaction of Ianos with a jet stream at larger scales and its subsequent evolution. The results help us understand the peculiar dynamics of medicanes and provide guidance for the next generation of weather and climate models.
George Pacey, Stephan Pfahl, and Lisa Schielicke
EGUsphere, https://doi.org/10.5194/egusphere-2024-2978, https://doi.org/10.5194/egusphere-2024-2978, 2024
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Cold fronts are often associated with areas of intense precipitation (cells) in the warm-season, but the drivers and environments of cells at different locations relative to the front are not well-understood. We show that cells ahead of the surface front have the highest amount of environmental instability and moisture. Also, low-level lifting is maximised ahead of the surface front and upper-level lifting is particularly important for cell initiation behind the front.
Dor Sandler, Hadas Saaroni, Baruch Ziv, Talia Tamarin-Brodsky, and Nili Harnik
Weather Clim. Dynam., 5, 1103–1116, https://doi.org/10.5194/wcd-5-1103-2024, https://doi.org/10.5194/wcd-5-1103-2024, 2024
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The North Atlantic region serves as a source of moisture and energy for Mediterranean storms. Its impact over the Levant region remains an open question due to its smaller weather systems and their longer distance from the ocean. We find an optimal circulation pattern which allows North Atlantic influence to reach farther into the eastern Mediterranean, thus making storms stronger and rainier. This may be relevant for future Mediterranean climate, which is projected to become much drier.
Raphaël Rousseau-Rizzi, Shira Raveh-Rubin, Jennifer L. Catto, Alice Portal, Yonatan Givon, and Olivia Martius
Weather Clim. Dynam., 5, 1079–1101, https://doi.org/10.5194/wcd-5-1079-2024, https://doi.org/10.5194/wcd-5-1079-2024, 2024
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We identify situations when rain and wind, rain and wave, or heat and dust hazards co-occur within Mediterranean cyclones. These hazard combinations are associated with risk to infrastructure, risk of coastal flooding and risk of respiratory issues. The presence of Mediterranean cyclones is associated with increased probability of all three hazard combinations. We identify weather configurations and cyclone structures, particularly those associated with specific co-occurrence combinations.
Jacob Perez, Amanda C. Maycock, Stephen D. Griffiths, Steven C. Hardiman, and Christine M. McKenna
Weather Clim. Dynam., 5, 1061–1078, https://doi.org/10.5194/wcd-5-1061-2024, https://doi.org/10.5194/wcd-5-1061-2024, 2024
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This study assesses existing methods for identifying the position and tilt of the North Atlantic eddy-driven jet, proposing a new feature-based approach. The new method overcomes limitations of other methods, offering a more robust characterisation. Contrary to prior findings, the distribution of daily latitudes shows no distinct multi-modal structure, challenging the notion of preferred jet stream latitudes or regimes. This research enhances our understanding of North Atlantic dynamics.
Alice Portal, Shira Raveh-Rubin, Jennifer L. Catto, Yonatan Givon, and Olivia Martius
Weather Clim. Dynam., 5, 1043–1060, https://doi.org/10.5194/wcd-5-1043-2024, https://doi.org/10.5194/wcd-5-1043-2024, 2024
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Mediterranean cyclones are associated with extended rain, wind, and wave impacts. Although beneficial for regional water resources, their passage may induce extreme weather, which is especially impactful when multiple hazards combine together. Here we show how the passage of Mediterranean cyclones increases the likelihood of rain–wind and wave–wind compounding and how compound–cyclone statistics vary by region and season, depending on the presence of specific airflows around the cyclone.
Yvonne Anderson, Jacob Perez, and Amanda C. Maycock
EGUsphere, https://doi.org/10.5194/egusphere-2024-2506, https://doi.org/10.5194/egusphere-2024-2506, 2024
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The impact of Arctic sea ice loss on the North Atlantic jet stream is debated, with some linking changes to ice loss and others to natural variability. This study uses a new method to explore how future sea ice loss will affect the jet stream. In half of the models, the jet shifts equatorward, but its speed and tilt are unchanged. Some models also exhibit more jet splitting. The results suggest that future sea ice loss is unlikely to significantly weaken the jet stream or make it more variable.
Antonio Segalini, Jacopo Riboldi, Volkmar Wirth, and Gabriele Messori
Weather Clim. Dynam., 5, 997–1012, https://doi.org/10.5194/wcd-5-997-2024, https://doi.org/10.5194/wcd-5-997-2024, 2024
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Planetary Rossby waves are created by topography and evolve in time. In this work, an analytical solution of this classical problem is proposed under the approximation of linear wave dynamics. The theory is able to describe reasonably well the evolution of the perturbation and compares well with full nonlinear simulations. Several relevant cases with single and double zonal jets are assessed with the theoretical framework
Moritz Deinhard and Christian M. Grams
Weather Clim. Dynam., 5, 927–942, https://doi.org/10.5194/wcd-5-927-2024, https://doi.org/10.5194/wcd-5-927-2024, 2024
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Stochastic perturbations are an established technique to represent model uncertainties in numerical weather prediction. While such schemes are beneficial for the forecast skill, they can also change the mean state of the model. We analyse how different schemes modulate rapidly ascending airstreams and whether the changes to such weather systems are projected onto larger scales. We thereby provide a process-oriented perspective on how perturbations affect the model climate.
Henri Rossi Pinheiro, Kevin Ivan Hodges, and Manoel Alonso Gan
Weather Clim. Dynam., 5, 881–894, https://doi.org/10.5194/wcd-5-881-2024, https://doi.org/10.5194/wcd-5-881-2024, 2024
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Cut-off lows (COLs) are weather systems with varied structures and lifecycles, from upper atmospheric to deep vortices. Deep, strong COLs are common around Australia and the southwestern Pacific in autumn and spring, while shallow, weak COLs occur more in summer near the Equator. Jet streams play a crucial role in COL development, with different jets influencing its depth and strength. The study also emphasizes the need for better representation of diabatic processes in reanalysis data.
Aleksa Stanković, Gabriele Messori, Joaquim G. Pinto, and Rodrigo Caballero
Weather Clim. Dynam., 5, 821–837, https://doi.org/10.5194/wcd-5-821-2024, https://doi.org/10.5194/wcd-5-821-2024, 2024
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The article studies extreme winds near the surface over the North Atlantic Ocean. These winds are caused by storms that pass through this region. The strongest storms that have occurred in the winters from 1950–2020 are studied in detail and compared to weaker but still strong storms. The analysis shows that the storms associated with the strongest winds are preceded by another older storm that travelled through the same region and made the conditions suitable for development of extreme winds.
Edward Groot, Patrick Kuntze, Annette Miltenberger, and Holger Tost
Weather Clim. Dynam., 5, 779–803, https://doi.org/10.5194/wcd-5-779-2024, https://doi.org/10.5194/wcd-5-779-2024, 2024
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Deep convective clouds (thunderstorms), which may cause severe weather, tend to coherently organise into structured cloud systems. Accurate representation of these systems in models is difficult due to their complex dynamics and, in numerical simulations, the dependence of their dynamics on resolution. Here, the effect of convective organisation and geometry on their outflow winds (altitudes of 7–14 km) is investigated. Representation of their dynamics and outflows improves at higher resolution.
Lucas Pfister, Lena Wilhelm, Yuri Brugnara, Noemi Imfeld, and Stefan Brönnimann
EGUsphere, https://doi.org/10.5194/egusphere-2024-1346, https://doi.org/10.5194/egusphere-2024-1346, 2024
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Our work compares different machine learning approaches for creating long-term classifications of daily atmospheric circulation patterns using input data from surface meteorological observations. Our comparison reveals a so-called feedforward neural network to perform best in this task. Using this model, we present a daily reconstruction of the CAP9 weather type classification for Central Europe back to 1728.
Stephen Outten and Richard Davy
Weather Clim. Dynam., 5, 753–762, https://doi.org/10.5194/wcd-5-753-2024, https://doi.org/10.5194/wcd-5-753-2024, 2024
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The North Atlantic Oscillation is linked to wintertime weather events over Europe. One feature often overlooked is how much the climate variability explained by the NAO has changed over time. We show that there has been a considerable increase in the percentage variance explained by the NAO over the 20th century and that this is not reproduced by 50 CMIP6 climate models, which are generally biased too high. This has implications for projections and prediction of weather events in the region.
Seraphine Hauser, Franziska Teubler, Michael Riemer, Peter Knippertz, and Christian M. Grams
Weather Clim. Dynam., 5, 633–658, https://doi.org/10.5194/wcd-5-633-2024, https://doi.org/10.5194/wcd-5-633-2024, 2024
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Blocking over Greenland has substantial impacts on the weather and climate in mid- and high latitudes. This study applies a quasi-Lagrangian thinking on the dynamics of Greenland blocking and reveals two pathways of anticyclonic anomalies linked to the block. Moist processes were found to play a dominant role in the formation and maintenance of blocking. This emphasizes the necessity of the correct representation of moist processes in weather and climate models to realistically depict blocking.
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.
Rachel H. White
EGUsphere, https://doi.org/10.5194/egusphere-2024-966, https://doi.org/10.5194/egusphere-2024-966, 2024
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Mid-latitude atmospheric jet streams sometimes create 'waveguides', thought to increase the chance of quasi-stationary waves — atmospheric circulation patterns that lead to extreme weather events. I describe a new algorithm for identifying atmospheric waveguides, and show maps of waveguide frequency and strength. Waveguide strength is associated with an increased probability of quasi-stationary waves, although not in all regions; the connection is particularly strong over Europe during summer.
Lucas Fery and Davide Faranda
Weather Clim. Dynam., 5, 439–461, https://doi.org/10.5194/wcd-5-439-2024, https://doi.org/10.5194/wcd-5-439-2024, 2024
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In this study, we analyse warm-season derechos – a type of severe convective windstorm – in France between 2000 and 2022, identifying 38 events. We compare their frequency and features with other countries. We also examine changes in the associated large-scale patterns. We find that convective instability has increased in southern Europe. However, the attribution of these changes to natural climate variability, human-induced climate change or a combination of both remains unclear.
Lukas Jansing, Lukas Papritz, and Michael Sprenger
Weather Clim. Dynam., 5, 463–489, https://doi.org/10.5194/wcd-5-463-2024, https://doi.org/10.5194/wcd-5-463-2024, 2024
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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.
Alexander Scherrmann, Heini Wernli, and Emmanouil Flaounas
Weather Clim. Dynam., 5, 419–438, https://doi.org/10.5194/wcd-5-419-2024, https://doi.org/10.5194/wcd-5-419-2024, 2024
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We show that the formation of Mediterranean cyclones follows the presence of cyclones over the North Atlantic. The distinct regions of cyclone activity in the Mediterranean in the different seasons can be linked to the atmospheric state, in particular the position of the polar jet over the North Atlantic. With this we now better understand the processes that lead to the formation of Mediterranean cyclones. We used a novel simulation framework in which we directly show and probe this connection.
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.
Alexandre Tuel and Olivia Martius
Weather Clim. Dynam., 5, 263–292, https://doi.org/10.5194/wcd-5-263-2024, https://doi.org/10.5194/wcd-5-263-2024, 2024
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Warm and cold spells often have damaging consequences for agriculture, power demand, human health and infrastructure, especially when they occur over large areas and persist for a week or more. Here, we split the Northern Hemisphere extratropics into coherent regions where 3-week warm and cold spells in winter and summer are associated with the same large-scale circulation patterns. To understand their physical drivers, we analyse the associated circulation and temperature budget anomalies.
Marta Wenta, Christian M. Grams, Lukas Papritz, and Marc Federer
Weather Clim. Dynam., 5, 181–209, https://doi.org/10.5194/wcd-5-181-2024, https://doi.org/10.5194/wcd-5-181-2024, 2024
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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.
Talia Tamarin-Brodsky and Nili Harnik
Weather Clim. Dynam., 5, 87–108, https://doi.org/10.5194/wcd-5-87-2024, https://doi.org/10.5194/wcd-5-87-2024, 2024
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Synoptic waves in the atmosphere tend to follow a typical Rossby wave lifecycle, involving a linear growth stage followed by nonlinear and irreversible Rossby wave breaking (RWB). Here we take a new approach to study RWB events and their fundamental relation to weather systems by combining a storm-tracking technique and an RWB detection algorithm. The synoptic-scale dynamics leading to RWB is then examined by analyzing time evolution composites of cyclones and anticyclones during RWB events.
Sebastian Schemm and Matthias Röthlisberger
Weather Clim. Dynam., 5, 43–63, https://doi.org/10.5194/wcd-5-43-2024, https://doi.org/10.5194/wcd-5-43-2024, 2024
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Climate change has started to weaken atmospheric circulation during summer in the Northern Hemisphere. However, there is low agreement on the processes underlying changes in, for example, the stationarity of weather patterns or the seasonality of the jet response to warming. This study examines changes during summertime in an idealised setting and confirms some important changes in hemisphere-wide wave and jet characteristics under warming.
Patrick Martineau, Swadhin K. Behera, Masami Nonaka, Hisashi Nakamura, and Yu Kosaka
Weather Clim. Dynam., 5, 1–15, https://doi.org/10.5194/wcd-5-1-2024, https://doi.org/10.5194/wcd-5-1-2024, 2024
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The representation of subweekly near-surface temperature variability trends over the Southern Hemisphere landmasses is compared across multiple atmospheric reanalyses. It is found that there is generally a good agreement concerning the positive trends affecting South Africa and Australia in the spring, and South America in the summer. A more efficient generation of subweekly temperature variance by horizontal temperature fluxes contributes to the observed rise.
Lea Eisenstein, Benedikt Schulz, Joaquim G. Pinto, and Peter Knippertz
Weather Clim. Dynam., 4, 981–999, https://doi.org/10.5194/wcd-4-981-2023, https://doi.org/10.5194/wcd-4-981-2023, 2023
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Mesoscale high-wind features within extratropical cyclones can cause immense damage. In Part 1 of this work, we introduced RAMEFI (RAndom-forest-based MEsoscale wind Feature Identification), an objective, flexible identification tool for these wind features based on a probabilistic random forest. Here, we use RAMEFI to compile a climatology of the features over 19 extended winter seasons over western and central Europe, focusing on relative occurrence, affected areas and further characteristics.
Tiina Nygård, Lukas Papritz, Tuomas Naakka, and Timo Vihma
Weather Clim. Dynam., 4, 943–961, https://doi.org/10.5194/wcd-4-943-2023, https://doi.org/10.5194/wcd-4-943-2023, 2023
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Despite the general warming trend, wintertime cold-air outbreaks in Europe have remained nearly as extreme and as common as decades ago. In this study, we identify six principal cold anomaly types over Europe in 1979–2020. We show the origins of various physical processes and their contributions to the formation of cold wintertime air masses.
Andrea Marcheggiani and Thomas Spengler
Weather Clim. Dynam., 4, 927–942, https://doi.org/10.5194/wcd-4-927-2023, https://doi.org/10.5194/wcd-4-927-2023, 2023
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There is a gap between the theoretical understanding and model representation of moist diabatic effects on the evolution of storm tracks. We seek to bridge this gap by exploring the relationship between diabatic and adiabatic contributions to changes in baroclinicity. We find reversed behaviours in the lower and upper troposphere in the maintenance of baroclinicity. In particular, our study reveals a link between higher moisture availability and upper-tropospheric restoration of baroclinicity.
Alice Portal, Fabio D'Andrea, Paolo Davini, Mostafa E. Hamouda, and Claudia Pasquero
Weather Clim. Dynam., 4, 809–822, https://doi.org/10.5194/wcd-4-809-2023, https://doi.org/10.5194/wcd-4-809-2023, 2023
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The differences between climate models can be exploited to infer how specific aspects of the climate influence the Earth system. This work analyses the effects of a negative temperature anomaly over the Tibetan Plateau on the winter atmospheric circulation. We show that models with a colder-than-average Tibetan Plateau present a reinforcement of the eastern Asian winter monsoon and discuss the atmospheric response to the enhanced transport of cold air from the continent toward the Pacific Ocean.
Charlie C. Suitters, Oscar Martínez-Alvarado, Kevin I. Hodges, Reinhard K. H. Schiemann, and Duncan Ackerley
Weather Clim. Dynam., 4, 683–700, https://doi.org/10.5194/wcd-4-683-2023, https://doi.org/10.5194/wcd-4-683-2023, 2023
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Atmospheric blocking describes large and persistent high surface pressure. In this study, the relationship between block persistence and smaller-scale systems is examined. Persistent blocks result from more interactions with small systems, but a block's persistence does not depend as strongly on the strength of these smaller features. This work is important because it provides more knowledge as to how blocks can be allowed to persist, which is something we still do not fully understand.
Emmanouil Flaounas, Leonardo Aragão, Lisa Bernini, Stavros Dafis, Benjamin Doiteau, Helena Flocas, Suzanne L. Gray, Alexia Karwat, John Kouroutzoglou, Piero Lionello, Mario Marcello Miglietta, Florian Pantillon, Claudia Pasquero, Platon Patlakas, María Ángeles Picornell, Federico Porcù, Matthew D. K. Priestley, Marco Reale, Malcolm J. Roberts, Hadas Saaroni, Dor Sandler, Enrico Scoccimarro, Michael Sprenger, and Baruch Ziv
Weather Clim. Dynam., 4, 639–661, https://doi.org/10.5194/wcd-4-639-2023, https://doi.org/10.5194/wcd-4-639-2023, 2023
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Cyclone detection and tracking methods (CDTMs) have different approaches in defining and tracking cyclone centers. This leads to disagreements on extratropical cyclone climatologies. We present a new approach that combines tracks from individual CDTMs to produce new composite tracks. These new tracks are shown to correspond to physically meaningful systems with distinctive life stages.
Cited articles
Birner, T.: Fine-scale structure of the extratropical tropopause region, J. Geophys. Res., 111, D04104, https://doi.org/10.1029/2005JD006301, 2006.
Birner, T., Dörnbrack, A., and Schumann, U.: How sharp is the tropopause at midlatitudes?, Geophys. Res. Lett., 29, 45-1–45-4, https://doi.org/10.1029/2002GL015142, 2002.
Birner, T., Sankey, D., and Shepherd, T. G.: The tropopause inversion layer in models and analyses, Geophys. Res. Lett., 33, L14804, https://doi.org/10.1029/2006GL026549, 2006.
Bland, J., Gray, S., Methven, J., and Forbes, R.: Characterizing extratropical near-tropopause analysis humidity biases and their radiative effects on temperature forecasts, Q. J. Roy. Meteor. Soc., 140, 3878–3898, https://doi.org/10.1002/qj.4150, 2021.
Boljka, L. and Birner, T.: Potential impact of tropopause sharpness on the structure and strength of the general circulation, npj Clim. Atmos. Sci., 5, 98, https://doi.org/10.1038/s41612-022-00319-6, 2022.
Bonavita, M.: On some aspects of the impact of GPSRO observations in global numerical weather prediction, Q. J. Roy. Meteor. Soc., 140, 2546–2562, https://doi.org/10.1002/qj.2320, 2014.
Borne, M., Knippertz, P., Weissmann, M., Martin, A., Rennie, M., and Cress, A.: Impact of Aeolus wind lidar observations on the representation of the West African monsoon circulation in the ECMWF and DWD forecasting systems, Q. J. Roy. Meteor. Soc., 149, 933–98, https://doi.org/10.1002/qj.4442, 2023.
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.
Cucurull, L. and Anthes, R. A.: Impact of infrared, microwave and radio occultation satellite observations in operational numerical weather prediction, Mon. Weather Rev., 142, 4164–4186, https://doi.org/10.1175/MWR-D-14-00101.1, 2014.
ECMWF: IFS Documentation – Cy43r1: Part III: Dynamics and Numerical Procedures, IFS Documentation, ECMWF, https://doi.org/10.21957/m1u2yxwrl, 2016.
ECMWF: Meteorological Archival and Retrieval System (MARS), ECMWF, https://www.ecmwf.int/en/forecasts/access-forecasts/access-archive-datasets, last access: 1 June 2023.
Gettelman, A., Hoor, P., Pan, L. L., Randel, W. J., Hegglin, M. I., and Birner, T.: The extratropical upper troposphere and lower stratosphere, Rev. Geophys., 49, RG3003, https://doi.org/10.1029/2011RG000355, 2011.
Gray, S., Dunning, C., Methven, J., Masato, G., and Chagnon, J.: Systematic model forecast error in Rossby wave structure, Geophys. Res. Lett., 41, 2979–2987, https://doi.org/10.1002/2014GL059282, 2014.
Grise, K. M., Thompson, D. W. J., and Birner, T.: A global survey of static stability in the stratosphere and upper troposphere, J. Climate, 23, 2275–2292, https://doi.org/10.1175/2009JCLI3369.1, 2010.
Haualand, K. F. and Spengler, T.: Relative importance of tropopause structure and diabatic heating for baroclinic instability, Weather Clim. Dynam., 2, 695–712, https://doi.org/10.5194/wcd-2-695-2021, 2021.
Harvey, B., Methven, J., and Ambaum, M. H. P.: An Adiabatic Mechanism for the Reduction of Jet Meander Amplitude by Potential Vorticity Filamentation, J. Atmos. Sci., 75, 4091–4106, https://doi.org/10.1175/JAS-D-18-0136.1, 2018.
Hodyss, D. and Nichols, N.: The error of representation: Basic understanding, Tellus A, 67, 1–17, https://doi.org/10.3402/tellusa.v67.24822, 2015.
Hoerling, M. P., Schaack, T. K., and Lenzen, A. J.: Global Objective Tropopause Analysis, Mon. Weather Rev., 119, 1816–1831, https://doi.org/10.1175/1520-0493(1991)119<1816:GOTA>2.0.CO;2, 1991.
Hoffmann, L. and Spang, R.: An assessment of tropopause characteristics of the ERA5 and ERA-Interim meteorological reanalyses, Atmos. Chem. Phys., 22, 4019–4046, https://doi.org/10.5194/acp-22-4019-2022, 2022.
Houchi, K., Stoffelen, A., Marseille, G. J., and De Kloe, J.: Comparison of wind and wind shear climatologies derived from high-resolution radiosondes and the ECMWF model, J. Geophys. Res.-Atmos., 115, D22123, https://doi.org/10.1029/2009JD013196, 2010.
Ingleby, B.: An assessment of different radiosonde types 2015/2016, ECMWF Technical Memorandum 69, https://doi.org/10.21957/0nje0wpsa, 2017.
Ingleby, B., Pauley, P., Kats, A., Ator, J., Keyser, D., Doerenbecher, A., Fucile, E., Hasegawa, J., Toyoda, E., Kleinert, T., Qu, W., St. James, J., Tennant, W., and Weedon, R.: Progress toward high-resolution, real-time radiosonde reports, B. Am. Meteorol. Soc., 97, 2149–2161, https://doi.org/10.1175/BAMS-D-15-00169.1, 2016.
Janjic, T., Bormann, N., Bocquet, M., Carton, J. A., Cohn, S. E., Dance, S. L., Losa, S. N., Nichols, N. K., Potthast, R., Waller, J. A., and Weston, P.: On the representation error in data assimilation, Q. J. Roy. Meteor. Soc., 144, 1257–1278, https://doi.org/10.1002/qj.3130, 2018.
Kaluza, T., Kunkel, D., and Hoor, P.: On the occurrence of strong vertical wind shear in the tropopause region: a 10-year ERA5 northern hemispheric study, Weather Clim. Dynam., 2, 631–651, https://doi.org/10.5194/wcd-2-631-2021, 2021.
König, N., Braesicke, P., and von Clarmann, T.: Tropopause altitude determination from temperature profile measurements of reduced vertical resolution, Atmos. Meas. Tech., 12, 4113–4129, https://doi.org/10.5194/amt-12-4113-2019, 2019.
Krüger, K., Schäfler, A., Wirth, M., Weissmann, M., and Craig, G. C.: Vertical structure of the lower-stratospheric moist bias in the ERA5 reanalysis and its connection to mixing processes, Atmos. Chem. Phys., 22, 15559–15577, https://doi.org/10.5194/acp-22-15559-2022, 2022.
Lavers, D. A., Torn, R. D., Davis, C., Richardson, D. S., Ralph, F. M., and Pappenberger, F.: Forecast evaluation of the North Pacific jet stream using AR Recon Dropwindsondes, Q. J. Roy. Meteor. Soc., 149, 3044–3063, https://doi.org/10.1002/qj.4545, 2023.
Martin, A., Weissmann, M., and Cress, A.: Investigation of links between dynamical scenarios and particularly high impact of Aeolus on numerical weather prediction (NWP) forecasts, Weather Clim. Dynam., 4, 249–264, https://doi.org/10.5194/wcd-4-249-2023, 2023.
Martius, O., Schwierz, C., and Davies, H. C.: Tropopause-Level Waveguides, J. Atmos. Sci., 67, 866–879, https://doi.org/10.1175/2009JAS2995.1, 2010.
Pan, L. L., Randel, W. J., Gary, B. L., Mahoney, M. J., and Hintsa, E. J.: Definitions and sharpness of the extratropical tropopause: A trace gas perspective, J. Geophys. Res.-Atmos., 109, D23103, https://doi.org/10.1029/2004JD004982, 2004.
Pauley, P., and Ingleby, B.: Assimilation of in-situ observations, in: Data Assimilation for Atmospheric, Oceanic and Hydrologic Applications (Vol. IV), edited by: Park, S. K. and Xu, L., Springer, ISBN 978-3-030-77722-7, https://link.springer.com/book/10.1007/978-3-030-77722-7 (last access: 1 June 2023), 2022.
Pilch Kedzierski, R., Matthes, K., and Bumke, K.: Synoptic-scale behavior of the extratropical tropopause inversion layer, Geophys. Res. Lett., 42, 10018–10026, https://doi.org/10.1002/2015GL066409, 2015.
Pilch Kedzierski, R., Neef, L., and Matthes, K.: Tropopause sharpening by data assimilation, Geophys. Res. Lett., 43, 8298–8305, https://doi.org/10.1002/2016GL069936, 2016.
Polichtchouk, I., Bechtold, P., Bonavita, M., Forbes, R., Healy, S., Hogan, R., Laloyaux, P., Rennie, M., Stockdale, T., Wedi, N., Diamantakis, M., Flemming, J., English, S., Isaksen, L., Vána, F., Gisinger, S., and Byrne, N.: Stratospheric Modelling and Assimilation, ECMWF Technical Memorandum 877, https://doi.org/10.21957/25hegfoq, 2021.
Rabier, F., Järvinen, H., Klinker, E., Mahfouf, J.-F., and Simmons, A.: The ECMWF operational implementation of fourdimensional variational assimilation. I: Experimental results with simplified physics, Q. J. Roy. Meteor. Soc., 126, 1148–1170, https://doi.org/10.1002/qj.49712656415, 2000.
Radnóti, G., Bauer, P., McNally, A., Cardinali, C., Healy, S., and de Rosnay, P.: ECMWF study on the impact of future developments of the space-based observing system on numerical weather prediction, ECMWF Technical Memorandum 638, https://doi.org/10.21957/skfhvask, 2010.
Saffin, L., Gray, S. L., Methven, J., and Williams, K. D.: Processes Maintaining Tropopause Sharpness in Numerical Models, J. Geophys. Res.-Atmos., 122, 9611–9627, https://doi.org/10.1002/2017JD026879, 2017.
Schäfler, A., Craig, G., Wernli, H., Arbogast, P., Doyle, J. D., McTaggart–Cowan, R., Methven, J., Rivière, G., Ament, F., Boettcher, M., Bramberger, M., Cazenave, Q., Cotton, R., Crewell, S., Delanoë, J., Dörnbrack, A., Ehrlich, A., Ewald, F., Fix, A., Grams, C. M., Gray, S. L., Grob, H., Groß, S., Hagen, M., Harvey, B., Hirsch, L., Jacob, M., Kölling, T., Konow, H., Lemmerz, C., Lux, O., Magnusson, L., Mayer, B., Mech, M., Moore, R., Pelon, J., Quinting, J., Rahm, S., Rapp, M., Rautenhaus, M., Reitebuch, O., Reynolds, C. A., Sodemann, H., Spengler, T., Vaughan, G., Wendisch, M., Wirth, M., Witschas, B., Wolf, K., and Zinner, T.: The North Atlantic Waveguide and Downstream Impact Experiment, B. Am. Meteorol. Soc., 99, 1607–1637, https://doi.org/10.1175/BAMS-D-17-0003.1, 2018.
Schäfler, A., Harvey, B., Methven, J., Doyle, J. D., Rahm, S., Reitebuch, O., Weiler, F., and Witschas B.: Observation of jet stream winds during NAWDEX and characterization of systematic meteorological analysis error, Mon. Weather Rev., 148, 2889–2907, https://doi.org/10.1175/MWR-D-19-0229.1, 2020.
Schindler, M., Weissmann, M., Schäfler, A., and Radnóti, G.: The impact of dropsonde and extra radiosonde observations during NAWDEX in autumn 2016, Mon. Weather Rev., 148, 809–824, https://doi.org/10.1175/MWR-D-19-0126.1, 2020.
Schmidt, T., Wickert, J., and Haser, A.: Variability of the upper troposphere and lower stratosphere observed with GPS radio occultation bending angles and temperatures, Adv. Space Res., 46, 150–161, https://doi.org/10.1016/j.asr.2010.01.021, 2010.
Schwierz, C., Dirren, S., and Davies, H. C.: Forced Waves on a Zonally Aligned Jet Stream, J. Atmos. Sci., 61, 73–87, https://doi.org/10.1175/1520-0469(2004)061<0073:FWOAZA>2.0.CO;2, 2004.
Shepherd, T. G., Polichtchouk, I., Hogan, R. J., and Simmons, A. J.: Report on Stratosphere Task Force, ECMWF Technical Memorandum 824, https://doi.org/10.21957/0vkp0t1xx, 2018.
Tinney, E. N., Homeyer, C. R., Elizalde, L., Hurst, D. F., Thompson, A. M., Stauffer, R. M., Vömel, H., and Selkirk, H. B.: A modern approach to stability-based definition of the tropopause, Mon. Weather Rev., 150, 3151–3174, https://doi.org/10.1175/MWR-D-22-0174.1, 2022.
Vaisala: Comparison of Vaisala Radiosondes RS41 and RS92, Vaisala, https://www.vaisala.com/sites/default/files/documents/RS-Comparison-White-Paper-B211317EN.pdf (last access: 1 December 2023), 2017.
Weissmann, M. and Cardinali, C.: Impact of airborne Doppler lidar observations on ECMWF forecasts, Q. J. Roy. Meteor. Soc., 133, 107–116, https://doi.org/10.1002/qj.16, 2007.
Weissmann, M., Busen, R., Dörnbrack, A., Rahm, S., and Reitebuch, O.: Targeted observations with an air-borne wind lidar, J. Atmos. Ocean. Tech., 22, 1706–1719, https://doi.org/10.1175/JTECH1801.1, 2005.
Weissmann, M., Langland, R. H., Cardinali, C., Pauley, P. M., and Rahm, S.: Influence of airborne Doppler wind lidar profiles near Typhoon Sinlaku on ECMWF and NOGAPS forecasts, Q. J. Roy. Meteor. Soc., 138, 118–130, https://doi.org/10.1002/qj.896, 2012.
World Meteorological Organization (WMO): Meteorology – A three-dimensional science, WMO Bull., 6, 134–138, 1957.
Short summary
Initial conditions of current numerical weather prediction models insufficiently represent the sharp vertical gradients across the midlatitude tropopause. Observation-space data assimilation output is used to study the influence of assimilated radiosondes on the tropopause. The radiosondes reduce systematic biases of the model background and sharpen temperature and wind gradients in the analysis. Tropopause sharpness is still underestimated in the analysis, which may impact weather forecasts.
Initial conditions of current numerical weather prediction models insufficiently represent the...
