The radiation budget of the Earth is a key determinant for the genesis and evolution of climate on our planet and provides the primary energy source for life. Anthropogenic interference with climate occurs first of all through a perturbation of the Earth radiation balance. We invite observational and modelling papers on all aspects of radiation in the climate system. A specific aim of this session is to bring together newly available information on the spatial and temporal variation of radiative and energy fluxes at the surface, within the atmosphere and at the top of atmosphere. This information may be obtained from direct measurements, satellite-derived products, climate modelling as well as process studies. Scales considered may range from local radiation and energy balance studies to continental and global scales. In addition, related studies on the spatial and temporal variation of cloud properties, albedo, water vapour and aerosols, which are essential for our understanding of radiative forcings and their relation to climate change, are encouraged. Studies focusing on the impact of radiative forcings on the various components of the climate system, such as on the hydrological cycle, on the cryosphere or on the biosphere and related carbon cycle, are also much appreciated. This session will include a dedicated section with the aim to move towards an harmonization of ground measurements of the surface radiation budget over land and ocean, with particular attention to the definition of best practices, uncertainties and traceability to standards.

Invited Speaker: Robert Weller (Woods Hole Oceanographic Institution, Massachusetts, USA)

Changes in seasonal timing affect species and ecosystem response to environmental change. Observations of plant and animal phenology as well as remote sensing and modeling studies document complex interactions and raise many open questions.

We invite contributions with cross-disciplinary perspectives that address seasonality changes based on recent plant and animal phenological observations, pollen monitoring, historical documentary sources, or seasonality measurements using climate data, remote sensing, flux measurements or modeling studies. Contributions across all spatial and temporal scales are welcome that compare and integrate seasonality changes, study effects of long-term climate change or single extreme events, emphasize applications and phenology informed decision-making, discuss species interactions and decoupling, advance our understanding of how seasonality change affects carbon budgets and atmosphere/biosphere feedbacks, and integrate phenology into Earth System Models.

We emphasize phenology informed applications for decision-making and environmental assessment, public health, agriculture and forest management, mechanistic understanding of the phenological processes, and effects of changing phenology on biomass production and carbon budgets. We also welcome contributions addressing international collaboration and program-building initiatives including citizen science networks and data analyses.

This session is organized by a consortium representing the International Society of Biometeorology (Phenology Commission), the Pan-European Phenology Network - PEP 725, the Swiss Academy of Science SCNAT, the TEMPO French Phenology Network and the USA National Phenology Network.

Large-scale atmospheric circulation dynamics are the major driver of near surface climatic and environmental variability. Synoptic climatology examines atmospheric circulation dynamics and their relationship with near surface environmental variables. Within synoptic climatological analyses, a wide variety of methods is utilized to characterize atmospheric circulation (e.g., circulation and weather type classification, regime analysis, teleconnection indices). Various linear and non-linear approaches (e.g., multiple regression, canonical correlation, neural networks) are applied to relate the circulation dynamics to diverse climatic and environmental elements (e.g., air temperature, air pollution, floods).

The session welcomes contributions from the whole field of synoptic climatology. This includes application studies for varying regions, time periods (past, present, future) and target variables and in particular contributions on the development and the comparison of methods (e.g., varying circulation type classifications) and conceptual approaches (e.g., circulation types versus circulation regimes).

As the most evident example of land use and land cover change, urban areas play a fundamental role in local to large-scale planetary processes, via modification of heat, moisture, and chemical budgets. With rapid urbanization ramping up globally it is essential to recognize the consequences of landscape conversion to the built environment. Given the capability of cities to serve as first responders to global change, considerable efforts are currently being dedicated across many cities to monitor and understand urban atmospheric dynamics and examine various adaptation and mitigation strategies aimed to offset impacts of rapidly expanding urban environments and influences of large-scale greenhouse gas emissions. 

This session solicits submissions from both the observational and modelling communities examining urban atmospheric and landscape dynamics, processes and impacts owing to urban induced climate change, the efficacy of various strategies to reduce such impacts, and techniques highlighting how cities are already using novel science data and products that facilitate planning and policies on urban adaptation to and mitigation of the effects of climate change. Emerging topics including, but not limited to, urban climate informatics, are highly encouraged.

The CL2.5 Session Solicited/Invited Talk will be given by Prof. Tony Brazel, recipient of the International Association of Urban Climate's Luke Howard Award, the American Meteorological Society's Helmut E. Landsberg Award, Lifetime Achievement Award of the Association of American Geographers' Climate Specialty Group, and the Jeffrey Cook Prize in Desert Architecture from Ben-Gurion University of the Negev, Israel.

Detecting and attributing the fingerprint of anthropogenic climate change in long-term observed climatic trends is an active area of research. Though the science is well established for temperature related variables, the study of other climate indicators including hydrometeorological variables pose greater challenges due to their greater complexity and rarity.

Complementary to this, assessing the extent to which extreme weather events, including compound events, are attributable to anthropogenic climate change is a rapidly developing science, with emerging schools of thought on the methodology and framing of such studies. Once again, the attribution of hydrometeorological events, is less straightforward than temperature-related events. The attribution of impacts, both for long-term trends and extreme events is even more challenging.

This session solicits the latest studies from the spectrum of detection and/or attribution approaches. By considering studies over a wide range of temporal and spatial scales we aim to identify common/new methods, current challenges, and avenues for expanding the detection and attribution community. We particularly welcome submissions that compare approaches, or address hydrometerological trends, extremes and/or impacts – all of which test the limits of the present science.

Public information:
This session was hosted as a zoom meeting. You can find the recording of the zoom meeting here : https://drive.google.com/file/d/18qSh8TkkNjSghvCAfe4EB5n0TKraXv7r/view?usp=sharing

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?

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!

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.

The Andes is the longest cordillera in the world and extends from northern South America (11°N) to the southern tip of the continent (∼53°S). The Andes runs through seven countries and provide resources for about 90 million inhabitants. The Andes is characterized by a rich variety of mountain climates and ecosystems, producing unique contrasting climate conditions over its eastern and western sides, but also across its latitudinal extent. Currently, the Andes hydroclimate faces several threats to sustainable development, such as water supply and the sustainability of ecosystem services, including global climate change, Andes and Amazon deforestation and local land use change, glaciers retreat, human encroachment, among others). In turn, diverse hydroclimatic high-impact extreme events affect the Andean communities owing to the prevailing weather and climate patterns, steep terrain, deforestation and human occupancy. This session aims to assess and discuss recent progress in the Andes hydroclimate and identify pressing research challenges and the development of associated human capabilities. We welcome submissions based on observational and modelling approaches, from the local to the continental scales and from diurnal to interdecadal time scales. Emerging new topics are particularly welcome, including water and energy budgets, high impact events, precipitation hotspots, climate change and deforestation impacts, climate-vegetation interactions, cryosphere studies, water resources availability, connections with the Amazon and the La Plata River basins and neighboring oceans, among others.

Public information:
Additional information:
i) This session will be divided into two sub-sessions:
1) Climatology and Atmospheric Sciences, and
2) Hydrology and Water Resources.

The session schedule is available at : (https://meetingorganizer.copernicus.org/EGU2020/sessionAssets/36767/materials.pdf)

ii) Each sub-session will be divided into blocks.
iii) The authors introduce themselves (following the order of the presentations) and provide a couple of sentences summarizing their main result/highlight/discussion topic.
iv) At the end of each block, we dedicate a few minutes to questions from the audience. Each block, including the questions, lasts 10 minutes.
v) We will spend a few minutes on the general discussion and conclusion.

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)

With the rapidly changing conditions in the Arctic and Antarctic, reliable weather and climate forecasts are becoming increasingly important in the polar regions due to new challenges and opportunities in the economic, touristic, transportation, and scientific sectors. Likewise, the weather and climate of the mid-latitudes are significantly affected by what happens at the poles. While the impacts of severe weather phenomena on business and infrastructure can be significant, the polar regions are yet among the least-observed areas of our planet, and model predictions are challenged by the complexity of the polar climate systems.
To enhance our models’ predictive skills, more and better use of observation systems of the polar atmosphere, sea ice, and ocean are needed. It is on these premises that the World Meteorological Organization’s project Year of Polar Prediction (YOPP) and the European Horizon2020 APPLICATE project are carrying out their activities, initiating and promoting collaboration among international institutes, operational forecasting centers and stakeholders in an effort to bring together scientific expertise and know-how to work on better polar predictive skill.
In this session, we welcome presentations on activities and results from the YOPP and APPLICATE projects as well as contributions from other projects and institutes that focus on how to best capitalise on existing and additional Arctic and Antarctic observations such as Copernicus to improve forecast initial states, verification, and model physics, and to optimise the future polar observing system.
We welcome abstracts on topics including, but not limited to: Arctic and Antarctic observations, modelling, prediction, data assimilation, verification, linkages to mid-latitudes, user engagement, and governance. New results, contributions from international projects with a focus in the polar regions, and cross-disciplinary approaches that involve natural and social sciences are particularly appreciated.

In recent years the interaction between the ocean and the cryosphere in the marginal seas of the Southern Ocean has become a major focus in climate research. Questions such as "Why has Antarctic sea ice only recently begun to decline?", "What controls the inflow of warm water into ice shelf cavities and how does it interact with the ice?", and “What are the dominant processes in ice-ocean boundary layers?” have attracted scientific and public attention. Recent advances in observational technology, data coverage, and modeling provide scientists with a better understanding of the mechanisms involving ice-ocean interactions of various types in the far South. Processes on the Antarctic continental shelf have been identified as missing links between the cryosphere, the global atmosphere and the deep open ocean that need to be captured in large-scale and global model simulations. Similarly, our limited knowledge of processes in ice-ocean boundary layers, such as heat and salt fluxes that control the melt rate, has been identified as a limitation on our ability to fully understand, let alone parameterize melting and freezing at interfaces between the ocean and ice shelves, icebergs, glaciers, and sea ice.

This session includes studies of the Southern Ocean's marginal seas including the Antarctic continental shelf and ice shelf cavities, as well as process studies with a particular focus on ice-ocean boundary layers and on all scales, from the ice-ocean interface to local to basin-scale to circumpolar. Physical and biogeochemical interactions between ice shelves, sea ice and the open ocean will be presented, along with their impacts on the greater Antarctic climate system. Presentations include theoretical studies as well as those based on in-situ observations, remote sensing, and process-scale, regional and global models. While the primary focus of the session is on ice-ocean interactions, we also includes contributions on ice-covered freshwater lakes.

Public information:
16:15-16:50 Characteristics of Polar Seas and connection with ice shelves and the open ocean
Chairs: Leo, Louis

16:15-16:20 Raquel Flynn (D2761 | EGU2020-21107)
16:20-16:25 Katherine Hutchinson (D2768 | EGU2020-112)
16:25-16:30 Roberto Grilli (D2772 | EGU2020-2984)
16:30-16:35 Chengyan Liu (D2770 | EGU2020-2319)
16:35-16:40 Ria Oelerich (D2763 | EGU2020-463)
16:40-16:45 Ute Hausmann (D2767 | EGU2020-22464)
16:45-16:50 General Discussion

16:50-17:20 Sea ice and its interaction with ice shelves and the Southern Ocean
Chairs: Nadine, Xylar

16:50-16:55 Lucile Ricard (D2765 | EGU2020-17820)
16:55-17:00 Pierre-Vincent Huot (D2780 | EGU2020-19677)
17:00-17:05 Isabelle Giddy (D2777 | EGU2020-9934)
17:05-17:10 F. Alexander Haumann (D2782 | EGU2020-22008)
17:10-17:15 Sönke Maus (D2762 | EGU2020-6039)
17:15-17:20 General Discussion

17:20-18:00 Turbulent Ice Shelf-Ocean Boundary Layers
Chairs: Irena, Xylar

17:20-17:25 Ryan Patmore (D2769 | EGU2020-10388)
17:25-17:30 Leo Middleton (D2781 | EGU2020-9112)
17:30-17:35 Louis-Alexandre Couston (D2776 | EGU2020-19054)
17:35-17:40 Carolyn Branecky Begeman (D2774 | EGU2020-10848)
17:40-17:45 Peter Davis (D2771 | EGU2020-50)
17:45-18:00 General Discussion

It has been shown that regional climate change interacts with many other man-made perturbations in both natural and anthropogenic coastal environments. Regional climate change is one of multiple drivers, which have a continuing impact on terrestrial, aquatic and socio-economic (resp. human) environments. These drivers interact with regional climate change in ways, which are not completely understood. Recent assessments all over the world have partly addressed this issue (e.g. Assessment of Climate Change for the Baltic Sea region, BACC (2008, 2015); North Sea Climate Change Assessment, NOSCCA (2011); Canada’s Changing Climate Report, CCCR (2019)).
This session invites contributions, which focus on the connections and interrelations between climate change and other drivers of environmental change, be it natural or human-induced, in different regional seas and coastal regions. Observation and modelling studies are welcome, which describe processes and interrelations with climate change in the atmosphere, in marine and freshwater ecosystems and biogeochemistry, coastal and terrestrial ecosystems as well as human systems. In particular, studies on socio-economic factors like aerosols, land cover, fisheries, agriculture and forestry, urban areas, coastal management, offshore energy, air quality and recreation, and their relation to climate change, are welcome.
The aim of this session is to provide an overview over the current state of knowledge of this complicated interplay of different factors, in different regional seas and coastal regions all over the world.

This session will focus on variability in the ocean and its role in the wider climate system using both observations and models. Areas to be considered will include both ocean heat uptake and circulation variability as well as exploring the use of sustained ocean observing efforts and models to make progress in understanding the ocean’s role in the climate system. More than 90% of the excess heat in the climate system has been stored in the ocean, which mitigates the rate of surface warming. Better understanding of ocean ventilation mechanisms, as well as the uptake, transport, and storage of oceanic heat are therefore essential for reducing the uncertainties on global warming projections. Circulation variability and connectivity, particularly from the South Atlantic to the North Atlantic and Arctic Ocean, are also of interest as well as how they are driven by local-, large- or global-scale processes or teleconnections. Sustained observations at sea are being made within a wide variety of programmes and are leading to significant advances in our ability to understand and model climate. Thus, this session will also explore ongoing and planned sustained ocean observing efforts and illuminate their roles in improving understanding of the ocean’s role in the climate system. For example, air-sea flux moorings are being maintained at select sites to assess models and air-sea flux fields. Deep temperature and salinity measurements are being made at time series moorings and will be made by deep Argo floats. Significant advances are also being made using Argo floats for biogeochemistry and carbon measurements. Such observations provide the means to develop linkages between sustained ocean observing and climate modelling. In conclusion, the session will consider key aspects of ocean variability and its climate relevance, as well as encouraging the use of observations and models to enhance understanding of these areas.

Public information:
Announcement: We'll host a webinar with speakers from our session next week. May 13., 15:00-18:30 CEST

Agenda for the webinar: http://iacweb.ethz.ch/staff/medhaugi/files/UnofficialEGUOS1p6ZoomMeetingProgramme.pdf.

The webinar will be open to everyone, but please sign up to receive login details: https://forms.gle/6qwNVrBq7aYc7pn78

The rapid decline of Arctic sea ice in the last decade is a dramatic indicator of climate change. The Arctic sea ice cover is now thinner, weaker and drifts faster. The ocean is also changing; the volume of freshwater stored in the Arctic and has increased as have the inputs of coastal runoff from Siberia and Greenland. Concurrently inflows from the Atlantic and Pacific Oceans have warmed. As the global surface temperature rises, the Arctic Ocean is speculated to become seasonally ice-free in the 21st century, which prompts us to revisit our perceptions of the Arctic system as a whole. What could the Arctic look like in the future? How are the present changes in the Arctic going to affect the lower latitudes? What aspects of the changing Arctic should future observations, remote sensing and modelling programmes address? The scientific community is investing considerable effort in making the current knowledge of the physical and biogeochemical properties of the Arctic more systematic, in exploring poorly understood coupled atmosphere-sea-ice-ocean processes to improve prediction of future changes in the Arctic.

In this session, we invite contributions from a variety of studies addressing the recent past, present and future Arctic. We encourage submissions examining interactions between the ocean, atmosphere and sea ice and on studies linking changes in the Arctic to the global ocean. Submissions with a focus on emerging cryospheric, oceanic and biogeochemical processes and their implications are particularly welcome.

The session promotes results from current Arctic programmes and discussions on future plans for Arctic Ocean modelling and measurement strategies, and encourage submissions on the results from the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC).

Public information:
Session structure file is back.

Yevegny

Observations and model simulation illustrate significant ocean variability and associated air-sea interactions from regional to global scale and on diurnal to inter-annual time scales. This session is devoted to the understanding of the tropical and subtropical ocean dynamics, its interaction with the overlying atmosphere from the equator to mid-latitudes and its climate impacts on adjacent to remote areas.
Relevant processes in the ocean include upper and deep ocean circulation, mild SST gradients to sharp fronts, eddies, filaments, tropical instability waves, warm pools, cold tongues and eastern boundary upwellings. Furthermore, we are interested in air-sea interactions related to both the seasonal cycle and the development of modes of variability from local to basin scale. Wind variations related to Madden-Julian Oscillation, cyclones, and convective systems, as well as those leading the air-sea coupled modes (e.g., the Meridional Mode and Atlantic Niño) are welcome. Finally, we also seek contributions examining the causes and impacts of systematic model errors in simulating the local to regional climate.
Studies based on direct observations, reanalysis, reconstructions as well as model simulations are welcome.

Snow cover characteristics (e.g. spatial distribution, surface and internal physical properties) are continuously evolving over a wide range of scales due to meteorological conditions, such as precipitation, wind and radiation.
Most processes occurring in the snow cover depend on the vertical and horizontal distribution of its physical properties, which are primarily controlled by the microstructure of snow (e.g. density, specific surface area). In turn, snow metamorphism changes the microstructure, leading to feedback loops that affect the snow cover on coarser scales. This can have far-reaching implications for a wide range of applications, including snow hydrology, weather forecasting, climate modelling, and avalanche hazard forecasting or remote sensing of snow. The characterization of snow thus demands synergetic investigations of the hierarchy of processes across the scales ranging from explicit microstructure-based studies to sub-grid parameterizations for unresolved processes in large-scale phenomena (e.g. albedo, drifting snow).

This session is therefore devoted to modelling and measuring snow processes across scales. The aim is to gather researchers from various disciplines to share their expertise on snow processes in seasonal and perennial snowpacks. We invite contributions ranging from “small” scales, as encountered in microstructure studies, over “intermediate” scales typically relevant for 1D snowpack models, up to “coarse” scales, that typically emerge for spatially distributed modelling over mountainous or polar snow- and ice-covered terrain. Specifically, we welcome contributions reporting results from field, laboratory and numerical studies of the physical and chemical evolution of snowpacks, statistical or dynamic downscaling methods of atmospheric driving data, assimilation of in-situ and remotely sensed observations, representation of sub-grid processes in coarse-scale models, and evaluation of model performance and associated uncertainties.

This session is closely linked to the session 'Snow and ice accumulation, melt, and runoff generation in catchment hydrology', which addresses monitoring and modelling of snow for hydrologic applications.

Atmosphere and Cryosphere are closely linked and need to be investigated as an interdisciplinary subject. Most of the cryospheric areas have undergone severe changes in last decades while such areas have been more fragile and less adaptable to global climate changes. This AS-CR session invites model- and observational-based investigations on any aspects of linkages between atmospheric processes and snow and ice on local, regional and global scales. Emphasis is given on the Arctic, high latitudes and altitudes, mountains, sea ice, Antarctic regions. In particular, we encourage studies that address aerosols (such as Black Carbon, Organic Carbon, dust, volcanic ash, diatoms, bioaerosols, bacteria, etc.) and changes in the cryosphere, e.g., effects on snow/ice melt and albedo. The session also focus on dust transport, aeolian deposition, and volcanic dust, including health, environmental or climate impacts at high latitudes, high altitudes and cold Polar Regions. We include contributions on biological and ecological sciences including dust-organisms interactions, cryoconites, bio-albedo, eco-physiological, biogeochemical and genomic studies. Related topics are light absorbing impurities, cold deserts, dust storms, long-range transport, glaciers darkening, polar ecology, and more. The scientific understanding of the AS-CR interaction needs to be addressed better and linked to the global climate predictions scenarios.

Observations and simulations of the terrestrial carbon and water budget are fundamental to understanding biosphere-atmosphere interactions under a changing climate. A wide range of processes, covering various spatial and temporal scales, influence the response of terrestrial carbon fluxes (NEE, GPP, TER, fires, methane, lateral export) to changes in land and atmospheric moisture availability. The vegetation and soils also contribute to regulating land-atmosphere moisture fluxes (evapotranspiration, precipitation), which in turn feeds back to the water cycle and the climate system. Observations or modeling assumptions made at different spatial and temporal resolutions also pose new challenges in terms of scaling and uncertainty quantification.

This session aims to synthesize our current understanding and identify knowledge gaps and transferability across scales, We encourage contributions exploring carbon-water interactions from multiple perspectives (remote-sensing, experimental, modelling) and covering all types of biomes (boreal, temperate and tropical forests, grasslands, wetlands, …). Contributions might include for example: 1) disentangling the impact of co-varying drought-driven changes to soil moisture, vapour pressure deficit, or temperature on land carbon fluxes, 2) using in-situ or satellite observations to evaluate or improve the representation of water-carbon interactions and biological processes in models, 3) developing and implementing new representations of plant and ecosystem responses to land and atmospheric moisture stress (e.g. through plant hydraulics, optimality approaches, etc.) and 4) scaling carbon- water interactions from the leaf-level to the global scale and bridging the gap between data streams taken at different temporal and spatial scales (e.g. using modeling, theoretical or statistical approaches).

Solicited speaker: Alexandra Konings, Stanford University

Public information:
Observations and simulations of the terrestrial carbon and water budget are fundamental to understanding biosphere-atmosphere interactions under a changing climate. A wide range of processes, covering various spatial and temporal scales, influence the response of terrestrial carbon fluxes (NEE, GPP, TER, fires, methane, lateral export) to changes in land and atmospheric moisture availability. The vegetation and soils also contribute to regulating land-atmosphere moisture fluxes (evapotranspiration, precipitation), which in turn feeds back to the water cycle and the climate system. Observations or modeling assumptions made at different spatial and temporal resolutions also pose new challenges in terms of scaling and uncertainty quantification.

This session aims to synthesize our current understanding and identify knowledge gaps and transferability across scales, We encourage contributions exploring carbon-water interactions from multiple perspectives (remote-sensing, experimental, modelling) and covering all types of biomes (boreal, temperate and tropical forests, grasslands, wetlands, …). Contributions might include for example: 1) disentangling the impact of co-varying drought-driven changes to soil moisture, vapour pressure deficit, or temperature on land carbon fluxes, 2) using in-situ or satellite observations to evaluate or improve the representation of water-carbon interactions and biological processes in models, 3) developing and implementing new representations of plant and ecosystem responses to land and atmospheric moisture stress (e.g. through plant hydraulics, optimality approaches, etc.) and 4) scaling carbon- water interactions from the leaf-level to the global scale and bridging the gap between data streams taken at different temporal and spatial scales (e.g. using modeling, theoretical or statistical approaches).

Solicited speaker: Alexandra Konings, Stanford University

Fire is an essential feature of terrestrial ecosystems and an important component of the Earth system. Climate, vegetation characteristics, and human activity regulate fire occurrence and spread, but fires also feedback to them in multiple ways. The mechanisms of interactions between fire, land, atmosphere, and society are complicated and remain poorly understood quantitatively. This session welcomes contributions on all aspects of links between fire, biosphere, climate, and humans to share recent advances and foster interdisciplinary discussions. We encourage all abstracts that explore the role of fire in the Earth system at any temporal and spatial scale using modeling, field and laboratory observations, and/or remote sensing, with an emphasis on studies that advance our understanding on (1) impacts of fire on weather, climate, and atmospheric chemistry, (2) interactions between fire, biogeochemical cycles, land water and energy budgets, and vegetation composition and structure, (3) influence of humans on fire and vice versa (e.g., impact of fire on air and water quality, human health, and economy), (4) fire characteristics (e.g. fire duration, emission factor, emission height, smoke transport), (5) spatial and temporal changes of fires in the past, present, and future, (6) fire products and models, and their validation and error/bias assessment, and (7) analytical tools designed to enhance situational awareness among fire practitioners and early warning systems, addressing specific needs of operational fire behavior modeling.

This session invites innovative Earth system and climate studies based on geodetic measuring techniques. Modern geodetic observing systems document a wide range of changes in the Earth’s solid and fluid layers at very diverging spatial and temporal scales related to processes as, e.g., glacial isostatic adjustment, the terrestrial water cycle, ocean dynamics and ice-mass balance. Different time spans of observations need to be cross-compared and combined to resolve a wide spectrum of climate-related signals. Geodetic observables are also often compared with geophysical models, which helps to explain observations, evaluate simulations, and finally merge measurements and numerical models via data assimilation.
We appreciate contributions utilizing geodetic data from diverse geodetic satellites including altimetry, gravimetry (CHAMP, GRACE, GOCE and GRACE-FO), navigation satellite systems (GNSS and DORIS) or remote sensing techniques that are based on both passive (i.e., optical and hyperspectral) and active (i.e., SAR) instruments. We welcome studies that cover a wide variety of applications of geodetic measurements and their combination to observe and model Earth system signals in hydrological, ocean, atmospheric, climate and cryospheric sciences. Any new approaches helping to separate and interpret the variety of geophysical signals are equally appreciated. Contributions working towards the newly established Inter-Commission Committee on "Geodesy for Climate Research" (ICCC) of the International Association of Geodesy (IAG) would be particularly interesting for this session.
With author consent, highlights from this session will be tweeted with a dedicated hashtag during the conference in order to increase the impact of the session.

This session is a result of a merge between GI1.3 and GM2.3:

Recent advances in image collection and topographic measurements are providing unprecedented insight into landscape and process characterization across the geosciences. In parallel, the increasing availability of digitised historical images, going back to the late 1800s, together with advances in digital photogrammetry software, have provided new opportunities for assessing and reconstructing long-term surface evolution from local to landscape scale. Such data can extend high-resolution time series into the pre-satellite era and offer exciting potential for distinguishing anthropogenic from natural causes of environmental change. For both historic and contemporary scenarios, augmenting classic techniques with digital imagery and ‘structure from motion’ (SfM) processing has democratized data access and offers a new measurement paradigm to geoscientists.

Such data are now available over spatial scales from millimetres to kilometres, and over durations of single events to lasting time series (e.g. from sub-second to century-duration time-lapse), allowing evaluation of event magnitude and frequency interrelationships. Despite a large volume of historical images available for reprocessing with modern methods, their full potential has not yet been widely exploited and uncertainties remain on the optimal types of information that can be extracted. Substantial opportunities are likely to be exposed by exploring such data resources with machine and deep learning approaches.

The session welcomes submissions from a broad range of geoscience disciplines such as geomorphology, cryosphere, volcanology, hydrology, bio-geosciences, and geology. Our goal is to create a diverse and interdisciplinary session to explore the potential of 2D and 3D image and topographic datasets for reconstructing and interpreting environments and processes, past and present. We aim to exchange experiences of modern photogrammetric and topographic measurement and modelling technologies, along with their associated data processing tools, to highlight their potentials, limitations, and challenges in different environments.

Public information:
We will have a video meeting on Friday evening starting from 6 pm CEST (UTC+2), in addition to the chat session on Friday morning, as scheduled. Authors will give talks in this video meeting, and there will be room for discussions, with the following agenda:

18:00 - 18:05 - Meeting setting and introduction to the session
18:05 - 18:17 - Amaury Dehecq, "Multidecadal elevation changes from spy satellite images: application to glaciers and landslides".
18:17 - 18:29 - Robert McNabb, "An open-source toolset for automated processing of historic spy photos: sPyMicMac".
18:29 - 18:41 - Penelope How, "PyTrx: a Python-based monoscopic terrestrial photogrammetry toolset for glaciology".
18.41 - 18:53 - Sebastian Flöry, "Development of a 3D Viewer for georeferencing and monoplotting of historical terrestrial images".
18.53 - 19:05 - Luca Carturan, "Use of WWI photos for quantitative reconstructions of glaciers along the Italian-Austrian front".
19:05 - 19:17 - Martino Terrone, "Coupling historical maps and Lidar data to recognize man-made landforms in urban areas".
19:17 - 19:25 - a little break
19:25 - 19:37 - William D. Harcourt. "Observing the cryosphere with millimetre wave radar: The case study of Rhône Glacier".
19.37 - 19:49 - Denis Feurer, "Time-SIFT: a frugal method for leveraging multi-temporal photogrammetric data without ancillary data"
19.49 - 20:01 - Helge Smebye, "Combined aerial and ground-based Structure-from-Motion modelling for a vertical rock wall face to estimate volume of failure"
20:01 - 20:13 - Sara Cucchiaro, "Terrestrial-Aerial-SfM and TLS data fusion for agricultural terrace surveys in complex topographic and land cover conditions".
20:13 - 20:25 - Andreas Mayr, "Close-range sensing and object based analysis of shallow landslides and erosion in grasslands".
20:25 - 20:37 - Kieran Wood, "UAS radiation hot-spot detection and refinement."
20:37 - break and discussion with an open end.

Join the video meeting using the following link:
https://kuei.zoom.us/j/99949141405

For an optimal audio and video experience, we suggest that you join the meeting using the Zoom application. When following the meeting link, you will be asked to install it. Alternatively, you may join the meeting using the Chrome browser.

The session presents applications of paleontology and paleoecology to evolutionary theory, environmental and paleoenvironmental reconstruction, biostratigraphy, paleoclimate, paleoceanography, sea-level change, and population dynamics, as well as modern experimental approaches and culture studies centered on the same fields. The diverse session program will stimulate discussions and the exchange of ideas which will lay the foundations for future paleontological research, particularly as a tool to understand the ongoing change of the global ecosystem.

Public information:
Three main themes: Episodes in the History of Life, Recent Impacts on Ecosystems, Macroevolution

In the current context of global change, assessing the impact of climate variability and changes on hydrological systems and water resources is increasingly crucial for society to better-adapt to future shifts in water resources as well as extreme conditions (floods and droughts). However, hitherto, important sources of uncertainties have been neglected in forecasting climate impacts on hydrological systems, especially uncertainties associated with internal/natural climate variability, whose contribution to near-future changes could be as important as forced anthropogenic climate changes at the regional scales. Internal climate modes of variability (e.g. ENSO, NAO, AMO) and their impact on the continent are not properly reproduced in the current global climate models, leading to large underestimations of decadal climate and hydroclimatic variability at the global scale. At the same time, hydrological response strongly depends on catchment properties, whose interactions with climate variability are little understood at the decadal timescales. These factors altogether reduce significantly our ability to understand long-term hydrological variability and to improve projection and reconstruction of future and past hydrological changes on which improvement of adaption scenarios depends.
We welcome abstracts capturing recent insights for understanding past or future impacts of large-scale climate variability on hydrological systems and water resources as well as newly developed projection and reconstruction scenarios. Results from model intercomparison studies are encouraged.

Public information:
Dear all,

We hope that you are all well, and ready to participate to the EGU 2020 “sharing geoscience online”.
Our session "HS2.4.6/CL2.29/NH1.21: Understanding the links between hydrological variability and internal/natural climate variability" is scheduled tomorrow (Thursday 07) at 10:45-12:30 (CET time).
As you might have noticed in the last days, chairing the online chat requires some managements. With the convener team, we therefore agreed on an organisation plan to enable everyone to present their displays, and discuss it smoothly with the session participants.

First, we would appreciate if you could upload your presentation materials as soon as possible. Because there is not much time per presentation in the chats, participants are reviewing materials in advance of the scheduled sessions, in order to maximise discussion time.

If the first author of your display will not be available, we request that you let us know in advance, who is attending, so we can be sure all expected presenters are online.

When posting your questions, as well as replying, we recommend you begin your questions/answers with @1stAuthorName (e.g. in my case @Bastien). This will make sure that the question/answer is addressed to the right correspondent.

Below are some information on the conduct of our session:

i) We will go through ONLY the presentations which have uploaded materials for displays, and we will follow the order provided on the session programme;

ii) After a brief introduction, we will give 10 minutes to all participants to look through the different displays;

iii) We will then call each author, who will have 2-3 minutes to tell us about their work. As this is not that easy, we strongly recommend you to prepare few highlights (context + bullet points; max. 6 sentences) in advance. So, you can just paste it at the time.

iv) We then will allow 2-3 minutes for questions to each author. Again, we recommend you to prepare any questions for the other authors in advance.

v) Finally, we will thank all the participants, and call for online comments on the website.
We hope to “see” you tomorrow morning, and we hope this will be a nice experience for everyone.

To help with this, we would appreciate if you could upload your material as soon as you can. Bear in mind that it can be updated at anytime.

Note that the time allocated to the presentation and questions might have to be adjusted tomorrow, depending on the final number of displays

Best Regards,
Bastien, Jean-Philippe, Katie and Nicolas

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.

Clouds play an important role in the polar climate due to their interaction with atmospheric radiation and their role in the hydrological cycle linking poleward water vapour transport with precipitation, thereby affecting the mass balance of the polar ice sheets. Cloud-radiative feedbacks have also an important influence on sea ice. Cloud and precipitation properties depend strongly on the atmospheric dynamics and moisture sources and transport, as well as on aerosol particles, which can act as cloud condensation and ice nuclei.

This session aims at bringing together researchers using observational and/or modeling approaches (at various scales) to improve our understanding of polar tropospheric clouds, precipitation, and related mechanisms and impacts. Contributions are invited on various relevant processes including (but not limited to):


- Drivers of cloud/precipitation microphysics at high latitudes,
- Sources of cloud nuclei both at local and long range,

- Linkages of polar clouds/precipitation to the moisture sources and transport,

- Relationship of the poleward moisture transport to processes in the tropics and extra-tropics, including extreme transport events (e.g., atmospheric rivers, moisture intrusions),

- Relationship of moisture/cloud/precipitation processes to the atmospheric dynamics, ranging from synoptic and meso-scale processes to teleconnections and climate indices,

- Role of the surface-atmosphere interaction in terms of mass, energy, and cloud nuclei particles (evaporation, precipitation, albedo changes, cloud nuclei sources, etc)
- Impacts that the clouds/precipitation in the Polar Regions have on the polar and global climate system, surface mass and energy balance, sea ice and ecosystems.

Papers including new methodologies specific to polar regions are encouraged, such as (i) improving polar cloud/precipitation parameterizations in atmospheric models, moisture transport events detection and attribution methods specifically in the high latitudes, and (ii) advancing observations of polar clouds and precipitation. We would like to emphasize collaborative observational and modeling activities, such as the Year of Polar Prediction (YOPP), Polar-CORDEX, the (AC)3 project on Arctic Amplification, SOCRATES, ACE and other campaigns in the Arctic and Southern Ocean/Antarctica, and encourage related contributions.

The session is endorsed by the SCAR Antarctic Clouds and Aerosols Action Group.


Public information:
Dear Authors,

Thank you all for your great contributions to this session. Hopefully, you have all already successfully uploaded your display material - if not please try to do it on Tuesday (before the Live Chat). If this is not possible - you can do it also during this month. Everyone in any case is welcome to participate in the Live Chat to share their work.

We invite everyone to check the posted material before our session's Live Chat, which is scheduled on 6 May, 08:30–10:15 (CEST=UTC+2). The Live Chat will be open from 8:15 to 10:45 CEST and is only by text chatting.

During the Live Chat we (conveners) will call the authors in the order of the Displays (which will be visible on the right from the chat's window) to shortly introduce their work (motivation.. main points..). It will be easier if everyone has this SHORT text prepared before hand. Please avoid copy/pasting the entire abstract, as all session participants have had the possibility to read the abstract and the posted material prior to the chat session. Then the chat will be open for questions and comments from all participants (we also recommend if possible to prepare your questions beforehand). With 21 abstracts we will have about 5 min to discuss each display.

If there are authors who are certainly not available to be present during the Live Chat - please let us know. You are also welcome to ask your co-authors or colleagues to present your work if the main author is not available at the chat time.

The Chat will be not recorded or stored. Only abstracts and displays will be available after this session. Everyone is welcome to post their comments directly to the Displays (commenting will be open until 1 June). This provides more freedom to discuss.

Looking forward to this new way of science sharing! Hope it goes smoothly:)

Best wishes to you all

Irina, Susanne, Manfred, Tom, Nicole

This PICO session addresses three sub-topics :

Precipitation variability: from drop scale to lot scale:
The understanding of small scale (sec – drop scale to min -km) spatio-temporal variability of precipitation is essential for larger scale studies, especially in highly heterogeneous areas (mountains, cities). Nevertheless grasping this variability remains an open challenge. An illustration of the range of scales involved is the ratio between the effective sampling areas of point measurement devices (rain gauges and disdrometers) and weather radars, which is greater than 10^7! This session aims at bridging this scale gap and improving the understanding of small scale precipitation variability, both liquid and solid, as well as its hydro-meteorological consequences at larger scales.

Hydroclimatic and hydrometeorologic stochastics: Extremes, scales, probabilities:
The departure of statistical properties of hydrometeorological processes from the classical statistical prototype has been established. This session aims at presenting the latest developments on:
- Coupling stochastic approaches with deterministic hydrometeorological predictions;
- Stochastic-dynamic approaches;
- Variability at climatic scales and its interplay with the ergodicity of space-time probabilities;
- Linking underlying physics and scaling stochastics of hydrometeorological extremes;
- Development of parsimonious representations of probability distributions of hydrometeorological extremes over a wide range of scales and states; as well as their applications in risk analysis and hazard predictions
The session is co-sponsored by the ICSH-IAHS, former STAHY.

The atmospheric water cycle under change: feedbacks, land use, hydrological changes and implications :
Traditionally, hydrologists have always considered precipitation and temperature as input to their models and evaporation as a loss. However, more than half of the evaporation globally comes back as precipitation on land. Anthropogenic pressure through land-use changes (and greenhouse gasses) alter, not only, the local hydrology, but through atmospheric water and energy feedbacks also effect the water cycle in remote locations. This session aims to:
- investigate the remote and local atmospheric feedbacks from human interventions, based on observations and coupled modelling approaches.
- explore the implications of atmospheric feedbacks on the hydrologic cycle for land and water management (ex. changing land cover)

Hydroclimatic conditions and the availability of water resources in space and time constitute important factors for maintaining an adequate food supply, the quality of the environment, and the welfare of inhabitants, in the context of sustainable growth and economic development. This session is designed to explore the impacts of hydroclimatic variability, climate change, and the temporal and spatial availability of water resources on: food production, population health, the quality of the environment, and the welfare of local ecosystems. We particularly welcome submissions on the following topics:

Complex inter-linkages between hydroclimatic conditions, food production, and population health, including: extreme weather events, surface and subsurface water resources, surface temperatures, and their impacts on food security, livelihoods, and water- and food-borne illnesses in urban and rural environments.

Quantitative assessment of surface-water and groundwater resources, and their contribution to agricultural system and ecosystem statuses.

Spatiotemporal modeling of the availability of water resources, flooding, droughts, and climate change, in the context of water quality and usage for food production, agricultural irrigation, and health impacts over a wide range of spatiotemporal scales

Intelligent infrastructure for water usage, irrigation, environmental and ecological health monitoring, such as development of advanced sensors, remote sensing, data collection, and associated modeling approaches.

Modelling tools for organizing integrated solutions for water, precision agriculture, ecosystem health monitoring, and characterization of environmental conditions.

Water re-allocation and treatment for agricultural, environmental, and health related purposes.

Impact assessment of water-related natural disasters, and anthropogenic forcings (e.g. inappropriate agricultural practices, and land usage) on the natural environment; e.g. health impacts from water and air, fragmentation of habitats, etc.

Climate change is projected to result in an increase in extreme and compound weather events, which pose a growing threat to human well-being and the achievement of the UN Sustainable Development Goals (SDGs). Further warming is also projected to reduce the efficacy of carbon sinks acting as negative feedbacks on warming and increase the risk of crossing tipping points and triggering cascading changes in the climate and ecosystems. These processes may reduce the Earth system’s resilience, which has the potential to further amplify climate change and extremes and worsen societal impacts.

Maintaining Earth in the Holocene-like conditions that have enabled the development of the world’s societies will require better understanding of feedbacks and tipping dynamics in both the human world and the biophysical Earth. Societies will need to embark on rapid socio-economic and governance transformations in order to both reduce the risk of triggering tipping points and to improve societal resilience to increasingly likely extreme events. Earth resilience brings the complex dynamics and perturbations associated with human activities into Earth system analysis, and increasingly captures socio-economic as well as biophysical dynamics.

In this session we welcome transdisciplinary and cross-scale contributions relating to climate extremes, tipping dynamics, and Earth resilience, covering topics ranging from the cascading impacts of extreme and compound events, key feedbacks and tipping points in both biophysical and human systems, enhancing societal resilience to extreme events, and the potential for rapid social transformations to global sustainability.

Public information:
EGU 2020 Session TS3.2/NH10.7
Climate Extremes, Tipping Dynamics, and Earth Resilience in the Anthropocene
6 May, 14:00-18:00

This session will run as an EGU website hosted text-based chat accessible here, as well as through a simultaneous Zoom video room (link to be provided during the livechat).

Both the EGU chatroom and the Zoom video room will be moderated.
Comments on the presentations can be made at the EGU website at any time, for asynchronous responses.
Comments and questions asked in the EGU chatroom will be forwarded to the Zoom presenters. This means all questions will get responses, but this may not happen within the timeslot of the presentation.
To facilitate real-time dialogue with the presenters, please go to the Zoom session.

When joining the Zoom session remember to mute yourself, and to ask questions please raise your hand (available from the 'participants' button) and unmute when the chair calls on you. If you are a presenter, unmute when called on and share your screen if you have a few slides to show. Each presenter gets 10 minutes max including Q&A, so we suggest presenting some summary slides for a few minutes and then taking questions for the rest.

Papers are solicited related to the understanding and prediction of weather, climate and geophysical extremes, from both an applied sciences and theoretical viewpoint.

In this session we propose to group together the traditional geophysical sciences and more mathematical/statistical approaches to the study of extremes. We aim to highlight the complementary nature of these two viewpoints, with the aim of gaining a deeper understanding of extreme events.

Potential topics of interest include but are not limited to the following:

· How extremes have varied or are likely to vary under climate change;
· How well climate models capture extreme events;
· Attribution of extreme events;
· Emergent constraints on extremes;
· Linking dynamical systems extremes to geophysical extremes;
· Extremes in dynamical systems;
· Downscaling of weather and climate extremes.
· Linking the dynamics of climate extremes to their impacts

Environmental systems often span spatial and temporal scales covering different orders of magnitude. The session is oriented in collecting studies relevant to understand multiscale aspects of these systems and in proposing adequate multi-platform and inter-disciplinary surveillance networks monitoring tools systems. It is especially aimed to emphasize the interaction between environmental processes occurring at different scales. In particular, a special attention is devoted to the studies focused on the development of new techniques and integrated instrumentation for multiscale monitoring high natural risk areas, such as: volcanic, seismic, energy exploitation, slope instability, floods, coastal instability, climate changes and other environmental context.
We expect contributions derived from several disciplines, such as applied geophysics, geology, seismology, geodesy, geochemistry, remote and proximal sensing, volcanology, geotechnical, soil science, marine geology, oceanography, climatology and meteorology. In this context, the contributions in analytical and numerical modeling of geological and environmental processes are also expected.
Finally, we stress that the inter-disciplinary studies that highlight the multiscale properties of natural processes analyzed and monitored by using several methodologies are welcome.

This session is linked to the Pan-Eurasian EXperiment (PEEX; www.atm.helsinki.fi/peex), a multi-disciplinary, -scale and -component climate change, air quality, environment and research infrastructure and capacity building programme. It is aimed at resolving major uncertainties in Earth system science and global sustainability issues concerning the Arctic, Northern Eurasia and China regions. This session aims to bring together researchers interested in (i) understanding environmental changes effecting in pristine and industrialized Pan-Eurasian environments (system understanding); (ii) determining relevant environmental, climatic, and other processes in Arctic-boreal regions (process understanding); (iii) the further development of the long-term, continuous and comprehensive ground-based, air/seaborne research infrastructures together with satellite data (observation component); (iv) to develop new datasets and archives of the continuous, comprehensive data flows in a joint manner (data component); (v) to implement validated and harmonized data products in models of appropriate spatio-temporal scales and topical focus (modeling component); (vi) to evaluate impact on society though assessment, scenarios, services, innovations and new technologies (society component).
List of topics:
• Ground-based and satellite observations and datasets for atmospheric composition in Northern Eurasia and China
• Impacts on environment, ecosystems, human health due to atmospheric transport, dispersion, deposition and chemical transformations of air pollutants in Arctic-boreal regions
• New approaches and methods on measurements and modelling in Arctic conditions;
• Improvements in natural and anthropogenic emission inventories for Arctic-boreal regions
• Physical, chemical and biological processes in a northern context
• Aerosol formation-growth, aerosol-cloud-climate interactions, radiative forcing, feedbacks in Arctic, Siberia, China;
• Short lived pollutants and climate forcers, permafrost, forest fires effects
• Carbon dioxide and methane, ecosystem carbon cycle
• Socio-economical changes in Northern Eurasia and China regions.
PEEX session is co-organized with the Digital Belt and Road Program (DBAR), abstracts welcome on topics:
• Big Earth Data approaches on facilitating synergy between DBAR activities & PEEX multi-disciplinary regime
• Understanding and remote connection of last decades changes of environment over High Asia and Arctic regions, both land and ocean.

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?

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 atmospheric water cycle is a key component of the climate system, and links across many scientific disciplines. Processes interact with dynamics at different scales throughout the atmospheric life cycle of water vapour from evaporation to precipitation. This session sets the focus on understanding the interaction between processes, their dynamics and characteristics of the water cycle, covering the entire atmospheric life cycle from evaporation, atmospheric moisture transport, to precipitation processes as observed from in-situ and remote sensing instrumentation, recorded by (paleo)climate archives, and as simulated by models for past, present and future climates.

We invite studies

* focusing on the understanding and impacts of features of the atmospheric water cycle related to weather systems, such as Atmospheric Rivers, Cold-Air Outbreaks, Warm Conveyor Belts, Tropical Moisture Exports, and the global Monsoon systems;

* investigating the large-scale drivers behind the variability and trends within the atmospheric water cycle, from long-term observations, reanalysis data, or regional to global model simulations;

* involving and connecting field campaigns (YOPP, MOZAiC, NAWDEX) with forecast and reanalysis data, indicators of past hydroclimate from climate proxies such as ice cores and stalagmites, and model predictions of the future evolution of the atmospheric water cycle;

* applying methods such as stable isotopes as physical tracers in the water cycle, tagged water tracers, and Lagrangian moisture source diagnostics to identify source-sink relationships and to evaluate model simulations of the water cycle;

* describing the global and regional state of the atmospheric water cycle with characteristics such as the recycling ratio, life time of water vapour, and moisture transport properties.

We particularly encourage contributions to link across neighbouring disciplines, such as atmospheric science, climate, paleoclimate, glaciology, and hydrology.

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.

Several large ensemble model simulations from General Circulation Models (GCM), Earth System Models (ESM), or Regional Climate Models (RCM), have been generated over the recent years to investigate internal variability and forced changes of the climate system - and to aid the interpretation of the observational record by providing a range of historical climate trajectories that could have been. The increased availability of large ensembles also enables broadening their application to new and inter-disciplinary fields.

This session invites studies using large GCM, ESM, or RCM ensembles looking at the following topics: 1) forced changes in internal variability and reinterpretation of observed record; 2) development of new approaches to attribution of observed events or trends; 3) impacts of natural climate variability; 4) assessment of extreme and compound event occurrence; 5) use of large ensembles for robust decision making; 6) large ensembles as testbeds for method development; and 7) novel methods for efficient analysis and post-processing of large ensembles.

We welcome research across the components of the Earth system and particularly invite studies that apply novel methods or cross-disciplinary approaches to leverage the potential of large ensembles.

Public information:
Announcement: Note that this session will be conducted in two parts:

1) The official #ShareEGU20 live chat. May 8, 14:00-15:45.
Agenda: https://meetingorganizer.copernicus.org/EGU2020/displays/36913

2) An additional live streaming of oral presentations. Friday, May 8, 16:15-18:00.
Agenda: bit.ly/2RX1hd9.
RSVP form: bit.ly/3bvzqZ4

Order of discussion for display items during the live chat:

Nathalie Schaller
2. Bin Yu
3. Benoit Hingray
4. Laura Suarez Gutierrez
5. Flavio Lehner
6. Bo Christiansen
7. Karsten Haustein
8. Renate Wilcke
9. Lea Beusch
10. Andrea Böhnisch
11. Satoshi Watanabe
12. Peter Watson
13. Tamas Bodai
14. Gabor Drotos
15. Gerhard Smiatek
16. Ralf Hand (1st display)
17. Ralf Hand (2nd display)
18. Mátyás Herein

19. Joel Zeder
20. Sebastian Milinski
21. Anna Merrifield
22. Raul R. Wood
23. Shipra Jain
24. Aaron Spring

Climate change (CC) is expected affecting weather forcing regulating the triggering, reactivation, and severity of slope failures and soil erosion. In this view, the influence of CC can be different according to the area, the time horizon of interest and to the specific trends of weather variables. Similarly, land use/cover change can play a pivotal role in exacerbating or reducing such hazards.
Thus, the overall impacts depend on the region, spatial scale, time frame and socio-economic context addressed. However, even the simple identification of the weather patterns regulating the occurrence of such phenomena represents a not trivial issue, also assuming steady conditions, due to the crucial role played by geomorphological details. To support hazards’ monitoring, predictions and projections, last-generation and updated datasets with high spatio-temporal resolution and quality - like those from the Copernicus Services’ Portals - are useful to feed models, big-data analytics and indicators’ frameworks enabling timely, robust and efficient decision making.
The Session aims at presenting studies concerning ongoing to future landslide dynamics and soil erosion hazards across different geographical contexts and scales (from slope to regional, to global scale) including analyses of historical records and related climate variables, or modeling approaches driven by future climate exploiting downscaled output of climate projections. Studies assessing variations in severity, frequency and/or timing of events and consequent risks are valuable. Finally, tested or designed adaptation strategies can be discussed.

Remote sensing, numerical models, and machine learning have been widely used for investigating environmental risks under climate change. It is known that they tend to do an excellent job in mapping, simulating, and projecting the long-term changes in average conditions. However, damages associated with extreme weathers by droughts, floods, forest fires, heat-related mortality, and crop yield loss are often more devastating than those caused by gradual climate changes. How remote sensing, numerical models, and machine learning can be used for assessing the impacts of extreme weathers on the natural and human systems remains uncertain.
This session aims to summarize current progress in assessing the ability of remote sensing, numerical models, and machine learning for quantifying climate risks in multiple sectors, such as water, agriculture, and human health.
We especially welcome investigations focusing on the inter-comparison of methodologies, as well as multi-sectoral, cross-sectoral, and integrated assessments.

Changes in the Arctic and Antarctic climate systems are strongly related to processes in the boundary layer and their feedbacks with the free troposphere, ocean and ice. An adequate understanding and quantification of these processes is necessary to improve predictions of future changes in the polar regions and their teleconnection with mid-latitude weather and climate, including meridional transport of heat, moisture and chemical constituents. Processes include atmosphere-ocean-ice (AOI) interactions, physical and chemical snow processes (e.g. snow photochemistry), exchange of chemical constituents including biogeochemical impacts , sources of aerosol, polynya formation processes, sea ice production and loss, and cloud formation, which represent key processes for the atmosphere, ocean and the cryosphere. AOI interactions are also triggered by and have feedbacks with synoptic systems and mesoscale weather phenomena such as cold air outbreaks, katabatic winds and polar lows. Associated processes also include the effect of extreme events such as warm air advection and clouds on the surface energy budget and related boundary layer exchanges. In addition, understanding natural processes including AOI interactions is essential to understand of the background atmosphere to quantify the anthropogenic impacts. Shallow inversions, mostly during winter-time, lead to high air pollutant concentrations. Even though severe air pollution episodes are frequently observed in the Arctic, knowledge on urban emission sources, transport and atmospheric chemical processing of pollution, especially under cold and dark conditions, are poorly understood. Similarly, the polar boundary layer can involve complicated radiative processes such as shallow stable layers with fog present. In addition, polar boundary layers can mediate chemical, aerosol, and isotope exchanges between the atmosphere and the firn important to the interpretation of ice core records.
This session is intended to provide an interdisciplinary forum to bring together researchers working in the area of boundary layer processes and high-latitude weather and climate (including snow physics, air/snow chemistry, and oceanography). Cryosphere and atmospheric chemistry processes (the focus of the IGAC/SOLAS activity “CATCH” and the IGAC/IASC activity “PACES”) are highly relevant to this session. We also encourage preliminary results from field programs such as MOSAiC and other high-latitude research efforts.