4-9 September 2022, Bonn, Germany

Session programme

UP – Understanding Weather & Climate Processes

Programme Stream Moderators: Frank Beyrich, Barbara Chimani

Keynote Presentation Understanding Weather & Climate Processes
Co-organized by UP
Convener: Frank Beyrich | Co-convener: Barbara Chimani
| Wed, 07 Sep, 17:30–18:00 (CEST)|Room HS 2

UP1 – Atmospheric processes and severe weather


The socio-economic impact of recent extreme events, e.g., the floods in Germany and China, and the heat waves and forest fires in Canada and the Mediterranean, highlight society's need for accurate weather forecasts and climate projections. Despite substantial progress in numerical modelling in recent decades, predictability for extreme events is often limited and the assessments of future changes in extremes remain uncertain. This underscores the need to improve our understanding of the complex, nonlinear interactions of dynamical and physical processes that influence predictability at different lead times and determine the location, timing, and magnitude of extreme events.

This session will discuss our current understanding of how physical and dynamical processes connect atmospheric motions across temporal and spatial scales and how this relates to intrinsic and practical predictability of various weather phenomena. We particularly welcome but are not limited to contributions advancing our understanding and prediction of weather and climate extremes, from both an applied and theoretical viewpoint.

Topics of interest include but are not limited to:

(1) Synoptic-scale atmospheric dynamics affecting the timing, positioning, and amplitude of weather events (e.g., the stationarity and amplitude of Rossby waves).
(2) Large-scale atmospheric and oceanic influences (e.g., the stratosphere, the Artic, or tropical oceans) on atmospheric variability and predictability in the midlatitudes.
(3) Intrinsic limits of predictability for various atmospheric phenomena and their link to the multi-scale, non-linear nature of atmospheric dynamics.
(4) Practical limits of predictability and the representation of atmospheric phenomena in numerical weather prediction and climate models including sensitivities to the model physics.
(5) Weather and climate extremes, including compound extreme events, their dynamics, predictability, and representation in weather and climate models.
(6) Statistical and mathematical approaches for the study of extreme events.
(7) Impact and risk assessment analyses of extreme events.
(8) Extreme event attribution and changes in extreme event occurrences under climate change.

Public information:

Dear Attendees and Presenters of the EMS 2022 UP1.1 Atmospheric dynamics, predictability, and extremes session,

thanks for the many contributions to UP1.1. We made an effort in arranging an interesting programme covering oral presentations on Thu and Fri and posters on Wednesday. 

The oral presentations will be fully hybrid and a chairperson team will moderate onsite and online discussions.

As the poster session is already on Wednesday, we can not offer poster pitches. Please visit the 11 interesting posters (thereof 1 online in gather.town) on Wednesday and meet the authors between 16:00-17:15.

All poster presenters, please upload your material before the conference on the conference webpage and consider using gather.town. This will allow you (virtual) interaction also outside the attendence time Wednesday 16:00-17:15. Unfortunately we will not be able to provide a chairperson in gather.town but hope it will still be a good virtual experience.

Looking forward to intersting discussions in UP1.1 on Wed, Thu, and Fri!

The convenor team

Including Young Scientist Conference Award
Conveners: Christian M. Grams, Gabriele Messori | Co-conveners: Michael Riemer, Sebastian Schemm, Davide Faranda
| Thu, 08 Sep, 09:00–10:30 (CEST), 14:00–17:15 (CEST)|Room HS 1, Fri, 09 Sep, 09:00–10:30 (CEST), 11:00–15:30 (CEST)|Room HS 1
| Wed, 07 Sep, 16:00–17:15 (CEST) | Display Wed, 07 Sep, 08:00–18:00|b-IT poster area

Atmospheric boundary-layer (ABL) processes and their interactions with the underlying surface are crucial for weather, climate, air-quality and renewable-energy forecasts. The multitude of interacting processes act on a variety of temporal and spatial scales and include atmospheric turbulence, atmosphere-soil-vegetation interactions, gravity waves, boundary-layer interactions with dry and moist convection, mesoscale flows, submeso motions, etc.

Although significant advances have been achieved during the last decades, an appropriate comprehension of ABL processes and their interactions under different conditions is still a challenge in meteorology. Improving this knowledge will help to correctly represent ABL processes in weather and climate models, allowing to provide more accurate numerical weather prediction (NWP) forecasts and climate scenarios.

This session welcomes conceptual, observational and modeling research related to the physical processes that appear in the ABL, including those devoted to study the interactions with the free atmosphere above and with the surface below. Current contributions evaluating existing models and schemes are also welcome, as well as the presentation of new implementation in numerical modelling.

The following topics are especially encouraged to be submitted to the session:

• Theoretical and experimental studies of the turbulence-closure problem with emphasis on very stable stratification and convection, accounting for interactions between the mean flow, turbulence, internal waves and large-scale self-organized structures.

• Boundary-layer clouds (including fog) and marine, cloud-topped boundary layers: physics and parameterization within NWP and climate models and observational studies.

• Orographic effects: form drag, wave drag and flow blocking, gravity waves.

• Challenges on the surface-exchange processes, including soil-vegetation-atmosphere transfers. Flux aggregation in atmospheric boundary layers over heterogeneous terrain.

• Representation of boundary layers and land-surface interaction in atmospheric models.

• Organization of deep convection across differing atmospheric scales.

• Large-eddy simulation and direct numerical simulation of turbulent flows.

• PBL and surface-layer studies using long-term data (climatology), detailed analysis of case studies and field campaigns presentation.

Including Young Scientist Conference Award
Convener: Gert-Jan Steeneveld | Co-conveners: Carlos Román-Cascón, Nikki Vercauteren, Bert Holtslag
| Thu, 08 Sep, 14:00–17:15 (CEST)|Room HS 2, Fri, 09 Sep, 09:00–10:30 (CEST), 11:00–15:15 (CEST)|Room HS 2
| Thu, 08 Sep, 11:00–13:00 (CEST) | Display Thu, 08 Sep, 08:00–Fri, 09 Sep, 14:00|b-IT poster area

This session will welcome all technical and scientific contributions devoted to increase our understanding of atmospheric phenomena that might represent a hazard for people, property and environment. Studies devoted to enhance physical understanding of severe weather phenomena (for example deep convection or intense straight lines winds) are of particular interest even if the severe weather phenomena are not linked directly to a specific hazard (multihazard events).
Embracing the proposal given by the organizers, this year will be particularly welcome contributions dealing (directly or indirectly) with severe droughts in Europe or connecting droughts events and atmospheric hazards.
Moreover, in line with the spirit of EMS, we would encourage contributions devoted to underline the intercultural aspects of methods and findings, and to point the attention not only to the physical and meteorological characteristics of atmospheric hazards and severe droughts, but also to their relevance in a changing climate, including possible impacts on human activities and the environment.
Contributions dealing with studies of specific episodes (case studies) will be welcome, provided they further increase physical understanding and are representative at least for the area where these events took place.
Particularly welcome will be contributions incorporating both numerical and conceptual modelling to improve our understanding of severe weather phenomena.
In general we will encourage the exchange of expertise and experiences related to the various topics connected to hazardous atmospheric phenomena and severe weather events. For this reason an interdisciplinary approach will be particularly welcome.
Potential topics for this session include i.a.:
• Severe droughts;
• Flash-floods and heavy rain events;
• Hail;
• Freezing rain, icing and intense snow falls;
• Cold/heat events, even those occurring at small time scales;
• Fog;
• Tornadoes, waterspouts, derechos and downbursts;
• Severe wind storms;
• Intense Mediterranean cyclones;
• Tropical like cyclones;
• Lightning;
• Polar lows, their evolution and impacts;
• Severe katabatic or foehn winds;
• Gap and orographic flows;
• Breaking of gravity waves, as well as severe turbulence;
The above-listed topics are of course not exclusive and the session’s Conveners eagerly anticipate papers on new ideas and approaches and novel understanding covering all aspects of atmospheric hazards and severe weather events.

Conveners: Sabrina Wahl, Fulvio Stel, Victoria Sinclair | Co-conveners: Julian Steinheuer, Irene Suomi, Dario Giaiotti, Mario Marcello Miglietta, Sante Laviola
| Tue, 06 Sep, 11:00–15:30 (CEST)|Room HS 7
| Tue, 06 Sep, 16:00–17:15 (CEST) | Display Tue, 06 Sep, 08:00–18:00|b-IT poster area

Measurements are essential to provide information on the actual state of the atmosphere for nowcasting purposes, for climate monitoring, for assimilation into numerical weather prediction (NWP) systems and to improve our understanding of atmospheric processes and their role in the climate system. In particular, there is a strong need for complex observations suitable to develop, improve and validate parameterizations used in NWP and climate models and to provide ground-truth against which to compare atmospheric parameters derived from satellite data. With a new generation of high-resolution forecast models (1-3 km) used for the prediction of high-impact weather, dense observational networks focusing on measurements in the lower few kilometers of the atmosphere are required.
This session is intended to give a forum to discuss recent developments and achievements in local to regional measurement concepts and technology. There will be a special emphasis on measurements which seek to improve our understanding of complex atmospheric processes – especially those characterizing interactions in the climate system – through obtaining comprehensive data sets. The focus is on measurements of atmospheric dynamics and thermodynamics, energy and water cycle components, and on the interaction of the atmosphere with the underlying surface.
The session will also include consideration of novel measurement approaches and networks under development for future operational use, e.g., within the frame of the Eumetnet observations program and various COST actions (such as PROBE), and the performance of new measurement techniques. Manufacturers of hydro-meteorological instruments and system solutions are thus explicitly invited to present news on sensor development, sensor performance and system integration.
Techniques may cover in-situ and remote sensing measurements from various platforms. Special attention will be given to the creation of a new generation of reliable unmanned instrument networks across Europe that provide calibrated and controlled data on the boundary layer structure in near-real time. This also includes metrological aspects of sensor characterization. Contributions are also invited that make use of advanced data sets for satellite data validation.
With reference to the special conference focus (“Connecting communities”) we particularly invite contributions that connect different measurement communities (in-situ vs. remote sensing, ground-based vs. air-/space-borne), that link experimentalists with modelers or that bridge different scales of atmospheric phenomena.

Convener: Frank Beyrich | Co-conveners: Fred C. Bosveld, Jens Bange, Domenico Cimini
| Wed, 07 Sep, 09:00–10:30 (CEST), 11:00–17:15 (CEST)|Room HS 1
| Thu, 08 Sep, 09:00–10:30 (CEST) | Display Thu, 08 Sep, 08:00–Fri, 09 Sep, 14:00|b-IT poster area

This session provides a platform for contributions on high-resolution precipitation measurements, analyses, and applications in real-time as well as climate studies. Special focus is placed on documenting the benefit of highly spatially and temporally resolved observations of different measurement platforms, e.g. satellites and radar networks. This also comprises the growing field of opportunistic sensing such as retrieving rainfall from microwave links. Papers on monitoring and analyzing extreme precipitation events including extreme value statistics, multi-scale analysis, and event-based data analyses are especially welcome, comprising definitions and applications of indices to characterize extreme precipitation events, e.g. in public communication. Contributions on long-term observations of precipitation and correlations to meteorological and non-meteorological data with respect to climate change studies are cordially invited. In addition, contributions on the development and improvement of gridded reference data sets based on in-situ and remote sensing precipitation measurements are welcome.
High-resolution measurements and analyses of precipitation are crucial, especially in urban areas with high vulnerabilities, in order to describe the hydrological response and improve water risk management. Thus, this session also addresses contributions on the application of high-resolution precipitation data in hydrological impact and design studies.
According to the special focus of the 2022 Annual Meeting contributions on “connecting communities to deliver seamless weather and climate science and services” are especially encouraged, such as, e.g., contributions on co-designed, high-quality and reliable products and services as well as on modern multiscale systems and technologies for atmospheric measurements, data distribution, and product generation regarding precipitation.
Summarizing, one or more of the following topics shall be addressed:
• Precipitation measurement techniques
• High-resolution precipitation observations from different platforms (e.g., gauges, disdrometers, radars, satellites, microwave links) and their combination
• Precipitation reference data sets (e.g., GPCC, OPERA)
• Drought monitoring and impact
• Statistical analysis of extreme precipitation (events)
• Statistical analysis of changes/trends in precipitation totals (monthly, seasonal, annual)
• Multi-scale analysis, including sub-kilometer scale statistical precipitation description and downscaling methods
• Definition and application of indices to characterize extreme precipitation events
• Climate change studies on extreme precipitation (events)
• Urban hydrology and hydrological impact as well as design studies
• New concepts of adaptation to climate change with respect to extreme precipitation in urban areas

Convener: Tanja Winterrath | Co-conveners: Elsa Cattani, Auguste Gires, Katharina Lengfeld, Miloslav Müller, Marie-Claire ten Veldhuis, Massimiliano Zappa, Markus Ziese
| Thu, 08 Sep, 14:00–17:15 (CEST)|Room HS 3-4
| Fri, 09 Sep, 09:00–10:30 (CEST) | Display Thu, 08 Sep, 08:00–Fri, 09 Sep, 14:00|b-IT poster area
UP1.7 SPARK session

Numerical modeling has become a cornerstone of atmospheric science. Applications cover all relevant scales, from microphysical processes (e.g., radiation, chemistry, cloud physics) to planetary-scale dynamics (weather and climate prediction). However, models are usually developed to represent a specific process on a specific scale, and processes on larger or smaller scales that may affect the problem of interest (e.g., due to scale interactions or scaling cascades) are simplified or neglected. Thus, a hierarchy of models and methods is often used to consider the effects of unresolved processes in a computationally efficient yet realistic way. Parameterization schemes often consider the mean effects of smaller, unresolved physical processes through effective descriptions and empirical correlations but with low fidelity and limited predictability. Larger scales are considered by boundary conditions that drive the development on the scale of interest. While increasing computational resources enable high-fidelity models to directly simulate complex physical processes on multiple scales, this is only possible for idealized configurations and a small fraction of the relevant parameter space. Thus, new and advanced methods are required to address the challenge of regime-overarching modeling and to bridge the gap between scales and processes. In this context, autonomous stochastic and machine-learning tools are increasingly explored, combining computational efficiency with validity across multiple scales and parameter regimes. Ranging from traditional statistical emulation to deep learning, data-driven approaches are expected to allow for qualitatively new atmospheric modeling and building digital twins of the atmosphere.

To provide a platform for the interdisciplinary exchange on accurate and economical representations of multi-scale physical processes in operational and research applications, the focus of this session is on novel modeling approaches in fluid dynamics, radiative transfer, cloud physics, atmospheric chemistry, and related disciplines, as well as their coupling in more complex frameworks, joining the UP and OSA sections of the meeting. We invite contributions on meteorological applications of fluctuation modeling, stochastic dynamics, data-driven and machine learning approaches, model coupling, nesting, grid adaptation, and regime-independent modeling, while welcoming promising approaches that have not yet been used in atmospheric science.

Co-organized by OSA1
Conveners: Fabian Hoffmann, Marten Klein, Franziska Glassmeier, Livia Freire
| Mon, 05 Sep, 14:00–15:25 (CEST)|Room HS 5-6
| Mon, 05 Sep, 16:00–17:30 (CEST) | Display Mon, 05 Sep, 08:00–18:00|b-IT poster area

UP2 – Interactions within the Earth System


Cities and urban environments are a key aspect of the United Nations (UN) Agenda for Sustainable Development, as well as in recent the scientific and socio-economic perspectives. As urbanization processes continue across the world, its representation, impact, and understanding need to be further studied in order to fully comprehend the extent of their impact on weather and/or climate. These aspects are crucial both for the advancing of the current knowledge and the creation of effective sustainable solutions. Key challenges to this task are the level of complexity and multi-scale dimension of diverse urban environments.

Urban environments have a complex structure as they include different typologies, e.g. industrial, residential, and recreational/green areas, which have a different impact on the Earth system and can vary over time. These typologies have a diverse impact on the air and water quality and consumption issues, energy consumption/production. Further, urban environments have a low resilience to changes in climate change and extremes, which affects the overall population living conditions.

This session presents and explores aspects of cities and urban environments within the Earth system. We welcome modeling and observational studies that aim to investigate different aspects of urbanization (e.g. urban heat island, population vulnerability, urban/peri-urban agriculture) and their feedback on the climate system, with a particular focus on application for sustainable adaptation plans. Novel methods that aim to assess urban representation and/or to bridge the different scales of representation within numerical models are encouraged. The impact of cities on weather, climate and/or their extremes (e.g. drought, precipitation), as well as on climate change and on population and adaptation will also be discussed in this session.

Topics may include:

• new urban parameterizations, methods to derive urban parameters for numeric models
• implementation of climate mitigations, adaptation strategies and self-government policies in cities and urban context
• impact of the different urban parameterizations on the atmosphere dynamics and on the different scales
• the impact of the urbanization including estate industrial on weather and/or climate extremes
• field measurements of urban climate, e.g. urban heat island
• impact of different surfaces (green areas, impermeable outer surfaces etc.) on climate and/or its extremes in build-up areas
• population vulnerability to urban climate and climate change
• extreme events (e.g. drought, rainfall events) impacts on town agglomeration
• urban and peri-urban agriculture

Conveners: Pavol Nejedlik, Arianna Valmassoi | Co-conveners: Silvana Di Sabatino, Jan Keller, Marina Neophytou
| Tue, 06 Sep, 16:00–17:15 (CEST)|Room HS 7, Wed, 07 Sep, 09:00–10:30 (CEST), 11:00–12:45 (CEST)|Room HS 7
| Wed, 07 Sep, 14:00–15:30 (CEST) | Display Wed, 07 Sep, 08:00–18:00|b-IT poster area

This session welcomes presentations discussing issues related to analysis, monitoring and prediction of topics related to chemical weather including air pollution. We are welcoming abstracts on the implementation and application of air quality forecast and attribution models around the world, the development and evaluation of air quality models, the downscaling techniques particularly focusing on regions with severe air pollution problems, the co-design and co-development of air quality products and services, and the knowledge transfer and capacity building activities of air quality related information.
A special aspect of the session will be the effects of the still ongoing COVID-19 pandemic that strongly affects the society-environment interactions. Restrictions associated with the pandemic have led to significant changes of the pollution and exposure levels across the world. This includes, i.a., emission and pollution changes associated to the countries and regions lockdowns stringency, and the influence of different atmospheric conditions (e.g. air quality, solar radiation, atmospheric dynamics, relative humidity and temperature) in the spread of COVID-19.

Co-organized by ES1
Conveners: Francesca Costabile, Cathy Wing Yi Li, Guy Brasseur | Co-conveners: Leena Järvi, Jan Semenza, Rajesh Kumar
| Mon, 05 Sep, 14:00–15:30 (CEST)|Room HS 1
| Mon, 05 Sep, 16:00–17:30 (CEST) | Display Mon, 05 Sep, 08:00–18:00|b-IT poster area

This session is open for abstracts on all aspects of solar and terrestrial radiation, clouds and aerosols. We welcome talks and posters on:
- Observations and measurement campaigns including the observation of optical properties of clouds and aerosols
- Radiative transfer in cloud-free and cloudy atmosphere including three-dimensional aspects and complex topography as well as radiative properties of the surface
- Parametrizations of radiation and clouds
- Modelling of radiation and clouds on all time-scales from nowcasting over short- and medium range numerical weather predication to decadal predictions and climate projections
- Verification of NWP and climate model outputs using satellite and ground-based observations
- Validation of satellite products using ground-based observations
- Use of modelled and observed radiation and cloud data in various applications such as renewable energy and agriculture.

Convener: Stefan Wacker | Co-conveners: Martin Wild, Laura Rontu, Antti Arola
| Fri, 09 Sep, 09:00–10:30 (CEST), 11:00–15:30 (CEST)|Room HS 3-4
| Thu, 08 Sep, 16:00–17:15 (CEST) | Display Thu, 08 Sep, 08:00–Fri, 09 Sep, 14:00|b-IT poster area

The cryosphere represents one of the Earth system compartments showing strong signs of dramatic changes due to climate forcing.
If global warming is the main common driver causing such changes, the rates, impacts, and processes acting in the mountain and Polar regions can differ markedly.
Estimating the response of the global cryosphere to climate change as well as the response of the components of the climate system to changes in the cryosphere relies on the understanding of climate-cryosphere interactions and processes in different regions and along with different spatial and temporal scales.

Mountain regions:
The seasonal snow cover, mountain glaciers, permafrost, and permanent ice deposits in caves are the main parts of the mountain's cryosphere.
They affect the hydrology of a vast range of river systems in the world and are vital for water availability, particularly in arid high mountain regions.
The water volume stored in mountain glaciers is small compared to the water storage in Polar Regions, but increasing rates of glacier mass loss result in a significant contribution to recent sea-level rise.
The observed permafrost degradation in mountain regions has severe implications on rock stability and increases the risk of natural hazards.
Permanent ice deposits in caves are probably the lesser-known as well as the smallest part of the earth’s cryosphere, but it has been shown recently that they can store important palaeoenvironmental information.
Investigating the micro-climate over snow and ice surfaces and its linkage to large-scale weather conditions and model climate is fundamental for tackling the mass and energy balance of the mountain cryosphere.

Polar regions:
Sea ice and ice sheets in both polar regions are sensitive to atmospheric forcing. Changes in these cryosphere components influence the climate through changes in atmospheric and ocean circulation, sea level, albedo, vegetation, and several related feedbacks.
In the Arctic, sea ice concentration and volume have recently experienced a sharp declining trend, and the Greenland Ice Sheet has similarly been losing mass at an increasing pace. Atmospheric forcing has played a crucial role in driving these trends and triggering positive feedback within the Arctic cryosphere-ocean-atmosphere system. These changes to the cryosphere may further feedback into large-scale climate variability through atmospheric and oceanic pathways.
At the other pole, sea and land ice in the Antarctic have heretofore experienced changes that strongly depend on the geographic location (e.g., east vs. west) and, overall, are less dramatic when compared to the changes observed in the Arctic cryosphere. Atmospheric influences on sea ice retreat and ice sheet/shelf surface melt are projected to become more prominent with continued climate warming.

Understanding the spatial and temporal variability of snow accumulation, storage and transport of ice and ice ablation in mountains and Polar Regions, and the interaction of the snow surface with the atmosphere within the boundary layer, are crucial for interpreting proxy records from various archives such as ice cores.
This session invites contributions addressing all aspects of cold regions' meteorology and the cryosphere interacting with the past, present, and future climate system from both modeling and observations.
We encourage submissions from multiple approaches, i.e. past records, meteorological and geophysical observations, numerical modeling, and downscaling methods aiming to advance the current knowledge of the feedback between the cryosphere and the climate system.
Presentations of interdisciplinary studies, as well as detailed process surveys, are highly welcome.

Conveners: Kay Helfricht, Renato R. Colucci, Andrea Fischer | Co-convener: Andrea Securo
| Mon, 05 Sep, 16:00–18:00 (CEST)|Room HS 5-6

The Sun is the main energy source for the Earth's atmosphere. The main manifestations of external forcing from space to the atmosphere are in variations in solar parameters such as the solar irradiance (including solar UV) and solar particle fluxes. These parameters can induce changes in the atmosphere both at local and global scales, and can influence over a large range of altitudes up to the thermosphere. Some of these changes have the potential to affect the troposphere through atmospheric coupling processes, particularly through the stratosphere-troposphere connection, and thus have the potential to influence weather and climate.
The field of space weather, that is the change in the environment between the Sun and the Earth, has seen a rapid increase in research activity in recent years and in associated large scientific advances. The weather and climate community can benefit from this via better representation of space weather effects and their associated impacts on the atmosphere.

The overarching goal of this session is to connect communities within the Sun-to-Earth system and in so doing promote Sun-to-Earth system science, products and services. The aim is to review the state-of-the-art and to identify possible interrelationships between Earth and the Sun and space weather by assessing the level of coupling in the relevant physical systems and processes.

Contributions from the following topics (but not exclusively) are welcome:
• Upper atmospheric dynamical variability and coupling between atmospheric layers e.g. thermosphere-ionosphere coupling
• Solar irradiance and energetic particle impacts on the atmosphere
• Solar variations and stratosphere-troposphere coupling
• Solar influence on climate variability
• Solar irradiance (spectral and total irradiance) variations
• Sun-Earth and Sun-planet interrelationships (of relevance to e.g. spacecraft for planetary exploration which require planet meteorology forecasts)
• Space weather observation, forecasting products and services

Convener: Mauro Messerotti | Co-conveners: Suzy Bingham, Jürgen Kusche
| Tue, 06 Sep, 09:00–10:30 (CEST)|Room HS 5-6
| Tue, 06 Sep, 11:00–13:00 (CEST) | Display Tue, 06 Sep, 08:00–18:00|b-IT poster area

Meteorology and hydrology act in tandem across the interface of the earth's surface, and as our understanding and predictive capabilities grow this interface is becoming increasingly important. For the good of society, the need to meld together the two disciplines is now stronger than ever. Indeed many national meteorological services around the world have been evolving, formally or informally, into national hydro-meteorological services. The aim of this session, which was new in 2019, is to provide a large and all-embracing hydro-meteorological forum where experts from both disciplines can join forces, to combine and exploit expertise, and to accelerate the integration process. We invite contributions across a wide-range of spatial scales (from 10s of metres up to global), and a wide-range of time scales (from ~1 hour up to seasonal and climate change), including, but not limited to, the following topics:
- land-atmosphere interaction and hydrological processes, including feedback mechanisms;
- understanding the meteorological processes driving hydrological extremes;
- tools, techniques, and expertise in forecasting hydro-meteorological extremes (e.g. river flooding, flash floods etc.);
- fully integrated numerical earth system modelling;
- quantification/propagation of uncertainties in hydro-meteorological models;
- quantification of (past/future) hydrological trends in observations and climate models;
- hydro-meteorological prediction that includes the associated impacts;
- related cryospheric processes;
- environmental variable monitoring by remote sensing.
- droughts (in tandem with the 2020 conference theme)

Conveners: Timothy Hewson, Fatima Pillosu | Co-convener: Stefan Kollet
| Wed, 07 Sep, 14:00–17:15 (CEST)|Room HS 7
| Thu, 08 Sep, 11:00–13:00 (CEST) | Display Thu, 08 Sep, 08:00–Fri, 09 Sep, 14:00|b-IT poster area

The session will focus on atmospheric processes specific to mountainous regions, which are strongly and mutually connected with the exchange of momentum, heat and mass between the Earth’s surface and the atmosphere. They intrinsically involve a variety of scales, in space and time, which are strongly interconnected. Spatial scales range from local surface layer processes to synoptic-scale effects and planetary waves, which may affect regions quite distant from the mountains where they originated. Time scales range from those of local turbulence to the multi-hour scales of fastest evolving mesoscale systems, to the long-range processes typical of climate change. Progress in understanding and predicting the above processes still poses significant challenges, which are being addressed by many recent mountain meteorology projects, and in particular within the international research programme TEAMx (http://www.teamx-programme.org/). TEAMx promotes a networking of activities and research projects covering different aspects and subjects related to the initiative’s focus. The session will therefore offer an opportunity to disseminate and discuss within a broader community advances and results achieved within TEAMx projects and activities. Contributions from every other project and initiative covering related topics are very welcome as well, in a synergistic perspective.

Including Young Scientist Conference Award
Convener: Dino Zardi | Co-conveners: Mathias Rotach, Chantal Staquet, Helen Ward
| Thu, 08 Sep, 09:00–10:30 (CEST)|Room HS 7
| Thu, 08 Sep, 11:00–13:00 (CEST) | Display Thu, 08 Sep, 08:00–Fri, 09 Sep, 14:00|b-IT poster area

UP3 – Climate modelling, analyses and predictions


Society will feel the impacts of climate change mainly through extreme weather and climate events, such as heat waves and droughts, heavy rainfall and associated flooding, and extreme winds. Determining from the observational record whether there have been significant changes in the frequency, amplitude and persistence of extreme events poses considerable challenges. Changes in the distributional tails of climate variables may not necessarily be coherent with the changes in their mean values. Also, attributing any such changes to natural or anthropogenic drivers is a challenge.

The aim of this session will be studies that bridge the spatial scales and reach the timescales of extreme events that impact all our lives. Papers are solicited on advancing the understanding of causes of observed changes in mean climate, in its variability and in the frequency and intensity of extreme events. In particular, papers are invited on trends in the regional climate of Europe, not just the mean, but variability and extremes, often for the latter measured through well-chosen indices.

Convener: Martine Rebetez | Co-conveners: Albert M.G. Klein Tank, Monika Lakatos
| Wed, 07 Sep, 09:00–10:30 (CEST), 11:00–13:00 (CEST)|Room HS 3-4
| Wed, 07 Sep, 14:00–15:30 (CEST) | Display Wed, 07 Sep, 08:00–18:00|b-IT poster area

Covariability between remote regions – often named teleconnections – are at the basis of our current knowledge of a large part of Earth’s climate variations and represent an important source of weather and climate predictability. Tropospheric and stratospheric pathways have been suggested to play a role in connecting internally-generated and radiatively-forced anomalies at mid-latitudes, as well as in settling tropical-extratropical and polar-nonpolar interactions. However, the underlying processes behind these linkages are still not properly understood, misled by different metrics and diagnostics, and/or generally poorly simulated by global climate models (GCMs). A continuous assessment of these atmospheric teleconnections is thus necessary, since advances in process understanding could translate into improving climate models and predictions.

This session aims at gathering studies on both empirical and modelling approaches, dealing with a dynamical characterization of mid-latitude atmospheric teleconnections. It invites contributions using observational datasets; coupled and uncoupled (atmosphere-only) GCM simulations; pre-industrial, present, and future climate conditions; idealised sensitivity experiments; or theoretical models.

Keynote talk:

TBD - ""

Convener: Javier Garcia-Serrano | Co-conveners: Paolo Davini, Yannick Peings
| Tue, 06 Sep, 11:00–13:00 (CEST)|Room HS 3-4
| Tue, 06 Sep, 14:00–15:30 (CEST) | Display Tue, 06 Sep, 08:00–18:00|b-IT poster area

Synoptic climatology examines all aspects of relationships between large-scale atmospheric circulation on one side, and surface climate and environmental variables on the other. The session addresses all topics of synoptic climatology; nevertheless, we would like to concentrate on the following areas: statistical (empirical) downscaling, circulation and weather classifications, teleconnections and circulation regimes, and climatology of cyclones and other pressure formations, including effects of the circulation features on surface climate conditions. We also encourage submissions on recent climate variability and change studied by tools of synoptic climatology or otherwise related to synoptic-climatological concepts.

We invite contributions on theoretical developments of classification methods as well as on their use in various tasks of atmospheric sciences, such as climate zonation, identification and analysis of circulation and weather types, and synoptic catalogues. Climatological, meteorological, and environmental applications of circulation classifications are particularly welcome.

The session will also include presentations on statistical (empirical) downscaling as a tool for evaluation and reconstruction of historical climate, gap filling in time series, analysis of extremes and non-climatic variables. Also intercomparisons among downscaling methods and their validation belong to this session.

Contributions on teleconnections (modes of low-frequency variability) and circulation regimes are expected to cover particularly their impacts on surface weather, climate, and environment.

The contributions on climatology of cyclones and other pressure formations will include analyses of cyclone tracks, life time and intensity of cyclones, as well as analyses of anticyclones and blockings. We also invite studies on impacts of the pressure formations on the environment and society, their relationships with large scale circulation patterns, as well as analyses of their recent trends and behavior in possible future climates.

Conveners: Radan Huth, Rasmus Benestad
| Tue, 06 Sep, 14:00–17:30 (CEST)|Room HS 3-4
| Wed, 07 Sep, 09:00–10:30 (CEST) | Display Wed, 07 Sep, 08:00–18:00|b-IT poster area

The exceptional amplitude and rate of warming recorded at global, hemispherical and regional scales within contemporary instrumental records should be placed in the context of longer-term multi-centennial and millennial climate variability in order to both assess its uniqueness and better understand the mechanisms that contribute to the background of natural climate variability. Systematic meteorological measurements only span over a relatively short time interval. Thus, documentary evidence and natural climate proxies are used for the reconstruction and understanding of longer term past climate variability.

This session welcomes presentations related to various topics related to this frame:
• early instrumental meteorological measurements, their history and use for the long-term series
• documentary evidence and its features (advantages, disadvantages limits)
• natural climate proxies and its features (advantages, disadvantages, limits)
• methodological improvements and analysis of climate reconstruction approaches both from documentary evidence and natural climatic proxies
• results of climate reconstructions over different regions based on various climatic sources
• hydrological and meteorological extremes (e.g. floods, hurricanes, windstorms, tornadoes, hailstorms, frosts) and their human impacts in relation to climate variability beyond the instrumental period.
• climate modelling of the last 2K and comparison of model outputs with reconstructed/observed climatological data
• past impacts of climate variability on natural processes and human society
• past and recent perception of the climate and its variability
• history of meteorology and meteorological and climatological knowledge
• discussion of natural and anthropogenic forcings as well as recent warming at global, regional and local scales in a long-term context.

Convener: Rudolf Brazdil | Co-conveners: Ricardo García-Herrera, Fidel González-Rouco
| Tue, 06 Sep, 09:00–10:30 (CEST)|Room HS 3-4
| Tue, 06 Sep, 11:00–13:00 (CEST) | Display Tue, 06 Sep, 08:00–18:00|b-IT poster area

Improved reanalyses of past weather can be obtained by retrospectively assimilating reprocessed observational datasets ranging from surface stations and satellites with a up-to-date Numerical Weather Prediction (NWP) model. The resulting time series of the atmospheric state is both dynamically consistent and close to observations. The interest in extracting climate information from reanalysis is rising and creating a request for reanalysis uncertainty estimation at various temporal-spatial scales.
These research questions have been addressed in EU-funded research projects (e.g.ERA-CLIM, EURO4M and UERRA). Regional reanalyses are now available for Europe and specific sub-domains, e.g. produced by national meteorological services. Global and regional reanalyses are also an important element of the Copernicus Climate Change Services.

This session invites papers that:
• Explore and demonstrate the capability of global and regional reanalysis data for climate applications
• Compare different reanalysis (global, regional) with each other and/or observations
• Improve recovery, quality control and uncertainty estimation of related observations
• Analyse the uncertainty budget of the reanalyses and relate to user applications

Convener: Frank Kaspar | Co-conveners: Eric Bazile, Jan Keller
| Wed, 07 Sep, 14:00–17:15 (CEST)|Room HS 3-4
| Wed, 07 Sep, 11:00–13:00 (CEST) | Display Wed, 07 Sep, 08:00–18:00|b-IT poster area

Prediction and predictability on timescales of several weeks to months is crucial for the advancement of our understanding and modeling of processes on these timescales. These processes include coupling processes in the global climate system, their representation and prediction in model systems, as well as the impacts associated with extreme events that exhibit probabilistic predictability on these timescales. This session invites contributions that span all aspects of prediction and predictability in the lead time range between 2 weeks and seasonal timescales. We encourage submissions on physical processes, including (but not limited to) the Madden Julian Oscillation (MJO), the monsoons, and El Nino Southern Oscillation (ENSO) and their remote effects, coupling between different parts of the globe, the vertical coupling in the atmosphere, as well as coupling between the atmosphere and the underlying surface in terms of land, ocean and the cryosphere. We further invite contributions on ensemble prediction and analysis methods as well as impact-based methods for socio-economic impacts related to processes and predictability on sub-seasonal to seasonal timescales.

Convener: Daniela Domeisen | Co-conveners: Johanna Baehr, Dominik Büeler, Maria Pyrina, Frederic Vitart, Christopher White, Priyanka Yadav
| Thu, 08 Sep, 11:00–13:00 (CEST)|Room HS 1
| Wed, 07 Sep, 16:00–17:15 (CEST) | Display Wed, 07 Sep, 08:00–18:00|b-IT poster area

Physical climate storylines (PCS) are physically self-consistent unfoldings of past events, or of plausible future events. The PCS approach is intended to inform stakeholders about the possible impact chains of climate hazards by either complementing or replacing probabilistic approaches to representing uncertainty about future climate. PCS are developed with the aim of incorporating stakeholder perspectives either by addressing questions identified by stakeholders or by co-producing storylines with stakeholders themselves. In many cases, developing PCS involves combining the analysis of model output and observations at varying spatiotemporal scales – and, in particular, the output of climate and weather prediction models. For this session, we encourage submissions that develop one of the following: (i) physical climate storylines to address information needs of stakeholders for climate risk assessment and management, (ii) critical/evaluative perspectives on existing storyline methods, (iii) critical perspectives on the PCS approach that evaluate their merits and shortcomings as tools for stakeholder engagement and/or tools for delivering information targeted to their intended users.

Co-organized by UP3
Convener: Marina Baldissera Pacchetti | Co-conveners: Bart van den Hurk, Theodore Shepherd, Suraje Dessai, Karin van der Wiel, Jana Sillmann
| Mon, 05 Sep, 16:00–17:30 (CEST)|Room HS 1
| Tue, 06 Sep, 09:00–10:30 (CEST) | Display Tue, 06 Sep, 08:00–18:00|b-IT poster area

Supporters & sponsors