Articles | Volume 4, issue 2
https://doi.org/10.5194/wcd-4-399-2023
© Author(s) 2023. 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-4-399-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
11 May 2023
Research article |
| 11 May 2023
| 11 May 2023
Towards a holistic understanding of blocked regime dynamics through a combination of complementary diagnostic perspectives
Seraphine Hauser
CORRESPONDING AUTHOR
Institute of Meteorology and Climate Research (IMK-TRO), Department Troposphere Research, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
Franziska Teubler
Institute for Atmospheric Physics, Johannes Gutenberg-University Mainz, Mainz, Germany
Michael Riemer
Institute for Atmospheric Physics, Johannes Gutenberg-University Mainz, Mainz, Germany
Peter Knippertz
Institute of Meteorology and Climate Research (IMK-TRO), Department Troposphere Research, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
Christian M. Grams
Institute of Meteorology and Climate Research (IMK-TRO), Department Troposphere Research, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
Related authors
Seraphine Hauser, Franziska Teubler, Michael Riemer, Peter Knippertz, and Christian M. Grams
Weather Clim. Dynam., 5, 633–658, https://doi.org/10.5194/wcd-5-633-2024, https://doi.org/10.5194/wcd-5-633-2024, 2024
Short summary
Short summary
Blocking over Greenland has substantial impacts on the weather and climate in mid- and high latitudes. This study applies a quasi-Lagrangian thinking on the dynamics of Greenland blocking and reveals two pathways of anticyclonic anomalies linked to the block. Moist processes were found to play a dominant role in the formation and maintenance of blocking. This emphasizes the necessity of the correct representation of moist processes in weather and climate models to realistically depict blocking.
Franziska Teubler, Michael Riemer, Christopher Polster, Christian M. Grams, Seraphine Hauser, and Volkmar Wirth
Weather Clim. Dynam., 4, 265–285, https://doi.org/10.5194/wcd-4-265-2023, https://doi.org/10.5194/wcd-4-265-2023, 2023
Short summary
Short summary
Weather regimes govern an important part of the sub-seasonal variability of the mid-latitude circulation. The year-round dynamics of blocked regimes in the Atlantic European region are investigated in over 40 years of data. We show that the dynamics between the regimes are on average very similar. Within the regimes, the main variability – starting from the characteristics of dynamical processes alone – dominates and transcends the variability in season and types of transitions.
Tanguy Jonville, Maurus Borne, Cyrille Flamant, Juan Cuesta, Olivier Bock, Pierre Bosser, Christophe Lavaysse, Andreas Fink, and Peter Knippertz
Atmos. Chem. Phys., 25, 9765–9786, https://doi.org/10.5194/acp-25-9765-2025, https://doi.org/10.5194/acp-25-9765-2025, 2025
Short summary
Short summary
Tropical waves structure the atmosphere. Four types of tropical waves (equatorial Rossby – ER, Kelvin, MRG-TD1, and MRG-TD2 – mixed Rossby gravity–tropical depressions) are studied using filters, satellite measurements, and in situ data from the Clouds–Atmosphere Dynamics–Dust Interaction in West Africa (CADDIWA) campaign held in September 2021 in Cabo Verde. ER waves impact temperature and humidity above 2500 m, MRG-TD1 around 3500 m, and MRG-TD2 around 2000 m. Interactions between these waves favor tropical cyclone formation.
Annie Y.-Y. Chang, Shaun Harrigan, Maria-Helena Ramos, Massimiliano Zappa, Christian M. Grams, Daniela I. V. Domeisen, and Konrad Bogner
EGUsphere, https://doi.org/10.5194/egusphere-2025-3411, https://doi.org/10.5194/egusphere-2025-3411, 2025
This preprint is open for discussion and under review for Hydrology and Earth System Sciences (HESS).
Short summary
Short summary
This study presents a machine learning-aided hybrid forecasting framework to improve early warnings of low flows in the European Alps. It combines weather regime information, streamflow observations, and model simulations (EFAS). Even using only weather regime data improves predictions over climatology, while integrating different data sources yields the best result, emphasizing the value of integrating diverse data sources.
Lina Lucas, Christian Barthlott, Corinna Hoose, and Peter Knippertz
EGUsphere, https://doi.org/10.5194/egusphere-2025-3069, https://doi.org/10.5194/egusphere-2025-3069, 2025
Short summary
Short summary
We studied how climate change and cleaner air could affect severe storms in Central Europe. Using high-resolution weather simulations of past supercell storms under warmer and less polluted conditions, we found that storms may become more intense, with heavier rainfall and larger hailstones. These changes suggest an increased risk of damage in the future. Our findings help improve understanding of how extreme storms may evolve in a changing climate.
Christopher Johannes Diekmann, Matthias Schneider, Peter Knippertz, Tim Trent, Hartmut Boesch, Amelie Ninja Roehling, John Worden, Benjamin Ertl, Farahnaz Khosrawi, and Frank Hase
Atmos. Chem. Phys., 25, 5409–5431, https://doi.org/10.5194/acp-25-5409-2025, https://doi.org/10.5194/acp-25-5409-2025, 2025
Short summary
Short summary
The West African Monsoon is the main source of rainfall over West Africa, and understanding the development of the monsoon remains challenging due to complex interactions of atmospheric processes. We make use of new satellite datasets of isotopes in tropospheric water vapour to characterize processes controlling the monsoon convection. We find that comparing different water vapour isotopes reveals effects of rain–vapour interactions and air mass transport.
Hannah Meyer, Konrad Kandler, Sylvain Dupont, Jerónimo Escribano, Jessica Girdwood, George Nikolich, Andrés Alastuey, Vicken Etyemezian, Cristina González Flórez, Adolfo González-Romero, Tareq Hussein, Mark Irvine, Peter Knippertz, Ottmar Möhler, Xavier Querol, Chris Stopford, Franziska Vogel, Frederik Weis, Andreas Wieser, Carlos Pérez García-Pando, and Martina Klose
EGUsphere, https://doi.org/10.5194/egusphere-2025-1531, https://doi.org/10.5194/egusphere-2025-1531, 2025
Short summary
Short summary
Mineral dust particles emitted from dry soils are of various sizes, yet the abundance of very large particles is not well understood. Here we measured the dust size distribution from fine to giant particles at an emission source during a field campaign in Jordan (J-WADI) using multiple instruments. Our findings show that large particles make up a significant part of the total dust mass. This knowledge is essential to improve climate models and to predict dust impacts on climate and environment.
Marc Federer, Lukas Papritz, Michael Sprenger, and Christian M. Grams
Weather Clim. Dynam., 6, 211–230, https://doi.org/10.5194/wcd-6-211-2025, https://doi.org/10.5194/wcd-6-211-2025, 2025
Short summary
Short summary
Although extratropical cyclones in the North Atlantic are among the most impactful midlatitude weather systems, their intensification is not entirely understood. Here, we explore how individual cyclones convert available potential energy (APE) into kinetic energy and relate these conversions to the synoptic development of the cyclones. By combining potential vorticity thinking with a local APE framework, we offer a novel perspective on established concepts in dynamic meteorology.
Matthias Fischer, Peter Knippertz, and Carsten Proppe
Weather Clim. Dynam., 6, 113–130, https://doi.org/10.5194/wcd-6-113-2025, https://doi.org/10.5194/wcd-6-113-2025, 2025
Short summary
Short summary
The West African monsoon is vital for millions but difficult to represent with numerical models. Our research aims at improving monsoon simulations by optimizing three model parameters – entrainment rate, ice fall speed, and soil moisture evaporation – using an advanced surrogate-based multi-objective optimization framework. Results show that tuning these parameters can sometimes improve certain monsoon characteristics, however at the expense of others, highlighting the power of our approach.
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
Short summary
Short summary
The detailed representation of sea surface temperature (SST) in numerical models is important for the prediction of atmospheric blocking in the North Atlantic. Yet the underlying physical processes are not fully understood. Using SST sensitivity experiments for a case study, we identify a physical pathway through which SST in the Gulf Stream region is linked to the downstream upper-level flow evolution in the North Atlantic.
Selina M. Kiefer, Patrick Ludwig, Sebastian Lerch, Peter Knippertz, and Joaquim G. Pinto
EGUsphere, https://doi.org/10.5194/egusphere-2024-2955, https://doi.org/10.5194/egusphere-2024-2955, 2024
Preprint withdrawn
Short summary
Short summary
Weather forecasts 14 days in advance generally have a low skill but not always. We identify reasons thereof depending on the atmospheric flow, shown by Weather Regimes (WRs). If the WRs during the forecasts follow climatological patterns, forecast skill is increased. The forecast of a cold-wave day is better when the European Blocking WR (high pressure around the British Isles) is present a few days before a cold-wave day. These results can be used to assess the reliability of predictions.
Joshua Dorrington, Marta Wenta, Federico Grazzini, Linus Magnusson, Frederic Vitart, and Christian M. Grams
Nat. Hazards Earth Syst. Sci., 24, 2995–3012, https://doi.org/10.5194/nhess-24-2995-2024, https://doi.org/10.5194/nhess-24-2995-2024, 2024
Short summary
Short summary
Extreme rainfall is the leading weather-related source of damages in Europe, but it is still difficult to predict on long timescales. A recent example of this was the devastating floods in the Italian region of Emiglia Romagna in May 2023. We present perspectives based on large-scale dynamical information that allows us to better understand and predict such events.
Moritz Deinhard and Christian M. Grams
Weather Clim. Dynam., 5, 927–942, https://doi.org/10.5194/wcd-5-927-2024, https://doi.org/10.5194/wcd-5-927-2024, 2024
Short summary
Short summary
Stochastic perturbations are an established technique to represent model uncertainties in numerical weather prediction. While such schemes are beneficial for the forecast skill, they can also change the mean state of the model. We analyse how different schemes modulate rapidly ascending airstreams and whether the changes to such weather systems are projected onto larger scales. We thereby provide a process-oriented perspective on how perturbations affect the model climate.
Christoph Fischer, Andreas H. Fink, Elmar Schömer, Marc Rautenhaus, and Michael Riemer
Geosci. Model Dev., 17, 4213–4228, https://doi.org/10.5194/gmd-17-4213-2024, https://doi.org/10.5194/gmd-17-4213-2024, 2024
Short summary
Short summary
This study presents a method for identifying and tracking 3-D potential vorticity structures within African easterly waves (AEWs). Each identified structure is characterized by descriptors, including its 3-D position and orientation, which have been validated through composite comparisons. A trough-centric perspective on the descriptors reveals the evolution and distinct characteristics of AEWs. These descriptors serve as valuable statistical inputs for the study of AEW-related phenomena.
Luise J. Fischer, David N. Bresch, Dominik Büeler, Christian M. Grams, Matthias Röthlisberger, and Heini Wernli
EGUsphere, https://doi.org/10.5194/egusphere-2024-1253, https://doi.org/10.5194/egusphere-2024-1253, 2024
Short summary
Short summary
Atmospheric flows over the North Atlantic can be meaningfully classified into weather regimes, and climate simulations suggest that the regime frequencies might change in the future. We provide a quantitative framework that helps assessing whether these regime frequency changes are relevant for understanding climate change signals in precipitation. At least in our example application, this is not the case, i.e., regime frequency changes explain little of the projected precipitation changes.
Seraphine Hauser, Franziska Teubler, Michael Riemer, Peter Knippertz, and Christian M. Grams
Weather Clim. Dynam., 5, 633–658, https://doi.org/10.5194/wcd-5-633-2024, https://doi.org/10.5194/wcd-5-633-2024, 2024
Short summary
Short summary
Blocking over Greenland has substantial impacts on the weather and climate in mid- and high latitudes. This study applies a quasi-Lagrangian thinking on the dynamics of Greenland blocking and reveals two pathways of anticyclonic anomalies linked to the block. Moist processes were found to play a dominant role in the formation and maintenance of blocking. This emphasizes the necessity of the correct representation of moist processes in weather and climate models to realistically depict blocking.
Matthias Fischer, Peter Knippertz, Roderick van der Linden, Alexander Lemburg, Gregor Pante, Carsten Proppe, and John H. Marsham
Weather Clim. Dynam., 5, 511–536, https://doi.org/10.5194/wcd-5-511-2024, https://doi.org/10.5194/wcd-5-511-2024, 2024
Short summary
Short summary
Our research enhances the understanding of the complex dynamics within the West African monsoon system by analyzing the impact of specific model parameters on its characteristics. Employing surrogate models, we identified critical factors such as the entrainment rate and the fall velocity of ice. Precise definition of these parameters in weather models could improve forecast accuracy, thus enabling better strategies to manage and reduce the impact of weather events.
Marta Wenta, Christian M. Grams, Lukas Papritz, and Marc Federer
Weather Clim. Dynam., 5, 181–209, https://doi.org/10.5194/wcd-5-181-2024, https://doi.org/10.5194/wcd-5-181-2024, 2024
Short summary
Short summary
Our study links air–sea interactions over the Gulf Stream to an atmospheric block in February 2019. We found that over 23 % of air masses that were lifted into the block by cyclones interacted with the Gulf Stream. As cyclones pass over the Gulf Stream, they cause intense surface evaporation events, preconditioning the environment for the development of cyclones. This implies that air–sea interactions over the Gulf Stream affect the large-scale dynamics in the North Atlantic–European region.
Maurus Borne, Peter Knippertz, Martin Weissmann, Benjamin Witschas, Cyrille Flamant, Rosimar Rios-Berrios, and Peter Veals
Atmos. Meas. Tech., 17, 561–581, https://doi.org/10.5194/amt-17-561-2024, https://doi.org/10.5194/amt-17-561-2024, 2024
Short summary
Short summary
This study assesses the quality of Aeolus wind measurements over the tropical Atlantic. The results identified the accuracy and precision of the Aeolus wind measurements and the potential source of errors. For instance, the study revealed atmospheric conditions that can deteriorate the measurement quality, such as weaker laser signal in cloudy or dusty conditions, and confirmed the presence of an orbital-dependant bias. These results can help to improve the Aeolus wind measurement algorithm.
Julian F. Quinting, Christian M. Grams, Edmund Kar-Man Chang, Stephan Pfahl, and Heini Wernli
Weather Clim. Dynam., 5, 65–85, https://doi.org/10.5194/wcd-5-65-2024, https://doi.org/10.5194/wcd-5-65-2024, 2024
Short summary
Short summary
Research in the last few decades has revealed that rapidly ascending airstreams in extratropical cyclones have an important effect on the evolution of downstream weather and predictability. In this study, we show that the occurrence of these airstreams over the North Pacific is modulated by tropical convection. Depending on the modulation, known atmospheric circulation patterns evolve quite differently, which may affect extended-range predictions in the Atlantic–European region.
Hyunju Jung, Peter Knippertz, Yvonne Ruckstuhl, Robert Redl, Tijana Janjic, and Corinna Hoose
Weather Clim. Dynam., 4, 1111–1134, https://doi.org/10.5194/wcd-4-1111-2023, https://doi.org/10.5194/wcd-4-1111-2023, 2023
Short summary
Short summary
A narrow rainfall belt in the tropics is an important feature for large-scale circulations and the global water cycle. The accurate simulation of this rainfall feature has been a long-standing problem, with the reasons behind that unclear. We present a novel diagnostic tool that allows us to disentangle processes important for rainfall, which changes due to modifications in model. Using our diagnostic tool, one can potentially identify sources of uncertainty in weather and climate models.
Lea Eisenstein, Benedikt Schulz, Joaquim G. Pinto, and Peter Knippertz
Weather Clim. Dynam., 4, 981–999, https://doi.org/10.5194/wcd-4-981-2023, https://doi.org/10.5194/wcd-4-981-2023, 2023
Short summary
Short summary
Mesoscale high-wind features within extratropical cyclones can cause immense damage. In Part 1 of this work, we introduced RAMEFI (RAndom-forest-based MEsoscale wind Feature Identification), an objective, flexible identification tool for these wind features based on a probabilistic random forest. Here, we use RAMEFI to compile a climatology of the features over 19 extended winter seasons over western and central Europe, focusing on relative occurrence, affected areas and further characteristics.
Annika Oertel, Annette K. Miltenberger, Christian M. Grams, and Corinna Hoose
Atmos. Chem. Phys., 23, 8553–8581, https://doi.org/10.5194/acp-23-8553-2023, https://doi.org/10.5194/acp-23-8553-2023, 2023
Short summary
Short summary
Warm conveyor belts (WCBs) are cloud- and precipitation-producing airstreams in extratropical cyclones that are important for the large-scale flow and cloud radiative forcing. We analyze cloud formation processes during WCB ascent in a two-moment microphysics scheme. Quantification of individual diabatic heating rates shows the importance of condensation, vapor deposition, rain evaporation, melting, and cloud-top radiative cooling for total heating and WCB-related potential vorticity structure.
Valerian Hahn, Ralf Meerkötter, Christiane Voigt, Sonja Gisinger, Daniel Sauer, Valéry Catoire, Volker Dreiling, Hugh Coe, Cyrille Flamant, Stefan Kaufmann, Jonas Kleine, Peter Knippertz, Manuel Moser, Philip Rosenberg, Hans Schlager, Alfons Schwarzenboeck, and Jonathan Taylor
Atmos. Chem. Phys., 23, 8515–8530, https://doi.org/10.5194/acp-23-8515-2023, https://doi.org/10.5194/acp-23-8515-2023, 2023
Short summary
Short summary
During the DACCIWA campaign in West Africa, we found a 35 % increase in the cloud droplet concentration that formed in a polluted compared with a less polluted environment and a decrease of 17 % in effective droplet diameter. Radiative transfer simulations, based on the measured cloud properties, reveal that these low-level polluted clouds radiate only 2.6 % more energy back to space, compared with a less polluted cloud. The corresponding additional decrease in temperature is rather small.
Axel Seifert, Vanessa Bachmann, Florian Filipitsch, Jochen Förstner, Christian M. Grams, Gholam Ali Hoshyaripour, Julian Quinting, Anika Rohde, Heike Vogel, Annette Wagner, and Bernhard Vogel
Atmos. Chem. Phys., 23, 6409–6430, https://doi.org/10.5194/acp-23-6409-2023, https://doi.org/10.5194/acp-23-6409-2023, 2023
Short summary
Short summary
We investigate how mineral dust can lead to the formation of cirrus clouds. Dusty cirrus clouds lead to a reduction in solar radiation at the surface and, hence, a reduced photovoltaic power generation. Current weather prediction systems are not able to predict this interaction between mineral dust and cirrus clouds. We have developed a new physical description of the formation of dusty cirrus clouds. Overall we can show a considerable improvement in the forecast quality of clouds and radiation.
Patrick Ludwig, Florian Ehmele, Mário J. Franca, Susanna Mohr, Alberto Caldas-Alvarez, James E. Daniell, Uwe Ehret, Hendrik Feldmann, Marie Hundhausen, Peter Knippertz, Katharina Küpfer, Michael Kunz, Bernhard Mühr, Joaquim G. Pinto, Julian Quinting, Andreas M. Schäfer, Frank Seidel, and Christina Wisotzky
Nat. Hazards Earth Syst. Sci., 23, 1287–1311, https://doi.org/10.5194/nhess-23-1287-2023, https://doi.org/10.5194/nhess-23-1287-2023, 2023
Short summary
Short summary
Heavy precipitation in July 2021 led to widespread floods in western Germany and neighboring countries. The event was among the five heaviest precipitation events of the past 70 years in Germany, and the river discharges exceeded by far the statistical 100-year return values. Simulations of the event under future climate conditions revealed a strong and non-linear effect on flood peaks: for +2 K global warming, an 18 % increase in rainfall led to a 39 % increase of the flood peak in the Ahr river.
Franziska Teubler, Michael Riemer, Christopher Polster, Christian M. Grams, Seraphine Hauser, and Volkmar Wirth
Weather Clim. Dynam., 4, 265–285, https://doi.org/10.5194/wcd-4-265-2023, https://doi.org/10.5194/wcd-4-265-2023, 2023
Short summary
Short summary
Weather regimes govern an important part of the sub-seasonal variability of the mid-latitude circulation. The year-round dynamics of blocked regimes in the Atlantic European region are investigated in over 40 years of data. We show that the dynamics between the regimes are on average very similar. Within the regimes, the main variability – starting from the characteristics of dynamical processes alone – dominates and transcends the variability in season and types of transitions.
Susanna Mohr, Uwe Ehret, Michael Kunz, Patrick Ludwig, Alberto Caldas-Alvarez, James E. Daniell, Florian Ehmele, Hendrik Feldmann, Mário J. Franca, Christian Gattke, Marie Hundhausen, Peter Knippertz, Katharina Küpfer, Bernhard Mühr, Joaquim G. Pinto, Julian Quinting, Andreas M. Schäfer, Marc Scheibel, Frank Seidel, and Christina Wisotzky
Nat. Hazards Earth Syst. Sci., 23, 525–551, https://doi.org/10.5194/nhess-23-525-2023, https://doi.org/10.5194/nhess-23-525-2023, 2023
Short summary
Short summary
The flood event in July 2021 was one of the most severe disasters in Europe in the last half century. The objective of this two-part study is a multi-disciplinary assessment that examines the complex process interactions in different compartments, from meteorology to hydrological conditions to hydro-morphological processes to impacts on assets and environment. In addition, we address the question of what measures are possible to generate added value to early response management.
Behrooz Keshtgar, Aiko Voigt, Corinna Hoose, Michael Riemer, and Bernhard Mayer
Weather Clim. Dynam., 4, 115–132, https://doi.org/10.5194/wcd-4-115-2023, https://doi.org/10.5194/wcd-4-115-2023, 2023
Short summary
Short summary
Forecasting extratropical cyclones is challenging due to many physical factors influencing their behavior. One such factor is the impact of heating and cooling of the atmosphere by the interaction between clouds and radiation. In this study, we show that cloud-radiative heating (CRH) increases the intensity of an idealized cyclone and affects its predictability. We find that CRH affects the cyclone mostly via increasing latent heat release and subsequent changes in the synoptic circulation.
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
Short summary
Short summary
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.
Christoph Fischer, Andreas H. Fink, Elmar Schömer, Roderick van der Linden, Michael Maier-Gerber, Marc Rautenhaus, and Michael Riemer
Geosci. Model Dev., 15, 4447–4468, https://doi.org/10.5194/gmd-15-4447-2022, https://doi.org/10.5194/gmd-15-4447-2022, 2022
Short summary
Short summary
Potential vorticity (PV) analysis plays a central role in studying atmospheric dynamics. For example, anomalies in the PV field near the tropopause are linked to extreme weather events. In this study, an objective strategy to identify these anomalies is presented and evaluated. As a novel concept, it can be applied to three-dimensional (3-D) data sets. Supported by 3-D visualizations, we illustrate advantages of this new analysis over existing studies along a case study.
Edgar Dolores-Tesillos, Franziska Teubler, and Stephan Pfahl
Weather Clim. Dynam., 3, 429–448, https://doi.org/10.5194/wcd-3-429-2022, https://doi.org/10.5194/wcd-3-429-2022, 2022
Short summary
Short summary
Strong winds caused by extratropical cyclones represent a costly hazard for European countries. Here, based on CESM-LENS coupled climate simulations, we show that future changes of such strong winds are characterized by an increased magnitude and extended footprint southeast of the cyclone center. This intensification is related to a combination of increased diabatic heating and changes in upper-level wave dynamics.
Adrien Deroubaix, Laurent Menut, Cyrille Flamant, Peter Knippertz, Andreas H. Fink, Anneke Batenburg, Joel Brito, Cyrielle Denjean, Cheikh Dione, Régis Dupuy, Valerian Hahn, Norbert Kalthoff, Fabienne Lohou, Alfons Schwarzenboeck, Guillaume Siour, Paolo Tuccella, and Christiane Voigt
Atmos. Chem. Phys., 22, 3251–3273, https://doi.org/10.5194/acp-22-3251-2022, https://doi.org/10.5194/acp-22-3251-2022, 2022
Short summary
Short summary
During the summer monsoon in West Africa, pollutants emitted in urbanized areas modify cloud cover and precipitation patterns. We analyze these patterns with the WRF-CHIMERE model, integrating the effects of aerosols on meteorology, based on the numerous observations provided by the Dynamics-Aerosol-Climate-Interactions campaign. This study adds evidence to recent findings that increased pollution levels in West Africa delay the breakup time of low-level clouds and reduce precipitation.
Julian F. Quinting and Christian M. Grams
Geosci. Model Dev., 15, 715–730, https://doi.org/10.5194/gmd-15-715-2022, https://doi.org/10.5194/gmd-15-715-2022, 2022
Short summary
Short summary
Physical processes in weather systems importantly affect the midlatitude large-scale circulation. This study introduces an artificial-intelligence-based framework which allows the identification of an important weather system – the so-called warm conveyor belt (WCB) – at comparably low computational costs and from data at low spatial and temporal resolution. The framework thus newly enables the systematic investigation of WCBs in large data sets such as climate model projections.
Julian F. Quinting, Christian M. Grams, Annika Oertel, and Moritz Pickl
Geosci. Model Dev., 15, 731–744, https://doi.org/10.5194/gmd-15-731-2022, https://doi.org/10.5194/gmd-15-731-2022, 2022
Short summary
Short summary
This study applies novel artificial-intelligence-based models that allow the identification of one specific weather system which affects the midlatitude circulation. We show that the models yield similar results as their trajectory-based counterpart, which requires data at higher spatiotemporal resolution and is computationally more expensive. Overall, we aim to show how deep learning methods can be used efficiently to support process understanding of biases in weather prediction models.
Christopher J. Diekmann, Matthias Schneider, Benjamin Ertl, Frank Hase, Omaira García, Farahnaz Khosrawi, Eliezer Sepúlveda, Peter Knippertz, and Peter Braesicke
Earth Syst. Sci. Data, 13, 5273–5292, https://doi.org/10.5194/essd-13-5273-2021, https://doi.org/10.5194/essd-13-5273-2021, 2021
Short summary
Short summary
The joint analysis of different stable water isotopes in water vapour is a powerful tool for investigating atmospheric moisture pathways. This paper presents a novel global and multi-annual dataset of H2O and HDO in mid-tropospheric water vapour by using data from the satellite sensor Metop/IASI. Due to its unique combination of coverage and resolution in space and time, this dataset is highly promising for studying the hydrological cycle and its representation in weather and climate models.
Fabienne Dahinden, Franziska Aemisegger, Heini Wernli, Matthias Schneider, Christopher J. Diekmann, Benjamin Ertl, Peter Knippertz, Martin Werner, and Stephan Pfahl
Atmos. Chem. Phys., 21, 16319–16347, https://doi.org/10.5194/acp-21-16319-2021, https://doi.org/10.5194/acp-21-16319-2021, 2021
Short summary
Short summary
We use high-resolution numerical isotope modelling and Lagrangian backward trajectories to identify moisture transport pathways and governing physical and dynamical processes that affect the free-tropospheric humidity and isotopic variability over the eastern subtropical North Atlantic. Furthermore, we conduct a thorough isotope modelling validation with aircraft and remote-sensing observations of water vapour isotopes.
Alberto Caldas-Alvarez, Samiro Khodayar, and Peter Knippertz
Weather Clim. Dynam., 2, 561–580, https://doi.org/10.5194/wcd-2-561-2021, https://doi.org/10.5194/wcd-2-561-2021, 2021
Short summary
Short summary
The prediction capabilities of GPS, operational (low-resolution) and targeted (high-resolution) radiosondes for data assimilation in a Mediterranean heavy precipitation event at different model resolutions are investigated. The results show that even if GPS provides accurate observations, their lack of vertical information hampers the improvement, demonstrating the need for assimilating radiosondes, where the location and timing of release was more determinant than the vertical resolution.
Franziska Teubler and Michael Riemer
Weather Clim. Dynam., 2, 535–559, https://doi.org/10.5194/wcd-2-535-2021, https://doi.org/10.5194/wcd-2-535-2021, 2021
Short summary
Short summary
Rossby wave packets impact all aspects of midlatitude weather systems, from their climatological distribution to predictability. Case studies suggest an important role of latent heat release in clouds. We investigate thousands of wave packets with a novel diagnostic. We demonstrate that, on average, the impact of moist processes is substantially different between troughs and ridges and that dry conceptual models of wave packet dynamics should be extended.
Emmanouil Flaounas, Suzanne L. Gray, and Franziska Teubler
Weather Clim. Dynam., 2, 255–279, https://doi.org/10.5194/wcd-2-255-2021, https://doi.org/10.5194/wcd-2-255-2021, 2021
Short summary
Short summary
In this study, we quantify the relative contribution of different atmospheric processes to the development of 100 intense Mediterranean cyclones and show that both upper tropospheric systems and diabatic processes contribute to cyclone development. However, these contributions are complex and present high variability among the cases. For this reason, we analyse several exemplary cases in more detail, including 10 systems that have been identified in the past as tropical-like cyclones.
Gregor Pante, Peter Knippertz, Andreas H. Fink, and Anke Kniffka
Atmos. Chem. Phys., 21, 35–55, https://doi.org/10.5194/acp-21-35-2021, https://doi.org/10.5194/acp-21-35-2021, 2021
Short summary
Short summary
Seasonal rainfall amounts along the densely populated West African Guinea coast have been decreasing during the past 35 years, with recently accelerating trends. We find strong indications that this is in part related to increasing human air pollution in the region. Given the fast increase in emissions, the political implications of this work are significant. Reducing air pollution locally and regionally would mitigate an imminent health crisis and socio-economic damage from reduced rainfall.
Cited articles
Alvarez-Castro, M. C., Faranda, D., and Yiou, P.:
Atmospheric Dynamics Leading to West European Summer Hot Temperatures since 1851, Complexity, 2018, 2494509, https://doi.org/10.1155/2018/2494509, 2018. a
Austin, J. F.:
The blocking of middle latitude westerly winds by planetary waves, Q. J. Roy. Meteorol. Soc., 106, 327–350, https://doi.org/10.1002/qj.49710644807, 1980. a
Benedict, J. J., Lee, S., and Feldstein, S. B.:
Synoptic view of the North Atlantic Oscillation, J. Atmos. Sci., 61, 121–144, https://doi.org/10.1175/1520-0469(2004)061<0121:SVOTNA>2.0.CO;2, 2004. a
Buehler, T., Raible, C. C., and Stocker, T. F.:
The relationship of winter season North Atlantic blocking frequencies to extreme cold or dry spells in the ERA-40, Tellus A, 63, 212–222, https://doi.org/10.1111/j.1600-0870.2010.00492.x, 2011. a
Cassou, C.:
Intraseasonal interaction between the Madden-Julian Oscillation and the North Atlantic Oscillation, Nature, 455, 523–527, https://doi.org/10.1038/nature07286, 2008. a
Chagnon, J. M., Gray, S. L., and Methven, J.:
Diabatic processes modifying potential vorticity in a North Atlantic cyclone, Q. J. Roy. Meteorol. Soc., 139, 1270–1282, https://doi.org/10.1002/qj.2037, 2013. a
Charney, J.:
The Use of the Primitive Equations of Motion in Numerical Prediction, Tellus, 7, 22–26, https://doi.org/10.1111/j.2153-3490.1955.tb01138.x, 1955. a
Charney, J. G. and DeVore, J. G.:
Multiple Flow Equilibria in the Atmosphere and Blocking, J. Atmos. Sci., 36, 1205–1216, https://doi.org/10.1175/1520-0469(1979)036<1205:MFEITA>2.0.CO;2, 1979. a
Cortesi, N., Torralba, V., Lledó, L., Manrique-Suñén, A., Gonzalez-Reviriego, N., Soret, A., and Doblas-Reyes, F. J.:
Yearly evolution of Euro-Atlantic weather regimes and of their sub-seasonal predictability (Climate Dynamics, (2021), 56, 11–12, (3933–3964), https://doi.org/10.1007/s00382-021-05679-y), Clim. Dynam., 56, 3965, https://doi.org/10.1007/s00382-021-05750-8, 2021. a
Davis, C. A.:
Piecewise Potential Vorticity Inversion, J. Atmos. Sci., 49, 1397–1411, https://doi.org/10.1175/1520-0469(1992)049<1397:PPVI>2.0.CO;2, 1992. a
Davis, C. A. and Emanuel, K. A.:
Potential Vorticity Diagnostics of Cyclogenesis, Mon. Weather Rev., 119, 1929–1953, https://doi.org/10.1175/1520-0493(1991)119<1929:PVDOC>2.0.CO;2, 1991. a
Donat, M. G., Leckebusch, G. C., Pinto, J. G., and Ulbrich, U.:
Examination of wind storms over Central Europe with respect to circulation weather types and NAO phases, Int. J. Climatol., 30, 1289–1300, https://doi.org/10.1002/joc.1982, 2010. a
Duchon, C. E.:
Lanczos Filtering in One and Two Dimensions, J. Appl. Meteorol. Clim., 18, 1016–1022, https://doi.org/10.1175/1520-0450(1979)018<1016:LFIOAT>2.0.CO;2, 1979. a
Ertel, H.:
Ein neuer hydrodynamischer Erhaltungssatz, Naturwissenschaften, 30, 543–544, https://doi.org/10.1007/BF01475602, 1942. a, b
Feldstein, S. B.:
The dynamics of NAO teleconnection pattern growth and decay, Q. J. Roy. Meteorol. Soc., 129, 901–924, https://doi.org/10.1256/qj.02.76, 2003. a, b
Ferranti, L., Corti, S., and Janousek, M.:
Flow-dependent verification of the ECMWF ensemble over the Euro–Atlantic sector, Q. J. Roy. Meteorol. Soc., 141, 916–924, https://doi.org/10.1002/qj.2411, 2015. a
Ferranti, L., Magnusson, L., Vitart, F., and Richardson, D. S.:
How far in advance can we predict changes in large-scale flow leading to severe cold conditions over Europe?, Q. J. Roy. Meteorol. Soc., 144, 1788–1802, https://doi.org/10.1002/qj.3341, 2018. a
Grams, C. M., Wernli, H., Böttcher, M., Čampa, J., Corsmeier, U., Jones, S. C., Keller, J. H., Lenz, C.-J., and Wiegand, L.:
The key role of diabatic processes in modifying the upper-tropospheric wave guide: a North Atlantic case-study, Q. J. Roy. Meteorol. Soc., 137, 2174–2193, https://doi.org/10.1002/qj.891, 2011. a
Grams, C. M., Magnusson, L., and Madonna, E.:
An Atmospheric Dynamics Perspective on the Amplification and Propagation of Forecast Error in Numerical Weather Prediction Models: A Case Study, Q. J. Roy. Meteorol. Soc., 144, 2577–2591, https://doi.org/10.1002/qj.3353, 2018. a, b, c, d
Grose, W. L. and Hoskins, B. J.:
On the Influence of Orography on Large-Scale Atmospheric Flow, J. Atmos. Sci., 36, 223–234, https://doi.org/10.1175/1520-0469(1979)036<0223:OTIOOO>2.0.CO;2, 1979. a
Henderson, S. A., Maloney, E. D., and Barnes, E. A.:
The influence of the Madden–Julian oscillation on Northern Hemisphere winter blocking, J. Climate, 29, 4597–4616, https://doi.org/10.1175/JCLI-D-15-0502.1, 2016. a
Hersbach, H., Bell, B., Berrisford, P., Biavati, G., Horányi, A., Muñoz Sabater, J., Nicolas, J., Peubey, C., Radu, R., Rozum, I., Schepers, D., Simmons, A., Soci, C., Dee, D., and Thépaut, J.-N.: ERA5 hourly data on pressure levels from 1940 to present, Copernicus Climate Change Service (C3S) Climate Data Store (CDS) [data set], https://doi.org/10.24381/cds.bd0915c6, 2018. a
Hersbach, H., Bell, B., Berrisford, P., Hirahara, S., Horányi, A., Muñoz-Sabater, J., Nicolas, J., Peubey, C., Radu, R., Schepers, D., Simmons, A., Soci, C., Abdalla, S., Abellan, X., Balsamo, G., Bechtold, P., Biavati, G., Bidlot, J., Bonavita, M., De Chiara, G., Dahlgren, P., Dee, D., Diamantakis, M., Dragani, R., Flemming, J., Forbes, R., Fuentes, M., Geer, A., Haimberger, L., Healy, S., Hogan, R. J., Hólm, E., Janisková, M., Keeley, S., Laloyaux, P., Lopez, P., Lupu, C., Radnoti, G., de Rosnay, P., Rozum, I., Vamborg, F., Villaume, S., and Thépaut, J.-N.:
The ERA5 global reanalysis, Q. J. Roy. Meteorol. Soc., 146, 1999–2049, https://doi.org/10.1002/qj.3803, 2020. a
Hong, C.-C., Hsu, H.-H., Lin, N.-H., and Chiu, H.:
Roles of European blocking and tropical-extratropical interaction in the 2010 Pakistan flooding, Geophys. Res. Lett., 38, L13806, https://doi.org/10.1029/2011GL047583, 2011. a
Hoskins, B.:
A potential vorticity view of synoptic development, Meteorol. Appl., 4, 325–334, https://doi.org/10.1017/S1350482797000716, 1997. a
Hoskins, B. J., McIntyre, M. E., and Robertson, A. W.:
On the Use and Significance of Isentropic Potential Vorticity Maps, Q. J. Roy. Meteorol. Soc., 111, 877–946, https://doi.org/10.1002/qj.49711147002, 1985. a, b, c
Houze, R. A., Rasmussen, K. L., Medina, S., Brodzik, S. R., and Romatschke, U.:
Anomalous Atmospheric Events Leading to the Summer 2010 Floods in Pakistan, B. Am. Meteorol. Soc., 92, 291–298, https://doi.org/10.1175/2010BAMS3173.1, 2011. a
Illari, L.:
A Diagnostic Study of the Potential Vorticity in a Warm Blocking Anticyclone, J. Atmos. Sci., 41, 3518–3526, https://doi.org/10.1175/1520-0469(1984)041<3518:ADSOTP>2.0.CO;2, 1984. a
Kautz, L.-A., Martius, O., Pfahl, S., Pinto, J. G., Ramos, A. M., Sousa, P. M., and Woollings, T.:
Atmospheric blocking and weather extremes over the Euro-Atlantic sector – a review, Weather Clim. Dynam., 3, 305–336, https://doi.org/10.5194/wcd-3-305-2022, 2022. a
Lavaysse, C., Vogt, J., Toreti, A., Carrera, M. L., and Pappenberger, F.:
On the use of weather regimes to forecast meteorological drought over Europe, Nat. Hazards Earth Syst. Sci., 18, 3297–3309, https://doi.org/10.5194/nhess-18-3297-2018, 2018. a
Luo, D., Cha, J., Zhong, L., and Dai, A.:
A nonlinear multiscale interaction model for atmospheric blocking: The eddy-blocking matching mechanism, Q. J. Roy. Meteorol. Soc., 140, 1785–1808, https://doi.org/10.1002/qj.2337, 2014. a
Lupo, A. R.:
Atmospheric blocking events: a review, Ann. N. Y. Acad. Sci., 1504, 5–24, https://doi.org/10.1111/nyas.14557, 2021. a
Madonna, E., Wernli, H., Joos, H., and Martius, O.:
Warm Conveyor Belts in the ERA-Interim Dataset (1979-2010). Part I: Climatology and Potential Vorticity Evolution, J. Climate, 27, 3–26, https://doi.org/10.1175/JCLI-D-12-00720.1, 2014. a, b
Magnusson, L.:
Diagnostic methods for understanding the origin of forecast errors, Q. J. Roy. Meteorol. Soc., 143, 2129–2142, https://doi.org/10.1002/qj.3072, 2017. a, b, c
Martineau, P., Nakamura, H., Yamamoto, A., and Kosaka, Y.:
Baroclinic Blocking, Geophys. Res. Lett., 49, e2022GL097791, https://doi.org/10.1029/2022GL097791, 2022. a, b, c
Matsueda, M. and Palmer, T. N.:
Estimates of flow-dependent predictability of wintertime Euro-Atlantic weather regimes in medium-range forecasts, Q. J. Roy. Meteorol. Soc., 144, 1012–1027, https://doi.org/10.1002/qj.3265, 2018. a
Methven, J.:
Potential vorticity in warm conveyor belt outflow, Q. J. Roy. Meteorol. Soc., 141, 1065–1071, https://doi.org/10.1002/qj.2393, 2015. a
Michelangeli, P. A., Vautard, R., and Legras, B.:
Weather regimes: recurrence and quasi stationarity, J. Atmos. Sci., 52, 1237–1256, https://doi.org/10.1175/1520-0469(1995)052<1237:WRRAQS>2.0.CO;2, 1995. a
Miller, D. E. and Wang, Z.:
Northern Hemisphere Winter Blocking: Differing Onset Mechanisms across Regions, J. Atmos. Sci., 79, 1291–1309, https://doi.org/10.1175/jas-d-21-0104.1, 2022. a
Nakamura, H. and Wallace, J. M.:
Observed Changes in Baroclinic Wave Activity during the Life Cycles of Low-Frequency Circulation Anomalies, J. Atmos. Sci., 47, 1100–1116, https://doi.org/10.1175/1520-0469(1990)047<1100:OCIBWA>2.0.CO;2, 1990. a
Nakamura, H. and Wallace, J. M.:
Synoptic Behavior of Baroclinic Eddies during the Blocking Onset, Mon. Weather Rev., 121, 1892–1903, https://doi.org/10.1175/1520-0493(1993)121<1892:SBOBED>2.0.CO;2, 1993. a
Nakamura, H., Nakamura, M., and Anderson, J. L.:
The role of high- and low-frequency dynamics in blocking formation, Mon. Weather Rev., 125, 2074–2093, https://doi.org/10.1175/1520-0493(1997)125<2074:TROHAL>2.0.CO;2, 1997. a
Nakamura, N. and Huang, C. S. Y.:
Atmospheric blocking as a traffic jam in the jet stream, Science, 361, 42–47, https://doi.org/10.1126/science.aat0721, 2018. a
Petoukhov, V., Rahmstorf, S., Petri, S., and Schellnhuber, H. J.:
Quasiresonant amplification of planetary waves and recent Northern Hemisphere weather extremes, P. Natl. Acad. Sci. USA, 110, 5336–5341, https://doi.org/10.1073/pnas.1222000110, 2013. a
Pfahl, S. and Wernli, H.:
Quantifying the relevance of atmospheric blocking for co-located temperature extremes in the Northern Hemisphere on (sub-)daily time scales, Geophys. Res. Lett., 39, L12807, https://doi.org/10.1029/2012GL052261, 2012. a
Quinting, J. F. and Grams, C. M.:
EuLerian Identification of ascending AirStreams (ELIAS 2.0) in numerical weather prediction and climate models – Part 1: Development of deep learning model, Geosci. Model Dev., 15, 715–730, https://doi.org/10.5194/gmd-15-715-2022, 2022. a
Rex, D. F.:
Blocking Action in the Middle Troposphere and its Effect upon Regional Climate, Tellus, 2, 196–211, https://doi.org/10.1111/j.2153-3490.1950.tb00331.x, 1950. a
Rossby, C.-G.:
Planetary flow patterns in the atmosphere, Q. J. Roy.
Meteor. Soc., 66, 68–87, 1940. a
Röthlisberger, M., Martius, O., and Wernli, H.:
Northern Hemisphere Rossby Wave Initiation Events on the Extratropical Jet—A Climatological Analysis, J. Climate, 31, 743–760, https://doi.org/10.1175/JCLI-D-17-0346.1, 2018. a
Schwierz, C., Croci-Maspoli, M., and Davies, H. C.:
Perspicacious indicators of atmospheric blocking, Geophys. Res. Lett., 31, L06125, https://doi.org/10.1029/2003GL019341, 2004. a, b, c
Shutts, G. J.:
The propagation of eddies in diffluent jetstreams: Eddy vorticity forcing of `blocking' flow fields, Q. J. Roy. Meteorol. Soc., 109, 737–761, https://doi.org/10.1002/qj.49710946204, 1983. a, b, c
Sillmann, J., Croci-Maspoli, M., Kallache, M., and Katz, R. W.:
Extreme Cold Winter Temperatures in Europe under the Influence of North Atlantic Atmospheric Blocking, J. Climate, 24, 5899–5913, https://doi.org/10.1175/2011JCLI4075.1, 2011. a
Sprenger, M. and Wernli, H.:
The LAGRANTO Lagrangian analysis tool – version 2.0, Geosci. Model Dev., 8, 2569–2586, https://doi.org/10.5194/gmd-8-2569-2015, 2015. a
Teubler, F., Riemer, M., Polster, C., Grams, C. M., Hauser, S., and Wirth, V.:
Similarity and variability of blocked weather-regime dynamics in the Atlantic–European region, Weather Clim. Dynam., 4, 265–285, https://doi.org/10.5194/wcd-4-265-2023, 2023. a
Vautard, R.:
Multiple weather regimes over the North Atlantic: analysis of precursors and successors, Mon. Weather Rev., 118, 2056–2081, https://doi.org/10.1175/1520-0493(1990)118<2056:MWROTN>2.0.CO;2, 1990. a
Vitart, F., Robertson, A. W., and Anderson, D. L. T.:
Sub-seasonal to seasonal prediction: The gap between weather and climate forecasting, in: Sub-seasonal to Seasonal Prediction: The Gap Between Weather and Climate Forecasting, edited by:
Robertson, A. W. and Vitart, F., Elsevier,
61, 1–585, https://doi.org/10.1016/C2016-0-01594-2, 2012.
a
Wernli, H.:
A Lagrangian-based analysis of extratropical cyclones. II: A detailed case-study, Q. J. Roy. Meteorol. Soc., 123, 1677–1706, https://doi.org/10.1002/qj.49712354211, 1997. a
Wirth, V., Riemer, M., Chang, E. K., and Martius, O.:
Rossby wave packets on the midlatitude waveguide – A review, Mon. Weather Rev., 146, 1965–2001, https://doi.org/10.1175/MWR-D-16-0483.1, 2018. a, b, c, d
Woollings, T., Barriopedro, D., Methven, J., Son, S. W., Martius, O., Harvey, B., Sillmann, J., Lupo, A. R., and Seneviratne, S.:
Blocking and its Response to Climate Change, Current Climate Change Reports, 4, 287–300, https://doi.org/10.1007/s40641-018-0108-z, 2018. a
Yamazaki, A. and Itoh, H.:
Selective absorption mechanism for the maintenance of blocking, Geophys. Res. Lett., 36, 4–7, https://doi.org/10.1029/2008GL036770, 2009. a, b, c, d
Yiou, P. and Nogaj, M.:
Extreme climatic events and weather regimes over the North Atlantic: When and where?, Geophys. Res. Lett., 31, L07202, https://doi.org/10.1029/2003GL019119, 2004. a
Zierl, B. and Wirth, V.:
The Influence of Radiation on Tropopause Behavior and Stratosphere-Troposphere Exchange in an Upper Tropospheric Anticyclone, J. Geophys. Res.-Atmos., 102, 23883–23894, https://doi.org/10.1029/97JD01667, 1997. a
Short summary
Blocking describes a flow configuration in the midlatitudes where stationary high-pressure systems block the propagation of weather systems. This study combines three individual perspectives that capture the dynamics and importance of various processes in the formation of a major blocking in 2016 from a weather regime perspective. In future work, this framework will enable a holistic view of the dynamics and the role of moist processes in different life cycle stages of blocked weather regimes.
Blocking describes a flow configuration in the midlatitudes where stationary high-pressure...
