Articles | Volume 3, issue 3
https://doi.org/10.5194/wcd-3-1037-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/wcd-3-1037-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
07 Sep 2022
Research article |
| 07 Sep 2022
| 07 Sep 2022
Meridional-energy-transport extremes and the general circulation of Northern Hemisphere mid-latitudes: dominant weather regimes and preferred zonal wavenumbers
Istittuto di Scienze dell'Atmosfera e del Clima, Consiglio Nazionale delle Ricerche (CNR-ISAC), Bologna, Italy
Federico Fabiano
Istittuto di Scienze dell'Atmosfera e del Clima, Consiglio Nazionale delle Ricerche (CNR-ISAC), Bologna, Italy
Vera Melinda Galfi
Department of Earth Sciences, Uppsala University, Uppsala, Sweden
Rune Grand Graversen
Department of Physics and Technology, UiT – The Arctic University of Norway, Tromsø, Norway
Norwegian Meteorological Institute, Tromsø, Norway
Valerio Lucarini
Department of Mathematics and Statistics, University of Reading, Reading, UK
Centre for the Mathematics of Planet Earth, University of Reading, Reading, UK
Gabriele Messori
Department of Earth Sciences, Uppsala University, Uppsala, Sweden
Centre of Natural Hazards and Disaster Science (CNDS), Uppsala University, Uppsala, Sweden
Department of Meteorology, Stockholm University, Stockholm, Sweden
Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
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Stefano Della Fera, Federico Fabiano, Piera Raspollini, Marco Ridolfi, Ugo Cortesi, Flavio Barbara, and Jost von Hardenberg
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Axel Kleidon, Gabriele Messori, Somnath Baidya Roy, Ira Didenkulova, and Ning Zeng
Earth Syst. Dynam., 14, 241–242, https://doi.org/10.5194/esd-14-241-2023, https://doi.org/10.5194/esd-14-241-2023, 2023
Patrick Johannes Stoll, Rune Grand Graversen, and Gabriele Messori
Weather Clim. Dynam., 4, 1–17, https://doi.org/10.5194/wcd-4-1-2023, https://doi.org/10.5194/wcd-4-1-2023, 2023
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Davide Faranda, Stella Bourdin, Mireia Ginesta, Meriem Krouma, Robin Noyelle, Flavio Pons, Pascal Yiou, and Gabriele Messori
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Gabriele Messori, Marlene Kretschmer, Simon H. Lee, and Vivien Wendt
Weather Clim. Dynam., 3, 1215–1236, https://doi.org/10.5194/wcd-3-1215-2022, https://doi.org/10.5194/wcd-3-1215-2022, 2022
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Alena Dekhtyareva, Mark Hermanson, Anna Nikulina, Ove Hermansen, Tove Svendby, Kim Holmén, and Rune Grand Graversen
Atmos. Chem. Phys., 22, 11631–11656, https://doi.org/10.5194/acp-22-11631-2022, https://doi.org/10.5194/acp-22-11631-2022, 2022
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Núria Pérez-Zanón, Louis-Philippe Caron, Silvia Terzago, Bert Van Schaeybroeck, Llorenç Lledó, Nicolau Manubens, Emmanuel Roulin, M. Carmen Alvarez-Castro, Lauriane Batté, Pierre-Antoine Bretonnière, Susana Corti, Carlos Delgado-Torres, Marta Domínguez, Federico Fabiano, Ignazio Giuntoli, Jost von Hardenberg, Eroteida Sánchez-García, Verónica Torralba, and Deborah Verfaillie
Geosci. Model Dev., 15, 6115–6142, https://doi.org/10.5194/gmd-15-6115-2022, https://doi.org/10.5194/gmd-15-6115-2022, 2022
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Valerio Lucarini, Larissa Serdukova, and Georgios Margazoglou
Nonlin. Processes Geophys., 29, 183–205, https://doi.org/10.5194/npg-29-183-2022, https://doi.org/10.5194/npg-29-183-2022, 2022
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Paolo Davini, Federico Fabiano, and Irina Sandu
Weather Clim. Dynam., 3, 535–553, https://doi.org/10.5194/wcd-3-535-2022, https://doi.org/10.5194/wcd-3-535-2022, 2022
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In climate models, improvements obtained in the winter mid-latitude circulation following horizontal resolution increase are mainly caused by the more detailed representation of the mean orography. A high-resolution climate model with low-resolution orography might underperform compared to a low-resolution model with low-resolution orography. The absence of proper model tuning at high resolution is considered the potential reason behind such lack of improvements.
Joshua Dorrington, Kristian Strommen, and Federico Fabiano
Weather Clim. Dynam., 3, 505–533, https://doi.org/10.5194/wcd-3-505-2022, https://doi.org/10.5194/wcd-3-505-2022, 2022
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We investigate how well current state-of-the-art climate models reproduce the wintertime weather of the North Atlantic and western Europe by studying how well different "regimes" of weather are captured. Historically, models have struggled to capture these regimes, making it hard to predict future changes in wintertime extreme weather. We show models can capture regimes if the right method is used, but they show biases, partially as a result of biases in jet speed and eddy strength.
Assaf Hochman, Francesco Marra, Gabriele Messori, Joaquim G. Pinto, Shira Raveh-Rubin, Yizhak Yosef, and Georgios Zittis
Earth Syst. Dynam., 13, 749–777, https://doi.org/10.5194/esd-13-749-2022, https://doi.org/10.5194/esd-13-749-2022, 2022
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Gaining a complete understanding of extreme weather, from its physical drivers to its impacts on society, is important in supporting future risk reduction and adaptation measures. Here, we provide a review of the available scientific literature, knowledge gaps and key open questions in the study of extreme weather events over the vulnerable eastern Mediterranean region.
Paolo Ghinassi, Federico Fabiano, and Susanna Corti
Weather Clim. Dynam., 3, 209–230, https://doi.org/10.5194/wcd-3-209-2022, https://doi.org/10.5194/wcd-3-209-2022, 2022
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In this work we examine the ability of global climate models in representing the atmospheric circulation in the upper troposphere, focusing on the eventual benefits of an increased horizontal resolution. Our results confirm that a higher horizontal resolution has a positive impact, especially in those models in which the resolution is increased in both the atmosphere and the ocean, whereas when the resolution is increased only in the atmosphere no substantial improvements are found.
Yumeng Chen, Alberto Carrassi, and Valerio Lucarini
Nonlin. Processes Geophys., 28, 633–649, https://doi.org/10.5194/npg-28-633-2021, https://doi.org/10.5194/npg-28-633-2021, 2021
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Chaotic dynamical systems are sensitive to the initial conditions, which are crucial for climate forecast. These properties are often used to inform the design of data assimilation (DA), a method used to estimate the exact initial conditions. However, obtaining the instability properties is burdensome for complex problems, both numerically and analytically. Here, we suggest a different viewpoint. We show that the skill of DA can be used to infer the instability properties of a dynamical system.
Francesco S. R. Pausata, Gabriele Messori, Jayoung Yun, Chetankumar A. Jalihal, Massimo A. Bollasina, and Thomas M. Marchitto
Clim. Past, 17, 1243–1271, https://doi.org/10.5194/cp-17-1243-2021, https://doi.org/10.5194/cp-17-1243-2021, 2021
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Far-afield changes in vegetation such as those that occurred over the Sahara during the middle Holocene and the consequent changes in dust emissions can affect the intensity of the South Asian Monsoon (SAM) rainfall and the lengthening of the monsoon season. This remote influence is mediated by anomalies in Indian Ocean sea surface temperatures and may have shaped the evolution of the SAM during the termination of the African Humid Period.
Federico Fabiano, Virna L. Meccia, Paolo Davini, Paolo Ghinassi, and Susanna Corti
Weather Clim. Dynam., 2, 163–180, https://doi.org/10.5194/wcd-2-163-2021, https://doi.org/10.5194/wcd-2-163-2021, 2021
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Global warming not only affects the mean state of the climate (i.e. a warmer world) but also its variability. Here we analyze a set of future climate scenarios and show how some configurations of the wintertime atmospheric flow will become more frequent and persistent under continued greenhouse forcing. For example, over Europe, models predict an increase in the NAO+ regime which drives intense precipitation in northern Europe and the British Isles and dry conditions over the Mediterranean.
Gabriele Messori and Davide Faranda
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Gabriele Messori, Nili Harnik, Erica Madonna, Orli Lachmy, and Davide Faranda
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Atmospheric jets are a key component of the climate system and of our everyday lives. Indeed, they affect human activities by influencing the weather in many mid-latitude regions. However, we still lack a complete understanding of their dynamical properties. In this study, we try to relate the understanding gained in idealized computer simulations of the jets to our knowledge from observations of the real atmosphere.
Assaf Hochman, Sebastian Scher, Julian Quinting, Joaquim G. Pinto, and Gabriele Messori
Earth Syst. Dynam., 12, 133–149, https://doi.org/10.5194/esd-12-133-2021, https://doi.org/10.5194/esd-12-133-2021, 2021
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Skillful forecasts of extreme weather events have a major socioeconomic relevance. Here, we compare two approaches to diagnose the predictability of eastern Mediterranean heat waves: one based on recent developments in dynamical systems theory and one leveraging numerical ensemble weather forecasts. We conclude that the former can be a useful and cost-efficient complement to conventional numerical forecasts for understanding the dynamics of eastern Mediterranean heat waves.
Patrick Johannes Stoll, Thomas Spengler, Annick Terpstra, and Rune Grand Graversen
Weather Clim. Dynam., 2, 19–36, https://doi.org/10.5194/wcd-2-19-2021, https://doi.org/10.5194/wcd-2-19-2021, 2021
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Polar lows are intense meso-scale cyclones occurring at high latitudes. The research community has not agreed on a conceptual model to describe polar-low development. Here, we apply self-organising maps to identify the typical ambient sub-synoptic environments of polar lows and find that they can be described as moist-baroclinic cyclones that develop in four different environments characterised by the vertical wind shear.
Paolo De Luca, Gabriele Messori, Davide Faranda, Philip J. Ward, and Dim Coumou
Earth Syst. Dynam., 11, 793–805, https://doi.org/10.5194/esd-11-793-2020, https://doi.org/10.5194/esd-11-793-2020, 2020
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In this paper we quantify Mediterranean compound temperature and precipitation dynamical extremes (CDEs) over the 1979–2018 period. The strength of the temperature–precipitation coupling during summer increased and is driven by surface warming. We also link the CDEs to compound hot–dry and cold–wet events during summer and winter respectively.
Rein Haarsma, Mario Acosta, Rena Bakhshi, Pierre-Antoine Bretonnière, Louis-Philippe Caron, Miguel Castrillo, Susanna Corti, Paolo Davini, Eleftheria Exarchou, Federico Fabiano, Uwe Fladrich, Ramon Fuentes Franco, Javier García-Serrano, Jost von Hardenberg, Torben Koenigk, Xavier Levine, Virna Loana Meccia, Twan van Noije, Gijs van den Oord, Froila M. Palmeiro, Mario Rodrigo, Yohan Ruprich-Robert, Philippe Le Sager, Etienne Tourigny, Shiyu Wang, Michiel van Weele, and Klaus Wyser
Geosci. Model Dev., 13, 3507–3527, https://doi.org/10.5194/gmd-13-3507-2020, https://doi.org/10.5194/gmd-13-3507-2020, 2020
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HighResMIP is an international coordinated CMIP6 effort to investigate the improvement in climate modeling caused by an increase in horizontal resolution. This paper describes EC-Earth3P-(HR), which has been developed for HighResMIP. First analyses reveal that increasing resolution does improve certain aspects of the simulated climate but that many other biases still continue, possibly related to phenomena that are still not yet resolved and need to be parameterized.
Veronika Eyring, Lisa Bock, Axel Lauer, Mattia Righi, Manuel Schlund, Bouwe Andela, Enrico Arnone, Omar Bellprat, Björn Brötz, Louis-Philippe Caron, Nuno Carvalhais, Irene Cionni, Nicola Cortesi, Bas Crezee, Edouard L. Davin, Paolo Davini, Kevin Debeire, Lee de Mora, Clara Deser, David Docquier, Paul Earnshaw, Carsten Ehbrecht, Bettina K. Gier, Nube Gonzalez-Reviriego, Paul Goodman, Stefan Hagemann, Steven Hardiman, Birgit Hassler, Alasdair Hunter, Christopher Kadow, Stephan Kindermann, Sujan Koirala, Nikolay Koldunov, Quentin Lejeune, Valerio Lembo, Tomas Lovato, Valerio Lucarini, François Massonnet, Benjamin Müller, Amarjiit Pandde, Núria Pérez-Zanón, Adam Phillips, Valeriu Predoi, Joellen Russell, Alistair Sellar, Federico Serva, Tobias Stacke, Ranjini Swaminathan, Verónica Torralba, Javier Vegas-Regidor, Jost von Hardenberg, Katja Weigel, and Klaus Zimmermann
Geosci. Model Dev., 13, 3383–3438, https://doi.org/10.5194/gmd-13-3383-2020, https://doi.org/10.5194/gmd-13-3383-2020, 2020
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The Earth System Model Evaluation Tool (ESMValTool) is a community diagnostics and performance metrics tool designed to improve comprehensive and routine evaluation of earth system models (ESMs) participating in the Coupled Model Intercomparison Project (CMIP). It has undergone rapid development since the first release in 2016 and is now a well-tested tool that provides end-to-end provenance tracking to ensure reproducibility.
Paolo De Luca, Gabriele Messori, Robert L. Wilby, Maurizio Mazzoleni, and Giuliano Di Baldassarre
Earth Syst. Dynam., 11, 251–266, https://doi.org/10.5194/esd-11-251-2020, https://doi.org/10.5194/esd-11-251-2020, 2020
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We show that floods and droughts can co-occur in time across remote regions on the globe and introduce metrics that can help in quantifying concurrent wet and dry hydrological extremes. We then link wet–dry extremes to major modes of climate variability (i.e. ENSO, PDO, and AMO) and provide their spatial patterns. Such concurrent extreme hydrological events may pose risks to regional hydropower production and agricultural yields.
Sebastian Scher and Gabriele Messori
Nonlin. Processes Geophys., 26, 381–399, https://doi.org/10.5194/npg-26-381-2019, https://doi.org/10.5194/npg-26-381-2019, 2019
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Neural networks are a technique that is widely used to predict the time evolution of physical systems. For this the past evolution of the system is shown to the neural network – it is
trained– and then can be used to predict the evolution in the future. We show some limitations in this approach for certain systems that are important to consider when using neural networks for climate- and weather-related applications.
Davide Faranda, Yuzuru Sato, Gabriele Messori, Nicholas R. Moloney, and Pascal Yiou
Earth Syst. Dynam., 10, 555–567, https://doi.org/10.5194/esd-10-555-2019, https://doi.org/10.5194/esd-10-555-2019, 2019
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We show how the complex dynamics of the jet stream at midlatitude can be described by a simple mathematical model. We match the properties of the model to those obtained by the jet data derived from observations.
Valerio Lembo, Frank Lunkeit, and Valerio Lucarini
Geosci. Model Dev., 12, 3805–3834, https://doi.org/10.5194/gmd-12-3805-2019, https://doi.org/10.5194/gmd-12-3805-2019, 2019
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The Thermodynamic Diagnostic Tool (TheDiaTo v1.0) is a collection of diagnostics for the study of the thermodynamics of the climate system in climate models. This is fundamental in order to understand where the imbalances affecting climate projections come from and also to allow for easy comparison of different scenarios and atmospheric regimes. The tool is currently being developed for the assessment of models that are part of the next phase of the Coupled Model Intercomparison Project (CMIP).
Sebastian Scher and Gabriele Messori
Geosci. Model Dev., 12, 2797–2809, https://doi.org/10.5194/gmd-12-2797-2019, https://doi.org/10.5194/gmd-12-2797-2019, 2019
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Currently, weather forecasts are mainly produced by using computer models based on physical equations. It is an appealing idea to use neural networks and “deep learning” for weather forecasting instead. We successfully test the possibility of using deep learning for weather forecasting by considering climate models as simplified versions of reality. Our work therefore is a step towards potentially using deep learning to replace or accompany current weather forecasting models.
Mallory Carlu, Francesco Ginelli, Valerio Lucarini, and Antonio Politi
Nonlin. Processes Geophys., 26, 73–89, https://doi.org/10.5194/npg-26-73-2019, https://doi.org/10.5194/npg-26-73-2019, 2019
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We explore the nature of instabilities in a well-known meteorological toy model, the Lorenz 96, to unravel key mechanisms of interaction between scales of different resolutions and time scales. To do so, we use a mathematical machinery known as Lyapunov analysis, allowing us to capture the degrees of chaoticity associated with fundamental directions of instability. We find a non-trivial group of such directions projecting significantly on slow variables, associated with long term dynamics.
Sindre Fritzner, Rune Graversen, Kai H. Christensen, Philip Rostosky, and Keguang Wang
The Cryosphere, 13, 491–509, https://doi.org/10.5194/tc-13-491-2019, https://doi.org/10.5194/tc-13-491-2019, 2019
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In this work, a coupled ocean and sea-ice ensemble-based assimilation system is used to assess the impact of different observations on the assimilation system. The focus of this study is on sea-ice observations, including the use of satellite observations of sea-ice concentration, sea-ice thickness and snow depth for assimilation. The study showed that assimilation of sea-ice thickness in addition to sea-ice concentration has a large positive impact on the coupled model.
Gabriele Vissio and Valerio Lucarini
Nonlin. Processes Geophys., 25, 413–427, https://doi.org/10.5194/npg-25-413-2018, https://doi.org/10.5194/npg-25-413-2018, 2018
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Constructing good parametrizations is key when studying multi-scale systems. We consider a low-order model and derive a parametrization via a recently developed statistical mechanical approach. We show how the method allows for seamlessly treating the case when the unresolved dynamics is both faster and slower than the resolved one. We test the skill of the parametrization by using the formalism of the Wasserstein distance, which allows for measuring how different two probability measures are.
Lesley De Cruz, Sebastian Schubert, Jonathan Demaeyer, Valerio Lucarini, and Stéphane Vannitsem
Nonlin. Processes Geophys., 25, 387–412, https://doi.org/10.5194/npg-25-387-2018, https://doi.org/10.5194/npg-25-387-2018, 2018
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The predictability of weather models is limited largely by the initial state error growth or decay rates. We have computed these rates for PUMA, a global model for the atmosphere, and MAOOAM, a more simplified, coupled model which includes the ocean. MAOOAM has processes at distinct timescales, whereas PUMA surprisingly does not. We propose a new programme to compute the natural directions along the flow that correspond to the growth or decay rates, to learn which components play a role.
Tamás Bódai, Valerio Lucarini, and Frank Lunkeit
Earth Syst. Dynam. Discuss., https://doi.org/10.5194/esd-2018-30, https://doi.org/10.5194/esd-2018-30, 2018
Revised manuscript not accepted
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We establish a framework to conduct a scenario analysis of the best possible outcomes under geoengineering. The scenarios may consist of scenarios of greenhouse gas emission the choice of the quantity that we want to keep under control. The motivation is the desire of an efficient way of assessing the side-effects of geoengineering, concerning the unwanted and uncontrolled changes. Countering CO2 emission by modulating insolation, we find considerable changes in local temperatures or rainfall.
Davide Faranda, Gabriele Messori, M. Carmen Alvarez-Castro, and Pascal Yiou
Nonlin. Processes Geophys., 24, 713–725, https://doi.org/10.5194/npg-24-713-2017, https://doi.org/10.5194/npg-24-713-2017, 2017
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We study the dynamical properties of the Northern Hemisphere atmospheric circulation by analysing the sea-level pressure, 2 m temperature, and precipitation frequency field over the period 1948–2013. The metrics are linked to the predictability and the persistence of the atmospheric flows. We study the dependence on the seasonal cycle and the fields corresponding to maxima and minima of the dynamical indicators.
Valerio Lembo, Isabella Bordi, and Antonio Speranza
Earth Syst. Dynam., 8, 295–312, https://doi.org/10.5194/esd-8-295-2017, https://doi.org/10.5194/esd-8-295-2017, 2017
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The study wishes to better characterize the annual and semiannual cycles of surface temperature and baroclinicity at midlatitudes as observed in ERA-Interim reanalysis data and AOGCM simulations. Results show that at the semiannual frequency model phases between surface temperature and baroclinicity have wide dispersion in both hemispheres with large errors in the estimates, denoting uncertainty and a degree of disagreement among models.
F. S. R. Pausata, M. Gaetani, G. Messori, S. Kloster, and F. J. Dentener
Atmos. Chem. Phys., 15, 1725–1743, https://doi.org/10.5194/acp-15-1725-2015, https://doi.org/10.5194/acp-15-1725-2015, 2015
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our study suggests that future aerosol abatement may be the primary driver of increased blocking events over the western Mediterranean. This modification of the atmospheric circulation over the Euro-Atlantic sector leads to more stagnant weather conditions that favour air pollutant accumulation especially in the western Mediterranean sector. Changes in atmospheric circulation should therefore be included in future air pollution mitigation assessments.
S. Hasson, V. Lucarini, M. R. Khan, M. Petitta, T. Bolch, and G. Gioli
Hydrol. Earth Syst. Sci., 18, 4077–4100, https://doi.org/10.5194/hess-18-4077-2014, https://doi.org/10.5194/hess-18-4077-2014, 2014
S. Hasson, V. Lucarini, S. Pascale, and J. Böhner
Earth Syst. Dynam., 5, 67–87, https://doi.org/10.5194/esd-5-67-2014, https://doi.org/10.5194/esd-5-67-2014, 2014
R. Deidda, M. Marrocu, G. Caroletti, G. Pusceddu, A. Langousis, V. Lucarini, M. Puliga, and A. Speranza
Hydrol. Earth Syst. Sci., 17, 5041–5059, https://doi.org/10.5194/hess-17-5041-2013, https://doi.org/10.5194/hess-17-5041-2013, 2013
S. Hasson, V. Lucarini, and S. Pascale
Earth Syst. Dynam., 4, 199–217, https://doi.org/10.5194/esd-4-199-2013, https://doi.org/10.5194/esd-4-199-2013, 2013
Related subject area
Dynamical processes in midlatitudes
Large-scale perspective on extreme near-surface winds in the central North Atlantic
Divergent convective outflow in ICON deep-convection-permitting and parameterised deep convection simulations
Changes in the North Atlantic Oscillation over the 20th century
Life cycle dynamics of Greenland blocking from a potential vorticity perspective
Warm conveyor belt characteristics and impacts along the life cycle of extratropical cyclones: case studies and climatological analysis based on ERA5
Influence of radiosonde observations on the sharpness and altitude of the midlatitude tropopause in the ECMWF IFS
Analysing 23 years of warm-season derechos in France: a climatology and investigation of synoptic and environmental changes
A Lagrangian framework for detecting and characterizing the descent of foehn from Alpine to local scales
The upstream–downstream connection of North Atlantic and Mediterranean cyclones in semi-idealized simulations
Understanding the vertical temperature structure of recent record-shattering heatwaves
Persistent warm and cold spells in the Northern Hemisphere extratropics: regionalisation, synoptic-scale dynamics and temperature budget
Linking Gulf Stream air–sea interactions to the exceptional blocking episode in February 2019: a Lagrangian perspective
Linking compound weather extremes to Mediterranean cyclones, fronts and air-streams
Process-based classification of Mediterranean cyclones using potential vorticity
The relation between Rossby wave-breaking events and low-level weather systems
Aquaplanet simulations with winter and summer hemispheres: model setup and circulation response to warming
Seasonally dependent increases in subweekly temperature variability over Southern Hemisphere landmasses detected in multiple reanalyses
Identification of high-wind features within extratropical cyclones using a probabilistic random forest – Part 2: Climatology over Europe
Cold wintertime air masses over Europe: where do they come from and how do they form?
Diabatic effects on the evolution of storm tracks
A storm-relative climatology of compound hazards in Mediterranean cyclones
Towards a process-oriented understanding of the impact of stochastic perturbations on the model climate
Atmospheric response to cold wintertime Tibetan Plateau conditions over eastern Asia in climate models
Exploring the vertical extent and deepening mechanisms of cut-off lows in the Southern Hemisphere: insights from eddy kinetic energy analysis
Transient anticyclonic eddies and their relationship to atmospheric block persistence
A composite approach to produce reference datasets for extratropical cyclone tracks: application to Mediterranean cyclones
Thunderstorm environments in Europe
What distinguishes 100-year precipitation extremes over central European river catchments from more moderate extreme events?
Towards a holistic understanding of blocked regime dynamics through a combination of complementary diagnostic perspectives
Moist available potential energy of the mean state of the atmosphere and the thermodynamic potential for warm conveyor belts and convection
Large spread in the representation of compound long-duration dry and hot spells over Europe in CMIP5
Similarity and variability of blocked weather-regime dynamics in the Atlantic–European region
A linear assessment of waveguidability for barotropic Rossby waves in different large-scale flow configurations
Anomalous subtropical zonal winds drive decreases in southern Australian frontal rain
Origin of low-tropospheric potential vorticity in Mediterranean cyclones
Robust poleward jet shifts in idealised baroclinic-wave life-cycle experiments with noisy initial conditions
Revisiting the wintertime emergent constraint of the southern hemispheric midlatitude jet response to global warming
The global atmospheric energy transport analysed by a wavelength-based scale separation
European heatwaves in present and future climate simulations: a Lagrangian analysis
Signatures of Eurasian heat waves in global Rossby wave spectra
Impact of grid spacing, convective parameterization and cloud microphysics in ICON simulations of a warm conveyor belt
Recurrent Rossby waves and south-eastern Australian heatwaves
Identification of high-wind features within extratropical cyclones using a probabilistic random forest – Part 1: Method and case studies
Classification of Alpine south foehn based on 5 years of kilometre-scale analysis data
Summertime Rossby waves in climate models: substantial biases in surface imprint associated with small biases in upper-level circulation
Diabatic processes modulating the vertical structure of the jet stream above the cold front of an extratropical cyclone: sensitivity to deep convection schemes
The role of cyclones and potential vorticity cutoffs for the occurrence of unusually long wet spells in Europe
Orographic resolution driving the improvements associated with horizontal resolution increase in the Northern Hemisphere winter mid-latitudes
Quantifying climate model representation of the wintertime Euro-Atlantic circulation using geopotential-jet regimes
Circumglobal Rossby wave patterns during boreal winter highlighted by space–time spectral analysis
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.
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.
Konstantin Krüger, Andreas Schäfler, Martin Weissmann, and George C. Craig
Weather Clim. Dynam., 5, 491–509, https://doi.org/10.5194/wcd-5-491-2024, https://doi.org/10.5194/wcd-5-491-2024, 2024
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Initial conditions of current numerical weather prediction models insufficiently represent the sharp vertical gradients across the midlatitude tropopause. Observation-space data assimilation output is used to study the influence of assimilated radiosondes on the tropopause. The radiosondes reduce systematic biases of the model background and sharpen temperature and wind gradients in the analysis. Tropopause sharpness is still underestimated in the analysis, which may impact weather forecasts.
Lucas Fery and Davide Faranda
Weather Clim. Dynam., 5, 439–461, https://doi.org/10.5194/wcd-5-439-2024, https://doi.org/10.5194/wcd-5-439-2024, 2024
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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.
Alice Portal, Shira Raveh-Rubin, Jennifer L. Catto, Yonatan Givon, and Olivia Martius
EGUsphere, https://doi.org/10.5194/egusphere-2024-270, https://doi.org/10.5194/egusphere-2024-270, 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 specially 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 varies by region and season, but also depends on the presence of specific airflows around the cyclone.
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.
Raphaël Rousseau-Rizzi, Shira Raveh-Rubin, Jennifer Catto, Alice Portal, Yonatan Givon, and Olivia Martius
EGUsphere, https://doi.org/10.5194/egusphere-2023-2322, https://doi.org/10.5194/egusphere-2023-2322, 2023
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We aim to identify the situations when rain and wind, rain and wave, or heat and dust hazards co-occur within cyclones in the Mediterranean. These poorly understood hazard combinations respectively enhance the risk to infrastructure, the risk of coastal flooding, and the risk of respiratory issues. We identify distinct weather configurations and distinct cyclone structures, which favor distinct co-occurrence combinations. This has implications for the forecasting of these hazards.
Moritz Deinhard and Christian M. Grams
EGUsphere, https://doi.org/10.5194/egusphere-2023-1938, https://doi.org/10.5194/egusphere-2023-1938, 2023
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Stochastic perturbations are a frequently used 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 focus on how different schemes modulate rapidly ascending air streams, such as warm conveyor belts, and whether the changes to these weather systems are projected onto larger scales. We thereby provide a process chain how perturbations affect the model climate.
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.
Henri Rossi Pinheiro, Kevin Ivan Hodges, and Manoel Alonso Gan
EGUsphere, https://doi.org/10.5194/egusphere-2023-1996, https://doi.org/10.5194/egusphere-2023-1996, 2023
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Our study on upper-level cyclones, known as cut-off lows (COLs), uncovers deepening mechanisms and geographical influences. Complex interactions, crucial for accurate forecasts, are revealed through advanced methods. Analysis of atmospheric data across regions like Australia, the western Pacific, and southeast South America shows frequent deep COLs. By assessing energy budgets, we unveil robust growth patterns, helping our predictive abilities for weather impacts.
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.
Deborah Morgenstern, Isabell Stucke, Georg J. Mayr, Achim Zeileis, and Thorsten Simon
Weather Clim. Dynam., 4, 489–509, https://doi.org/10.5194/wcd-4-489-2023, https://doi.org/10.5194/wcd-4-489-2023, 2023
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Two thunderstorm environments are described for Europe: mass-field thunderstorms, which occur mostly in summer, over land, and under similar meteorological conditions, and wind-field thunderstorms, which occur mostly in winter, over the sea, and under more diverse meteorological conditions. Our descriptions are independent of static thresholds and help to understand why thunderstorms in unfavorable seasons for lightning pose a particular risk to tall infrastructure such as wind turbines.
Florian Ruff and Stephan Pfahl
Weather Clim. Dynam., 4, 427–447, https://doi.org/10.5194/wcd-4-427-2023, https://doi.org/10.5194/wcd-4-427-2023, 2023
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In this study, we analyse the generic atmospheric processes of very extreme, 100-year precipitation events in large central European river catchments and the corresponding differences to less extreme events, based on a large time series (~1200 years) of simulated but realistic daily precipitation events from the ECMWF. Depending on the catchment, either dynamical mechanisms or thermodynamic conditions or a combination of both distinguish 100-year events from less extreme precipitation events.
Seraphine Hauser, Franziska Teubler, Michael Riemer, Peter Knippertz, and Christian M. Grams
Weather Clim. Dynam., 4, 399–425, https://doi.org/10.5194/wcd-4-399-2023, https://doi.org/10.5194/wcd-4-399-2023, 2023
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Blocking describes a flow configuration in the midlatitudes where stationary high-pressure systems block the propagation of weather systems. This study combines three individual perspectives that capture the dynamics and importance of various processes in the formation of a major blocking in 2016 from a weather regime perspective. In future work, this framework will enable a holistic view of the dynamics and the role of moist processes in different life cycle stages of blocked weather regimes.
Charles G. Gertler, Paul A. O'Gorman, and Stephan Pfahl
Weather Clim. Dynam., 4, 361–379, https://doi.org/10.5194/wcd-4-361-2023, https://doi.org/10.5194/wcd-4-361-2023, 2023
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The relationship between the time-mean state of the atmosphere and aspects of atmospheric circulation drives general understanding of the atmospheric circulation. Here, we present new techniques to calculate local properties of the time-mean atmosphere and relate those properties to aspects of extratropical circulation with important implications for weather. This relationship should help connect changes to the atmosphere, such as under global warming, to changes in midlatitude weather.
Colin Manning, Martin Widmann, Douglas Maraun, Anne F. Van Loon, and Emanuele Bevacqua
Weather Clim. Dynam., 4, 309–329, https://doi.org/10.5194/wcd-4-309-2023, https://doi.org/10.5194/wcd-4-309-2023, 2023
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Climate models differ in their representation of dry spells and high temperatures, linked to errors in the simulation of persistent large-scale anticyclones. Models that simulate more persistent anticyclones simulate longer and hotter dry spells, and vice versa. This information is important to consider when assessing the likelihood of such events in current and future climate simulations so that we can assess the plausibility of their future projections.
Franziska Teubler, Michael Riemer, Christopher Polster, Christian M. Grams, Seraphine Hauser, and Volkmar Wirth
Weather Clim. Dynam., 4, 265–285, https://doi.org/10.5194/wcd-4-265-2023, https://doi.org/10.5194/wcd-4-265-2023, 2023
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Weather regimes govern an important part of the sub-seasonal variability of the mid-latitude circulation. The year-round dynamics of blocked regimes in the Atlantic European region are investigated in over 40 years of data. We show that the dynamics between the regimes are on average very similar. Within the regimes, the main variability – starting from the characteristics of dynamical processes alone – dominates and transcends the variability in season and types of transitions.
Antonio Segalini, Jacopo Riboldi, Volkmar Wirth, and Gabriele Messori
EGUsphere, https://doi.org/10.5194/egusphere-2023-316, https://doi.org/10.5194/egusphere-2023-316, 2023
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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
Acacia S. Pepler and Irina Rudeva
Weather Clim. Dynam., 4, 175–188, https://doi.org/10.5194/wcd-4-175-2023, https://doi.org/10.5194/wcd-4-175-2023, 2023
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In recent decades, cold fronts have rained less often in southeast Australia, which contributes to decreasing cool season rainfall. The largest changes in front dynamics are found to the north of the area where rain changes. Wet fronts have strong westerly winds that reach much further north than dry fronts do, and these fronts are becoming less common, linked to weakening subtropical winds and changes in the Southern Hemisphere circulation.
Alexander Scherrmann, Heini Wernli, and Emmanouil Flaounas
Weather Clim. Dynam., 4, 157–173, https://doi.org/10.5194/wcd-4-157-2023, https://doi.org/10.5194/wcd-4-157-2023, 2023
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We investigate the dynamical origin of the lower-atmospheric potential vorticity (PV; linked to the intensity of cyclones) in Mediterranean cyclones. We quantify the contribution of the cyclone and the environment by tracing PV backward in time and space and linking it to the track of the cyclone. We find that the lower-tropospheric PV is produced shortly before the cyclone's stage of highest intensity. We investigate the driving processes and use a global dataset and a process-resolving one.
Felix Jäger, Philip Rupp, and Thomas Birner
Weather Clim. Dynam., 4, 49–60, https://doi.org/10.5194/wcd-4-49-2023, https://doi.org/10.5194/wcd-4-49-2023, 2023
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Mid-latitude weather is dominated by the growth, breaking and decay of baroclinic waves and associated jet shifts. A way to study this process is via idealised life-cycle simulations, which are often classified as LC1 (anticyclonic breaking, poleward shift) or LC2 (cyclonic breaking, equatorward shift), depending on details of the initial state. We show that all systems exhibit predominantly anticyclonic character and poleward net shifts if multiple wave modes are allowed to grow simultaneously.
Philipp Breul, Paulo Ceppi, and Theodore G. Shepherd
Weather Clim. Dynam., 4, 39–47, https://doi.org/10.5194/wcd-4-39-2023, https://doi.org/10.5194/wcd-4-39-2023, 2023
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Accurately predicting the response of the midlatitude jet stream to climate change is very important, but models show a variety of possible scenarios. Previous work identified a relationship between climatological jet latitude and future jet shift in the southern hemispheric winter. We show that the relationship does not hold in separate sectors and propose that zonal asymmetries are the ultimate cause in the zonal mean. This questions the usefulness of the relationship.
Patrick Johannes Stoll, Rune Grand Graversen, and Gabriele Messori
Weather Clim. Dynam., 4, 1–17, https://doi.org/10.5194/wcd-4-1-2023, https://doi.org/10.5194/wcd-4-1-2023, 2023
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The atmosphere is in motion and hereby transporting warm, cold, moist, and dry air to different climate zones. In this study, we investigate how this transport of energy organises in different manners. Outside the tropics, atmospheric waves of sizes between 2000 and 8000 km, which we perceive as cyclones from the surface, transport most of the energy and moisture poleward. In the winter, large-scale weather situations become very important for transporting energy into the polar regions.
Lisa Schielicke and Stephan Pfahl
Weather Clim. Dynam., 3, 1439–1459, https://doi.org/10.5194/wcd-3-1439-2022, https://doi.org/10.5194/wcd-3-1439-2022, 2022
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Projected future heatwaves in many European regions will be even warmer than the mean increase in summer temperature suggests. To identify the underlying thermodynamic and dynamic processes, we compare Lagrangian backward trajectories of airstreams associated with heatwaves in two time slices (1991–2000 and 2091–2100) in a large single-model ensemble (CEMS-LE). We find stronger future descent associated with adiabatic warming in some regions and increased future diabatic heating in most regions.
Iana Strigunova, Richard Blender, Frank Lunkeit, and Nedjeljka Žagar
Weather Clim. Dynam., 3, 1399–1414, https://doi.org/10.5194/wcd-3-1399-2022, https://doi.org/10.5194/wcd-3-1399-2022, 2022
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We show that the Eurasian heat waves (HWs) have signatures in the global circulation. We present changes in the probability density functions (PDFs) of energy anomalies in the zonal-mean state and in the Rossby waves at different zonal scales in relation to the changes in intramonthly variability. The skewness of the PDF of planetary-scale Rossby waves is shown to increase during HWs, while their intramonthly variability is reduced, a process referred to as blocking.
Anubhav Choudhary and Aiko Voigt
Weather Clim. Dynam., 3, 1199–1214, https://doi.org/10.5194/wcd-3-1199-2022, https://doi.org/10.5194/wcd-3-1199-2022, 2022
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The warm conveyor belt (WCB), which is a stream of coherently rising air parcels, is an important feature of extratropical cyclones. This work presents the impact of model grid spacing on simulation of cloud diabatic processes in the WCB of a North Atlantic cyclone. We find that the refinement of the model grid systematically enhances the dynamical properties and heat releasing processes within the WCB. However, this pattern does not have a strong impact on the strength of associated cyclones.
S. Mubashshir Ali, Matthias Röthlisberger, Tess Parker, Kai Kornhuber, and Olivia Martius
Weather Clim. Dynam., 3, 1139–1156, https://doi.org/10.5194/wcd-3-1139-2022, https://doi.org/10.5194/wcd-3-1139-2022, 2022
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Persistent weather can lead to extreme weather conditions. One such atmospheric flow pattern, termed recurrent Rossby wave packets (RRWPs), has been shown to increase persistent weather in the Northern Hemisphere. Here, we show that RRWPs are also an important feature in the Southern Hemisphere. We evaluate the role of RRWPs during south-eastern Australian heatwaves and find that they help to persist the heatwaves by forming upper-level high-pressure systems over south-eastern Australia.
Lea Eisenstein, Benedikt Schulz, Ghulam A. Qadir, Joaquim G. Pinto, and Peter Knippertz
Weather Clim. Dynam., 3, 1157–1182, https://doi.org/10.5194/wcd-3-1157-2022, https://doi.org/10.5194/wcd-3-1157-2022, 2022
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Mesoscale high-wind features within extratropical cyclones can cause immense damage. Here, we present RAMEFI, a novel approach to objectively identify the wind features based on a probabilistic random forest. RAMEFI enables a wide range of applications such as probabilistic predictions for the occurrence or a multi-decadal climatology of these features, which will be the focus of Part 2 of the study, with the goal of improving wind and, specifically, wind gust forecasts in the long run.
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
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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.
Fei Luo, Frank Selten, Kathrin Wehrli, Kai Kornhuber, Philippe Le Sager, Wilhelm May, Thomas Reerink, Sonia I. Seneviratne, Hideo Shiogama, Daisuke Tokuda, Hyungjun Kim, and Dim Coumou
Weather Clim. Dynam., 3, 905–935, https://doi.org/10.5194/wcd-3-905-2022, https://doi.org/10.5194/wcd-3-905-2022, 2022
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Recent studies have identified the weather systems in observational data, where wave patterns with high-magnitude values that circle around the whole globe in either wavenumber 5 or wavenumber 7 are responsible for the extreme events. In conclusion, we find that the climate models are able to reproduce the large-scale atmospheric circulation patterns as well as their associated surface variables such as temperature, precipitation, and sea level pressure.
Meryl Wimmer, Gwendal Rivière, Philippe Arbogast, Jean-Marcel Piriou, Julien Delanoë, Carole Labadie, Quitterie Cazenave, and Jacques Pelon
Weather Clim. Dynam., 3, 863–882, https://doi.org/10.5194/wcd-3-863-2022, https://doi.org/10.5194/wcd-3-863-2022, 2022
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The effect of deep convection representation on the jet stream above the cold front of an extratropical cyclone is investigated in the global numerical weather prediction model ARPEGE. Two simulations using different deep convection schemes are compared with (re)analysis datasets and NAWDEX airborne observations. A deeper jet stream is observed with the less active scheme. The diabatic origin of this difference is interpreted by backward Lagrangian trajectories and potential vorticity budgets.
Matthias Röthlisberger, Barbara Scherrer, Andries Jan de Vries, and Raphael Portmann
Weather Clim. Dynam., 3, 733–754, https://doi.org/10.5194/wcd-3-733-2022, https://doi.org/10.5194/wcd-3-733-2022, 2022
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We examine the palette of synoptic storylines accompanying unusually long wet spells in Europe. Thereby, we identify a hitherto not documented mechanism for generating long wet spells which involves recurrent Rossby wave breaking and subsequent cutoff replenishment. Understanding the synoptic processes behind long wet spells is relevant in light of projected changes in wet spell characteristics as it is a prerequisite for evaluating climate models with regard to such events.
Paolo Davini, Federico Fabiano, and Irina Sandu
Weather Clim. Dynam., 3, 535–553, https://doi.org/10.5194/wcd-3-535-2022, https://doi.org/10.5194/wcd-3-535-2022, 2022
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In climate models, improvements obtained in the winter mid-latitude circulation following horizontal resolution increase are mainly caused by the more detailed representation of the mean orography. A high-resolution climate model with low-resolution orography might underperform compared to a low-resolution model with low-resolution orography. The absence of proper model tuning at high resolution is considered the potential reason behind such lack of improvements.
Joshua Dorrington, Kristian Strommen, and Federico Fabiano
Weather Clim. Dynam., 3, 505–533, https://doi.org/10.5194/wcd-3-505-2022, https://doi.org/10.5194/wcd-3-505-2022, 2022
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We investigate how well current state-of-the-art climate models reproduce the wintertime weather of the North Atlantic and western Europe by studying how well different "regimes" of weather are captured. Historically, models have struggled to capture these regimes, making it hard to predict future changes in wintertime extreme weather. We show models can capture regimes if the right method is used, but they show biases, partially as a result of biases in jet speed and eddy strength.
Jacopo Riboldi, Efi Rousi, Fabio D'Andrea, Gwendal Rivière, and François Lott
Weather Clim. Dynam., 3, 449–469, https://doi.org/10.5194/wcd-3-449-2022, https://doi.org/10.5194/wcd-3-449-2022, 2022
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A revisited space and time spectral decomposition allows us to determine which harmonics dominate the upper-tropospheric flow evolution over a given time period as well as their propagation. This approach is used to identify Rossby wave patterns with a circumglobal extent, affecting weather evolution over different Northern Hemisphere regions. The results cast light on the processes originating and supporting these wave patterns, advocating at the same time for the usefulness of the technique.
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Short summary
Eddies in mid-latitudes characterize the exchange of heat between the tropics and the poles. This exchange is largely uneven, with a few extreme events bearing most of the heat transported across latitudes in a season. It is thus important to understand what the dynamical mechanisms are behind these events. Here, we identify recurrent weather regime patterns associated with extreme transports, and we identify scales of mid-latitudinal eddies that are mostly responsible for the transport.
Eddies in mid-latitudes characterize the exchange of heat between the tropics and the poles....
