Smart monitoring and observation systems for hazards, including satellites, seismometers, global networks, uncrewed vehicles (e.g., UAV), and other linked devices, have become increasingly abundant. With these data, we observe our Earth’s restless nature and work towards improving our understanding of hazard processes such as landslides, debris flows, earthquakes, floods, storms, volcanic eruptions, and tsunamis. The large amount of data we have now accumulated with diverse measurements presents an opportunity for earth scientists to employ statistically driven approaches that speed up data processing, improve model forecasts, and give insights into the underlying physical processes. Such big-data approaches are supported by the wider scientific, computational, and statistical research communities who are constantly developing data science and machine learning techniques and software. Hence, data science and machine learning methods are rapidly impacting the fields of geohazards. In this session, we will see research into hazards spanning a broad range of time and spatial scales.

Extreme events and natural hazards are frequent occurrences on our unstable planet. They are predicted to become more common, severe and costly in the future and this session explores their role in human prehistory and history. In order to understand the potential of contemporary and future extreme events to impact human societies, it is critical to understand the mechanisms of how they may have occurred in the past, and elucidate their effects. This session invites contributions from across relevant disciplines. Global in scope and not limited to specific types of extreme events or natural hazards, we hope to compare and contrast differing methods and datasets that address the character and role of extreme events in the human past. Ultimately, we also seek to discuss how the evidence base of Pleistocene and Holocene calamities can be brought into play in the discussion about sustainability and disaster risk reduction in the Anthropocene, as well as to explore how extreme events may have shaped our past.

This session is a merge session and jointly lead by the group of NH1.1 and NH1.2.
NH1.1: Innovative Techniques for Flood Forecasting, Assessment and Flood Risk Management
This session invites presentations on research based on high-resolution aerial, satellite and ML techniques for flood monitoring and modeling, including mapping of inundation extent, flow depths, velocity fields, flood-induced morphodynamics, and debris transport. It also invites the presentation of innovative modelling techniques of flood hydrodynamics, flood hazard, damage and risk assessment, as well as flood relief prioritization, dam and dike (levees) break floods, and flood mitigation strategies. Studies dealing with the modelling uncertainties and modern techniques for model calibration and validation are particularly welcome. Furthermore, real-time flood inundation mapping is a critical aspect for the evacuation of people from low-lying areas and to reduce casualties. Acquisition of real-time data gained through UAV-based flood inundation mapping, ML and modelling techniques, as well as assessment of uncertainties in real-time aerial surveying are welcome in this session. We also encourage contributions in integrative solutions at local, regional or global perspectives. Invited Speaker: Prof.Paul Bates (https://research-information.bris.ac.uk/en/persons/paul-d-bates)
NH1.2: Advances in modeling, failure assessment and monitoring of levees and other flood defences
The present session aims to provide a platform for the interdisciplinary exchange of knowledge among flood risk and other flood hazard related scientific communities interested in the modeling, assessment and monitoring of soil made flood defences, to share their experiences and advances in the field. Hence the session aims to present contributions regarding: 1) Numerical and experimental advances on failure mechanism understanding (e.g. Overtopping, piping erosion, Slope stability, etc) 2) Probabilistic assessment of flood defence design and reliability assessment. 3) Monitoring techniques of flood defences based on remote and direct instrumentation. 4) Alternative flood defence studies for evaluation of effect and performance of controlled failure, retention basins and fast infiltration surfaces on inundation models. 5) Artificial intelligence and data driven techniques for modeling, assessment and monitoring of soil flood defences.

Heat extremes are already one of the deadliest meteorological events and they are projected to increase in intensity and frequency due to rising CO2 emissions. The hazard these events pose to society may therefore increase dramatically, and society will need to adapt if the worst impacts are to be avoided. This session therefore welcomes a broad range of new research addressing the challenge of extreme heat. Suitable contributions may: (i) assess the drivers and underlying processes of extreme heat in observations and/or models; (ii) explore the diverse socio-economic impacts of extreme heat events (for example, on aspects relating to human health or economic productivity); (iii) address forecasting of extreme heat at seasonal to sub-seasonal time scales; (iv) focus on societal adaptation to extreme heat, including (but not limited to) the implementation of Heat-Health Early Warning Systems.

Severe hydro-meteorological phenomena (i.e. extreme weather in terms of precipitation, heat waves and wind storms) on land and sea have a high impact globally as well as in European territories. The increasing frequency and severity of hydro-meteorological events such as hurricanes, intense cyclones, or destructive thunderstorms appear to be associated with climate change and an increasing number of people is exposed to climate-related hazards each year – particularly the most vulnerable. The science behind these phenomena is complex, but advancement in evidence-based knowledge, together with progress in technology and data-driven measurement systems, allow more detailed monitoring and forecasting capability to target interventions at the appropriate time-scale. The employment of nature-based solutions (NBS) to mitigate the impact of hydro-meteorological phenomena could be a viable approach requiring coordinated efforts.
The session intends to stimulate the international scientific community across several fields to demonstrate how nature-based solutions (NBSs) could contribute to disaster risk reduction in line with the EU Roadmap for achieving the goals of the Sendai Framework. It aims to promote and share experience with the best available science and knowledge to establish a coherent approach towards risk mitigation. Results from the EU H2020 projects NAIAD, OPERANDUM, PHUSICOS and RECONECT are encouraged as well as contributions discussing the main drivers and barriers for NBSs implementation . Also contributions documenting how NBS can be beneficial in land use planning, risk assessment, climate change impact, disaster prevention are welcome.
Specific topics are related to the following questions
- How can we mainstream the adoption of innovative, systemic and locally-attuned nature-based solutions for hydro-meteorological risk reduction at watershed/landscape scale? - What are the required features of comprehensive framework for comparing green and blue/grey/hybrid hydro-meteorological risk prevention and reduction solutions? - What is the evidence on the effectiveness of these solutions? How can we capture the potential (insurance) value of ecosystems?
Additional topics are
- Methods for NBS co-designing and co-development - Methods for the identification and assessment of barriers related to social and cultural acceptance and in regulatory frameworks that hinder the adoption of NBS

In many parts of the world, weather represents one of the major uncertainties affecting performance and management of agricultural systems. Due to global climate changes the climatic variability and the occurrence of extreme weather events is likely to increase leading to substantial increase in agricultural risk and destabilisation of farm incomes. This issue is not only important for farm managers but also for policy makers, since income stabilisation in agriculture is frequently considered as a governmental task.

The aim of this session is to discuss the state of the art research in the area of analysis and management of weather-related risks in agriculture. Both structural and non-structural measures can be used to reduce the impact of climate variability including extreme weather on crop production. While the structural measures include strategies such as irrigation, water harvesting, windbreaks etc., the non-structural measures include the use of the medium-range weather forecast and crop insurance.

The topic is at the borderline of different disciplines, in particular agricultural and financial economics, meteorology, modelling and agronomy. Thus, the session offers a platform to exchange ideas and views on weather-related risks across these disciplines with the focus on quantifying the impact of extreme weather on agricultural production including impacts of climate change, analysis of financial instruments that allow reducing or sharing weather-related risks, evaluation of risk management strategies on the farm level, development of the theory of risk management and to exchange practical experiences with the different types of weather insurance.

This session has been promoted by:
• Natural hazard Early career scientists Team (NhET, https://blogs.egu.eu/divisions/nh/tag/early-career-scientists/)
• Boosting Agricultural Insurance based on Earth Observation data (BEACON, https://beacon-h2020.com/)
• Research Center for the Management of Agriculutral and Environmental Risks (CEIGRAM, http://www.ceigram.upm.es/ingles/)

Lightning is the energetic manifestation of electrical breakdown in the atmosphere, occurring as a result of charge separation processes operating on micro and macro-scales, leading to strong electric fields within thunderstorms. Lightning is associated with tropical storms and 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 with 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 with emphasis on:

Atmospheric electricity in fair weather and the global electrical circuit
Effects of dust and volcanic ash on atmospheric electricity
Thunderstorm dynamics and microphysics
Middle atmospheric Transient Luminous Events
Energetic radiation from thunderstorms and lightning
Experimental investigations of lightning discharge physics processes
Remote sensing of lightning and related phenomena by ASIM and GLM
Thunderstorms, flash floods, tropical storms and severe weather
Modeling of thunderstorms and lightning
Now-casting and forecasting of thunderstorms using machine learning and AI
Regional and global lightning detection networks
Lightning Safety and its Societal Effects

With global climate change affecting the frequency and severity of extreme meteorological and hydrological events, it is particularly necessary to develop models and methodologies for a better understanding and forecasting of present day weather induced hazards. Future changes in the event characteristics as well as changes in vulnerability and exposure are among the further factors for determining risks for infrastructure and society, and for the development of suitable adaptation measures. 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 or sequences 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 applications like insurance issues.

Hydroinformatics has emerged over the last decades to become a recognised and established field of independent research within the hydrological sciences. Hydroinformatics is concerned with data acquisition, development and hydrological application of mathematical modelling, information technology, systems science and computational intelligence tools. We also have to face the challenges of the so-called Big Data: large data sets, both in size and complexity. Methods and technologies for data handling, visualization and knowledge acquisition are often referred to as Data Science.

The aim of this session is to provide an active forum in which to demonstrate and discuss the integration and appropriate application of emergent computational technologies in a hydrological modelling context. Topics of interest are expected to cover a broad spectrum of theoretical and practical activities that would be of interest to hydro-scientists and water-engineers. We aim to address the following classes of methods and technologies:

* Predictive and analytical models based on the methods of statistics, computational intelligence, machine learning : neural networks (including deep learning), fuzzy systems, genetic programming, cellular automata, chaos theory, etc.
* Innovative sensing techniques: satellites, gauges and citizens (crowdsourcing)
* Methods for the analysis of complex data sets, including remote sensing data: principal and independent component analysis, time series analysis, information theory, etc.
* Specific concepts and methods of Big Data and Data Science
* Optimisation methods associated with heuristic search procedures: various types of evolutionary algorithms, randomised and adaptive search, etc.
* Applications of systems analysis and optimisation in water resources
* Hybrid modelling involving different types of models both process-based and data-driven, combination of models (multi-models), etc.
* Data assimilation and model reduction in integrated modelling
* Novel methods of analysing model uncertainty and sensitivity
* Software architectures for linking different types of models and data sources

Applications could belong to any area of hydrology or water resources: rainfall-runoff modelling, flow forecasting, sedimentation modelling, analysis of meteorological and hydrologic data sets, linkages between numerical weather prediction and hydrologic models, model calibration, model uncertainty, optimisation of water resources, etc.

This session provides a platform for transdisciplinary science that addresses the continuum of the river and its catchment to the coastal sea. We invite studies across geographical borders; from the source to the sea including groundwater, and across the freshwater-marine water transition, including estuaries, deltas and marshlands. The session particularly welcomes studies that link environmental and social science, addressing the impacts of climate change and extreme events and impact of human activities on water and sediment quality and quantity, hydromorphology, biodiversity, ecosystem functioning and services of River-Sea continua. Such a systems approach is required to develop solutions for sustainable management of River-Sea social-ecological systems.

We need to fully understand how River-Sea Systems function. How are River-Sea continua changing due to human pressures? What is the impact of processes in the catchment on coastal and marine systems function, and vice versa? How can we discern between human-induced changes or those driven by natural processes from climate-induced variability and extreme events? What will the tipping points of socio-ecologic system states be and what will they look like? How can we better characterise river-sea systems from the latest generation Earth observation to citizen science based observatories. How can we predict short and long term changes in River-Sea-Systems to manage them sustainably? What is the limit to which it is possible to predict the natural and human-influenced evolution of River-Sea-Systems? The increasing demand to jointly enable intensive human use and environmental protection in River-Sea Systems requires holistic and integrative research approaches with the ultimate goal of enhanced system understanding as the knowledge base for sustainable management solutions.

Water is our planet’s most vital resource, and the primary agent in some of the biggest hazards facing society and nature. The twin pressures of population growth and a rapidly changing global climate act as multipliers of water’s value and of water-related hazards.

River streamflow is one of the most crucial hydrological variables for ecology, for people and industry, for flood risk management and for understanding long term changes to the hydrological regime. However, despite significant efforts, long-term, spatially dense monitoring networks remain scarce, and even the best monitoring networks can fail to perform when faced with extreme conditions, and lack the precision and spatial coverage to fully represent crucial aspects of the hydrological cycle.

Happily, a number of new technologies and techniques are emerging which show great potential to meet these challenges. In this context, this session focuses on:
1) Innovative methodologies for measuring/modelling/estimating river stream flows;
2) Real-time acquisition of hydrological variables;
3) Remote sensing for hydrological & morphological monitoring;
4) Measuring extreme conditions associated with a changing climate;
5) Measurement of sudden-onset extreme flows associated with catastrophic events;
6) Strategies to quantify and describe hydro-morphological evolution of rivers;
7) New methods to cope with data-scarce environments;
8) Inter-comparison of innovative & classical models and approaches;
9) Evolution and refinement of existing methods;
10) Guidelines and standards for hydro-morphological streamflow monitoring;
11) Quantification of uncertainties;
12) Development of expert networks to advance methods.

Contributions are welcome with an emphasis on innovation, efficiency, operator safety, and meeting the growing challenges associated with the changing climate, and with natural and anthropogenically driven disasters such as dam failures and flash floods.

Additionally, presentations will be welcomed which explore options for greater collaboration in advancing riverflow methods and which link innovative research to operational monitoring.

This session is sponsored by the COST Action CA16219, Harmonisation of UAS techniques for agricultural and natural ecosystems monitoring (HARMONIOUS).

The global cryosphere with all its components is strongly impacted by climate change and has been undergoing significant changes over the past decades. Glaciers are shrinking and thinning. Snow cover and duration is reduced, and permafrost, in both Arctic and mountain environments, is thawing. Changes in sea ice cover and characteristics have attracted widespread attention, and changes in ice sheets are monitored with care and concern. Risks associated with one or several of these cryosphere components have been present throughout history. However, with ongoing climate change, we expect changes in the magnitude and frequency of hazards with profound implications for risks, especially when these interact with other aspects relating to context vulnerability, exposure, and other processes of biophysical and/or socioeconomic drivers of change. New or growing glacier lakes pose a threat to downstream communities through the potential for sudden drainage. Thawing permafrost can destabilize mountain slopes, and eventually result in large landslide or destructive rock and ice avalanches. An accelerated rate of permafrost degradation in low-land areas poses risk to existing and planned infrastructure and raises concerns about large-scale emission of greenhouse gases currently trapped in Arctic permafrost. Decreased summertime sea ice extent may produce both risks and opportunities in terms of large-scale climate feedbacks and alterations, coastal vulnerability, and new access to transport routes and natural resources. Furthermore, rapid acceleration of outlet glacier ice discharge and collapse of ice sheets is of major concern for sea level change. This session invites contributions across all cryosphere components that address risks associated with observed or projected physical processes. Contributions considering more than one cryosphere component (e.g. glaciers and permafrost) are particularly encouraged, as well as contributions on cascading processes and interconnected risks. Contributions can consider hazards and risks related to changes in the past, present or future. Furthermore, Contributions may consider one or several components of risks (i.e. natural hazards, exposure, vulnerability) as long as conceptual clarity is ensured. Furthermore, cases that explore diverse experiences with inter- and transdisciplinary research, that sought to address these risks with communities through adaptation and resilience building, are also be considered.

This session is devoted to the dynamics of dense and powder snow avalanches and their accompanying transitional regimes. One focus is their interaction with, and impact on, vulnerable elements, such as buildings, protection dams, forests, and roads. We welcome novel experimental and computational contributions including, but not limited to the topics of avalanche dynamics and related processes, physical vulnerability of structures impacted by snow avalanches, avalanche hazard zoning and avalanche mitigation strategies. These include field, laboratory and numerical studies that rely on new methods and techniques (radars, drone, satellite, etc.) as well as practical case studies.

Furthermore, we solicit novel contributions from the area of granular flows, viscoplastic flows, density currents, turbulent flows, as well as contributions from other gravitational mass flows communities, which can improve our understanding and modeling of snow avalanche propagation and their interaction with natural or man-made structures.

While the main focus of this session is on snow avalanche dynamics from basic knowledge to mitigation strategies, it is closely linked to CR session entitled "Snow avalanche formation: from snow mechanics to avalanche detection" which addresses avalanche formation, detection and forecasting.

Urban hydrological processes are characterized by high spatial variability and short response times resulting from a high degree of imperviousness. Therefore, urban catchments are especially sensitive to space-time variability of precipitation at small scales. High-resolution precipitation measurements in cities are crucial to properly describe and analyses urban hydrological response. At the same time, urban landscapes pose specific challenges to obtaining representative precipitation and hydrological observations.

This session focuses on high-resolution precipitation and hydrological measurements in cities and on approaches to improve modeling of urban hydrological response, including:
- Novel techniques for high-resolution precipitation measurement in cities and for multi-sensor data merging to improve the representation of urban precipitation fields.
- Novel approaches to hydrological field measurements in cities, including data obtained from citizen observatories.
- Precipitation modeling for urban applications, including convective permitting models and stochastic rainfall generators.
- Novel approaches to modeling urban catchment properties and hydrological response, from physics-based, conceptual and data-driven models to stochastic and statistical conceptualization.
- Applications of measured precipitation fields to urban hydrological models to improve hydrological prediction at different time horizons to ultimately enable improved management of urban drainage systems (including catchment strategy development, flood forecasting and management, real-time control and proactive protection strategies aimed at preventing flooding and pollution).
- Strategies to deal with upcoming challenges, including climate change and rapid urbanization.

Over the last decades, a significant body of empirical and theoretical work has revealed the departure of statistical properties of hydrometeorological processes from the classical statistical prototype, as well as the scaling behaviour of their variables in general, and extremes in particular, in either state, space and/or time. In the meantime, extremes and more generally the statistics of hydrometeorologic processes are the key input for hydrological applications. As a classic example the estimation of design rainfall should be mentioned. Beside the estimation of the absolute rainfall amount related to a certain return period, the intra-event rainfall distribution, its spatial extension and the rainfall intensities at neighbouring stations can be required, depending on the intended application and thus the analysed scale. But design rainfall is only one among numerous hydrologic applications, which shape the framework for this session.

The estimation of the hydrometeorological extremes and probability distribution, the identification and involvement of supporting information and the hydrologic application over wide range of scales are open challenges, especially under non-stationary conditions. On the other side, hydrometeorologists had never access to so much computer power and data to face these open challenges.

This session welcomes, but is not limited to submissions on:
- Coupling stochastic approaches with deterministic hydrometeorological predictions, in order to better represent predictive uncertainty
- Development of robust statistics under non-stationary conditions for dimensioning purposes
- Development of parsimonious representations of probability distributions of hydrometeorological extremes over a wide range of scales in risk analysis applications and hazard prediction
- Improvements for reliable estimation of extremes with high return periods under consideration of upper or lower limits due to physical constraints
- Linking underlying physics and stochastics of hydrometeorologic extremes
- Exploration of supporting data sets for additional stochastic information (e.g. unintended use of other measurements, citizen scientist data, soft data, …)

An overall aim of the session is to bridge the gap between the theoretical stochastic analysis of hydrometeorological processes and its practical hydrological application.

Hydro-meteorological extremes such as floods, droughts, storms, or heatwaves often affect large regions therefore causing large damages and costs. Hazard and risk assessments, aiming at reducing the negative consequences of such extreme events, are often performed with a focus on one location despite the spatial nature of extreme events. While spatial extremes receive a lot of attention by the media, little is known about their driving factors and it remains challenging to assess their risk by modelling approaches. Key challenges in advancing our understanding of spatial extremes and in developing new modeling approaches include the definition of multivariate events, the quantification of spatial dependence, the dealing with large dimensions, the introduction of flexible dependence structures, the estimation of their probability of occurrence, the identification of potential drivers for spatial dependence, and linking different spatial scales.

This session invites contributions which help to better understand processes governing spatial extremes and/or propose new ways of describing and modeling spatial extremes at different spatial scales.

Target audience: hydrologists, climatologists, statisticians, machine learners, and researchers interested in spatial risk assessments.

Extreme hydro-meteorological events drive many hydrologic and geomorphic hazards, such as floods, landslides and debris flows, which pose a significant threat to modern societies on a global scale. The continuous increase of population and urban settlements in hazard-prone areas in combination with evidence of changes in extreme weather events lead to a continuous increase in the risk associated with weather-induced hazards. To improve resilience and to design more effective mitigation strategies, we need to better understand the aspects of vulnerability, risk, and triggers that are associated with these hazards.

This session aims at gathering contributions dealing with various hydro-meteorological hazards that address the aspects of vulnerability analysis, risk estimation, impact assessment, mitigation policies and communication strategies. Specifically, we aim to collect contributions from the academia, the industry (e.g. insurance) and government agencies (e.g. civil protection) that will help identify the latest developments and ways forward for increasing the resilience of communities at local, regional and national scales, and proposals for improving the interaction between different entities and sciences.

Contributions focusing on, but not limited to, novel developments and findings on the following topics are particularly encouraged:
- Physical and social vulnerability analysis and impact assessment of hydro-meteorological hazards
- Advances in the estimation of socioeconomic risk from hydro-meteorological hazards
- Characteristics of weather and precipitation patterns leading to high-impact events
- Relationship between weather and precipitation patterns and socio-economic impacts
- Hazard mitigation procedures
- Strategies for increasing public awareness, preparedness, and self-protective response
- Impact-based forecast and warning systems
- Insurance and reinsurance applications

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.

Heavy precipitation events in small and medium size catchments can trigger flash floods, which are characterized by very short response times and high specific peak discharges, and often occur in ungauged basins. Under appropriate geomorphological conditions, such rainstorms also cause debris flows or shallow landslides mobilizing large amounts of unconsolidated material. Although significant progress has been made in the management of these different hazards and related risks, they remain poorly understood and their predictability is affected by large uncertainties, due to the fast evolution of triggering rainfall events, the lack of appropriate observations, the high variabilities and non-linearities in the physical processes, and the high variability and complexity of societal vulnerability.
This session aims to illustrate current advances in monitoring, understanding, modelling, and forecasting flash floods and associated geomorphic processes, and documenting and anticipating the societal impacts and social responses.
Contributions on the following scientific themes are more specifically expected:
- Development of new measurement techniques adapted to flash floods and/or rainfall-induced geomorphic hazards monitoring (including in-situ sensors and remote sensing data, such as weather radar, and lightning ..), and quantification of the associated uncertainties,
- Identification of processes leading to flash flood events and/or rainfall-induced geomorphic hazards from data analysis and/or modelling, and of their characteristic space-time scales,
- Possible evolutions in hazard characteristics and frequency related to climate change,
- Development of short-range (0-6h) rainfall forecasting techniques adapted to heavy precipitation events, and representation of associated uncertainties,
- Development of hydro-meteorological forecasting chains for predicting flash floods and/or rainfall-induced geomorphic hazards in gauged and ungauged basins,
- Development of inundation mapping approaches specifically designed for an integration in flash floods monitoring or forecasting chains,
- Use of new criteria such as specific “hydrological signatures” (high water marks, impacts and damages, ..) or other proxy data for model and forecast evaluation,
- Observation, understanding and prediction of the societal vulnerability and social responses to flash floods and/or associated hydro-geomorphic hazards.

Hydrological forecasting can benefit from a better understanding of urban floods and of the thresholds values of the hydrological variables that are crucial for making decisions. This session addresses these two aspects.
Urban flooding is becoming a major issue in many megacities around the world due to a lack of adequate storm water management, hydrologic design, and failure of aging hydrologic infrastructure. To model such extreme flood events, it is of utmost importance to develop state-of-the-art disaster mitigation and damage reduction measures, as well as one and two-dimensional hydrologic and coupled hydrodynamic modelling approaches. Innovative methods are needed to address the modelling and management of urban floods and their spatial and temporal complexity. The session discusses urban floods analysis and measures to mitigate the effects of these events, emerging (e.g., Internet-of-Things (IoT)-based) flood monitoring systems, street-level flood forecasting, dissemination of flood warnings and measures to evacuate people, case studies that provide a better understanding of urban flood management, and innovative methods of floodwater conservation, including strategies and practices to control surface runoff at its sources in a sustainable way.
In hydrological forecasting, where the stochastic nature of the processes makes impossible a deterministic forecast of both the magnitude of the processes and their effects, threshold values can be of great importance and usefulness. Thresholds can be simple (e.g., the threshold of rainfall intensity that might separate stratiform from convective rainfall) or complex and multi-variate (e.g., the threshold for damaging snow-melt flooding, or the threshold for intense hillslope erosion in an agricultural field). They can be useful for real-time forecasts based on simple thresholds on rainfall data (e.g., activation of mass movements such as landslides, debris flow, rill and inter-rill erosion, etc.), for the adoption of satellite data in the management of ground actions (e.g., values of the satellite indexes to be used in irrigation management), for distinguishing among water flow regimes, among other applications.

Drought and water scarcity are important issues in many regions of the Earth. While an increase in the severity and frequency of droughts can lead to water scarcity situations, particularly in regions that are already water-stressed, overexploitation of available water resources can exacerbate the consequences of droughts. In the worst case, this can lead to long-term environmental and socio-economic impacts. It is, therefore, necessary to improve both monitoring and sub-seasonal to seasonal forecasting for droughts and water availability and to develop innovative indicators and methodologies that translate the information provided into effective drought early warning and risk management. This session addresses statistical, remote sensing and physically-based techniques, aimed at monitoring, modelling and forecasting hydro-meteorological variables relevant to drought and/or water scarcity. These include, but are not limited to, precipitation, snow cover, soil moisture, streamflow, groundwater levels, and extreme temperatures. The development and implementation of drought indicators meaningful to decision-making processes, and ways of presenting and explaining them to water managers, policymakers and other stakeholders, are further issues that are addressed. The session aims to bring together scientists, practitioners and stakeholders in the fields of hydrology and meteorology, as well as in the field of water resources and/or risk management; interested in monitoring, modelling and forecasting drought and water scarcity, and in analyzing their interrelationships, hydrological impacts, and the feedbacks with society. Particularly welcome are applications and real-world case studies in regions subject to significant water stress, where the importance of drought warning, supported through state-of-the-art monitoring and forecasting of water resources availability is likely to become more important in the future. Contributors to the session are invited to submit papers to the Special Issue (SI) entitled "Recent advances in drought and water scarcity monitoring, modelling, and forecasting", to be published in the open-access journal Natural Hazard and Earth System Sciences (https://www.natural-hazards-and-earth-system-sciences.net/special_issues/schedule.html). Submission is open until 31 December 2020, for manuscripts that are not under consideration for publication elsewhere.

Transport of sediments in geophysical flows occurs in mountainous, fluvial, estuarine, coastal, aeolian and other natural or man-made environments on Earth and has been shown to play important formative roles in planets and satellites such as Mars, Titan, and Venus. Understanding the motion of sediments is still one of the most fundamental problems in hydrological and geophysical sciences. Such processes can vary across a wide range of scales - from the particle to the landscape - which can directly impact both the form (geomorphology) and, on Earth, the function (ecology and biology) of natural systems and the built infrastructure surrounding them. In particular, feedback between flow and sediment transport as well as interparticle interactions including size sorting are a key processes in surface dynamics, finding a range of important applications, from hydraulic engineering and natural hazard mitigation to landscape evolution and river ecology.

Specific topics of interest include (but are not restricted to):

A) particle-scale interactions and transport processes:
-mechanics of entrainment and disentrainment (for fluvial and aeolian flows)
-momentum (turbulent impulses) and energy transfer between turbulent flows and particles
-upscaling and averaging techniques for stochastic transport processes
-interaction among grain sizes in poorly sorted mixtures, including particle segregation

B) reach-scale sediment transport and geomorphic processes
-bedform generation, evolution and disintegration dynamics (e.g. for dunes and other formations)
-discrete element modelling of transport processes and upscaling into continuum frameworks
-derivation and solution of equations for multiphase flows (including fluvial and aeolian flows)
-shallow water hydro-sediment-morphodynamic processes

C) large-scale, highly unsteady and complex water-sediment flows:
-flash floods, debris flows and landslides due to extreme rainfall
-natural and build dam failures and compound disasters (due to landslides, debris flow intrusion and downstream flooding)
-reservoir operation schemes and corresponding fluvial processes
-design of hydraulic structures such as fish passages, dam spillways, also considering the impact of sediment
-dredging, maintenance and regulation for large rivers and navigational waterways

Snow avalanches range among the most prominent natural hazards which threaten mountain communities worldwide. Snow avalanche formation is a complex critical phenomenon which starts with failure processes at the scale of snow crystals and ends with the release of a large volume of snow at a scale of up to several hundred meters. The practical application of avalanche formation is avalanche forecasting, requiring a thorough understanding of the physical and mechanical properties of snow as well as the influence of meteorological boundary conditions (e.g. precipitation, wind and radiation).

This session aims to improve our understanding of avalanche formation processes and to foster the application to avalanche forecasting. We therefore welcome contributions from novel field, laboratory and numerical studies on topics including, but not limited to, the mechanical properties of snow, snow cover simulations, snow instability assessment, meteorological driving factors including drifting and blowing snow, spatial variability, avalanche release mechanics, remote avalanche detection and avalanche forecasting. While the main focus of this session is on avalanche formation, detection and forecasting, it is closely linked to session ‘CR5.2 Snow avalanche dynamics: from basic physical knowledge to mitigation strategies’, which addresses avalanche dynamics, risk assessment and mitigation strategies.

Worldwide over 500 million people live in low-lying coastal deltaic areas, existential to global food security, economic activities and biodiversity. Despite climate change severity at global scale, in many densely populated deltas its effect is currently evidently dwarfed by anthropogenic pressures in the river basin such as river flow modifications, damming and the overexploitation of the natural resources groundwater or sand, as well as profound land use changes and process such as urbanisation. As a result, many major deltas rapidly sink and shrink because of accelerated land subsidence and erosion rates. This increases relative sea-level rise and vulnerability to floods and storms, increases salinization of surface and groundwater and reduces freshwater availability, leading to significant losses in biodiversity, habitat degradation, reduced agricultural and economic productivity. A fundamental change in management approach is required to address these trends and challenges to sustain deltas environments, economies and populations through the 21st Century.

The processes resulting in sinking, shrinking and saltier deltas are interconnected and developing sustainable and inclusive management requires a multidisciplinary system approach. For this, we need to understand the full range of interrelated disciplines, including, amongst others, geology, river and estuarine dynamics, sediment dynamics, hydrology, hydrogeology, geomechanics, bio-morphodynamics as well as the human dimension of delta demography, economy and land use. This session aims to bring together contributions from the full range of scientific disciplines involved in understanding and managing the combined integrated environmental threats that our world’s deltas face. These includes recent advancements in measuring, modeling and projecting environmental dynamics, especially focused on distinguishing (quantifying) anthropogenic and climate change impacts on observed natural dynamics. In particular, inter- and multidisciplinary contributions on the interactions between different environmental processes and efforts towards developing integrated management and development strategies for our sinking, shrinking and saltier deltas are warmly welcomed.

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 focuses 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.

Nature-based Solutions (NBS) are reframing discussion and policy responses worldwide to environmental challenges. Thus, NBS is of growing implementation, supported namely by the EU political agenda (e.g., green deal), as a way to attain the United Nations (UN) Sustainable Development Goals (SDG), and to reinforce the New Urban Agenda. The NBS concept recognise the importance of nature and outline requirements for a systemic and holistic approach to environmental change, based on an understanding of the structure and functioning of ecosystems, and the social and institutional context within which they are situated. Furthermore, there is a growing recognition that human activities exert pressure on natural resources affecting the ecosystem dynamics and therefore the nexus (synergies and trade-offs) between their different functions and services. However, quantification of existing NBS’ effectiveness, their operationalisation and replication in different environmental settings has not been presented in such a way that allows them to be both widely accepted and incorporated in policy development and in practical implementation to achieve the UN SDGs.
This session aims to discuss and advance knowledge of innovative NBS approaches to face environmental challenges, such as water supply and management, agricultural production and healthy ecosystems, and simultaneously provide better understanding of associated social-ecological interactions, contributing to enhance the scientific basis for sustainable development and resilience.
This session seeks to:
- Better understanding of advantages and disadvantages of NBS to address global environmental and societal challenges;
- Studies on adaptation and mitigation options for the effect of climate change on water provisioning and livelihoods;
- New methods and tools to investigate the role of NBS in the context of environmental change; in particular, the effectiveness of NBS for hydro-meteorological risk reduction at landscape/watershed scale;
- New insights, methodologies, tools and best practices enabling successful implementation and upscaling of NBS in multiple contexts;
- Identifying opportunities for and barriers to NBS within current regulatory frameworks and management practices;
- Presenting overviews and case studies of NBS projects that also involve the private sector and market-based mechanisms;
- NBS towards achieving the Sustainable Development Goals (SDGs).

As highlighted by the UN development goals, climate change is a reality to which we need to adapt. Our ability to effectively address the adaptation issue must come from a communal effort to link our knowledge in different fields and transform it into useful information for stakeholders and policymakers.

Up to now, physical climate modelling and natural hazard impact and risk assessment have been two separate disciplines that have suffered difficulties in communicating and interacting due to different languages and backgrounds. Until recently, climate modellers did not have the capability to generate long-term projections at a spatial and temporal resolution useful for impact studies such as flood risk assessment, soil erosion or urban modelling. With the advent of kilometre-scale atmospheric models, called convection-permitting models CPMs, we are now in a position to bridge the gap between the two communities, sharing knowledge and understanding. Compared to traditional climate models, CPMs improve substantially the representation of sub-daily precipitation characteristics and have a spatial resolution closer to what many impacts modellers, for example hydrologists, need. Several CPM datasets are already available over different parts of the world and more internationally coordinated projects on CPMs, such as the CORDEX Flagship Pilot Study (CORDEX-FPS) and the European Climate Prediction System (EUCP), are already in place. Now is the time to exploit these high-resolution physically-consistent datasets as input for impact studies and adaptation strategies; to foster interdisciplinary collaboration to build a common language and understand limitations and needs of the different fields; to learn together how to provide policymakers with information and practical cases that can be used to design effective measures at the regional level to adapt to climate change as well as to inform mitigation decisions.

This interdisciplinary session invites contributions that address the linkages between high-resolution modellers and users with examples of good practice, storylines and communication to both stakeholders and policymakers.

Predictions of climate from seasonal to decadal time scales and their applications will be discussed in this session. With a time horizon from a few months up to thirty years, such predictions are of major importance to society, and improving them presents an interesting scientific challenge. This session aims to embrace advances in our understanding of the origins of seasonal to decadal predictability, as well as in improving the respective forecast skill and making the most of this information by building and testing new applications and climate services.

The session will cover dynamical as well as statistical predictions (including machine learning methods), and their combination. It will investigate predictions of various climate phenomena, including extremes, from global to regional scales, and from seasonal to multidecadal time scales ("seamless predictions"). Physical processes relevant to long-term predictability sources (e.g. ocean, cryosphere, or land) as well as predicting large-scale atmospheric circulation anomalies associated to teleconnections will be discussed, as will observational and emergent constraints on climate variability and predictability on the seasonal-to-(multi)decadal time scale. Also, the time-dependence of the predictive skill, or windows of opportunity (hindcast period), will be investigated. Analysis of predictions in a multi-model framework, and ensemble forecast initialization and generation, including innovative ensemble approaches to minimize initialization shocks, will be another focus of the session. The session will pay particular attention to innovative methods of quality assessment and verification of climate predictions, including extreme-weather frequencies, post-processing of climate hindcasts and forecasts, and quantification and interpretation of model uncertainty. We particularly invite contributions presenting the use of seasonal-to-decadal predictions for risk assessment, adaptation and further applications.

One of the big challenges in Earth system science consists in providing reliable climate predictions on sub-seasonal, seasonal, decadal and longer timescales. The resulting data have the potential to be translated into climate information leading to a better assessment of multi-scale global and regional climate-related risks.
The latest developments and progress in climate forecasting on subseasonal-to-decadal and longer timescales will be discussed and evaluated. This will include presentations and discussions of predictions for a time horizon of up to ten years from dynamical ensemble and statistical/empirical forecast systems, as well as the aspects required for their application: forecast quality assessment, multi-model combination, bias adjustment, downscaling, etc.
Following the new WCPR strategic plan for 2019-2029, prediction enhancements are solicited from contributions embracing climate forecasting from an Earth system science perspective. This includes the study of coupled processes, impacts of coupling and feedbacks, and analysis/verification of the coupled atmosphere-ocean, atmosphere-land, atmosphere-hydrology, atmosphere-chemistry & aerosols, atmosphere-ice, ocean-hydrology, ocean-ice, ocean-chemistry and climate-biosphere (including human component). Contributions are also sought on initialization methods that optimally use observations from different Earth system components, on assessing and mitigating the impacts of model errors on skill, and on ensemble methods.
We also encourage contributions on the use of climate predictions for climate impact assessment, demonstrations of end-user value for climate risk applications and climate-change adaptation and the development of early warning systems.

A special focus will be put on the use of operational climate predictions (C3S, NMME, S2S), results from the CMIP5-CMIP6 decadal prediction experiments, and climate-prediction research and application projects (e.g. EUCP, APPLICATE, PREFACE, MIKLIP, MEDSCOPE, SECLI-FIRM, S2S4E, CONFESS).
An increasingly important aspect for climate forecast's applications is the use of most appropriate downscaling methods, based on dynamical or statistical approaches or their combination, that are needed to generate time series and fields with an appropriate spatial or temporal resolution. This is extensively considered in the session, which therefore brings together scientists from all geoscientific disciplines working on the prediction and application problems.

Weather and Climate Services (WCS) involve the production, translation, delivery, and use of science-based information for decision-making. The production of WCS makes use of long-term climate projections, climate and weather predictions from daily to decadal timescales, historical hydrometeorological data, and sectoral models to predict risks of climate impacts to society. These services are developed and delivered in support of (i) climate-sensitive sectors such as agriculture, management of water resource, health, energy and disaster risk reduction, and (ii) developing countries where the vulnerability to climate change and extreme weather events is high. This session, interdisciplinary in nature, aims at showcasing tools, products and methodologies that could be standardized for an operational and innovative system of WCS delivery in developing countries. The session invites contributions that include a) improvements of models and data analysis for WCS; b) engagement with end-users of WCS; c) assessment of the value of WCS’s outcomes and the corresponding impacts on societies and the environment; d) strategies for broad communication of WCS information to multiple audiences; and e) WCS partnerships between multiple stakeholders such as end-users, NGOs, government ministries, policymakers, and the private sector. The session particularly encourages lessons learned and results from different case studies coming from the global South.

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.

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?

Volcanic hazards and risk lie at the heart of global geoscience, with about 800 million people threatened by eruptions and other related phenomena. Volcanoes strongly affect humans and the environment through submarine explosions, tephra fallout, pyroclastic flows, earthquakes, tsunamis, and ocean acidification. Evaluation of the impact of volcanic activity on a given region mostly relies on the reconstruction of the eruptive history of volcanoes through the identification, correlation and dating of tephra layers preserved in terrestrial and marine depositional records. In addition, more recent interdisciplinary studies are being used to deepen our understanding of the formation and destruction of volcanoes and the accompanying mass transport processes, as they might significantly contribute to the volcanic hazard assessment. This session will focus on different approaches for reconstructing the history, processes, and evolution of volcanic regions. We invite contributions from all related scientific fields to derive a more comprehensive perspective on the past and present impact of volcanic eruptions, and their potential impacts on the environment and surrounding populations.

The session deals with the documentation and modelling of the tectonic, deformation and geodetic features of any type of volcanic area, on Earth and in the Solar System. The focus is on advancing our understanding on any type of deformation of active and non-active volcanoes, on the associated behaviours, and the implications for hazards. We welcome contributions based on results from fieldwork, remote-sensing studies, geodetic and geophysical measurements, analytical, analogue and numerical simulations, and laboratory studies of volcanic rocks.
Studies may be focused at the regional scale, investigating the tectonic setting responsible for and controlling volcanic activity, both along divergent and convergent plate boundaries, as well in intraplate settings. At a more local scale, all types of surface deformation in volcanic areas are of interest, such as elastic inflation and deflation, or anelastic processes, including caldera and flank collapses. Deeper, sub-volcanic deformation studies, concerning the emplacement of intrusions, as sills, dikes and laccoliths, are most welcome.
We also particularly welcome geophysical data aimed at understanding magmatic processes during volcano unrest. These include geodetic studies obtained mainly through GPS and InSAR, as well as at their modelling to imagine sources.


The session includes, but is not restricted to, the following topics:
• volcanism and regional tectonics;
• formation of magma chambers, laccoliths, and other intrusions;
• dyke and sill propagation, emplacement, and arrest;
• earthquakes and eruptions;
• caldera collapse, resurgence, and unrest;
• flank collapse;
• volcano deformation monitoring;
• volcano deformation and hazard mitigation;
• volcano unrest;
• mechanical properties of rocks in volcanic areas.

Developing physical-mathematical models able to describe the evolution of eruptive phenomena is a key point in volcanology. In the case of high-risk phenomena, such as lava flows or ash dispersal, predicting their spatial and temporal evolution and determining the potentially affected areas is fundamental in supporting every action directed at mitigating the risk as well as for environmental planning. This session aims to address unresolved challenging questions related to complex geophysical flow modeling and simulation, gathering physical-mathematical models, numerical methods and field and satellite data analysis in order to: (i) expand knowledge of complex volcanic processes and their space-time dynamics; (ii) monitor and model volcanic phenomena; (iii) evaluate model robustness through validation against real case studies, analytical solutions and laboratory experiments; (iv) quantify the uncertainty propagation through both forward (sensitivity analyses) and inverse (optimization/calibration) modelling in all components of volcanic hazard modelling in response to eruptive crises.

Over the past few years, major technological advances allowed to significantly increase both the spatial coverage and frequency bandwidth of multi-disciplinary observations at active volcanoes. Networks of instruments for the quantitative measurement of many parameters now permit an unprecedented, multi-parameter vision of the surface manifestations of mass transport beneath volcanoes. Furthermore, new models and processing techniques have led to innovative paradigms for inverting observational data to image the structures and interpret the dynamics of volcanoes. Within this context, this session aims at bringing together a multidisciplinary audience to discuss the most recent innovations in volcano imaging and monitoring, and to present observations, methods and models that increase our understanding of volcanic processes. New attention has recently been paid to quiescent volcanoes since multidisciplinary investigations showed that magma accumulation at depth can contribute to degassing of volatiles for a long time after the last activity, highlighting the risk of reactivation after a long phase of inactivity. Furthermore, mantle degassing and magma accumulation in continental regions far from volcanism might play an active role in seismicity.
We welcome contributions (1) related to methodological and instrumental advances in geophysical, geological and geochemical imaging of volcanoes, and (2) to explore new knowledge provided by these studies on the internal structure and physical processes of volcanic systems.
We invite contributors from all geophysical, geological and geochemical disciplines such as seismology, electromagnetics, geoelectrics, gravimetry, magnetics, muon tomography, volatile measurements and analysis; from in-situ monitoring networks to high resolution remote sensing and innovative processing methods, applied to volcanic systems ranging from near-surface hydrothermal activity to magmatic processes at depth. We hope in this way to highlight the scientific advances available through the combination of these complementary research areas and to encourage future collaborative efforts.

Glaciers and volcanoes interact in a number of ways, including instances where volcanic/geothermal activity alters glacier dynamics or mass balance, via subglacial eruptions or the deposition of supraglacial tephra. Glaciers can also impact volcanism, for example by directly influencing mechanisms of individual eruptions resulting in the construction of distinct edifices. Glaciers may also influence patterns of eruptive activity when mass balance changes adjust the load on volcanic systems, the water resources and hydrothermal systems. However, because of the remoteness of many glacio-volcanic environments, these interactions remain poorly understood.
In these complex settings, hazards associated with glacier-volcano interaction can vary from lava flows to volcanic ash, lahars, landslides, pyroclastic flows or glacial outburst floods. These can happen consecutively or simultaneously and affect not only the earth, but also glaciers, rivers and the atmosphere. As accumulating, melting, ripping or drifting glaciers generate signals as well as degassing, inflating/ deflating or erupting volcanoes, the challenge is to study, understand and ultimately discriminate these potentially coexisting signals. We wish to fully include geophysical observations of current and recent events with geological observations and interpretations of deposits of past events. Glaciovolcanoes also often preserve a unique record of the glacial or non-glacial eruptive environment that is capable of significantly advancing our knowledge of how Earth's climate system evolves.
We invite contributions that deal with the mitigation of the hazards associated with ice-covered volcanoes in the Arctic, Antarctic or globally, that improve the understanding of signals generated by ice-covered volcanoes, or studies focused on volcanic impacts on glaciers and vice versa. Research on recent activity is especially welcomed. This includes geological observations e.g. of deposits in the field or remote-sensing data, together with experimental and modelling approaches. We also invite contributions from any part of the world on past activity, glaciovolcanic deposits and studies that address climate and environmental change through glaciovolcanic studies. We aim to bring together scientists from volcanology, glaciology, seismology, geodesy, hydrology, geomorphology and atmospheric science in order to enable a broad discussion and interaction.

Magmatic processes occurring at depth within magmatic plumbing systems are complex and play a fundamental role in controlling the tempo and style of volcanic activity, the formation of cumulate rocks and the generation of orthomagmatic and magmatic-hydrothermal ore deposits. To unravel the complexity and temporal evolution of magmatic plumbing systems a multidisciplinary approach is necessary. This session aims to bring together scientists working on the understanding of the structural, chemical and temporal evolution of magmatic systems using, for example, fieldwork, petrology, geochemistry, geophysics, geodesy, experiments or numerical modelling to diffuse the boundaries between disciplines and lead to a comprehensive understanding of the inner workings of Volcanic and Igneous Plumbing Systems (VIPS).

This session is sponsored by the IAVCEI Commission on Volcanic and Igneous Plumbing Systems.

Volcanoes release gas effluents and aerosol particles into the atmosphere during eruptive episodes and by quiescent emissions. Volcanic degassing exerts a dominant role in forcing the timing and nature of volcanic unrest and eruptions. Understanding the exsolution processes of gas species dissolved in magma, and measuring their emissions is crucial to characterise eruptive mechanism and evaluate the sub-sequent impacts on the atmospheric composition, the environment and the biosphere. Emissions range from silent exhalation through soils to astonishing eruptive clouds that release gas and particles into the atmosphere, potentially exerting a strong impact on the Earth’s radiation budget and climate over a range of temporal and spatial scales. Strong explosive volcanic eruptions are a major natural driver of climate variability at interannual to multidecadal time scales. Quiescent passive degassing and smaller-magnitude eruptions on the other hand can impact on regional climate system. Through direct exposure and indirect effects, volcanic emissions may influence local-to-regional air quality and seriously affect the biosphere and environment. Volcanic gases can also present significant hazards to populations downwind of an eruption, in terms of human, animal and plant health, which subsequently can affect livelihoods and cause socio-economic challenges. Gas emissions are measured and monitored via a range of in-situ and remote sensing techniques, to gain insights into both the subterranean-surface processes and quantify the extent of their impacts. In addition, modelling of the subsurface and atmospheric/climatic processes, as well as laboratory experiments, are fundamental to the interpretation of field-based and satellite observations.

This session focuses on the state-of-the-art and interdisciplinary science concerning all aspects of volcanic degassing and impacts of relevance to the Volcanology, Environmental, Atmospheric and Climate sciences (including regional climate), and Hazard assessment. We invite contributions on all aspects of volcanic plumes science, their observation, modelling and impacts. We welcome contributions that address issues around the assessment of hazards and impacts from volcanic degassing both in crises and at persistently degassing volcanoes.

Volcanic aerosol clouds from major tropical eruptions cause periods of strong surface cooling in the historical climate record and are dominant influences within decadal surface temperature trends.

Even the transition from the unusual 1998-2002 period of a “fully decayed to quiescence” stratospheric aerosol layer, into a more typical period of modest volcanic activity temporarily offset a substantial proportion of the subsequent decadal forcing from increased greenhouse gases.

Advancing our understanding of the influence of volcanoes on climate relies upon better knowledge of (i) the radiative forcings of past eruptions and the microphysical, chemical and dynamical processes which affect the evolution of stratospheric aerosol properties and (ii) the response mechanisms governing post-eruption climate variability and their dependency on the climate state at the time of the eruption. This can only be achieved by combining information from satellite and in-situ observations of recent eruptions, stratospheric aerosol and climate modelling activities, and reconstructions of past volcanic histories and post-eruption climate state from proxies.

In recent years the smoke from intense wildfires in North America and Australia has also been an important component of the stratospheric aerosol layer, the presence of organic aerosol and meteoric particles in background conditions now also firmly established.

This session seeks presentations from research aimed at better understanding the stratospheric aerosol layer, its volcanic perturbations and the associated impacts on climate through the post-industrial period (1750-present) and also those further back in the historical record.

We also welcome contributions to understand the societal impacts of volcanic eruptions and the human responses to them. Contributions addressing volcanic influences on atmospheric composition, such as changes in stratospheric water vapour, ozone and other trace gases are also encouraged.

The session aims to bring together research contributing to several current international co-ordinated activities: SPARC-SSiRC, CMIP6-VolMIP, CMIP6-PMIP, and PAGES-VICS.

Extreme convective events are increasing in northern and eastern Europe in frequency and intensity accounting for major economic damages related to natural disasters in several countries. Forecasting the land convection locally developed in a short time range is very challenging since the models are not able to resolve them and this is an issue for the air traffic management.

In recent years, attention was paid to the detection and monitoring of volcanic clouds as their impact on the European air traffic control system was unprecedented (e.g. Eyjafjallajökull 2010 eruption). Volcanic clouds are very dangerous for the aviation operations 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 Convective and Volcanic Clouds (CVC) 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, forecasting and modeling the CVC, to develop early warning systems and to support end-users (such as air traffic managers and pilots) and policy makers. Furthermore, there is a need for improved information exchange regarding the impact of the CVC on daily aviation operations. In this regard, we will draw on the work of the Single European Sky ATM Research (SESAR) Joint Undertaking, with special focus on the latest funded exploratory research projects dealing with these topics.

The objective of the session is to connect different communities in touch with the CVC and to promote discussions between scientists working in remote sensing, modelers, meteorologists, physicists, sensors engineers, engines manufacturers, pilots and aviation managers, allowing the researchers to understand the end-users’ needs and allowing the end-users to understand the research capabilities.

This session solicits the latest studies from the spectrum of:
- detection, monitoring and modeling of CVC with novel techniques and new sensors,
- forecasting and nowcasting extreme weather events,
- study of the CVC structure,
- understanding the impact of the CVC on air traffic management,
- proposal of new products, tools or services focused on the end-users prospective.

Landslides are ubiquitous geomorphological phenomena with potentially catastrophic consequences. In several countries, landslide mortality can be higher than that of any other natural hazard. Predicting landslides is a difficult task that is of both scientific interest and societal relevance that may help save lives and protect individual properties and collective resources. The session focuses on innovative methods and techniques to predict landslide occurrence, including the location, time, size, destructiveness of individual and multiple slope failures. All landslide types are considered, from fast rockfalls to rapid debris flows, from slow slides to very rapid rock avalanches. All geographical scales are considered, from the local to the global scale. Of interest are contributions investigating theoretical aspects of natural hazard prediction, with emphasis on landslide forecasting, including conceptual, mathematical, physical, statistical, numerical and computational problems, and applied contributions demonstrating, with examples, the possibility or the lack of a possibility to predict individual or multiple landslides, or specific landslide characteristics. Of particular interest are contributions aimed at: the evaluation of the quality of landslide forecasts; the comparison of the performance of different forecasting models; the use of landslide forecasts in operational systems; and investigations of the potential for the exploitation of new or emerging technologies e.g., monitoring, computational, Earth observation technologies, in order to improve our ability to predict landslides. We anticipate that the most relevant contributions will be collected in the special issue of an international journal.

Debris flows are among the most dangerous natural hazards that threaten people and infrastructures in both mountainous and volcanic areas. The study of the initiation and dynamics of debris flows, along with the characterization of the associated erosion/deposition processes, is of paramount importance for hazard assessment, land-use planning and design of mitigation measures, including early warning systems. In addition, the impacts of climate change on debris-flow activity must be considered and carefully analysed, as the number of mountain areas prone to these events may increase in future.
A growing number of scientists with diverse backgrounds are studying debris flows and lahars. The difficulties in measuring parameters related to their initiation and propagation have progressively prompted research into a wide variety of laboratory experiments and monitoring studies. However, there is a need of improving the quality of instrumental observations that would provide knowledge for more accurate hazards maps and modeling. Nowadays, the combination of distributed sensor networks and remote sensing techniques represents a unique opportunity to gather direct observations of debris flows to better constrain their physical properties.
Scientists working in the field of debris flows are invited to present their recent advancements. In addition, contributions from practitioners and decision makers are also welcome. Topics of the session include: field studies and documentation, mechanics of debris-flow initiation and propagation, laboratory experiments, modeling, monitoring, impacts of climate change on debris-flow activity, hazard and risk assessment and mapping, early warning, and alarm systems.

Rockfalls, rockslides and rock avalanches are among the primary hazards in steep terrain. To better understand the processes driving rock slope degradation, mechanisms contributing to the triggering, transport, and deposition of resulting rock slope instabilities, and mitigation measures for associated hazards, we must develop insight into both the physics of intact and rock mass failure and the dynamics of transport processes.

This session aims to bring together state-of-the-art methods for predicting, assessing, quantifying, and protecting against rock slope hazards. We seek innovative contributions from investigators dealing with all stages of rock slope hazards, from weathering and/or damage accumulation, through detachment, transport and deposition, and finally to the development of protection and mitigation measures. In particular, we seek studies presenting new theoretical, numerical or probabilistic modelling approaches, novel data sets derived from laboratory, in situ, or remote sensing applications, and state-of-the-art approaches to social, structural, or natural protection measures.

The global increase in damaging landslide events is raising the attention of governments, practitioners and scientists to develop functional, reliable and (when possible) low cost monitoring strategies. Several case studies have demonstrated how a well-planned monitoring system of landslides is of fundamental importance for long and short-term risk reduction.
Today, the temporal evolution of a landslide is addressed in several ways, encompassing classical and more complex in situ measurements or remotely sensed data acquired from satellite and aerial platforms. All these techniques are adopted for the same final scope: measure landslide motion over time, trying to forecast its future evolution or at least to reconstruct its recent past. Real time, near-real time and deferred time strategies can be profitably used for landslide monitoring, depending on the type of phenomenon, the selected monitoring tool, and the acceptable level of risk.
The session follows the general objectives of the International Consortium on Landslides, namely: (i) promote landslide research for the benefit of society, (ii) integrate geosciences and technology within the cultural and social contexts to evaluate landslide risk, and (iii) combine and coordinate international expertise.
Considering these key conceptual drivers, we aim to present successful monitoring experiences worldwide based on both in situ and/or remotely sensed data. The integration and synergic use of different techniques is welcome, as well as newly developed tools or data analysis approaches (focusing on big data management). We expect case studies in which multi-temporal and multi-platform monitoring data are exploited for risk management and Civil Protection aims with positive effects in social and economic terms.

This session covers both new scientific approaches and state-of-the-art techniques for investigating landslides, including Earth Observation (EO), Geophysical Surveying (GS) and close-range Remote Sensing techniques (RS).

A series of remarkable technological progresses are driven new scientific opportunities to better understand landslide dynamics worldwide, including integrated information about rheological properties, water content, rate of deformation and time-varying changes of these parameters through seasonal changes and/or progressive slope damage.

This session welcomes innovative contributions and lessons learned from significant case studies and/or original methods aiming to increase our capability to detect, model and predict landslide processes at different scales, from site specific to regional studies, and over multiple dimensions (e.g. 2D, 3D and 4D).

A special emphasis is expected not only on the particularities of data collection from different platforms (e.g. satellite, aerial, UAV, Ground Based...) and locations (e.g. surface- and borehole-based geophysics) but also on new solutions for digesting and interpreting datasets of high spatiotemporal resolution, landslide characterization, monitoring, modelling, as well as their integration on real-time EWS, rapid mapping and other prevention and protection initiatives. Examples of previous submissions include using one or more of the following techniques: optical and radar sensors, new satellite constellations (including the emergence of the Sentinel-1A and 1B), Remotely Piloted Aircraft Systems (RPAS) / Unpiloted Aerial Vehicles (UAVs) / drones, high spatial resolution airborne LiDAR missions, terrestrial LIDAR, Structure-from-Motion (SfM) photogrammetry, time-lapse cameras, multi-temporal DInSAR, GPS surveying, Seismic Reflection, Surface Waves Analysis, Geophysical Tomography (seismic and electrical), Seismic Ambient Vibrations, Acoustic Emissions, Electro-Magnetic surveys, low-cost sensors, commercial use of small satellites, Multi-Spectral images, etc. Other pioneering applications using big data treatment techniques, data-driven approaches and/or open code initiatives for investigating mass movements using the above-described techniques will also be very welcomed.

GUEST SPEAKER (to be confirmed). Previous guest speakers include prof. J. Chambers (British Geological Survey - UK) and prof. D. Jongmans (Isterre, Université Grenoble Alpes - France).

In many parts of the world, landslide phenomena are a direct response to rapid environmental changes caused by global warming, human influences or other natural or technological hazards. The development of methods and strategies to evaluate hazard and risk posed by different types of landslides with different magnitudes in different environments has significantly progressed in the last decades due to rapid advance of computational and monitoring technologies. However, prognostic hazard and risk evaluations are highly challenged by the fact that local and regional environmental and meteorological conditions are subjected to rapid changes due to global warming and its consequences, modifying the local terrain susceptibility to landslides. Additionally, global change leads to significant changes in patterns of objects-at-risk due to population changes and concurring infrastructural developments.
This session aims to collect papers dealing with the advancement of methods and strategies for the prognostic spatio-temporal development of landslide hazard and risk scenarios and potentials in times of rapid global environmental change. Contributions dealing with the preparation and use of event-based landslide inventories for landslide hazard scenario assessments are welcomed as well as papers describing new advancements in process-oriented techniques for landslide hazard modelling at different spatial scales. Of particular interest are contributions concerned with the assessment of changing patterns of landslide-related risk posed to developing population and infrastructure in times of rapid environmental change.
Submarine mass wasting (including landslides, turbidites and debrites) presents similar characteristics to subaerial ones posing risk to submarine infrastructure, the session will also include various methods using foraminiferal assemblages and taphonomy for characterization of submarine mass wasting events.

Large rock slope instabilities have been recognised under very different geological and environmental conditions, lithological and geological domains, and on other planets. Slow to extremely fast moving, complex mass movements have been recognized, sometimes described as interrelated or as evolution stages of a same phenomenon. Many types of slope instabilities can be grouped within this broad class, presenting different types of hazard and risk. This phenomena, triggered by earthquakes, rainfall, snowmelt or deglaciation can originate relevant cascade events (e.g. tsunamis, landslide dams and overtopping, flooding).
Major aspects of these instabilities are still debated:
- distribution both on Earth and other planets;
- triggering and controlling factors and events;
- dating of initial movements and reactivation episodes;
- style and state of past and present activity;
- passive and/or active control of structural features;
- possible displacement evolution and modelling;
- hazard assessment inclusive of cascade events;
- influence of anthropogenic factors and effects on structures;
- role on the erosional and sediment yield regime;
- technologies for monitoring and warning systems, and the interpretation of monitoring data.
Study of these instabilities is interdisciplinar and multidisciplinar. Site investigation, geophysical survey and dating techniques can support geometrical and geomechanical characterization, recognition of activity episodes, monitoring data interpretation for warning thresholds. Different hydrologic boundary conditions and hydrochemistry are involved, both at failure and during reactivations. Modelling is a key element for understanding and evaluating instability and failure (initiation, propagation), triggering (rainfall, seismicity, volcanic eruption, deglaciation), collapse, and secondary failures as well as the effect on the local and regional geomorphological evolution (e.g. sediment yield). Cascade-like events are definitively a possible result and advanced modeling techniques are requested for studying these phenomena and for reliable and robust hazard zonation. Size and evolution of large instabilities require major efforts when assessing the potential impacts on structures and infrastructures, and human activities enforcing a deep understanding and modeling. On the other hand, instabilities on other planets can support indirect environmental and geomechanical characterization.

Many natural hazards can interact with each other and lead to or exacerbate the effects of additional catastrophic events, such as landslides following earthquakes, floods following snow-avalanches or landslides and floods induced simultaneously by heavy rainfall. According to the 2019 IPCC special report, the frequency and magnitude of mountain hazards, i.e. snow avalanches, floods due to glacier lake outburst (GLOF), flash-floods, rockfalls and landslides, are projected to increase in a scale never seen, potentially impacting new locations and/or occurring in different seasons than previously. In combination with growth in the population and economy, this changing landscape of mountain hazards will dramatically increase the risk to local populations, leading to growing economic damages in mountainous regions. Prediction of the areas threatened by such processes are a key part of hazard assessment in mountainous regions. Whatever the material transported (debris, snow, etc.), the mass wasting process involves determining the initiation mechanisms, initial volume, physical transport, and probable entrainment processes and as well as deposition mechanisms. Because of the number of scientific disciplines needed to solve it, there is a substantial benefit from inter- and transdisciplinary research. This session aims to serve as a forum, allowing discussion and debate on the future development of the field. In particular, we encourage presentations ranging from innovative monitoring and documentation methods related to hazard processes in mountain settings to studies focusing on an improved mechanical understanding of the physical processes involved, including modelling, laboratory research, and theoretical studies.

The session aims to discuss hydrological and geomorphological processes related to deformation of natural slopes as well as human-modified slopes both on local and regional scale. It focuses on the detailed monitoring, analysis and modelling of hydrological and geomorphological processes required to improve our understanding and prediction of the spatio-temporal patterns of both triggering factors and slope deformation mechanisms.

The session also focuses on landslide early warning systems (LEWSs) at both regional and local scales. The session wishes to highlight operational approaches, original achievements and developments useful to operate reliable (efficient and effective) local and territorial LEWS. Moreover, the different schemes describing the structure of a LEWS available in literature clearly highlight the importance of both social and technical aspects in the design and management of such systems.

For the above-mentioned reasons, contributions addressing the following topics are welcome:
• hydrological and geomorphological processes
• rainfall thresholds definition;
• monitoring systems for early warning purposes;
• warning models for warning levels issuing;
• performance analysis of landslide warning models;
• communication strategies;
• emergency phase management;
• landslide risk perception.

Rock deformation at different stress levels in the brittle regime and across the brittle-ductile transition is controlled by damage processes occurring on different spatial scales, from grain scale to fractured rock masse. These lead to a progressive increase of micro- and meso-crack intensity in the rock matrix and to the growth of inherited macro-fractures at rock mass scale. Coalescence of these fractures forms large-scale structures such as brittle fault zones and deep-seated rock slide shear zones. Diffuse or localized rock damage have a primary influence on rock properties (strength, elastic moduli, hydraulic and electric properties) and their evolution across multiple temporal scales spanning from geological times to highly dynamic phenomena as earthquakes, volcanic eruptions and landslides. In subcritical stress conditions, damage accumulation results in brittle creep processes key to the long-term evolution of geophysical, geomorphological and geo-engineering systems.
Damage and progressive failure processes must be considered to understand the time-dependent hydro-mechanical behaviour of faults (e.g. stick-slip vs asesismic creep), volcanic systems and slopes (e.g. slow rock slope deformation vs catastrophic rock slides), as well as the response of rock masses to stress perturbations induced by artificial excavations (tunnels, mines) and static or dynamic loadings. At the same time, damage processes control the brittle behaviour of the upper crust and are strongly influenced by intrinsic rock properties (strength, fabric, porosity, anisotropy), geological structures and their inherited damage, as well as by the evolving pressure-temperature with increasing depth and by fluid pressure, transport properties and chemistry. However, many complex relationships between these factors and rock damage are yet to be understood.
In this session we will bring together researchers from different communities interested in a better understanding of rock damage processes and consequence. We welcome innovative contributions on experimental studies (both in the laboratory and in situ), continuum / micromechanical analytical and numerical modelling, and applications to fault zones, reservoirs, slope instability and landscape evolution, and engineering applications. Studies adopting novel approaches and combined methodologies are particularly welcome.

Two significant flow hazard cascades have been captured with unprecedented detail, with events in Elliot Creek and Bute Inlet (Canada) and the Chamoli and Uttarakhand (India) both occurring with the past few months. These events both have a suite of background observations and baseline datasets on which to contextually place and explore these flows end events in a depth and breadth of detail that is unprecedented, potentially unlocking new understanding of hazard cascades from source to sink.
We welcome contributions that (i) investigate the processes of production, mobilisation, transport, and deposition of sediment in these two events, (ii) explore the feedbacks between erosion and deposition of the flows through these systems, (iii) consider how these flows shape new understanding of hazards cascades through the source to sink linkages. We invite papers that are observational, analytical or modelling based in their approach, across a variety of temporal and spatial scales. We particularly welcome new and innovative methodologies that show potential to unlock new understanding.

The main concern of the occurrence of an earthquake is the ground shaking, although past events worldwide demonstrated that damage and death toll depends on both the strong ground motion and the ground effects. The variability of earthquake ground motion is caused by local geological conditions beneath a given site, due to the stratigraphic or topographic setting that can give rise to amplification and resonances. Earthquake-induced ground effects are mainly landslides, soil liquefaction, and ground subsidence. They can affect an area with damages related to the full collapse or loss in functionality of facilities, roads, pipelines, and other lifelines. The purpose of this session is to provide a forum for discussion among researchers and other professionals who study seismic amplification of the ground motion and the related hazards and to encourage multidisciplinary research in these fields.
Topics of interest include the following:
- Subsoil investigation and characterization for Seismic Microzonation mapping;
- Evaluation of seismic site response (1D-2D-3D)
- Case histories of earthquake-triggered landslides analyzed at either local or regional scale
- Slope stability analyses and runout modeling of seismically/volcanically-induced landslides;
- Studies on Soil liquefaction and earthquake-induced subsidence

A focused special issue in an EGU-journal will be edited based on the contributions of this session.

From the real-time integration of multi-parametric observations is expected the major contribution to the development of operational t-DASH systems suitable for supporting decision makers with continuously updated seismic hazard scenarios. A very preliminary step in this direction is the identification of those parameters (seismological, chemical, physical, biological, etc.) whose space-time dynamics and/or anomalous variability can be, to some extent, associated with the complex process of preparation of major earthquakes.
This session wants then to encourage studies devoted to demonstrate the added value of the introduction of specific, observations and/or data analysis methods within the t-DASH and StEF perspectives. Therefore, studies based on long-term data analyses, including different conditions of seismic activity, are particularly encouraged. Similarly welcome will be the presentation of infrastructures devoted to maintain and further develop our present observational capabilities of earthquake related phenomena also contributing in this way to build a global multi-parametric Earthquakes Observing System (EQuOS) to complement the existing GEOSS initiative.
To this aim this session is not addressed just to seismology and natural hazards scientists but also to geologist, atmospheric sciences and electromagnetism researchers, whose collaboration is particular important for fully understand mechanisms of earthquake preparation and their possible relation with other measurable quantities. For this reason, all contributions devoted to the description of genetic models of earthquake’s precursory phenomena are equally welcome.

Earthquake disaster mitigation involves different elements, ranging from analysis of hazards (e.g. physical description of ground shaking) to its impact on built and natural environment, from vulnerability and exposure to hazards to capacity building and resilience, from long-term preparedness to post-event response. The scientific base of this process involves various seismic hazard/risk models, developed at different time scales and by different methods, as well as the use of heterogeneous observations and multi-disciplinary information. Accordingly, we welcome contributions about different types of seismic hazards research and assessments, both methodological and practical, and their applications to disaster risk reduction in terms of physical and social vulnerability, capacity and resilience.
This session aims to tackle theoretical and implementation issues, as well as aspects of communication and science policy, which are all essential elements towards effective disasters mitigation, and include:
⇒ earthquake hazard and risk estimation at different time and space scales, including their performance verification against observations (including unconventional seismological observations);
⇒ time-dependent seismic hazard and risk assessments (including contribution of aftershocks), and post-event information (early warning, alerts) for emergency management;
⇒ earthquake-induced cascading effects (e.g. landslides, tsunamis, etc) and multi-risk assessment (e.g. earthquake plus flooding).
Different hazards can combine and mutually enhance their impact, turning into a disaster. The COVID-19 pandemic pointed out the low preparedness of human society to large-scale crises. In particular, there have been several damaging earthquakes during the pandemic (Croatia, Greece, USA, Iran), which highlighted the impacts of concurrent hazards and the complexity in handling such situations.
The interdisciplinary session will provide an opportunity to share lessons learned from recent events, best practices and experience gained with different methods, providing opportunities to advance our understanding of disaster risk in "all its dimensions of vulnerability, capacity, exposure of persons and assets, hazard characteristics and the environment", while simultaneously highlighting existing gaps and future research directions.

New models based on seismicity patterns, considering their physical meaning and their statistical significance, shed light on the preparation process of large earthquakes and on the evolution in time and space of clustered seismicity.
Opportunities for improved model testing are being opened by the increasing amount of earthquake data available on local to global scales, together with accurate assessments of the catalogues’ reliability in terms of location precision, magnitude of completeness and coherence in magnitude determination.
Moreover, it is possible to reliably integrate the models with additional information, like geodetic deformation, active fault data, source parameters of previously recorded seismicity, fluid contents, tomographic information, or laboratory and numerical experiments of rock fracture and friction. Such integration allows a detailed description of the system and hopefully an improved forecasting of the future distribution of seismicity in space, time and magnitude.
In this session, we invite researchers to submit their latest results and insights on the physical and statistical models and machine learning approaches for the space, time and magnitude evolution of earthquake sequences. Particular emphasis will be placed on:

• physical and statistical models of earthquake occurrence;
• analysis of earthquake clustering;
• spatial, temporal and magnitude properties of earthquake statistics;
• quantitative testing of earthquake occurrence models;
• reliability of earthquake catalogues;
• time-dependent hazard assessment;
• methods for earthquake forecasting;
• data analyses and requirements for model testing;
• pattern recognition in seismology;
• machine learning applied to seismic data; and
• methods for quantifying uncertainty in pattern recognition and machine learning.

Confirmed solicited speaker: Robert Shcherbakov (University of Western Ontario, London, Ontario, Canada)

Seismic hazard assessment in regions of low lithospheric strain rely on a global-analogues approach for parameterizing seismic hazard models. In this approach, seismicity rate and earthquake recurrence distributions are generated by amalgamating aerial source zones with limited seismicity data or by drawing on more far‐field analogue regions of slow lithospheric strain. The premise is that regions of low lithospheric strain have the same seismogenic potential. This session seeks to discuss new insights into this premise.

We invite contributions that (1) present new observations that place constraints on earthquake occurrence in low-strain regions, (2) explore patterns of stable or temporally varying earthquake occurrence, and (3) provide insight into the mechanisms that control earthquakes in regions of slow deformation via observation and/or modeling.

These contributions cover two different research components. The first component calls upon researchers with recently developed paleoseismic, geomorphic, geodetic, geophysical, and seismologic datasets that provide insight into the earthquake cycle in low-strain settings. The second component includes contributions that more broadly synthesize recent insights into the seismotectonics of low strain regions and/or explore the driving mechanisms for earthquakes in these regions. Collectively, these contributions provide a current view of the global-analogues premise.

Vetted probabilistic earthquake forecasts can contribute to more earthquake-resilient societies. Forecasts underpin seismic hazard assessments and thus determine building and life safety. They also provide scientifically sound information about the time-dependence of earthquake potential before, during and after earthquake sequences. To ensure forecasts are trustworthy and to assess the scientific hypotheses underlying the forecasts, models should be tested both retrospectively and prospectively (i.e., against yet-to-be-collected data). For this purpose, the Collaboratory for the Study of Earthquake Predictability (CSEP) provides tools and methods for testing the consistency and precision of earthquake forecasts. This session welcomes contributions that showcase advances in the science of earthquake forecasting and model testing. These can include: new approaches for identifying precursory activity (e.g. b-value variations, aseismic slip transients); forecasts based on empirical machine-learning or physical stress-transfer algorithms; applications of models to earthquake sequences around the globe; advances in model evaluation techniques; or contributions to software tools for model developers. Presentations may also highlight progress of community efforts, such as the EU H2020 project RISE (Real-time earthquake rIsk reduction for a reSilient Europe, www.rise-eu.org) and other initiatives.

Earthquake swarms are characterized by a complex temporal evolution and a delayed occurrence of the largest magnitude event. In addition, seismicity often manifests with intense foreshock activity or develops in more complex sequences where doublets or triplets of large comparable magnitude earthquakes occur. The difference between earthquake swarms and these complex sequences is subtle and usually flagged as such only a posteriori. This complexity derives from aseismic transient forcing acting on top of the long-term tectonic loading: pressurization of crustal fluids, slow-slip and creeping events, and at volcanoes, magmatic processes (i.e. dike and sill intrusions or magma degassing). From an observational standpoint, these complex sequences in volcanic and tectonic regions share many similarities: seismicity rate fluctuations, earthquakes migration, and activation of large seismogenic volume despite the usual small seismic moment released. The underlying mechanisms are local increases of the pore-pressure, loading/stressing rate due to aseismic processes (creeping, slow slip events), magma-induced stress changes, earthquake-earthquake interaction via static stress transfer or a combination of those. Yet, the physics behind such processes and the ultimate reasons for the occurrence of swarm-like rather than mainshock-aftershocks sequences, is still far beyond a full understanding.

This session aims at putting together studies of swarms and complex seismic sequences driven by aseismic transients in order to enhance our insights on the physics of such processes. Contributions focusing on the characterization of these sequences in terms of spatial and temporal evolution, scaling properties, and insight on the triggering physical processes are welcome. Multidisciplinary studies using observation complementary to seismological data, such as fluid geochemistry, deformation, and geology are also welcome, as well as laboratory and numerical modeling simulating the mechanical condition yielding to swarm-like and complex seismic sequences.

Recent developments in understanding of faulting and the earthquake cycle are improving our approaches to seismic hazard assessment. These developments are due to the increasing availability of datasets, including remote sensing, geochemical, offshore geophysics, boreholes and numerical modelling, and have been applied to both onshore and offshore faults which contribute to seismic hazard. From these datasets and developments, it is clear that there is more variability in the earthquake cycle and the seismogenic potential of faults than previously accounted for in seismic hazard assessment. This session will explore a range of datasets and study locations and discuss how they can be applied to different aspect of seismic hazard assessment.

Geological structures such as faults, fractures, folds, and associated fabrics are complex 3-D geological objects and, therefore, their thorough understanding intrinsically requires a 3-, in addition to 2-D analysis. In this session, we invite contributions that address the geometrical complexities of geological structures by taking into account their inherent 3-D nature, and we aim at promoting discussion on any similarities or disparities between the geometries of different structures, and on the processes that may develop them. As the integration of different data types can provide insights on the characteristics of geological structures at different scales, we invite contributions that build on a broad spectrum of data, such as outcrop, geophysical imaging, earthquake seismicity, and analogue and numerical modelling data. Contributions based on innovative quantitative methods for building high-resolution 3-D geological models such as, for example, micro-computed tomography or photogrammetric techniques, are also welcome. Further, discussions on the predictive nature of geological structures are encouraged for use in a wide range of industries. This can include estimating fluid flow in reservoirs associated with hydrogeology and hydrocarbons to “green” industries such as CO2 storage and the production of geothermal energy, as well as discussing their importance for earthquake hazard assessment or within the geotechnical, mining or civil engineering sectors.

Seismic techniques are becoming widely used to detect and quantitatively characterise a wide variety of natural processes occurring at the Earth’s surface. These processes include mass movements such as landslides, rock falls, debris flows and lahars; glacial phenomena such as icequakes, glacier calving/serac falls, glacier melt and supra- to sub-glacial hydrology; snow avalanches; water storage and water dynamics phenomena such as water table changes, river flow turbulence and fluvial sediment transport. Where other methods often provide limited spatial and temporal coverage, seismic observations allow recovering sequences of events with high temporal resolution and over large areas. These observational capabilities allow establishing connections with meteorological drivers, and give unprecedented insights on the underlying physics of the various Earth’s surface processes as well as on their interactions (chains of events). These capabilities are also of first interest for real time hazards monitoring and early warning purposes. In particular, seismic monitoring techniques can provide relevant information on the dynamics of flows and unstable slopes, and thus allow for the identification of precursory patterns of hazardous events and timely warning.

This session aims at bringing together scientists who use seismic methods to study Earth surface dynamics. We invite contributions from the field of geomorphology, cryospheric sciences, seismology, natural hazards, volcanology, soil system sciences and hydrology. Theoretical, field based and experimental approaches are highly welcome.

Solicited presenter: Kate Allstadt - USGS Geologic Hazards Science Center, Golden, CO, USA

On 29 December 2020, a major earthquake (Mw 6.4) occurred in Croatia close to Petrinja, only nine months after another Mw 5.5 damaging earthquake in Zagreb, the capital city located 45 km north of Petrinja. The December shock is the strongest event in continental Europe since the Norcia sequence (Italy) in 2016 and was caused by the rupture of a NW-SE dextral strike-slip fault at the boundary between the Dinarides and the Pannonian basin ; it was preceded by two strong foreshocks (M~5) the day before. Seismic shaking was widely felt across Europe, and caused extensive damage to buildings and infrastructures in the epicentral region. The earthquake resulted in liquefaction over large areas, and many cracks and a surface rupture have been observed in the field.
This late-breaking session aims at gathering contributions to discuss the 2020 Petrinja earthquake sequence, its surface effects on human and natural environment in terms of shaking and faulting. We encourage presentations dealing with the seismological, geodetical or geological observations related to this earthquake and the ongoing seismic sequence, as well as insights on the regional faults, their historical seismicity or recent geological activity. All this together can help in understanding the geodynamics of this seismically active but poorly characterized region.

Tsunamis can produce catastrophic damage on vulnerable coastlines, essentially following major earthquakes, landslides or atmospheric disturbances. After the disastrous tsunamis in 2004 and 2011, tsunami science has grown significantly, opening new fields of research in various domains, and also in regions where the tsunami hazard was previously underestimated.

Tsunamis with the most disastrous impacts at large distances are usually generated following large subduction earthquakes. In this session, the different disciplines used to better understand subduction earthquakes mechanics and quantify the related hazards will be addressed. This includes integrated observations, both seismological and geophysical models, as well as rock physics experiments.

Tsunami hazard can be estimated through numerical modeling, complemented with laboratory experiments. Complete databases are essential to describe past tsunami observations, including both historical events and results of paleotsunami investigations. Furthermore, a robust hazard analysis has to take into account uncertainties and probabilities with the more advanced approaches such as PTHA.
Because the vulnerability of populations, of infrastructures and of the built environment in coastal zones increases, integrated plans for tsunami risk prevention and mitigation should be encouraged in any exposed coastline, consistent with the procedures now in place in a growing number of Tsunami Warning System.
This merged NH5.1/OS4.15/SM4.3 session welcomes multidisciplinary contributions covering any of the aspects mentioned here, encompassing field data, geophysical models, regional hazard studies, observation databases, numerical and experimental modeling, risk studies, real time networks, operational tools and procedures towards a most efficient warning.

The scope of this session includes different aspects of large-amplitude wave phenomena in the ocean such as freak or rogue waves, surface and internal waves, as well as waves trapped by currents and bathymetry. The session is focused on the understanding of the physical mechanisms which cause extreme events, and the derivation of appropriate mathematical models for their description and advanced methods for their analysis. An essential part of such studies is the validation of new models and techniques versus laboratory and in-situ data. Special attention is paid to the description of wave breaking processes, and the interaction of large-amplitude waves with coastal structures.

Tsunamis and storm surges pose significant hazards to coastal communities around the world. Geological investigations, including both field studies and modelling approaches, significantly enhance our understanding of these events. Past extreme wave events may be reconstructed based on sedimentary and geomorphological evidence from low and high energy environments, from low and high latitude regions and from coastal and offshore areas. The development of novel approaches to identifying, characterising and dating evidence for these events supplements a range of established methods. Nevertheless, the differentiation between evidence for tsunamis and storms still remains a significant question for the community. Numerical and experimental modelling studies complement and enhance field observations and are crucial to improving deterministic and probabilistic approaches to hazard assessment. This session welcomes contributions on all aspects of paleo-tsunami and paleo-storm surge research, including studies that use established methods or recent interdisciplinary advances to reconstruct records of past events, or forecast the probability of future events.

Coastal areas are vulnerable to erosion, flooding and salinization driven by hydrodynamic hydro-sedimentary and biological processes and human interventions. This vulnerability is likely to be exacerbated in future with, for example, sea-level rise, changing intensity of tropical cyclones, increased subsidence due to groundwater extraction, tectonics, as well as increasing socio-economic development in the coastal zone. This calls for a better understanding of the underlying physical processes and their interaction with the coast. Numerical models therefore play a crucial role in characterizing coastal hazards and assigning risks to them. Drawing firm conclusions about current and future changes in this environment is challenging because uncertainties are often large, such as coastal impacts of likely and unlikely (also called high-end) sea-level changes for the 21st century. Furthermore, studies addressing coastal impacts beyond this century pose new questions regarding the timescale of impacts and adaptation activity. This session invites submissions focusing on assessments and case studies at global, regional and local scales of potential physical impacts of tsunamis, storm surge, sea-level rise, waves, and currents on coasts. We also welcome submissions on near-shore ocean dynamics and also on the socio-economic impact of these hazards along the coast.

Lakes, as well as engineered reservoirs, can be affected by geohazards at various temporal and spatial scales. Examples of such geohazards include gravitational mass movements that occur either subaqueously at the lateral slopes of lakes, or subaerially as rockfalls or landslides that enter water bodies. It has been documented that both these types of mass movements have caused lake tsunamis in the past. Other examples of geohazards in lakes can be caused by meteorological and volcanic phenomena, as well as human activity. As shorelines of many lakes are densely populated, the knowledge and assessment of lacustrine geohazards is essential. Apart from such geohazards directly related to the lake itself, lacustrine sediments can record a wide range of geohazards affecting their catchment, such as volcanic activity, earthquake shaking, and more climate related hazards such as floods and droughts. Lakes thus provide valuable archives to analyse recurrence patterns of geohazards, which can feed into hazard assessments. Due to their relatively small scales compared to the marine realm, lakes constitute very valuable environments for analysing, modelling, and monitoring natural hazards. However, the lakes’ small scales also constitute an obstacle for early warning systems related to lacustrine geohazards.
We encourage contributions by experts from science and praxis that address the broad topic “Geohazards in lacustrine settings”, from hazard documentation to mitigation strategies.

The multitude of processes of various scales occurring simultaneously under strong winds in the air and sea boundary layers presents a true challenge for nonlinear science. We want to understand the physics of these processes, their specific role, their interactions and how they can be probed remotely, how these processes differ from their counterparts under moderate/weak winds. We welcome theoretical, experimental and numerical works on all aspects of processes in turbulent boundary layers above and below the ocean surface. Although we are particularly interested in the processes and phenomena occurring under strong wind conditions, the works concerned with similar processes under weaker winds which might provide an insight for rough seas are also welcomed. We are also very interested in works on remote sensing of these processes.
The areas of interest include the processes at and in the vicinity of the interface (nonlinear dynamics of surface water, wave-turbulence interactions, wave breaking, generation and dynamics of spray and air bubbles, thermodynamics of the processes in the boundary layers, heat and gas exchange), all the processes above and below the aIr/water interface, as long as they are relevant for strong wind conditions (such as, e.g. inertial waves generated by changing winds). Relevant nonlinear biological phenomena are also welcomed.
The main aims of the session is to initiate discussion of the multitude of processes active under strong winds across the narrow specializations as a step towards creating an integrated picture. Theoretical, numerical, experimental and observational works are welcomed.

Geophysical Fluid Dynamics (GFD) is a truly interdisciplinary field, including different topics dealing with rotating stratified fluids. It emerges in the late 50s, when scientists from meteorology, oceanography, astrophysics, geological fluid dynamics, and applied mathematics began to mathematically model complex flows and thereby unify these fields. Since then many new aspects were added and deeper insight into many problems has been achieved. New mathematical and statistical tools were developed, standard techniques were refined, classical problems were varied. In this session we primarily focus on contributions from dynamic meteorology and physical oceanography that model flows by mathematical analysis. However, it is also a forum for experimental GFD and for astrophysical and geological aspects of GFD as well.

We welcome submissions on all aspects of tides in the ocean, atmosphere and solid Earth, from regional to global scales and covering all time scales on Earth and other planets. Tides impact many Earth system processes such as ocean mixing, global ocean circulation, ice sheet dynamics and biogeochemical processes. Tides interacting with storm surges and sea level rise can cause coastal flooding, and harnessing of tidal energy can provide a source of renewable energy. Accurate tide models are necessary for the analysis of satellite gravimetry and altimetry data, especially in light of the upcoming Surface Water Ocean Topography (SWOT) mission.
We encourage contributions on progress in numerical modelling of both surface and internal tides and assessments of their accuracy, observations of long-term changes in tides and tidal processes on global to regional scales, insights on tidal variability from global geodetic observing techniques, and research into the role of tides in shaping Earth’s evolutionary processes. We also invite submissions on tidal dynamics in estuaries, rivers and lakes.

We invite presentations on ocean surface waves, and wind-generated waves in particular, their dynamics, modelling and applications. This is a large topic of the physical oceanography in its own right, but it is also becoming clear that many large-scale geophysical processes are essentially coupled with the surface waves, and those include climate, weather, tropical cyclones, Marginal Ice Zone and other phenomena in the atmosphere and many issues of the upper-ocean mixing below the interface. This is a rapidly developing area of research and geophysical applications, and contributions on wave-coupled effects in the lower atmosphere and upper ocean are strongly encouraged.

Deltas and estuaries are home to 7% of the world’s population but they are also hotspots for disasters. These riverine landforms face a wide range of challenges, now and in the future, including climatic changes (sea level rise, changing river discharge), biodiversity loss, subsidence, sediment mining, groundwater extraction, dredging and engineering measures (dams, embankments, sluices etc.). Deltas and estuaries lie at the interface of complex river, tidal and wave processes which create distinctive morphologies and environments. They provide the hinterland with protection from flooding and erosion but are also key resource areas for freshwater, ecology and sediment. Protecting delta regions and estuaries is therefore a key research area for science and policy. Understanding the functioning of delta and estuarine processes, including hydrodynamic processes, morphological development and the effects of human interference, is key for a sustainable future for these systems. To prepare for future changes it is crucial to identify the present state of these systems and learn from their past development. This session aims to bring together knowledge from multiple disciplines such as geomorphology, hydrology, ecology, social sciences and science policy to identify how deltas and estuaries change and what future societal challenges might arise along their shores. We particularly encourage early career researchers to submit to this session and welcome contributions from those working on estuary and delta management, future issues in estuaries and deltas, and process and system based science of estuaries and deltas.

Coasts worldwide face a great variety of environmental impacts as well as increased anthropogenic pressures of coastal zone urbanization and rapid population growth. Over the last decade coastal erosion has emerged as a widespread problem that causes shoreline retreat and irreversible land losses. The attempts of managers and other stakeholders to cope with erosion using different types of hard engineering methods may often aggravate this problem, damaging natural landscape and coastal ecosystems in unexpected and unpredicted ways. Other negative impacts of human activities on littoral environments are chronic and punctual pollution of beach and coastal sediments with associated health risks for human beings. Chronic pollution is often observed in coastal areas close to factories, industries and human settlements - because of waste water discharges, punctual contamination is often linked to beach oiling.
The session gives priority to the subjects of coastal geomorphology: evolution of coastal landforms, coastal morphodynamics, coastline alterations and various associated processes in the coastal zone, e.g. waves and sediment drift, which shape coastal features and cause morphological changes. Contributions to this session will focus on the mechanisms responsible for coastal erosion and shoreline behaviour (advance or retreat) and will address the many natural and human factors involved. The topics may include work on predictions of shoreline change and discussions on the effects of human activities and their continuing contribution to coastal changes. The session will also cover submissions on coastal vulnerability to the combined effects of natural and human-related hazards, any type of coastal and environmental sensitivity classifications, and risk assessments. Globally, coastal dunes are seriously threatened as people tend to modify landforms and habitats through their actions and regulations, and the session invites also studies on natural and human-induced geomorphological changes of sand dunes, and recent projects and examples of dune eco-restoration and re-building.
Last, but not the least, studies related to Marine Spatial Planning (MSP), including Integrated Coastal Management (ICM), are also welcome. For any MSP and ICM, it is essential to consider the dynamics across the land-sea interface, i.e. the Land-Sea Interactions (LSI) that involve both natural processes and the impact of human activities.

Low-lying coastal areas can be an early casualty to the acceleration of sea-level rise, especially where enhanced by land subsidence. An ever increasing number of studies indicates that land subsidence due to natural and anthropogenic causes has induced damage to wetland ecosystems in many countries worldwide, and increased flooding hazard and risk. Coastal subsidence causes include excessive groundwater extraction from aquifers, peat oxidation due to surface water drainage through land reclamation, urbanization and agricultural use, as well as sediment starvation due to construction of dams and artificial levees. Contrary to the global processes behind sea-level rise, natural and anthropogenic coastal subsidence is primarily a local phenomenon, and causes and severity may vary substantially from place to place.

The combination of geological and historical measurements with remote sensing data is required to understand all drivers of coastal vertical land motion and the contributions to past, present, and future subsidence. Understanding coastal subsidence requires multidisciplinary expertise, including measuring and modeling techniques from geology, geodesy, natural hazards, oceanography, hydrogeology, and geomechanics. In this session, we aim to bring together all the involved disciplines. We invite contributions on all aspects of coastal subsidence research and applications, including recent advances on: i) measurement through ground-based, aerial and satellite remote sensing techniques, ii) numerical models and future projections, iii) their applicability to distinguish between the different drivers contributing to land subsidence, and iv) quantification of coastal hazards associated with relative sea-level rise. In particular, efforts towards characterizing human intervention on coastal vertical land motion are welcomed.

Scientific ocean and continental drilling provides unique opportunities to investigate the workings of the interior of our planet, Earth’s cycles, natural hazards and the distribution of subsurface microbial life. The past and current scientific drilling programs IODP (International Ocean Discovery Program) and ICDP (International Continental Scientific Drilling Program) have brought major advances in many multidisciplinary fields of socio-economic relevance, such as climate and ecosystem evolution, palaeoceanography, the deep biosphere, deep crustal and tectonic processes, geodynamics and geohazards. This session encourages contributions that outline perspectives and visions for future drilling projects, in particular projects using a multi-platform approach, and invites contributions that present and/or review recent scientific results from deep Earth sampling and monitoring through ocean and continental drilling projects.
This year, a particular focus will be given on contributions based on sedimentary records from outcrops or the often more complete sedimentary sections recovered by scientific drilling that reconstruct sedimentary processes and their products preserved in deltas, canyons and submarine fans (former session SSP 2.9).

During the past decades numerous sediment records have become available from lakes and paleolakes through shallow and (ICDP) deep drilling. These records have proven to be valuable archives of past climate and environmental change, human activities as well as tectonic and volcanic activity. We invite contributions emphasizing quantitative and spatial assessments of rates of change, causes and consequences of long- and short-term climate variability, impact, magnitude, and frequency of tectonic and volcanic activity as deduced from sedimentological, geochemical, biological, and chronological tools.

SAR remote sensing is a valuable tool for monitoring and responding to natural and anthropogenic hazards. Especially with the unprecedented spatio-temporal resolution and the rapid accumulation of SAR data collections from various dedicated SAR missions, we have more opportunities to exploit hazard-related signals from the SAR phase and amplitude imagery, characterize the associated spatio-temporal ground deformations and land alterations, and decipher the operating mechanism of the geosystems in geodetic timescales. Yet, optimally extracting relevant information from SAR imagery, designing a proper strategy for each individual hazard, optimally managing and archiving SAR data, and integrating all possible data, are still considerable challenges. Therefore, in this session, we welcome contributions that focus on (1) new algorithms to retrieve critical products from SAR remote sensing (big data) in an accurate, automated, and efficient framework; (2) SAR applications for anthropogenic and natural hazards including mining, oil/gas production, fluid injection/extraction, critical infrastructure, sinkholes, land degradation, peatlands, glaciers, permafrost, flooding, landslides, earthquakes, and volcanoes; and (3) mathematical and physical modeling of the SAR products such as estimating displacement velocities and time series for a better understanding on the surface and subsurface processes. In addition, we welcome applications on ground deformation in coastal areas in the context of sea level rise.

This session is devoted to the analysis of very low/low frequency (VLF/LF) techniques applied to investigate ionospheric disturbances related to natural and technological hazards. Such disturbances lasting from several milliseconds to several days can be used to study natural disasters occurring before, during and after the main event. The capability of the VLF/LF radio waves (3 kHz – 300 kHz) leads the remote sensing of the ionosphere due to the relatively low path attenuation of such frequencies allowing propagation over long distances. The purpose of this session is to provide a forum for discussion among researchers involved in studies of natural hazards like earthquakes, volcano activity, tropical cyclones and lightning, as well as in studies of technological hazards induced by high-energy solar radiation by means of VLF/LF detection system. We encourage contributions on the studies of ionospheric disturbances detected by ground-based networks like International Network for Frontier Research on Earthquake Precursors (INFREP) in Europe, South America VLF NETwork (SAVNET) in South America, World Wide Lightning Location Network (WWLLN) and others. We welcome new methods and techniques applied for the detections and the processing of the VLF/LF signals. Particular attention is given to the comprehension of the physical mechanisms at the origin of precursor signals observed before the natural hazards occurrence.

Many regions worldwide are coping with the climatic global change, which is modifying the water cycle and is increasing the occurrence of extreme hydro-meteorological events. Floods and landslides across a territory could increase significantly respect to actual and past scenarios, causing a modification of the susceptibility of a region and of the frequency of natural hazards.
The use of techniques able to monitor and to improve the prediction of these phenomena at different scales and in scarcely instrumented regions is fundamental. Soil moisture and rainfall estimates measured through remote sensing techniques can furnish reliable and widespread data at different scales. For satellite rainfall measures, state-of-the-art products cover time series of tens of years (e.g., TRMM Multisatellite Precipitation Analysis, Global Precipitation Measurement, EUMETSAT). Regarding soil moisture, different products can bring reliable measurements from a local/landscape to continental scales (e.g., SMMR, AMSR2, SMOS, SMAP, Metop/ASCAT, Sentinel). Innovative products, as soil moisture derived rainfall, allow to retrieve rainfall from different satellite soil moisture products or integrating field measurements of precipitation. Thanks to the improvement of the spatial and temporal resolutions of all of these products, they could become a fundamental tool also for early warning system strategies.
This session aims to collect and present researches concerning the most recent progress on the use of soil moisture and rainfall data from remote sensing for the monitoring and the prediction of landslides and floods. Those phenomena can cause hazards and risks towards population and anthropic elements. We encourage presentations related to:
• inter-comparison and inter-validation between land surface models, remote sensing approaches and in-situ validation networks;
• evaluation and trend analysis of soil moisture or rainfall satellite time series for monitoring landslides or floods and for identifying their possible triggering conditions;
• implementation of satellite measures of rainfall and soil moisture in physically-based or data-driven methods for the prediction of landslides and floods;
• use of remote sensing products of soil moisture and rainfall in early warning system tools;
• use of remote sensing products for investigating the effects of climatic global changes on the susceptibility and hazards towards landslides and floods.

Remote sensing and Earth Observations (EO) are used increasingly in the different phases of the risk management and in development cooperation, due to the challenges posed by contemporary issues such as climate change, and increasingly complex social interactions. The advent of new, more powerful sensors and more finely tuned detection algorithms provide the opportunity to assess and quantify natural hazards, their consequences, and vulnerable regions, more comprehensively than ever before.
Several agencies have now inserted permanently into their program the applications of EO data to risk management. During the preparedness and prevention phase, EO revealed, fundamental for hazard, vulnerability, and risk mapping. EO data intervenes both in the emergency forecast and early emergency response, thanks to the potential of rapid mapping. EO data is also increasingly being used for mapping useful information for planning interventions in the recovery phase, and then providing the assessment and analysis of natural hazards, from small to large regions around the globe. In this framework, Committee on Earth Observation Satellites (CEOS) has been working from several years on disasters management related to natural hazards (e.g., volcanic, seismic, landslide and flooding ones), including pilots, demonstrators, recovery observatory concepts, Geohazard Supersites, and Natural Laboratory (GSNL) initiatives and multi-hazard management projects.

The session is dedicated to multidisciplinary contributions focused on the demonstration of the benefit of the use of EO for natural hazards and risk management.
The research presented might focus on:
- Addressed value of EO data in hazard/risk forecasting models
- Innovative applications of EO data for rapid hazard, vulnerability and risk mapping, the post-disaster recovery phase, and in support of disaster risk reduction strategies
- Development of tools for assessment and validation of hazard/risk models

The use of different types of remote sensing (e.g. thermal, visual, radar, laser, and/or the fusion of these) is highly recommended, with an evaluation of their respective pros and cons focusing also on future opportunities (e.g. new sensors, new algorithms).
Early-stage researchers are strongly encouraged to present their research. Moreover, contributions from international cooperation, such as CEOS and GEO initiatives, are welcome.

Tangible Cultural Heritage (TCH) plays a key role in building the memory and roots of human society. Unfortunately, TCH sites are often threatened by soil erosion and natural hazards (e.g. landslides, earthquakes, flooding, tropical storms, forest fire); further damage can also arise from the fragility of the site’s structures and materials with respect to anthropogenic hazards (destructive sabotage, war) and incorrect urban planning. The protection and conservation of TCH sites are pressing issues not only for the conservators/scientist’s community but for the whole society. For a correct conservation strategy it is necessary to implement a specific inter-disciplinary approach, that should be planned considering the site characteristics (topography, geomorphological-geological setting) and typology of the related hazard. In this perspective the use of remote sensing (RS) techniques applied from spaceborne, airborne and ground-based to UAV platforms (including, but not limited to, Radar interferometry, Lidar, Digital photogrammetry, Optical and Infrared imaging) combined with detailed field surveys, sample laboratory analysis, geotechnical and geophysical analysis, can provide the fundamental data for the implementation of mapping products and geodatabases, especially in developing countries with limited data, to be used as a starting point for TCH management plans. The goal of this Session is to gather high-quality original contributions and case studies applications on the use of RS techniques for protection and conservation of tangible Cultural and Natural Heritage sites (these include but are not limited to the UNESCO World Heritage and Tentative Lists) for risk mitigation practices and management plans.

The leading-edge computational and data facilities of the forthcoming Exascale era will bring a variety of currently inaccessible Solid Earth computational challenges within reach. Firstly, many Geoscience calculations that are currently unaffordable due to the size of the computational domain, necessary model resolution, or insurmountable data requirements, will become increasingly tractable. Secondly, Exascale supercomputing will facilitate probabilistic framework approaches to ever larger and more complex problems, through larger ensembles of model realizations and incorporating high-end data inversion, model data assimilation, and uncertainty quantification. Finally, Urgent High Performance Computing will become a reality with complex numerical simulations, potentially with large model ensembles, becoming possible in near real-time. Numerous natural hazards which pose a direct threat to human life and critical infrastructure (e.g. earthquakes, volcanic eruptions, wildfire, landslides, and tsunamis) can require rapid and well-informed decision making in the emergency management process. The basis for these decisions is often provided by complex and data-intensive numerical models and we face a challenge of designing and implementing robust and powerful workflows (including computing, data management, sharing and logistics, and post processing) which present stakeholders with relevant and accurate results in a timely manner. This transdisciplinary session seeks contributions related to the preparation of codes for Exascale, geoscience workflows and services, adapting codes for emerging hybrid hardware architectures, e-services demanding Urgent HPC, early warning and forecasts for geohazards, hazard assessment, and high-performance data analytics. Examples include codes and workflows for near real-time seismic simulations, full-waveform seismic inversion, ensemble-based forecasts, faster than real-time tsunami simulation, magneto-hydrodynamics simulations, and physics-based hazard assessment.
This session is organized by the Center of Excellence for Exascale in Solid Earth (ChEESE) with the support of the European Plate Observatory System (EPOS), the EUDAT Collaborative Data Infrastructure (EUDAT CDI) and the Partnership for Advanced Computing in Europe (PRACE). The organisers plan to submit a proposal for an Advances in Geosciences (ADGEO) EGU General Assembly special volume on one or more EGU Divisions.

The socio-economic impacts associated with floods are increasing. According to the International Disaster Database (EM-DAT), floods represent the most frequent and most impacting, in terms of the number of people affected, among the weather-related disasters: nearly 0.8 billion people were affected by inundations in the last decade (2006–2015), while the overall economic damage is estimated to be more than $300 billion. Despite this evidence, and the awareness of the environmental role of rivers and their inundation, our knowledge and accurate prediction of flood dynamics remain poor, mainly related to the lack of measurements and ancillary data at the global level.

In this context, remote sensing represents a value source of data and observations that may alleviate the decline in field surveys and gauging stations, especially in remote areas and developing countries. The implementation of remotely-sensed variables (such as digital elevation model, river width, flood extent, water level, land cover, etc.) in hydraulic modelling promises to considerably improve our process understanding and prediction. During the last decades, an increasing amount of research has been undertaken to better exploit the potential of current and future satellite observations, from both government-funded and commercial missions. In particular, in recent years, the scientific community has shown how remotely sensed variables have the potential to play a key role in the calibration and validation of hydraulic models, as well as provide a breakthrough in real-time flood monitoring applications. With the proliferation of open data and more Earth observation data than ever before, this progress is expected to increase.

We encourage presentations related to flood monitoring and mapping through remotely sensed data including:

- Remote sensing data for flood hazard and risk mapping, including commercial satellite missions;
- Remote sensing techniques to monitor flood dynamics;
- The use of remotely sensed data for the calibration, or validation, of hydrological or hydraulic models;
- Data assimilation of remotely sensed data into hydrological and hydraulic models;
- Improvement of river discretization and monitoring based on Earth observations;
- River flow estimation from remote sensing;
- River and flood dynamics estimation from satellite (especially time lag, flow velocity, etc.).

The vast majority of all telecommunications data (99%) transit through submarine and land-based fibre-optic cables. Global networks of cables encircle the Earth and cover the most remote regions of the continents and oceans. At the same time fibre-optic cables are being used as distributed sensors to measure temperature or strain for a variety of objectives (e.g. fault detect) and environments (e.g. land, marine). Consequently, fibre technologies are becoming a standard tool for crustal exploration and seismic monitoring.

In recent years there have been significant breakthroughs in the use of fibre-optic sensing techniques developed to interrogate cables at very high precision over very large distances both on land and at sea, in boreholes and at the surface. For example, laser reflectometry using DAS (Distributed Acoustic Sensing) on both dedicated experimental and commercial fiber optic cables have successfully detected a variety of signals including microseism, local and teleseismic earthquakes, volcanic events, ocean dynamics, etc. Other laser reflectometry techniques have long been used for the monitoring of large-scale engineering infrastructures (dams, tunnels, bridges, pipelines, etc.). Additionally, fibre-optic technologies have also been applied to natural hazard studies on land (for e.g. monitoring landslides or sinkholes), where in the case of cities, signals of cars can be exploited for exploration, allowing new approaches for urban seismic hazard characterisation.

We welcome contributions that involve the application of fiber-optic cables or sensors in seismology, geodesy, geophysics, natural hazards, oceanography, urban environment, geothermal application, etc. with an emphasis on laboratory studies, large-scale field tests and modelling.

Recent advances in image collection, e.g. using uncrewed aerial vehicles (UAVs), and topographic measurements, e.g. using terrestrial or airborne LiDAR, are providing an unprecedented insight into landscape and process characterization in geosciences. In parallel, historical data including terrestrial, aerial, and satellite photos as well as historical digital elevation models (DEMs), can extend high-resolution time series and offer exciting potential to distinguish anthropogenic from natural causes of environmental change and to reconstruct the long-term evolution of the surface from local to landscape scale.

For both historic and contemporary scenarios, the rise of techniques with ‘structure from motion’ (SfM) processing has democratized data access and offers a new measurement paradigm to geoscientists. Photogrammetric and remote sensing data are now available on spatial scales from millimetres to kilometres and over durations of single events to lasting time series (e.g. from sub-second to decadal-duration time-lapse), allowing the evaluation of event magnitude and frequency interrelationships.

The session welcomes contributions from a broad range of geoscience disciplines such as geomorphology, cryosphere, volcanology, hydrology, bio-geosciences, and geology, addressing methodological and applied studies. Our goal is to create a diversified and interdisciplinary session to explore the potential, limitations, and challenges of topographic datasets for the reconstruction and interpretation of past and present 2D and 3D changes in different environments and processes. We further encourage contributions describing workflows that optimize data acquisition and processing to guarantee acceptable accuracies and to automate data application (e.g. geomorphic feature detection and tracking), and field-based experimental studies using novel multi-instrument and multi-scale methodologies. This session invites contributions on the state of the art and the latest developments in i) modern photogrammetric and topographic measurements, ii) remote sensing techniques as well as applications, iii) modelling technologies, and iv) data processing tools, for instance, using machine learning approaches.

Geomorphometry and geomorphological mapping are important tools used for understanding landscape processes and dynamics on Earth and other planetary bodies. The recent rapid advances in technology and data collection methods has made available vast quantities of geospatial data for such morphometric analysis and mapping, with the geospatial data offering unprecedented spatio-temporal range, density, and resolution, but it also created new challenges in terms of data processing and analysis.

This inter-disciplinary session on geomorphometry and landform mapping aims to bridge the gap between process-focused research fields and the technical domain where geospatial products and analytical methods are developed. The increasing availability of a wide range of geospatial datasets requires the continued development of new tools and analytical approaches as well as landform/landscape classifications. However, a potential lack of communication across disciplines results in efforts to be mainly focused on problems within individual fields. We aim to foster collaboration and the sharing of ideas across subject-boundaries, between technique developers and users, enabling us as a community to fully exploit the wealth of geospatial data that is now available.

We welcome perspectives on geomorphometry and landform mapping from ANY discipline (e.g. geomorphology, planetary science, natural hazard assessment, computer science, remote sensing). This session aims to showcase both technical and applied studies, and we welcome contributions that present (a) new techniques for collecting or deriving geospatial data products, (b) novel tools for analysing geospatial data and extracting innovative geomorphometric variables, (c) mapping and/or morphometric analysis of specific landforms as well as whole landscapes, and (d) mapping and/or morphometric analysis of newly available geospatial datasets. Contributions that demonstrate multi-method or inter-disciplinary approaches are particularly encouraged. We also actively encourage contributors to present tools/methods that are “in development”.

Remote sensing measurements, acquired using different platforms - ground, UAV, aircraft and satellite - have increasingly become rapidly developing technologies to study and monitor Earth surface, to perform comprehensive analysis and modeling, with the final goal of supporting decision systems for ecosystem management. The spectral, spatial and temporal resolutions of remote sensors have been continuously improving, making environmental remote sensing more accurate and comprehensive than ever before. Such progress enables understanding multiscale aspects of high-risk natural phenomena and development of multi-platform and inter-disciplinary surveillance monitoring tools. The session welcomes contributions focusing on present and future perspectives in environmental remote sensing, from multispectral/hyperspectral optical and thermal sensors. Applications are encouraged to cover, but not limited to, the monitoring and characterization of environmental changes and natural hazards from volcanic and seismic processes, landslides, and soil science. Specifically, we are looking for novel solutions and approaches including the topics as follows: (i) state-of-the-art techniques focusing on novel quantitative methods; (ii) new applications for state-of-the-art sensors, including UAVs and other close-range systems; (iii) techniques for multiplatform data fusion.

Wildfires represent a hazardous and harmful phenomenon to people and the environment, especially in populated areas where the primary cause of ignition is related to human activities. This has motivated governments to develop spatio-temporal datasets and to produce risk and prognostic maps. A key tool in this respect is to investigate the spatial and temporal distribution of wildfires and to understand its relationships with the surrounding environmental, climatological and socio-economic factors.
Innovative algorithms and methodologies have been developed in recent years to analyze spatially distributed natural hazards and ongoing phenomena such as wildfires. Considering the fast growing availability of high quality digital geo-referenced databases, it is important to promote methods and new tools for their study, especially for large-scale analysis. A new exciting challenge is to convert available datasets into meaningful and valuable information.
This session will bring together wildfire hazard scientists and researchers of various geo-environmental disciplines, economists, managers and people responsible for territorial and urban defense and planning policies. The main goal is to improve the understanding of the fire regime and to discuss new strategies to mitigate the disastrous effects of wildfires. We will examine empirical studies, new and innovative technologies, theories, models and strategies for wildfire research, seeking especially to identify and characterize spatial and temporal variability patterns of wildfires.

Research topics include, but are not limited, to the following:
• development of methodologies based on expert knowledge or data driven approaches, for the recognition, modelling and prediction of structured patterns in wildfires;
• pre- and post-fire assessment: fire incidence mapping and variability, fire severity and damage, including fire-planning and risk management;
• long-term trend patterns: relation between wildfires and global changes such as climate and land use/land cover changes;
• fire impacts on the environment, in particular on the atmosphere, human health and natural/anthropogenic environment;
• fire spread models, ranging from case studies to long-term climatological assessments;
• post-fire vegetation recovery and vegetation phenology.

Fire is an essential Earth system process that is rapidly changing in response to climate and human land use changes. Climate, vegetation and human activity regulate fire occurrence and spread, but fires also feedback to them in multiple ways. This session welcomes contributions on all aspects of linkages between fire, vegetation, 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 interactions between fire and (1) weather, climate, and atmospheric chemistry, (2) biogeochemical cycles, land water and energy budgets, and vegetation composition and structure, and (3) human land management (e.g. impact of fire on air and water quality, deforestation, human health, and economy). We also welcome contributions focusing on fire characterization, including (4) fire behavior and emissions (e.g. fire duration, intensity, emission factors, 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.

Wildfires are a global phenomenon responsible for tremendous environmental, social and economic losses, which combined with land abandonment, absence of appropriate land management, and urban planning, are expected to exacerbate land degradation and deteriorate the ecosystem services.
But now, wildfires are becoming a persistent threat as shown by the fire risk increase as a consequence of a warmer and drier climate, demanding from the scientific community novel tools for integrated post-fire land management and impact mitigation. This research urges the attention of researchers, stakeholders and decision-makers all over the world since wildfire impacts on soils and ecosystems are severely affecting ecosystem services supply such as raw material and water provisioning, carbon storage, erosion and flood control, and habitat support, which are essential for human life on earth.
The aim of this session is to join researchers that study the effects of wildfires on ecosystems from wildfire prevention to post-fire mitigation. We warmly invite studies that approach by means of laboratory, field experiments, and/or numerical modeling, the following subjects:
i. prescribed and/or experimental fires;
ii. fire severity and burn severity;
iii. fire effects on vegetation, soils and water;
iv. post-fire hydrological and erosive response;
v. post-fire management and mitigation;
vi. , and socio-economic studies on post-fire land management.

Climate induced geo-hazards are known to increase due to climate change causing more intense rainfall and more frequent extreme weather events. Use of vegetation on potentially unstable slopes and along stream banks is an example of Nature-Based Solutions (NBS) that can mitigate climate induced geo-hazards due their role at the soil-atmosphere interface. Vegetating slopes or stream banks are also key for riparian buffers for agricultural nutrient uptake, CO2 storage, improvement of water quality, ecological restoration and rewilding. However, researchers in different fields of science do not easily communicate, even though they are addressing aspects of the same problem.
Interdisciplinary research is needed to document the effects of vegetation in hazard-prone areas in a measurable and quantifiable manner. These NBS must have an ecological approach, where in the long-term perspective, a multiple approach for biodiversity and ecosystem services will give mutual synergies.

This session aims to stimulate interdisciplinary and international communication, knowledge exchange and dissemination on plant-soil-atmosphere interaction, with focus on vegetation based NBS for mitigating climate-induced geohazards, with a special focus on shallow landslides and erosion, and associated consequences.
Contributions documenting how vegetation and associated roots can be beneficial in landslide mitigation as well as in land use planning, restoration ecology, climate change adaptation are welcome within the fields of geotechnical engineering, plant ecology, root-soil biophysics, biodiversity, alpine timberline, hydrogeology and agronomy.

Specific topics are related to the following questions:

• How the plant-soil-atmosphere interaction affects the unsaturated zone and thus the slope stability?
• Measuring and quantifying the effects of vegetation as NBS for mitigating climate induced geo-hazards and associated consequences at or near instable slopes and along stream banks – case studies at full scale or laboratory scale.
• How to ensure interdisciplinary interaction for sustainability and mutual synergies for studies containing vegetation as NBS for mitigating climate induced geo-hazards and associated consequences at or near instable slopes and along stream banks.

Radon is applied as a powerful investigation tool in various fields of the geosciences (as fault tracer, geochemical precursor), though the main concern regards the radiation protection due to its important effects on human health, as reported in the EURATOM Directive 59 of 2013.
At the surface the indoor radon concentrations and the exposure from radon are controlled by many factors such as anthropogenic and meteorological factors. However, the pore structure of outcropping or shallow rocks and soils mainly control its concentration in the shallow environment. Geologic rock units have varying concentrations of Rn parent nuclide (U, Th and K) thus producing fluctuating amounts of radon around the BG production from rocks and soils.
Furthermore, tectonic radon migrating along permeable routes, such as active faults and fractured zones, may enhance the background production of Rn derived by its parent nuclide decay, this modifying the shallow distribution of the geogenic potential. Radon potential maps that account for geological factors and observed soil gas radon values may be used to define radon-priority areas that could help target population-based lung cancer prevention interventions given the inequities that exist related to radon.
While geogenic and tectonic radon govern the transport in-soil and the surface emission, entry paths indoors are defined by other factors such as permeability, building, and architectural features, ventilation, occupation patterns, etc.
Interdisciplinary scientific collaborations will be whished for gaining information on the radon hazard assessment and to produce radon maps that are a clear and easy way of presenting the radon issue to the public and policy-makers, and are essential for persuading people to take it seriously.
This session aims to discuss concepts and frameworks that improve the understanding of radon concentrations (in the soil and indoor) and geological formations, and to examine potential population-level lung cancer risk from radon exposure.
This session welcomes contributions from geochemists, physicists, geologists, physicians for examining the spatial and statistical associations between radon values and geological factors, discussing and sharing ideas and knowledge on the influence of geology on radon emission, health implications, measuring and mitigation methods, and its areal representation using the most promising techniques of the geospatial analysis.

The International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) senses the solid Earth, the oceans and the atmosphere with a global network of seismic, infrasound, and hydroacoustic sensors as well as detectors for atmospheric radioactivity. The primary purpose of the IMS data is for nuclear explosion monitoring regarding all aspects of detecting, locating and characterizing nuclear explosions and their radioactivity releases. On-site verification technologies apply similar methods on smaller scales as well as geophysical methods such as ground penetrating radar and geomagnetic surveying with the goal of identifying evidence for a nuclear explosion close to ground zero. Papers in this session address advances in the sensor technologies, new and historic data, data collection, data processing and analysis methods and algorithms, uncertainty analysis, machine learning and data mining, experiments and simulations including atmospheric transport modelling. This session also welcomes papers on applications of the IMS and OSI instrumentation data. This covers the use of IMS data for disaster risk reduction such as tsunami early warning, earthquake hazard assessment, volcano ash plume warning, radiological emergencies and climate change related monitoring. The scientific applications of IMS data establish another large range of topics, including acoustic wave propagation in the Earth crust, stratospheric wind fields and gravity waves, global atmospheric circulation patterns, deep ocean temperature profiles and whale migration. The use of IMS data for such purposes returns a benefit with regard to calibration, data analysis methods and performance of the primary mission of monitoring for nuclear explosions.

The shorter return period of climate and hydrological extremes has been observed in the changing climate, which affects the distribution and vitality of ecosystems. In many regions, available water is a crucial point of survival, especially in forests. Risk can be enhanced by the exposure and/or by the vulnerability of the affected ecosystem as well as by land use/land cover change.
The session should provide a multidisciplinary platform for sharing experiences and discussing results of local and catchment scale case studies from a wider range of relevant fields such as
• observed impacts and damage chains in natural, agricultural, and forest ecosystems induced by droughts and intense rainfall events;
• correlation between the underlying environmental factors (e.g. climate, soil parameters, topographic factors) and the distribution/vitality of ecosystems;
• integrated application or comparison of databases and methods for the identification and complex assessment of ecosystem responses to abiotic stress factors;
• contribution to the increase of knowledge of adaptive forestry, the sustainability of management, and the conservation and improvement of mixed forests to support rural development;
Contributions are encouraged from international experiences, ongoing research activities as well as national, regional, and local initiatives.

Soil erosion is a major global soil degradation threat to land, freshwater and oceans. Scientific understanding of all erosional physical processes controlling soil detachment, transportation, and deposition is vital when developing methods and conservation alternatives to minimize the impacts associated with soil degradation.

This session will discuss the State-of-the-Art of the latest soil erosion measurements, monitoring and modelling techniques in agriculture, forest and rangelands. Our main objective is to scientifically discuss soil erosion but also to explore/present solutions that may help farmers and policy makers; supporting the ongoing activities aiming at achieving the SDG Target 15.3 land degradation neutral world by 2030 and the upcoming UN Decade on Ecosystem Restoration (2021-2030). This session will also discuss recent studies supporting improved understanding of gully and rill erosional physical processes, their impact locally, their off-site effects on sedimentation, and subsequent development of mitigation strategies.

Wildfires induce physical and chemical alterations on soil properties, affecting both the quantity and composition of soil organic matter (SOM), and transforming biomass and SOM into pyrogenic carbon (PyC), also known as black carbon. PyC can derive from natural (e.g., wildfire charcoal), as well as anthropogenic sources (e.g., biochar) and it is recognized as important carbon sink in terrestrial and aquatic systems.

Wildfires and PyC can influence physical-, chemical-, and microbial soil functions by: changing composition and properties of native SOM which can modify soil physical properties (e.g. texture, structure, and moisture), changing redox- and pH conditions, and forming aggregates by mineral surface interaction of PyC micro- and nanoparticles. These changes can impact nutrient cycling and plant productivity, pollutant mobility, the soil microbiome, and edaphic fauna. These processes are of high importance for soil biochemistry, functioning, and carbon cycling, and to assess the environmental impact of wildfires for generating predictive tools that can be useful for post-fire restoration actions. To better understand the effects of Wildfires and PyC on soil, a wider knowledge of the abovementioned interlinked processes is urgently needed.

This session aims to bring together monodisciplinary as well interdisciplinary research on wildfire- and PyC-soil biochemistry, and carbon cycling, including studies on the alterations, impacts and cause-effect relationships induced by fire on SOM, as well as on describing recent advances on analytical techniques in the field. It welcomes submissions from lab- to field scale experiments as well as modelling, or meta-analytical approaches. Early career researchers and underrepresented groups in the field are strongly encouraged to apply.

This session offers an opportunity to present studies or professional works regarding irrigated agriculture with disciplinary and multidisciplinary approaches copying with the challenges that the COVID19 scenario brings to the researches and society, such as:
• Resilience of irrigated areas at different spatial scales, mainly when water and soil are limiting factors.
• Estimation of crop transpiration/crop water requirement, even considering the possibility to apply controlled water deficit conditions.
• Coupling natural and human systems where ground and surface water and land are limiting resources for irrigation
• Safety in marginal water use in irrigated agriculture
• Traditional, novel, and transitional technologies for irrigation management, control and practical application at different spatial scales.
• Reducing the cost of technology monitoring soil and plant water status, and improving the quality of data acquired from the sensors, as well as on integrating the acquired data into easy-to-use Decision Support System.
• Potential of available remotely and proximal sensed data, mainly referring to those platforms and instruments acquiring frequently high-resolution data, to tackle current and future irrigation problems at different spatial scales.
• Improving the integration of climate change scenarios and weather forecast into agro-hydrological models and decision support systems to improve decisions in irrigation management and in safe surface water-groundwater interactions.
Posters and oral communications are available.

Biogeomorphology addresses the two-way interaction between biotic and abiotic elements that shape landscapes at various spatio-temporal scales. Yet, developing theory, methods and quantifying processes at the abiotic/biotic interface remains challenging due to the interdisciplinarity of biogeomorphology, integrating concepts from ecology, evolutionary biology, engineering, geomorphology, geology and Quaternary science. On the other side, there is an urgent need to understand the interactions among abiotic and biotic processes in natural and managed systems to adapt to for instance climate change.
Consequently, a wide range of interdisciplinary projects in fields related to biogeomorphology have emerged. Such projects have included field, computational, and laboratory studies across a wide range of scales to understand the effects of underlying physical and ecological processes on biogeomorphic interactions.
This session focuses on the lessons learned from such approaches: advantages, limitations, best practices, and the future of the discipline of biogeomorphology. Research topics include, but are not limited to: 1) Biogeomorphic processes, rates and feedbacks, 2) Organism-Habitat interaction, 3) Biota as ecosystem engineers, 4) Effects of biogeomorphic interactions on nutrient and pollutant transport, 5) Biogeomorphology for the development of nature-based-solutions.

One of the most challenging sustainable goals of the UN 2030 Agenda and other international agreements is that urban systems have to increase well-being and health. Indeed, these networked systems already host more than half of the world's population and are going to host most of its growth, while they have been mostly designed and managed with limited visions, in particular with respect to their geophysical environment.
This goal got an unforeseen acuity with the Covid-19 pandemic, starting with the confinement strategies that radically brought into question the functioning of these systems, e.g., drastically reducing mobility and breaking its ever increasing trend. Covid-19 was not without precursor (e.g., SARS, MERS) and will not be without successors.

Long term visions based on transdisciplinary scientific advances are therefore indispensable, particularly from the geoscience community. As a consequence, this session calls for contributions from data-driven and theory-driven approaches of urban health under global change. This includes:
- qualitative improvements of epidemic modelling, as trans-disciplinary and nonlinear as possible
- possible interplays between meteorological and/or climate drivers and epidemic/health issues
- novel monitoring capabilities (including contacts tracking), data access, assimilation and multidimensional analysis techniques
- managing field works, geophysical monitoring and planetary missions
- how to have the highest science output during corona pandemic
- a fundamental revision of our urban systems, their greening as well as their mobility offer
- a particular focus on urban biodiversity, in particular to better manage virus vectors
- urban resilience must include resilience to epidemics, and therefore requires revisions of urban governance.

The session gathers geoscientific aspects such as dynamics, reactions, and environmental/health consequences of radioactive materials that are massively released accidentally (e.g., Chernobyl and Fukushima nuclear power plant accidents, wide fires, etc.) and by other human activities (e.g., nuclear tests).

The radioactive materials are known as polluting materials that are hazardous for human society, but are also ideal markers in understanding dynamics and physical/chemical/biological reactions chains in the environment. Thus, the radioactive contamination problem is multi-disciplinary. In fact, this topic involves regional and global transport and local reactions of radioactive materials through atmosphere, soil and water system, ocean, and organic and ecosystem, and its relation with human and non-human biota. The topic also involves hazard prediction and nowcast technology.

By combining 35 years (> halftime of Cesium 137) monitoring data after the Chernobyl Accident in 1986, 10 years dense measurement data by the most advanced instrumentation after the Fukushima Accident in 2011, and other events, we can improve our knowledgebase on the environmental behavior of radioactive materials and its environmental/biological impact. This should lead to improved monitoring systems in the future including emergency response systems, acute sampling/measurement methodology, and remediation schemes for any future nuclear accidents.

The following specific topics have traditionally been discussed:
(a) Atmospheric Science (emissions, transport, deposition, pollution);
(b) Hydrology (transport in surface and ground water system, soil-water interactions);
(c) Oceanology (transport, bio-system interaction);
(d) Soil System (transport, chemical interaction, transfer to organic system);
(e) Forestry;
(f) Natural Hazards (warning systems, health risk assessments, geophysical variability);
(g) Measurement Techniques (instrumentation, multipoint data measurements);
(h) Ecosystems (migration/decay of radionuclides).

The session consists of updated observations, new theoretical developments including simulations, and improved methods or tools which could improve observation and prediction capabilities during eventual future nuclear emergencies. New evaluations of existing tools, past nuclear contamination events and other data sets also welcome.

Agriculture is an important sector of any economy of the world. Agriculture productions are highly dependent on the climate change and variability. Changes in hydro-meteorological variables can influence crop yield and productivity at many places. Further, climate change can influence nutrient levels, soil moisture, water availability and other terrestrial parameters related to the agricultural productivity. Changes in the frequency and severity of droughts and floods could pose challenges for farmers and ranchers and threaten food safety. Further, changes in climate can influence meteorological conditions and thus can influence the crop growth pattern. It may also influence irrigation scheduling and water demand of the crops. The effects of climate change also need to be considered along with other evolving factors that affect agricultural production, such as changes in farming practices and technology.

The purpose of the proposed session is to gather scientific researchers related to this topic aiming to highlight ongoing researches and new applications in the field of climate change and agriculture. In this framework, original works concerned with the development or exploitation of advanced techniques for understanding the impact of climate change on agriculture will be invited.

The conveners of this session will encourage both applied and theoretical research in this area.

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.

Reducing natural hazard risk is high on the global political agenda. In response, more and more risk datasets, methods, and models are being developed and applied together with stakeholders in the decision-making process. At the same time, climate change, globalisation, urbanisation, and increased interconnectedness between ecological, physical, human, and technological systems pose major challenges to disaster risk reduction in a globally interconnected world. COVID-19 has clearly shown that single-hazard approaches to disaster risk management can leave countries unprepared. This calls for novel scientific approaches and new types of data, including loss data, to integrate the study of multiple natural and human processes. The integration of socioeconomic loss databases in risk assessments allows for effective use for both science and policy. This session is a merger between the following sessions:

Global and continental scale risk assessment for natural hazards: methods, practice and open loss and risk assessment
In this sub-session we: (1) showcase current state-of-the-art in global and continental natural hazard risk science, assessment, and application; (2) foster exchange of knowledge and good practice between scientists and practitioners; and (3) collaboratively identify future research avenues. We examine all aspects of natural hazard risk assessment at the continental to global scale, including contributions focusing on single hazards, multiple hazards, or a combination or cascade of hazards. It includes contributions focusing on globally applicable methods, such as using globally available datasets to force more local models or inform more local risk assessment.

Interplay between natural hazards and vulnerable societies in the context of global change
This sub-session aims to: (1) gather research, empirical studies, and observation data that are useful for understanding and assessing risk to inform resilience building strategies in the context of global change, (2) identify persistent gaps, and (3) propose potential ways forward. The session welcomes contributions on the following topics, among others: What can we learn from comparative studies of past successes and failures? Why do we still see increasing impacts of natural hazards despite major progress in understanding their drivers and constant innovation in methods? Which approaches are needed to assess and manage multi-hazard and multi-risk?

Global losses due to natural hazards have shown an increasing trend over the last decades, which is expected to continue due to growing exposure in disaster-prone areas and the effects of climate change. In response, recent years have seen greater worldwide commitment to reducing disaster risk. Working towards this end requires the implementation of increasingly effective disaster risk management (DRM) and financing strategies. These must necessarily be supported by reliable estimates of risk and loss before, during, and after a disaster. In this context, innovation plays a key role.
This session aims to provide a forum to the scientific, public and private discourse on the challenges to innovate DRM. We welcome submissions on the development and application of groundbreaking technologies, artificial intelligence and innovative modeling and visualization approaches for disaster risk assessment and DRM decision-making. This includes the quantification and mapping of natural hazard risks and their components (i.e. hazard, exposure, and vulnerability), as well as the forecasting of hazard and impacts prior to a disaster event, or as it is unfolding (in real- or near real-time). We are particularly interested in contributions covering one or more of the following thematic areas in the context of disaster risk assessment and reduction: artificial intelligence and machine learning, big data, remote sensing and earth observation, social media, volunteered geographic information (VGI), mobile applications, crowdsourcing, internet of things (IoT), and blockchain. We also welcome submissions exploring how these or other innovations can support real-world DRM strategies and translate into improved DRM decisions.

Increasing impacts from natural hazard events have been observed over the last decades in many regions. For the future, a further rise of losses and damages is expected as a consequence of anthropogenic climate change, increasing exposure and insufficient attention put to reducing vulnerabilities. Hence, the further reduction of disaster mortality, number of people affected, economic and intangible losses remain high priority targets for disaster risk management and adaptation as stipulated in the Paris Agreement and Sendai Framework with a view also towards learning from observed events. In this regard, the provisions of effective emergency response capabilities, as well as informed adaptation planning, are relevant issues on the research agenda.
Event-centred multi-disciplinary forensic investigations offer unique opportunities to gain insights and to better understand risk systems, dynamics including cascading effects as well as interactions between hazard, exposure and vulnerability as the key drivers of risk. Monitoring and documenting natural hazard events, its impacts and causes is an important element and a valuable basis for learning from disasters, revising current risk management strategies, as well as improving risk analyses and risk modelling. In addition, rapid impact assessment of natural hazard events may provide decision-makers with richer information to make more informed and timely decisions on emergency measures and recovery. Another key aspect that needs to be better studied and communicated in line with forensics and rapid assessments in climate attribution of observed extreme events, such as heatwaves, storms or floods. This line of study has emerged as a particular field of event assessment concerned with understanding and quantifying to what extent anthropogenic climate forcing has changed the probability of occurrence or magnitude of events with high impact.
All of these mentioned pose important and interesting challenges to the research community across disciplines. For this aim this session invites contributions on a) event monitoring and disaster forensics, b) rapid impact assessment of hazard events, and c) climate attribution for all types of natural hazards. Abstracts that highlight analyses of recent events, methodological advances or practical implementations with an inter-disciplinary perspective are particularly encouraged.

Assessing the costs of the overall economic impacts of natural hazards, costs of prevention and costs of emergency response, the supply of information on costs and benefits is crucial for decision-making in disaster risk reduction, hazard and risk management and climate change adaptation planning. This session aims to review current methodological approaches for assessing individual cost types and aims to show how these methods are used in the context of various natural hazards. We welcome submissions in the areas of assessing these various types of damage induced by any kind of natural hazard. Also, we are interested in contributions that focus on the cost-effectiveness or efficiency of risk reduction measures to natural hazards and adaptation to increasing weather risks due to climate change or other developments.
Additionally, this session aims at the better understanding of vulnerability of the built environment (building envelope, building content and infrastructure) to different types of natural hazards. The main focus herein is to present different models and approaches to bridge the gap between ex-post loss and damage assessment and ex-ante predictive models. Studies on loss, damage and vulnerability often address different scales and spatial patterns obstructing the comparison and transfer of results and methods. Moreover, although existing models (matrices, indices and functions) demonstrate high variance, analysis of the associated uncertainties remains fragmentary. We invite contributions addressing vulnerability, loss, damage assessment and we provide a platform for scientific exchange and implementation for successful disaster risk reduction strategies focusing on building back better, mitigation and adaptation.

Critical infrastructures and other technological systems such as transportation systems, telecommunication networks, power lines, pipelines, and reservoirs are at risk of natural hazards (e.g., earthquakes, floods, landslides, wildfires) in many urban and rural areas worldwide. A key to safe and affordable operations of these types of infrastructure is an in-depth knowledge of their exposure and vulnerability to natural hazards and the impact of damage experienced either locally or across the network. Fundamental understanding of hazard and risk involves (a) systematic identification, monitoring, and mapping of potential infrastructure exposure; (b) integrated assessment of impact as result of damage, repair and/or mitigation; (c) indirect losses from infrastructure disruption and synergistic effects; (d) consideration of interactions between hazards and/or cascades of hazards. This session welcomes contributions with a focus on natural hazards risk assessment for critical infrastructures and technological systems, and compilation of databases to record impact and elements at risk. We also encourage abstracts addressing the development and application of tools for cost modeling. The session is dedicated to contributions with national, regional, and local perspective and intends to bring together experts from science and practice as well as young scientists. We encourage submissions for interactive presentations, which can be presented online in virtual discussion.

The adverse effects of droughts are felt all over the globe, especially in recent years. Droughts often lead to direct and indirect impacts on different sectors from local to global scales. The likelihood of such impacts, understood as drought risk, is caused by the combination of drought hazards, exposure and systems’ vulnerabilities. To support the identification and planning of drought risk reduction and adaptation options, information is needed on the root causes, patterns and dynamics of drought risk and its related impacts. Even though the effects of drought are widespread and well known, research focusing on the different drought risk dimensions lags behind other natural hazard research. Common standards for risk analysis and its components, as well as for impact assessment, are missing. Furthermore, there are no common criteria for assessing the impacts of past and potential future droughts. Whether this is due to the difficulty to grasp the hazard, the lack of standards for vulnerability, exposure and risk assessment, the myriad of different sectors involved, or the complex web of direct and indirect impacts remains unknown so far.
This session addresses drought research beyond the hazard. This includes techniques to collect drought impact information, methods to assess exposure, vulnerability and drought risk for different sectors (e.g. agriculture, forestry, energy production, public water supply, commercial shipping, tourism, wildfires, human health), at different spatial (local to global) and temporal (past trends, current patterns, future scenarios) scales. The session aims to gather examples from around the globe at different scales, discussing best practices, existing challenges and potential ways forward. We welcome the full variety of thematic foci (hazard, exposure, vulnerability, risk, and impact assessment) based on qualitative, quantitative and mixed-methods approaches. The session aims to bring together scientists and practitioners to evaluate the current state-of-the-art, foster drought risk research, establish a community of researchers and practitioners, and shape the future of drought vulnerability and risk research.
The session is closely linked to the NHESS special issue “Drought vulnerability, risk, and impact assessments: bridging the science-policy gap” https://nhess.copernicus.org/articles/special_issue1113.html of which we strongly encourage all session contributors to be part.

In spite of advances in our scientific knowledge, disaster losses continue to rise globally, and this trend is expected to continue under climate change. Several global frameworks call for greater attention to the interface between science, policy and action to achieve resilience and reduce disaster losses. This session explores innovations in the area of applied sciences for assessing and communicating risk and resilience. Themes include: (i) concepts and novel methods of data collection to measure risk and resilience, (ii) best practice for engaging with communities and schoolchildren, (iii) ways to visualise and share information and (iv) reflections on policy and frameworks.

Urban areas are at risk from multiple hazards, including urban flooding, droughts and water shortages, sea level rise, disease spread and issues with food security. Consequently, many urban areas are adapting their approach to hazard management and are applying Green Infrastructure (GI) solutions as part of wider integrated schemes.

This session aims to provide researchers with a platform to present and discuss the application, knowledge gaps and future research directions of urban GI and how sustainable green solutions can contribute towards an integrated and sustainable urban hazard management approach. We welcome original research contributions across a series of disciplines with a hydrological, climatic, soil sciences, ecological and geomorphological focus, and encourage the submission of abstracts which demonstrate the use of GI at a wide range of scales and geographical distributions. We invite contributions focusing on (but not restricted to):

· Monitored case studies of GI, Sustainable Drainage Systems (SuDS) or Nature Based Solutions (NBS), which provide an evidence base for integration within a wider hazard management system;
· GIS and hazard mapping analyses to determine benefits, shortcomings and best management practices of urban GI implementation;
· Laboratory-, field- or GIS-based studies which examine the effectiveness or cost/benefit ratio of GI solutions in relation to their wider ecosystem potential;
· Methods for enhancing, optimising and maximising GI system potential;
· Innovative and integrated approaches or systems for issues including (but not limited to): bioretention/stormwater management; pollution control; carbon capture and storage; slope stability; urban heat exchange, and; urban food supply;
· Catchment-based approaches or city-scale studies demonstrating the opportunities of GI at multiple spatial scales;
· Rethinking urban design and sustainable and resilient recovery following crisis onset;
· Engagement and science communication of GI systems to enhance community resilience.

This interactive session aims to bridge the gap between science and practice in operational forecasting for different water-related natural hazards. Operational (early) warning systems are the result of progress and innovations in the science of forecasting. New opportunities have risen in physically based modelling, coupling meteorological and hydrological forecasts, ensemble forecasting, impact-based forecasting and real time control. Often, the sharing of knowledge and experience about developments are limited to the particular field (e.g. flood forecasting or landslide warnings) for which the operational system is used.
The focus of this session will be on bringing the expertise from different fields together as well as exploring differences, similarities, problems and solutions between forecasting systems for varying natural hazards. Real-world case studies of system implementations - configured at local, regional and national scales - will be presented, including trans-boundary issues. An operational warning system can include, for example, monitoring of data, analysing data, making forecasts, giving warning signals and suggesting response measures.
Contributions are welcome from both scientists and practitioners who are involved in developing operational forecasting and/or management systems for water-related natural or man-made hazards, such as flood, drought, tsunami, landslide, hurricane, hydropower, pollution etc.

This session aims to share innovative approaches to developing multi-hazard risk assessments and their components, and to explore their applications to disaster risk reduction. Effective disaster risk reduction practices and the planning of resilient communities requires the evaluation of multiple hazards and their interactions. This approach is endorsed by the UN Sendai Framework for Disaster Risk Reduction. Multi-hazard risk and multi-hazard impact assessments look at interaction mechanisms among different natural hazards, and how spatial and temporal overlap of hazards influences the exposure and vulnerability of elements at risk. Moreover, the uncertainty associated with multi-hazard risk scenarios needs to be considered, particularly in the context of climate change and ongoing effects of the Covid-19 pandemic on evolving vulnerabilities.

This session, therefore, aims to profile a diverse range of multi-hazard risk and impact approaches, including hazard interactions, multi-vulnerability studies, and multi-hazard exposure characterization. In covering the whole risk assessment chain, we propose that it will be easier to identify potential research gaps, synergies and opportunities for future collaborations.

We encourage abstracts which present innovative research, case study examples and commentary throughout the whole disaster risk cycle on (i) multi-hazard risk methodologies which address multi-vulnerability and multi-impact aspects; (ii) methodologies and tools for multi-hazard risk management and inclusive risk-informed decision making and planning; (iii) methodologies and tools for multi-hazard disaster scenario definition and management for (near) real-time applications; (iv) cross-sectoral approaches to multi-hazard risk, incorporating the physical, social, economic, and/or environmental dimensions; (v) uncertainty in multi-hazard risk and multi-hazard impact assessment; (vi) evaluation of multi-hazard risk under future climate and pandemic changes; (vii) implementation of disaster risk reduction measures within a multi-hazard perspective.

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?

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.

Extreme climate and weather events, associated disasters, geohazards and emergent risks interact with other stressors, especially growing anthropogenic pressures, and are so becoming increasingly critical in the context of global environmental change. They are a potential major threat to reaching the Sustainable Development Goals (SDGs) and one of the most pressing challenges for future human well-being and safety.
This session explores the linkages between extreme climate and weather events, geohazards, associated disasters, societal dynamics and resilience.
Emphasis is laid on 1) Which impacts are caused by extreme climate events (including risks emerging from compound events) and cascades of impacts on various aspects of ecosystems and societies? 2) Which feedbacks across ecosystems, infrastructures and societies exist? 3) What are key obstacles towards societal resilience and reaching the SDGs, while facing climate extremes? 4) What can we learn from past experiences? 5) What local to global governance arrangements best support equitable and sustainable risk reduction?
Nowadays, to answer this last question, the careful application of social media and crowdsourcing (SMCS) begins to make a contribution, notably in the field of geosciences. SMCS have been integrated into crisis and Disaster Risk Management (DRM) for improved information gathering and collaboration across communities, and for collaboratively coping with critical situations. Numerous governments and EU-funded projects have been exploring the implementation and use of SMCS by developing and adopting new technologies, procedures, and applications. The effectiveness of SMCS on European disaster resilience, however, remains unclear, due to the diversity among disaster risk perception and vulnerability. In general, this second part addresses ways to govern and understand the effectiveness of SMCS for Disaster Risk Management and the related Disaster Resilience is focused.
In this session we welcome empirical with practical applications, theoretical and modelling studies from local to global scale from the fields of natural sciences, social sciences, humanities and related disciplines since the creation of novel effective approaches necessitates a coordinated and coherent effort between them.

Natural hazards pose significant threats to public safety, infrastructure integrity, natural resources, and economic development. In recent years, the frequency and impacts of extreme events have increased substantially in many parts of the world fostering a paradigm shift from traditional stationary statistical models towards models capable of capturing the changing properties of extremes, i.e., nonstationary statistical models. The nonstationarity in such models can be defined by a temporal or process-informed dependence of the observed extremes on an explanatory variable (i.e., a physical driver). Further, a solely statistical-based model might lead to results inconsistent with physics, e.g. unrealistic wave heights in shallow waters. This highlights the need of traditional statistical models including physical constraints in the inference process.

The proposed short course presents the Matlab toolbox ProNEVA which enables users to perform Bayesian statistical analysis under the assumption of nonstationarity, and its latest extension ProNEVAwave specific for analyzing extreme wave heights considering physical constraints in the inference process. The main features of ProNEVA are: parameters estimation of Generalized Extreme Value distribution (GEV), Generalized Pareto distribution (GP), and Log Pearson type III distribution based on Bayesian inference approach; analysis under temporal and process-informed nonstationarity; uncertainty quantification; estimation of return period-return level values for nonstationary analysis (i.e., effective return level and waiting time). The extension ProNEVAwave is developed for statistical analysis of wave heights with the following features: events selection; parameter estimation of stationary GP distribution based on Bayesian inference considering physical constraints via informative priors; uncertainty quantification; estimation of return period-return level curves.

This hands-on short course will provide attendees with some basic knowledge of extreme value analysis under stationary and nonstationary assumptions. Attendees will have hands-on experience on how to apply ProNEVA and ProNEVAwave through a number of applications (e.g., modeling extreme wave heights).

In order to be able to have predictive power on extreme events we need to rely on mathematical approaches that provide us with some degree of universality, so that we have rigorous ways to extrapolate information beyond what has been already recorded. In this short course we will introduce frameworks based on dynamical systems theory and statistical mechanics that allow for a rigorous and effective treatment and analysis of extreme events. We will show how extreme value theory and large deviation theory allows for a better understanding of high-impact weather and climate extremes as well as of the basic dynamical properties of the atmosphere. We will introduce the basic theory and show applications on a range of datasets, including outputs of numerical models of various levels of complexity as well as observational data.

You have observed timeseries or observed fields from hydroclimatic variables (e.g., rainfall, wind, etc.) or from other environmental variables. You wish to generate synthetic ones that reproduce precisely the observed statistical properties, but you do not how to do it. No worries! Join us and you will find out!

The short course will introduce you to a unified method of stochastic modelling and the CoSMoS R-package that makes generation of random fields and of univariate or multivariate time series piece of cake. The generated random fields or time series preserve any desired probability distribution and correlation structure including features like spatial and temporal intermittency. We will talk about the stochastic properties of hydroclimatic processes such as precipitation, streamflow, wind, temperature, etc., and highlight features such as stationarity, cyclostationarity, marginal distributions, spatiotemporal correlations structures, and intermittency. We will explain how AR and multivariate AR models work and describe step-by-step the parent-Gaussian framework that allows precise and easy simulation of random fields and time series. Real-world examples include rainfall simulation at different spatiotemporal scales as well as simulating variables such as temperature, relative humidity, etc.

Early Career Scientists (ECS) and student are more than welcome! As always, we organize this short course in cooperation with the Young Hydrologic Society (YHS; younghs.com)!

Meet editors of internationally renowned journals in biogeosciences and soil system science and gain exclusive insights into the publishing process. After a short introduction into some basics, we will start exploring various facets of academic publishing with short talks given by the editors on - What are the duties and roles of editors, authors and reviewers? - How to choose a suitable journal for your manuscript and what is important for early career authors? - How can early career scientists get involved in successful peer-reviewing? - What is important for appropriate peer-reviewing? - What are ethical aspects and responsibilities of publishing? - Together with the audience and the editors, we will have an open discussion of all steps and factors shaping the publication process of a manuscript. This short course aims to provide early career scientists across several EGU divisions (e.g. BG, SSS, NH and GM) the opportunity of using first hand answers of experienced editors of international journals to successfully publish their manuscripts and get aware of the potentials and pitfalls in academic publishing.

Forecasting and Early Warning Systems (EWSs) help societies prepare for and respond to all types of disasters, including those due to hydro-meteorological hazards. In recent years, there has been a consensus on the need for an interdisciplinary approach to forecasting, and communicating warnings and their inherent uncertainties. The integration of methods and knowledge such as risk, probabilistic and risk-based forecast, impact-based assessments, Information and Communication Technology (ICT) fields, social science and local knowledge can (1) improve the quality of forecast, (2) improve decision making and (3) support better communication of warnings and response. However, one of the biggest challenges is the need to collaborate across relevant disciplines. Therefore new ways of thinking are required on the necessary skills to facilitate more collaborative work.

This short course aims to highlight the benefits and skills required for an interdisciplinary approach in EWS in the form of a role-playing game and discussion. Participants will have the opportunity to understand more about the role of diverse disciplines, their importance in EWS and most importantly, collaborate with people from different backgrounds to come up with a successful solution. The game will be based on a hypothetical emergency situation, in which participants will be required to make decisions based on their assigned role. After the game, an active discussion with all participants will be carried out to propose take away action points on how to improve interdisciplinarity in EWS and how Early Career Scientist (ECS) can contribute to promoting this approach.
At the end of the short course participants should have:
(1) increased awareness and understanding of the roles of EWS actors
(2) Understanding of the necessity to engage and collaborate with professionals from different backgrounds
(3) Newly acquired skills to improve interdisciplinary working and communication

We especially encourage, but not limit, the participation of Early Career Scientists (ECS) interested in the field of Natural Hazards Social, Hydrological and Atmospheric Sciences as well as those who are already working or have in interest working in interdisciplinary fields.
This short course is organised by the Early Warning Systems Young Professionals (EWSYP) Network and the Water Youth Network (WYN)

Most often observations and measurements of geophysical systems and dynamical phenomena are obtained as time series whose dynamics usually manifests a nonlinear behavior. During the past decades, nonlinear approaches in geosciences have rapidly developed to gain novel insights on fluid dynamics, greatly improving weather forecasting, on turbulence and stochastic behaviors, on the development of chaos in dynamical systems, and on concepts of networks, nowadays frequently employed in climate research.

In this short course, we will offer a broad overview of the development and application of nonlinear concepts across the geosciences in terms of recent successful applications from various fields, ranging from climate to solar-terrestrial relations. The focus will be on a comparison between different methods to investigate various aspects of both known and unknown physical processes, moving from past accomplishments to future challenges.