The session welcomes papers on:

1) Forecasting and simulating high impact weather events - research on improvement of high-resolution numerical model prediction of severe weather events (such as winter storms, tropical storms, and severe mesoscale convective storms) using data from various observational platforms, evaluation of the impact of new remote sensing data;

2) Development and improvement of model numerics - basic research on advanced numerical techniques for weather and climate models (such as cloud resolving global model and high-resolution regional models specialized for extreme weather events on sub-synoptic scales);

3) Development and improvement of model physics - progress in research on advanced model physics parametrization schemes (such as stochastic physics, air-wave-oceans coupling physics, turbulent diffusion and interaction with the surface, sub-grid condensation and convection, grid-resolved cloud and precipitation, land-surface parametrization, and radiation);

4) Model evaluation - verification of model components and operational NWP products against theories and observations, regional and global re-analysis of past observations, diagnosis of data assimilation systems;

5) Data assimilation systems - progress in the development of data assimilation systems for operational applications (such as reanalysis and climate services), research on advanced methods for data assimilation on various scales (such as treatment of model and observation errors in data assimilation, and observational network design and experiments);

6) Ensemble forecasts and predictability - strategies in ensemble construction, model resolution and forecast range-related issues, and applications to data assimilation;

7) Advances and challenges in high-resolution simulations and forecasting.

Data assimilation systems and numerical weather and climate models are essential to understand the current and past state of the Earth System, and to predict it's future. This session will summarize the latest progress in the development of such models including the assimilation of space-borne and conventional observations, developments for the numerical formulation of the models regarding both the fluid dynamic solver and physical parametrisation schemes, and developments towards weather and climate simulations at higher resolution on modern supercomputers.

Public information:
We will divide the session chats into smaller groups of 4 abstracts based on the order of abstracts in the session programme. Each group will have ~15 minutes. Each mini-session will be organized as follows:

- All authors post a few sentences to present their work.
- Everyone attending the mini-session can post questions or comments to the authors.
- All post related to one particular abstract should begin with the name of the first author. E.g. @David: What is the y-axis of Figure 2?

Forecasting the weather, in particular severe and extreme weather has always been the most important subject in meteorology. This session will focus on recent research and developments on forecasting techniques, in particular those designed for operations and impact oriented. Contributions related to nowcasting, meso-scale and convection permitting modelling, ensemble prediction techniques, and statistical post-processing are very welcome.
Topics may include:
 Nowcasting methods and systems, use of observations and weather analysis
 Mesoscale and convection permitting modelling
 Ensemble prediction techniques
 Ensemble-based products for severe/extreme weather forecasting
 Seamless deterministic and probabilistic forecast prediction
 Post-processing techniques, statistical methods in prediction
 Use of machine learning, data mining and other advanced analytical techniques
 Impact oriented weather forecasting
 Presentation of results from relevant international research projects of EU, WMO, and EUMETNET etc.

High-impact climate and weather events typically result from the interaction of multiple hazards across various spatial and temporal scales. These events, also known as Compound Events, often cause more severe socio-economic impacts than single-hazard events, rendering traditional univariate extreme event analyses and risk assessment techniques insufficient. It is therefore crucial to develop new methodologies that account for the possible interaction of multiple physical drivers when analysing high-impact events. Such an endeavour requires (i) a deeper understanding of the interplay of mechanisms causing Compound Events and (ii) an evaluation of the performance of climate/weather, statistical and impact models in representing Compound Events.

The European COST Action DAMOCLES coordinates these efforts by building a research network consisting of climate scientists, impact modellers, statisticians, and stakeholders. This session creates a platform for this network and acts as an introduction of the work related to DAMOCLES to the research community.

We invite papers studying all aspects of Compound Events, which might relate to (but are not limited to) the following topics:

Synthesis and Analysis: What are common features for different classes of Compound Events? Which climate variables need to be assessed jointly in order to address related impacts? How much is currently known about the dependence between these variables?
Stakeholders and science-user interface: Which events are most relevant for stakeholders? What are novel approaches to ensure continuous stakeholder engagement?
Impacts: What are the currently available sources of impact data? How can they be used to link observed impacts to climate and weather events?
Statistical approaches, model development and evaluation: What are possible novel statistical models that could be applied in the assessment of Compound Events?
Realistic model simulations of events: What are the physical mechanisms behind different types of Compound Events? What type of interactions result in the joint impact of the hazards that are involved in the event? How do these interactions influence risk assessment analyses?

Today, it is almost certain that global climate change will affect the frequency and severity of extreme meteorological and hydrological events. It is necessary to develop models and methodologies for the better understanding, forecasting, hazard prevention of weather induced extreme events and assessment of disaster risk. This session considers extreme events that lead to disastrous hazards induced by severe weather and climate change. These can, e.g., be tropical or extratropical rain- and wind-storms, hail, tornadoes or lightning events, but also floods, long-lasting periods of drought, periods of extremely high or of extremely low temperatures, etc. Papers are sought which contribute to the understanding of their occurrence (conditions and meteorological development), to assessment of their risk and their future changes, to the ability of models to reproduce them and methods to forecast them or produce early warnings, to proactive planning focusing to damage prevention and damage reduction. Papers are also encouraged that look at complex extreme events produced by combinations of factors that are not extreme by themselves. The session serves as a forum for the interdisciplinary exchange of research approaches and results, involving meteorology, hydrology, hazard management and/or applications like insurance issues.

Public information:
NH1.6/AS1.5/HS13.10

Extreme meteorological and hydrological events induced by severe weather and climate change
Display presentations Monday, 04 May, 08:30–12:30

The presentation of Displays during the chat will be made in the following order:

Severe storms/precipitation (8:30-10:15): D1932, D1933, D1934, D1936, D1938, D1940, D1942, D1943, D1944, D1951, D1952, D1953, D1955, D1956, D1957, D1958, D1960, D1962, D1963 (not presented), D1964, D1965, D1966, D1967, D1969, D1974, D1977, D1982

Floods (10:45-11:05): D1935, D1937, D1939, D1941, D1954, D1959

Droughts and other extreme weather events (11:05-12:30): D1945, D1946, D1947, D1948, D1949, D1950, D1961, D1968 (not presented), D1970, D1971, D1972, D1973 (not presented), D1975, D1976, D1977, D1978, D1979, D1980, D1981, D1983, D1984, D1985

Information (video and text) how to use the chats could be found at https://egu2020.eu/sharing_geoscience_online/how_to_use_the_chats.html

The chairpersons will handle and organize the questions and replies of the presentations, following the above line of presentations. Each author is asked for an introduction (please prepare). Then, we will take questions.

Conveners, co-conveners, and chairpersons of the sessions reserve the right to ban participants showing abusive behaviour or violating EGU's Code of Conduct.

The conveners of the session
Athanasios Loukas
Maria Carmen Llasat
Uwe Ulbrich

Wind and solar power are the predominant new sources of electrical power in recent years. Portugal’s renewable energy production in March 2018 was 104% of its electricity demand in the same month. By their very nature, wind and solar power, as well as hydro, tidal, wave and other renewable forms of generation are dependent on weather and climate. Modelling and measurement for resource assessment, site selection, long-term and short term variability analysis and operational forecasting for horizons ranging from minutes to decades are of paramount importance.

The success of wind power means that wind turbines are increasingly put in sites with complex terrain or forests, with towers extending beyond the strict logarithmic profile, and in offshore regions that are difficult to model and measure. Major challenges for solar power are notably accurate measurements and the short-term prediction of the spatiotemporal evolution of the effects of cloud field and aerosols. Planning and meteorology challenges in Smart Cities are common for both.

For both solar and wind power, the integration of large amounts of renewable energy into the grid is another critical research problem due to the uncertainties linked to their forecast and to patterns of their spatio-temporal variabilities.

We invite contributions on all following aspects of weather dependent renewable power generation:

• Wind conditions (both resources and loads) on short and long time scales for wind power development, especially in complex environments (e.g. mountains, forests, coastal or urban).
• Long term analysis of inter-annual variability of solar and wind resource
• Typical Meteorological Year and probability of exceedance for wind and solar power development,
• Wind and solar resource and atlases.
• Wake effect models and measurements, especially for large wind farms and offshore.
• Performance and uncertainties of forecasts of renewable power at different time horizons and in different external conditions.
• Forecast of extreme wind events and wind ramps.
• Local, regional and global impacts of renewable energy power plants or of large-scale integration.
• Dedicated wind measurement techniques (SODARS, LIDARS, UAVs etc.).
• Dedicated solar measurement techniques (pyranometric sensors, sun-photometer, ceilometer, fish-eye cameras, etc.) from ground-based and space-borne remote sensing.
• Tools for urban area renewable energy supply strategic planning and control.

Public information:
Update:
We will go with running the chat as recommended by EGU, so going one by one through the different displays and allocating around 7 minutes to each. For the authors, please prepare a 1-3 sentence presentation of your idea, answering to the questions: who am I, what did I do, and (especially) what did I find out?

Mountains cover approximately one quarter of the total land surface on the planet, and a significant fraction of the world’s population lives in their vicinity. Orography critically affects weather and climate processes at all scales and, in connection with factors such as land-cover heterogeneity, is responsible for high spatial variability in mountain weather and climate.

Due to this high complexity, monitoring and modeling the atmosphere and the other components of the climate system in mountain regions is challenging both at short (meteorological) and long (climatological) time-scales. This session is devoted to the better understanding of weather and climate processes in mountain and high-elevation areas around the globe, as well as their modification induced by global environmental change.

We welcome contributions describing the influence of mountains on the atmosphere on meteorological time-scales, including terrain-induced airflow, orographic precipitation, land-atmosphere exchange over mountains, forecasting and predictability of mountain weather. Furthermore we invite studies that investigate climate processes and climate change in mountain areas and its impacts on dependent systems, based on monitoring and modeling activities. Particularly welcome are contributions that merge various sources of information and reach across disciplinary borders (atmospheric, hydrological, cryospheric, ecological and social sciences). In this respect the session invites also contributions on outcomes of the WMO "High Mountain Summit" taking place in October 2019.

Public information:
Online survey (including questions about a possible follow-up webinar): https://form.jotformeu.com/83462227858365

The large-scale atmospheric circulation strongly influences Earth's climate, both locally and globally, via its transport of energy, moisture, and momentum. While our ability to simulate the global circulation is improving, large model biases and uncertainties in climate change projections persist. Our theoretical understanding of how atmospheric circulations respond to climate changes is also limited, particularly on regional scales and in the presence of zonal asymmetries. Advancing our knowledge of the underlying dynamics is therefore crucial for reliable climate projections and for correctly interpreting palaeoclimate records.

The objective of this session is to advance our mechanistic understanding of atmospheric circulation changes and to analyse their impacts at global and regional scales, specifically on precipitation in past, present, and future climates. We encourage theoretical, observational and modelling contributions on tropical (ITCZ, monsoons, Hadley & Walker circulations, MJO) and extratropical circulations (jet streams, storm tracks, blocking).

With the advent of the sub-seasonal to seasonal (S2S) prediction project, research communities now have unprecedented access to a comprehensive database of forecasts and hindcasts from a large number of forecasting centres from across the globe.

This session invites contributions that span all aspects of meteorological/oceanographic prediction in the 2 weeks to 2 months lead time range. The session will include both meteorological and impacts studies, that may use the S2S project’s database, but that can also use alternative sources of forecast information. Contributions are welcome for studies of phenomena such as the Madden Julian Oscillation (MJO), tropical/extratropical waves, stratospheric variability and stratosphere - troposphere coupling, in addition to studies of predictability/skill of atmospheric or surface variables and case studies of high impact weather events.

Contributions regarding impacts studies at the S2S time-range are also highly welcome, including, but not limited to, the areas of hydrology, health, fire, agriculture, and energy. These can include modeling studies of the impacts right through to presentations of how S2S-derived information can be integrated into decision support systems at the local, regional and country level.


******************* UPDATES********************************************************
Our two solicited speaker this year are:

Dr Adrian M Tompkins (ICTP,Italy) talking us about the potential to forecast malaria outbreaks at the S2S time scale.
Dr Suzana Camargo (columbia University, US) looking at the predictability of tropical cyclones at the S2S time scale

***************************************************************************************

The S2S dinner will take place as for tradition on the day of the session. You will receive an email with instruction if you would like to participate.

Public information:
S2S Session AS 1.9 Subseasonal-to-Seasonal Prediction: meteorology and impacts

Session 1: Monday 4 May 14:00-15:45 PM CET


14:00-15:15 Discussion/questions on individual displays

1. On the Resonances and Teleconnections of the North Atlantic and Madden-Julian Oscillations
Gilbert Brunet

2. Sub-seasonal prediction of the extreme weather conditions associated with the northeastern Australia floods in February 2019
Tim Cowan

3. Predictable weather regimes at the S2S time scale
Nicola Cortesi

4. The mutual impact of weather regimes and the stratospheric circulation on European surface weather
Christian Grams

5. Troposphere-Stratosphere Coupling In S2S Models and Its Importance for a Realistic Extratropical Response to the Madden-Julian Oscillation
Chen Schwartz

6. Impacts of ocean model resolution in S2S forecasts with the ECMWF coupled model
Chris Roberts

7. Convective-Permitting Modeling for Retrospective Subseasonal-to-Seasonal (S2S) Forecasting Using the Framework of the Coordinated Regional Ensemble Downscaling Experiment (CORDEX)
Hsin-I Chang

8. Tropical cyclone activity prediction on subseasonal time-scales
Suzana Camargo

9. Subseasonal forecasts for humanitarian decision-making in Kenya: understanding forecast skill and the latest results from the S2S ForPAc real-time pilot study.
Dave MacLeod

10. Forecasting climate extremes to aid decisions on multi-week timescales
Catherine de Burgh-Day

11. Understanding and forecasting the subseasonal meteorological drivers of the European electricity system in winter
Hannah Bloomfield

12. Sub-seasonal Monsoon Onset forecasting over West Africa
Elisabeth Thompson

13. Using a statistical model to verify warm conveyor belts in ECMWF’s sub-seasonal forecasts
Julian Quinting

14. Enhanced extended-range predictability of the 2018 late-winter Eurasian cold spell due to the stratosphere
Lisa-Ann Kautz

15. Promising subseasonal forecasting results based on machine learning
Matti Kämäräinen

15:15-15:45 General Discussion on S2S predictability/Modelling issues



Session 2: Monday 4 May 16:15-18:00 PM CET


16:15-17:30 Discussion/questions on individual displays


16. A new approach to subseasonal multi-model forecasting: Online prediction with expert advice
Paula Gonzalez

17. Heatwaves over Europe: Identification and connection to large-scale circulation
Emmanuel Rouges

18. Is Tuning of Auto-conversion Important for the Realistic Simulation of Indian Summer Monsoon Intraseasonal Oscillations and MJO in Coupled Climate Model?
Ushnanshu Dutta

19. Lagged ensemble vs burst sampling strategy for initializing sub-seasonal forecasts
Frederic Vitart

20. Sub-seasonal precipitation forecast skills over China during the boreal summer monsoon
Yuan Li

21. Quasi-Biweekly Oscillation over the tropical western Pacific in boreal winter： Its climate influences on North America
Zizhen Dong

22. The influence of aggregation and statistical post-processing on the sub-seasonal predictability of European temperatures
Chiem van Straaten

23. Flow-dependent sub-seasonal forecast skill for Atlantic-European weather regimes
Dominik Büeler

24. Jet Latitude Regimes and the Predictability of the North Atlantic Oscillation
Kristian Strommen

25. Relationship between meningitis occurrence and atmospheric conditions over the African meningitis belt
Cheikh Dione

26. Climate Advanced Forecasting of sub-seasonal Extremes (CAFE), ITN Project
Alvaro Corral


27. The potential predictability of Singapore and Maritime Continent weather regimes in relation to the MJO and ENSO
Mohammad Eeqmal Hassim

28. Subseasonal Forecasting of Aedes-borne Disease Transmission
Laurel DiSera

29. Quantifying the usefulness of European subseasonal forecasts using a real-world energy-sector framework
Joshua Dorrington

30 Teleconnection patterns in the Southern Hemisphere in subseasonal to seasonal models hindcasts and influences on South America
Iracema Cavalcanti

17:30-18:00 General Discussion on S2S prediction/applications

ENSO and its interactions with other tropical basins are the dominant source of interannual climate variability in the tropics and across the globe. Understanding the dynamics, predictability, and impacts of ENSO and tropical basins interactions, and anticipating their future changes are thus of vital importance for society. This session invites contributions regarding all aspects of ENSO and tropical basins interactions, including: dynamics, multi-scale interactions; low frequency, decadal and paleo variability; theoretical approaches; ENSO diversity; global teleconnections; impacts on climate, society and ecosystems; seasonal forecasting and climate change projections of ENSO and its tropical basins interactions. Studies aimed at understanding ENSO and its tropical basins interactions in models of a range of complexity are especially welcomed, including analysis of CMIP model intercomparisons.

Public information:
Dear all,
welcome to the virtual EGU 2020. This is just a reminder that we will have the "ENSO and Tropical Basins Interactions: Dynamics, Predictability and Modelling" (CL4.20/AS1.12/NP2.6/OS1.27) session Thu, 07 May, 14:00–15:45 (Vienna time zone). It will be an online chat only session.

In addition to the EGU chat session on Thursday we plan to do a video meeting for the "ENSO and Tropical Basins Interactions: Dynamics, Predictability and Modelling" session with presentations from the authors (you) some time later this year (e.g. June/July). More on this we will discuss on Thursday in the EGU chat of this session.

Best regards and hope to chat with you on Thursday!
Dietmar Dommenget, Antonietta Capotondi, Daniela Domeisen and Eric Guilyardi

Please note that this session will be linked to a special session for the presentation of the Fridtjof Nansen Medal. We also have Daniela Domeisen and Caroline Katsman as invited speakers.

The North Atlantic exhibits a high level of natural variability from interannual to centennial time scales, making it difficult to extract trends from observational time series. Climate models, however, predict major changes in this region, which in turn will influence sea level and climate, especially in western Europe and North America. In the last years, several projects have been focused on the Atlantic circulation changes, for instance OVIDE, RACE, OSNAP, and ACSIS. Another important issue is the interaction between the atmosphere and the ocean as well as the cryosphere with the ocean, and how this affects the climate.

We welcome contributions from observers and modelers on the following topics:

-- climate relevant processes in the North Atlantic region in the atmosphere, ocean, and cryosphere
-- atmosphere - ocean coupling in the North Atlantic realm on time scales from years to centuries (observations, theory and coupled GCMs)
-- interpretation of observed variability in the atmosphere and the ocean in the North Atlantic sector
-- comparison of observed and simulated climate variability in the North Atlantic sector and Europe
-- response of the atmosphere to changes in the North Atlantic
-- dynamics of the Atlantic Meridional Overturning Circulation
-- variability in the ocean and the atmosphere in the North Atlantic sector on a broad range of time scales
-- changes in adjacent seas related to changes in the North Atlantic
-- role of water mass transformation and circulation changes on anthropogenic carbon and other parameters
-- linkage between the observational records and proxies from the recent past

Public information:
This session will continue at 12:45 with OS1.0 (https://meetingorganizer.copernicus.org/EGU2020/session/38390)

Recent extreme weather and climate episodes, including the European heatwaves of summer 2003 and June/July 2019, highlight the need to further our understanding of linear and non-linear (quasi-stationary) planetary and synoptic-scale Rossby wave dynamics in the atmosphere, and their impacts on weather and climate events. Abstracts are solicited that are dedicated to:
i) the dynamics of linear wave propagation or quasi-stationarity, of wave breaking, atmospheric blocking, or jets as atmospheric Rossby waveguides. This includes the role of local and remote drivers (e.g., the tropics, Arctic, or stratosphere).
ii) exploring the links between extreme weather/climate events and linear and non-linear Rossby waves, including wave breaking and/or blocking.
iii) quantifying model representation of Rossby waves in climate and numerical weather prediction models, including wave propagation and breaking.
iv) exploring the role of Rossby wave trains on predictability at lead times from medium range (~2 weeks) to seasonal time-scales. This includes blocking and wave propagation.
v) analyzing projected future changes in planetary or synoptic-scale Rossby waves, or in their future impacts on weather and climate events.

The global monsoon system and its regional monsoon components have profound impacts on society and are among the most complex phenomena involving coupled atmosphere-ocean-land interactions. Monsoons can cause severe floods and droughts in the tropics as well as undergoing climate variability on subseasonal, interannual and decadal or longer time scales. In addition to its profound local effects, monsoon variability is also associated with global-scale impacts since the energy released by monsoon systems can influence the global circulation. However, it is notoriously difficult to simulate and forecast the monsoons on temporal scales from numerical weather prediction (NWP), subseasonal-to-seasonal and interannual-to-decadal predictions, and longer timescale climate projections. A better understanding of monsoon physics and dynamics, with more accurate simulation, prediction and projection of monsoon systems is therefore of a great importance to society.

The combination of modern- and palaeo-monsoon research can help us better understand the fundamental nature of the monsoon and its variability. Comparisons of monsoon responses to large-scale forcings found in the palaeoclimate record can help us to understand how the monsoon will respond to changes in forcings in the future, potentially allowing us to constrain estimates of climate change. Similarly, the wealth of observations, reanalysis products and modelling work in the contemporary period can help us piece together data from point-proxy records of the past.

This session therefore invites presentations on all aspects of monsoon research in contemporary, future and palaeoclimate periods (observational, modeling, attribution, prediction and projection) from the natural and anthropogenic variability and predictability of the monsoon systems on multiple time scales, to the impact of monsoons on extreme weather and climate events (floods, droughts, tropical cyclones, heat waves, etc.), as well as the links between monsoons and global climate change and feedbacks with the biosphere. Theoretical works based on idealized planetary and ITCZ frameworks are also invited.

Public information:
10:45 Welcome
10:50 Arvind Singh: Increase in summer monsoon rains in northeast India during ENSO periods: a multiproxy analysis
10:58 Michael Byrne: Radiative effects of clouds and water vapour on the monsoon
11:06 Feng Shi: A reconstruction of the East Asian summer monsoon index over the past half millennium
11:14 Marcia Zilli Synoptic climatology and changes in precipitation associated with the SACZ using a cloud band identification technique
11:22 Qiaoling Ren: Effects of the Tibetan Plateau on East Asian Summer Monsoon via Weakened Transient Eddies
11:30 Tresa Mary Thomas: Statistics of Monsoon Low Pressure Systems in the Indian Subcontinent and Estimation of Related Extreme Rainfall Risk
11:38 Junbin Wang: Is the Current Subtropical Position of the Tibetan Plateau Optimal for Intensifying the Asian Monsoon?
11:46 Kyung-Ja Ha: Future changes of summer monsoon characteristics and evaporative demand over Asia in CMIP6 simulations
11:54 Marco Gaetani: Role of friction and orography in the Asian-African monsoonal system
12:02 Nitin Babu George: Abrupt transition in organized convection during the monsoon onset in central India and Climate change effect
12:10 Xin-Gang Dai: A climate classification: Mediterranean, monsoon and westerlies
climates
12:18 Lun Dai: Classification and Diagnosis of Summer Monsoon Rainfall Patterns and their Potential Predictability in Southeast China

As a weather pattern, the Asian monsoon impacts the lives of more than a billion people. With rapid population and economic growth across the monsoon region, it becomes a pressing concern that the convection coupled to surface emissions is playing a significant role in the region’s air quality. The uplift of pollutants also enhances aerosol–cloud interactions that may change the behaviour of the monsoon. The monsoon system is therefore relevant to scales and processes bridging regional air quality, climate change, and global
chemistry-climate interaction and the chemical transport effect of the monsoon system is seen from satellites as an effective transport path for pollutants to enter the stratosphere.
The session will focus on the dynamical, micro-physical, and chemical processes dominating transport, chemical transformations and particle and cloud formation throughout the Upper-Troposphere Lower-Stratosphere above the Asian Monsoon system as well their internal and ozone and climate couplings. Here we especially encourage experimental and modelling (process to global) studies from recent programmes (such as StratoClim, BATAL, OMO). Contributions addressing tropospheric processes within the Atmospheric Composition and Asian Monsoon (ACAM) Programme objectives, such as the coupling to local emission on air quality and aerosols, clouds, interactions with the Asian monsoon are also welcome.

Public information:
The session goes from 12h30 with anticipation of a group of papers
and is supported by a live video / audio session (https://talk.icg.kfa-juelich.de/b/str-cr4-27w)

Virtual video session: 12:30-14:00 – Paper block #1
https://talk.icg.kfa-juelich.de/b/str-cr4-27w - please keep your mic muted and video off -
The link will be active 30 minutes before the session time
@all: make use of the live chat for questions
Please keep your mic muted and video off
9’ presentation + 1’ for one eventual question

EGU Live chat: 14:00-15:30 Discussion block #1 & Paper block #2
@all: make use of the live chat for questions
(https://egu2020.eu/sharing_geoscience_online/how_to_use_the_chats.html)
5' for each paper of block #1
3’ to present/summarize with reference to the displays + 5’ minutes for the questions for block #2

The variability of the stratosphere plays a key role for many atmospheric phenomena. Examples include the dynamical two-way coupling between the stratosphere and troposphere during sudden stratospheric warming events, the transport of trace gases through the meridional circulation of the stratosphere, or the connection between the Quasi-Biennial Oscillation of the tropical stratosphere and the Madden-Julian Oscillation.

This session is interested in all aspects of stratospheric circulation variability, including the mechanisms behind the vertical coupling between the stratosphere and troposphere in tropics and extratropics, the importance of stratospheric dynamics for explaining both short-term atmospheric weather and long-term climate variability, and the role of the stratospheric circulation for the chemical composition of the atmosphere. We welcome abstracts that study this problem from an observational, modelling, or theoretical viewpoint on all temporal and spatial scales.

In many respects internal gravity waves (IGWs) still pose major questions both to the atmospheric and ocean sciences, and to stellar physics. Important issues are IGW radiation from their various relevant sources, IGW reflection at boundaries, their propagation through and interaction with a larger-scale flow, wave-induced mean flow, wave-wave interactions in general, wave breaking and its implications for mixing, and the parameterization of these processes in models not explicitly resolving IGWs. Also the observational record, both on a global scale and with respect to local small-scale processes, is not yet sufficiently able to yield appropriate constraints. The session is intended to bring together experts from all fields of geophysical and astrophysical fluid dynamics working on related problems. Presentations on theoretical, modelling, experimental, and observational work with regard to all aspects of IGWs are most welcome. Besides, this year we welcome abstracts reporting results on the SouthTRAC campaign in the Southern Hemisphere, as well as any other major collaborative projects such as MS-GWaves.

The infrasound field, the science of low-frequency acoustic waves, has developed into a broad interdisciplinary field encompassing academic disciplines of geophysics and recent technical and scientific developments. The infrasound network of the International Monitoring Network (IMS) for nuclear test ban verification and regional cluster arrays deployed around the globe have demonstrated their capacity for detecting and locating most of the disturbances in the atmosphere. Infrasound is capable of traveling up to thermospheric altitudes and over enormous ranges, where its propagation is controlled by the wind and temperature structure. Recent studies point out new insights on quantitative relationships between observables and atmospheric characteristics, and therefore opening a new field for atmospheric remote sensing.

New studies using lidar, radar, microwave spectrometer and mesospheric airglow observations complemented by satellite measurements help to better determine the interaction between atmospheric layers from the ground to the mesosphere and the influence of atmospheric waves on the mean flow. It is expected that further developing multi-instruments platforms would improve gravity wave parameterizations and enlarge the science community interested by operational infrasound monitoring. The ARISE project, funded by the European Commission, coordinates such studies. It proposes to design a novel infrastructure that integrates different atmospheric observation networks to infer a new 3D image of the atmosphere from the ground to mesosphere. In a higher frequency range, this monitoring system also offers a unique opportunity to provide in near-real time continuous relevant information about natural hazards with high societal benefits, like large volcanic eruptions, surface earthquakes or meteorites.

We invite contributions on current studies on sensors, characterization of different sources and large scale atmospheric phenomena, characterization of phenomena which affect acoustic propagation, utilization of acoustic waves to probe the atmosphere, contribution of gravity and planetary waves to the atmospheric dynamics and the coupling of atmospheric layers. In the session, we will also consider the role that infrasound and acoustic-gravity waves play in the coupled Earth’s crust – ocean – atmosphere system and, in particular, in ionospheric manifestations of physical processes in the ocean and in the solid Earth.

The understanding of tropical phenomena and their representation in numerical models still raise important scientific and technical questions, particularly in the coupling between the dynamics and diabatic processes. Among these phenomena, tropical cyclones (TC) are of critical interest because of their societal impacts and because of uncertainties in how their characteristics (cyclogenesis processes, occurrence, intensity, latitudinal extension, translation speed) will change in the framework of global climate change. The monitoring of TCs, their forecasts at short to medium ranges, and the prediction of TC activity at extended range (15-30 days) and seasonal range are also of great societal interest.

The aim of the session is to promote discussions between scientists focusing on the physics and dynamics of tropical phenomena. This session is thus open to contributions on all aspects of tropical meteorology between the convective and planetary scale, such as:

- Tropical cyclones,
- Convective organisation,
- Diurnal variations,
- Local circulations (i.e. island, see-breeze, etc.),
- Monsoon depressions,
- Equatorial waves and other synoptic waves (African easterly waves, etc.),
- The Madden-Julian oscillation,
- etc.

We especially encourage contributions of observational analyses and modelling studies of tropical cyclones and other synoptic-scale tropical disturbances including the physics and dynamics of their formation, structure, and intensity, and mechanisms of variability of these disturbances on intraseasonal to interannual and climate time scales.

Findings from recent field campaigns such as YMC and PISTON are also encouraged.

This session investigates mid-latitude cyclones and storms on both hemispheres. We invite studies considering cyclones in different stages of their life cycles from the initial development, to large- and synoptic-scale conditions influencing their growth to a severe storm, up to their dissipation and related socioeconomic impacts.
Papers are welcome, which focus also on the diagnostic of observed past and recent trends, as well as on future storm development under changed climate conditions. This will include storm predictability studies on different scales. Finally, the session will also invite studies investigating impacts related to storms: Papers are welcome dealing with vulnerability, diagnostics of sensitive social and infrastructural categories and affected areas of risk for property damages. Which risk transfer mechanisms are currently used, depending on insured and economic losses? Which mechanisms (e.g. new reinsurance products) are already implemented or will be developed in order to adapt to future loss expectations?

Clouds and aerosols play a key role in climate and weather-related processes over a wide range of spatial and temporal scales. An initial forcing due to changes in the aerosol concentration and composition may also be enhanced or dampened by feedback processes such as modified cloud dynamics, surface exchange or atmospheric circulation patterns. This session aims to link research activities in observations and modelling of radiative, dynamical and microphysical processes of clouds and aerosols and their interactions. Studies addressing several aspects of the aerosol-cloud-radiation-precipitation system are encouraged.

Topic covered in this session include:
- Cloud and aerosol macro- and microphysical properties, precipitation formation mechanisms
- The role of aerosols and clouds for the radiative energy budget
- Observational constraints on aerosol-cloud interactions
- Cloud-resolving modelling
- Parameterization of cloud and aerosol microphysics/dynamics/radiation
- Use of observational simulators to constrain aerosols and clouds in models
- Experimental cloud and aerosol studies
- Aerosol, cloud and radiation interactions and feedbacks in the climate system

Invited Speakers:
Nicolas Bellouin (University of Reading)
Anna Possner (Goethe University Frankfurt)

This session deals with atmospheric convection, being dry, shallow, or deep convection. Contributions on these aspects resulting from the use of large-eddy simulations, convection-permitting simulations, coarser-resolution simulations using parameterised convection and observations are welcome. This year we will have a special emphasis on convective organization. Studies that investigate the organization of convection, being in idealized set-ups (radiative convective equilibrium and self-aggregation) or in observations, as well as studies that investigate the importance of organization for climate are particularly welcome. Besides this, studies that investigate general aspects of convection such as processes controlling the lifecycle of convection, interactions of convection with other physical processes and representation of convection in numerical weather prediction and climate models are also welcome.

The uncertain response of clouds to global warming is a major contributor to the spread in climate sensitivity across climate models. Cloud feedback uncertainty is related to a limited understanding of the coupling between clouds, convection and the large-scale circulation. This session focuses on efforts to advance our understanding of the cloud-circulation coupling and its role in climate change. Contributions from dedicated field campaigns such as EUREC4A, from various observing platforms like ground-based and satellite remote sensing or in situ measurements, as well as modelling and theoretical studies are welcomed. We also invite abstracts focusing on the role of convective organization and precipitation in modulating the cloud-circulation coupling and cloud feedbacks.

Precipitation is an essential aspect of climate, and also drives many climate impacts. The primary tool for projecting future precipitation is climate models. Climate models are already being used, both directly and indirectly, to quantify anticipated impacts of climate for the purpose of making decisions. Improving precipitation in models requires (1) quantifying characteristics of precipitation in relevant observational datasets, (2) comprehensive comparison of climate model precipitation against observations, and (3) sustained model development efforts focus on improving precipitation in models. It also requires addressing the many characteristics of precipitation, ranging from its mean spatial pattern through its variability across timescales from hourly and diurnal extending through extreme events (whether dry or wet).

We invite presentations in this session that address:
- metrics to quantify the characteristics of precipitation in observations,
- evaluation of climate model simulations against observations, and
- development efforts aimed at improving precipitation in models (including seamless modeling systems).

Public information:
Please have a look at the displays, leave a comment, and start a discussion!

This session explores advances and challenges in convection-permitting atmospheric modelling: the newest generation of atmospheric models that allow for the explicit treatment of convective processes (grid spacing ≤ 4 km).

Convection-permitting models (CPMs) are a rapidly growing research area and improve both the diurnal convective cycle and the representation of convective precipitation, particularly extremes. CPMs often exhibit important differences in feedback mechanisms and climate change signals compared to coarser models. CPMs thus offer a promising tool to better understand fine-scale processes and provide critical information to end users, especially in areas affected by convective extremes, and have thus sparked wider interest in their applications and development. For example, the CORDEX-FPS on convective phenomena over Europe and the Mediterranean.

The session brings together numerical modellers, the observational community, cloud physicists, forecasters and CORDEX-FPS participants, with the aim of advancing understanding of convection and high-resolution modelling in general (including convective storm life cycle and convective organization) with new modelling and statistical observation approaches. Contributions on new high-resolution/sub-daily observational datasets, and their application to CPM evaluation, are particularly welcome. This session calls for papers on state-of-the-art development and application of CPM activities, including examination of interactions between convection and other atmospheric phenomena (e.g. boundary layers, cloud physics, radiation), as well as CPM investigations of local- to regional-scale phenomena (e.g. land-use change, land-ocean contrasts, flow-orography interactions, urban-rural transitions, aerosol effects, etc.). We welcome studies of past, present or future climates, and CPM modelling across time scales. Particular attention is given to extremes.

Other topics include, but are not limited to:
-- Model setup and parametrization, including sensitivity to resolution and dynamics
-- Model evaluation and new evaluation metrics/methods
-- Ensemble-based approaches to quantify uncertainty at convective scale
-- Physical understanding of added value over coarser models
-- Land-atmosphere coupling at convection-permitting scale
-- Climate studies
-- Tropical phenomena
-- Convection, energy balance and hydrological cycle
-- Lightning in CPMs
-- Teleconnection across scales
-- Novel high-resolution experiments

Public information:
More information on EGU online this year 2020:
https://egu2020.eu/sharing_geoscience_online/sharing_geoscience_online.html

There is a recipe on how to prepare your display and upload your file following this link:
https://egu2020.eu/sharing_geoscience_online/presentation_upload_recipe.html

A reminder: you do not have to pay a registration fee to participate in Sharing Geoscience Online.

The assessment of precipitation variability and uncertainty is crucial in a variety of applications, such as flood risk forecasting, water resource assessments, evaluation of the hydrological impacts of climate change, determination of design floods, and hydrological modelling in general. Within this framework, this session aims to gather contributions on research, advanced applications, and future needs in the understanding and modelling of precipitation variability, and its sources of uncertainty.
Specifically, contributions focusing on one or more of the following issues are particularly welcome:
- Novel studies aimed at the assessment and representation of different sources of uncertainty versus natural variability of precipitation.
- Methods to account for different accuracy in precipitation time series, e.g. due to change and improvement of observation networks.
- Uncertainty and variability in spatially and temporally heterogeneous multi-source precipitation products.
- Estimation of precipitation variability and uncertainty at ungauged sites.
- Precipitation data assimilation.
- Process conceptualization and modelling approaches at different spatial and temporal scales, including model parameter identification and calibration, and sensitivity analyses to parameterization and scales of process representation.
- Modelling approaches based on ensemble simulations and methods for synthetic representation of precipitation variability and uncertainty.
- Scaling and scale invariance properties of precipitation fields in space and/or in time.
- Physically and statistically based approaches to downscale information from meteorological and climate models to spatial and temporal scales useful for hydrological modelling and applications.

In recent years, attention was paid to the detection and monitoring of volcanic ash clouds as their impact on the air traffic control system was unprecedented. Volcanic clouds are dangerous for the aviation as they can cause damage of the aircraft systems and engines not only close to active volcanoes but also at large distance from the eruption.
The intensity of the extreme convective events is supposed to increase worldwide due to the climate change and they can also cause large damages and affect air safety.

The recent Anak Krakatau, Raikoke and Ulawun eruptions highlighted the issue on different techniques to distinguish volcanic ash clouds from convective clouds, and the unsolved problem to understand if the cloud top is tropospheric or stratospheric.

The “extreme clouds” detection and estimation of their physical parameters is a highly multidisciplinary and challenging topic since the same techniques and instruments can be used for meteorology, volcanic monitoring, atmospheric physics and climate purposes. There is an urgent need to develop new techniques and instruments for monitoring, detecting and modeling “extreme clouds” to develop early warning systems and to support users, decision makers and policy makers.

This session solicits the latest studies from the spectrum of:
- Volcanic and Convective Clouds (CVC) remote sensing, detection, monitoring, modeling, forecasting and nowcasting
- understanding of CVC structure, including overshooting and ice clouds
- understanding the impact of CVC on climate changes and air safety
- proposal of new products or services focused on the end-users prospective (air traffic management and air safety)
- discussion on the recent Anak Krakatau, Raikoke and Ulawun eruptions

By considering studies over this range of topics we aim to identify new methods, detail current challenges, understand common techniques/methods and identify common discussions within the communities of atmospheric physicists, meteorologists, modelers, air traffic managers, pilots sensors engineers and engines manufacturers.

We particularly welcome and encourage contributions connecting different fields such as:
- forecasting tools to support air traffic management improving the limits of the present science and new products/tools providing better services to the end-users,
- extreme clouds remote sensing with novel techniques and new sensors,
- novel techniques to detect overshooting and their impact on climate.

Lightning is the energetic manifestation of electrical breakdown, occurring after charge separation processes operating on micro and macro-scales, leading to strong electric fields within thunderstorms. Lightning is associated with severe weather, torrential rains and flash floods. It has significant effects on various atmospheric layers and drives the fair-weather electric field. It is a strong indicator of convective processes on regional and global scales, potentially associated with climate change. Thunderstorms and lightning are also associated to the production of energetic radiation up to tens of MeV on time scales from sub-millisecond (Terrestrial Gamma-ray Flashes) to tens of seconds (gamma-ray glows).

This session seeks contributions from research in atmospheric electricity on:

Atmospheric electricity in fair weather and the global electrical circuit
Atmospheric chemical effects of lightning and Lightning-produced NOx
Middle atmospheric Transient Luminous Events
Energetic radiation from thunderstorms and lightning
Remote sensing of lightning from space and by lightning detection networks
Results from the Atmosphere-Space Interaction Monitor (ASIM) mission.
Thunderstorms, flash floods and severe weather
Lightning and electrical phenomena on other planets
Lightning, tropical storms and climate
Modeling of thunderstorms and lightning
Now-casting and forecasting of thunderstorms
Laboratory investigation of lightning discharge physics processes

Ice and mixed-phase clouds largely contribute to the Earth’s radiation budget because of their high temporal and spatial coverage. Yet, the variability and complexity of their macro- and microphysical properties - consequence of intricate ice particle nucleation and growth processes - makes their study extremely challenging. As a result, large uncertainties still exist of our understanding of ice cloud processes, radiative effects and interactions with their environment (in particular, aerosols).

This session aims to advance our comprehension of ice clouds by bringing observation- and modelling-based research together. A PICO format is selected to further encourage exchanges between the communities.

A diversity of research topics shall be covered, highlighting recent advances in ice cloud observation techniques, modelling and subsequent process studies:

(1) Ice cloud observations from airborne, spaceborne, ground- or laboratory-based measurements and their derived products (retrievals), which are useful to understand process details, formation mechanisms and provide climatology.

(2) Model simulations (process-based, regional and global) on the other hand allow putting the detailed observations in a wider perspective, providing additional insights in the formation mechanisms and allowing for future predictions.

Both approches brought together can uniquely answer question regarding dynamical influence on ice cloud formation, life cycle, coverage, microphysical and radiative properties, crystal shapes, sizes and variability of ice particles in mixed-phase as well as ice clouds. Joint observation-modelling contributions are therefore particularly encouraged.

The southeast Atlantic off the African south western coast is the location for interactions between aerosols, clouds, and radiation ultimately affecting climate. A wide-spread stratocumulus cloud deck is a permanent feature in this region shaping the regional radiation budget, the local water budget through the formation of coastal fog, and potentially the global climate. Aerosols from multiple sources, including biomass and fuel burning, mineral dust, and marine, emitted or transported below or above the cloud deck, can significantly change the microphysical and radiative properties of the clouds. Currently these processes are poorly understood, which is reflected in the diversity of model simulation results of radiative forcing. Studies that present new observations and modelling of the aforementioned properties, interactions and implications over the southeast Atlantic and adjacent continental regions are solicited

This joint session invites papers that are related to the mesosphere and lower thermosphere. It addresses the topical fields of the VarSITI (Variability of the Sun and Its Terrestrial Impact) program initiated by SCOSTEP, focusing on the role of the sun and the middle atmosphere/thermosphere/ionosphere in climate (ROSMIC). Contributions studying radiation, chemistry, energy balance, atmospheric tides, planetary waves, gravity waves, neutral-ion coupling, and the interaction of the various processes involved are welcome.
This includes work on model data as well as measurements from satellites and ground based platforms such as ALOMAR.

With the launch of the unique Aeolus wind profiling mission, new perspectives on atmospheric dynamics are being revealed to benefit a number of prospective applications. For example, improvements in Numerical Weather Prediction (NWP), General Circulation Models (GCMs) and their included parameterized processes, such as land and ocean drag, convection, stratosphere-troposphere interaction and atmospheric waves. In this session, we aim at discussing the new data products and their validation, as well as studies using the Aeolus data for application in meteorology. Topics may vary from observation interpretation, GCM or NWP model diagnostics, parameterization and data assimilation experiments. We welcome all presentations based on Aeolus mission data, including inter-comparisons of different remote sensing measurements dedicated to wind profiling, clouds or aerosol, and/or using analyses with ground-based measurements and GCMs. This includes also studies on the optical properties as measured by Aeolus and their use for clouds and aerosol studies.

Public information:
The text chat session will follow the AS1.35 session list, distributing available time over all uploaded presentations. Authors, please prepare a 1-2 sentence summary in advance, which you can paste in when your display is called up for discussion. Participants, please prepare your brief questions for pasting into the text chat session. Looking forward to an animated session!

Precipitation, both liquid and solid, is a central element of the global water/energy cycle through its coupling with clouds, water vapor, atmospheric motions, ocean circulation, and land surface processes. Precipitation is also the primary source of freshwater, while it can have tremendous socio-economical impacts associated with extreme weather events such as hurricanes, floods, droughts, and landslides. Accurate and timely knowledge of precipitation characteristics at regional and global scales is essential for understanding how the Earth system operates under changing climatic conditions and for improved societal applications that range from numerical weather prediction to freshwater resource management. This session will host papers on all aspects of precipitation, especially contributions in the following four research areas: Precipitation Measurement: Precipitation measurements (amount, duration, intensity etc) by ground-based in situ sensors (e.g., rain gauges, disdrometers); estimation of accuracy of measurements, comparison of instrumentation. Precipitation Climatology: Regional and global climatology; areal distribution of measured precipitation; classification of precipitation patterns; spatial and temporal characteristics of precipitation; methodologies adopted and their uncertainties; comparative studies. Precipitation Remote Sensing: Remote sensing of precipitation (spaceborne, airborne, ground-based, underwater, or shipborne sensors); methodologies to estimate areal precipitation (interpolation, downscaling, combination of measurements and/or estimates of precipitation); methodologies used for the estimation (e.g., QPE), validation, and assessment of error and uncertainty of precipitation as estimated by remote sensors. A special focus will be on international contributions to the exploitation of the international Global Precipitation Measurement (GPM) mission that provides state-of-the-art precipitation estimates (including solid precipitation) from space with unprecedented accuracy, time-space coverage, and improved information for microphysics.

The AMANOM session will focus on observations related to contrails, fog, clouds, precipitation, and short range forecasting of weather conditions associated with aviation operations. Abstracts for all areas of aviation meteorology, including Polar regions, high altitude conditions, as well as airport environments, can be submitted to this session. Work on aviation meteorology parameters such as visibility, icing, gusts and turbulence, as well as fog and precipitation, will be considered for this session. Topics related to In-situ observations obtained from aircraft, Unmanned Aerial Vehicles (UAVs), and supersites, remote sensing retrievals of meteorological parameters from satellites, radars, lidars, and MicroWave Radiometers (MWRs), as well as other emerging technological platforms, and predictions of meteorological parameters from the numerical weather prediction models will be considered highly related to the goals of this session.