This session will present the award and medal lecture of the EGU Division of Cryospheric Sciences for 2020 and 2021.

The 2020 Division Outstanding Early Career Scientist Award is awarded to Anna E. Hogg for outstanding research in the field of satellite remote sensing of the cryosphere and her contributions to science communications.

The 2021 Division Outstanding Early Career Scientist Award is awarded to Christine L. Batchelor for her contributions to cryospheric sciences by her studies on glacial history and palaeo-ice sheet reconstructions.

The 2020 Julia and Johannes Weertman Medal is awarded to Julienne C. Stroeve for her fundamental contributions to improved satellite observations of sea ice, better understanding of causes of sea ice variability and change, and her compelling communication to the wider public.

The 2021 Julia and Johannes Weertman Medal is awarded to Martyn Tranter for his outstanding fundamental contributions in the innovative and emerging field of glacial biogeochemistry, leading to the paradigm shift in recognizing bio-albedo effects.

The largest single source of uncertainty in projections of future global sea level is associated with the mass balance of the Antarctic Ice Sheet (AIS). In the short-term, it cannot be stated with certainty whether the mass balance of the AIS is positive or negative; in the long-term, the possibility exists that melting of the coastal shelves around Antarctica will lead to an irreversible commitment to ongoing sea level rise. Observational and paleoclimate studies can help to reduce this uncertainty, constraining the parameterizations of physical processes within ice sheet models and allowing for improved projections of future global sea level rise. This session welcomes presentations covering all aspects of observation, paleoclimate reconstruction and modeling of the AIS. Presentations that focus on the mass balance of the AIS and its contribution towards changes in global sea level are particularly encouraged.

This session will explore improvements in our understanding of past and future ice sheet and sea-level changes, together with a focus on model to data integration and comparison. It therefore includes contributions on the use of observations to improve the reliability of models and the use of models to identify observational needs and aid in the interpretation of observations. Contributions target both the Greenland and Antarctic ice sheets, mass balance and model intercomparison exercises, as well as quantification of uncertainties.

Overall, this session aims to bring together modellers and observational scientists to quantify the past, present and future state of the Greenland and Antarctic ice sheets, and to discuss how model-data integration can improve our understanding of the evolution of these ice masses.

This session is a merger of two originally proposed sessions: "Ice sheet mass balance and sea level: ISMASS/ISMIP6/ISMIP7" and "Advances and future opportunities for the integration of ice sheet models and observations”, and incorporates both ISMASS (http://www.climate-cryosphere.org/activities/ismass) and ISMIP6 (http://www.climate-cryosphere.org/mips/ismip6) contributions.

Glaciers and ice caps are major contributors to sea-level rise and have large impacts on runoff from glacierized basins. Major mass losses of glaciers and ice caps have been reported around the globe for the recent decades. This is a general session on glaciers outside the Greenland and Antarctic ice sheets, emphasizing their past, present and future responses to climate change. Although much progress in understanding the link between glaciers and climate and the impacts of their wastage on various systems has recently been achieved, many substantial unknowns remain. It is necessary to acquire more direct observations, both applying novel measurement technologies and releasing unpublished data from previous years, as well as combining in situ observations with new remote sensing products and modelling. In order to improve our understanding of the processes behind the observed glacier changes, the application of models of different complexity in combination with new data sets is crucial. We welcome contributions on all aspects of glacier changes – current, past and future – based on field observations, remote sensing and modelling. Studies on the physical processes controlling all components of glacier mass balance are especially encouraged, as well as assessments of the impact of retreating glaciers and ice caps on sea-level rise, runoff and other downstream systems.

The Andean Cordillera is cryospherically diverse, with high mountain glaciation in the north and large temperate ice masses in the south. These ice masses are critical for water security, the prevalence of geohazards, and a potentially substantial contribution to global sea level. The climatic influences on these ice masses vary across the Cordillera, and are strongly affected by large scale ocean-atmospheric systems such as ENSO and the Southern Annular Mode.

South America is one of the few landmasses in the ocean-dominated Southern Hemisphere available for terrestrial environmental and climate reconstructions. Palaeoclimatic records suggest that Patagonia was sensitive to the Antarctic Cold Reversal and variations in the Southern Annular Mode, which drives changes in the Southern Westerly Winds. Changes in these winds affect both Patagonia and Antarctica today. Further north, the glaciers in Peru and Bolivia are receding rapidly, threatening water security in these latitudes. These glaciers are strongly affected by rising atmospheric air temperatures and changes in ENSO. The high climate sensitivity of these glaciers and icefields, as well as their large latitudinal transect across the Andes, renders them a useful barometer of changes in large-scale atmospheric circulation and palaeoclimate.

We invite interdisciplinary contributions that investigate climate and cryosphere interactions over a range of timescale. This session will bring together researchers working on contemporary mass balance and climatology in the Andean Cordillera, Quaternary palaeoclimatic reconstructions from proxy data (including from lakes, bogs, marine records, aeolian records, ice cores, etc.), (palaeo)climate modelling, and reconstructions of former, present and future ice extent and dynamics from field-based studies and numerical modelling. It will provide a forum in which researchers can contrast their data and shed light on Quaternary glaciations and their palaeoclimatic drivers in South America. We especially invite studies that use data-model comparisons to improve projections of future climate and ice mass behaviour in the Andean Cordillera.

This session will focus on recent and upcoming advances in satellite remote sensing of the global cryosphere. We welcome presentations providing new insights into cryospheric processes in the broadest sense, ranging from ice sheets, glaciers, snow cover and its properties, frozen soil, sea ice and extraterrestrial glaciology. While the advent of remote sensing has revolutionized the field of glaciology, a vast reservoir of potential remains to be unlocked by using these observations in concert with other data sets. We particularly encourage presentations discussing multi-platform data merging, integration of GIS and ground validation data, integration of remote sensing data into earth system models, as well as cloud computing and processing of super large data sets. We also encourage contributions focusing on historic satellite data re-analysis, novel processing approaches for upcoming satellite missions, and presentations outlining pathways to next-generation satellite missions for the coming decades.

Process understanding is key to assessing the sensitivity of glacier systems to changing climate. Comprehensive glacier monitoring provides the base for large-scale assessment of glacier distribution and changes. Glaciers are observed on different spatio-temporal scales, from extensive seasonal mass-balance studies at individual glaciers to decadal assessments of glacier mass changes and repeat inventories at the scale of entire mountain ranges. Internationally coordinated glacier monitoring aims at combining in-situ measurement with remotely sensed data, and local process understanding with global coverage. We invite contributions from a variety of disciplines, from tropical to polar glaciers, addressing both in-situ and remotely sensed monitoring of past and current glacier distribution and changes, as well as related uncertainty assessments. A special focus of this year’s session shall be on (i) how to reach global coverage with decadal surveys from space, (ii) how to develop the in-situ networks to real-time monitoring of glacier changes, and (iii) how best to combine studies with focus on local process understanding with regional to global change assessments?

Snow constitutes a freshwater resource for over a billion of people world-wide. High percentage of this snow mainly come from seasonal snow located in mid-latitude regions. The current warming situation alerts that these snow water storages are in high risk to be dramatically reduced, affecting not only water supply but also ecosystems in these areas. Remote sensing has been the main technique used to monitor the snow properties across mid-large extensions for decades. The recent advances are focused on the study of snow dynamics at higher spatio-temporal scales (i.e., small-scale snow-topography interactions, diurnal variation of snow).

This session will focus on remote sensing studies dealing with techniques and data from different technologies, such as time-lapse imagery, laser scanners, radar, optical photography, thermal and hyperspectral technologies, or other new applications, with the aim of quantifying and better understanding snow characteristics (i.e., snow grain size, snow depth, albedo, pollution load, snow specific area and snow density), snow related processes (snowfall, melting, evaporation and sublimation), snow dynamics, snow hydrological impacts and snow environmental effects.

Geophysical and in-situ measurements of the cryosphere offer important baseline datasets, as well as validation for modelling and remote sensing products. In this session we welcome contributions related to a wide spectrum of methods, including, but not limited to radioglaciology, active and passive seismology, acoustic sounding, Global Navigation Satellite System (GNSS) reflectometry or time delay techniques, cosmic ray neutron sensing, remotely operated vehicle (ROV) or drone applications, geoelectrics, nuclear magnetic resonance (NMR) and methods in radiative transfer (i.e. infrared photography, thermal sounding...).

Contributions could be related to field applications, new approaches in geophysical or in-situ survey techniques, or theoretical advances in data analysis processing or inversion. Case studies from all parts of the cryosphere such as snow and firn, alpine glaciers, ice sheets, glacial and periglacial environments, permafrost, or sea ice, are highly welcome. The focus of the session is to compare experiences in the application, processing, analysis and interpretation of different geophysical and in-situ techniques in these highly complex environments.

This year our session will be a virtual PICO session. The session begins with each presenter giving a “quick fire” 2-minute overview of their research, followed by breakout "rooms" - one per presentation, for authors to further discuss their research. We hope the virtual PICO format will provide as much lively discussion as our normal in-person PICO!

++++++++++++++++++++ Invited Speaker ++++++++++++++++++++

Amy R. Macfarlane: Quasi in-situ snow and sea ice interface microstructure measured by micro-computed tomography

Understanding and predicting climate variability is vital if we are to properly prepare for the impact of climate change in an increasingly warmer world, including rising sea level as a result of melting ice and iceberg discharge. Fortunately, technological developments mean that 1) our numerical models of the cryospheric and climate systems are increasingly able to capture their inherent complexity, and 2) we are able to acquire much more detailed observations of our polar regions by satellite than ever before. This also brings an important challenge however: how can we extract the maximum possible meaning from these data while minimizing the increase in uncertainty that added volume/complexity/heterogeneity brings?

In this session we invite submissions on research that applies Data Science techniques to answer research questions in Glaciology and Polar Climate studies. This includes, but is not limited to, studies using machine learning and AI, advanced statistics (e.g. extreme value analysis or changepoint methods), surrogate modelling (emulators), network analysis and innovative software/computing solutions. These could be applied to any, or any combination of, data sources including remote sensing, numerical model output and field/ground/lab observations. We are particularly interested in contributors interested in a wider discussion about Data Science and its application in Climate and Cryospheric research and in contributions which reveal new insight that would not be possible using traditional methods.

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.

Satellite altimetry provides the possibility to observe key parts of the hydrosphere, namely the ocean, ice, and continental surface water from space. Since the launch of Topex/Poseidon in 1992 the applications of altimetry have expanded from the open oceans to coastal zones, inland water, land and sea ice. Today, seven missions are in orbit, providing dense and near-global observations of surface elevation and several other parameters. Satellite altimetry has become an integral part of the global observation of the Earth‘s system and changes therein.

In recent years, new satellite altimetry missions have been launched carrying new instruments; the CryoSat-2/Sentinel-3 missions equipped with a Delay/Doppler altimeter, the Saral AltiKa mission carrying the first Ka band altimeter, and the 2018 launched six beam photon counting laser altimeter on-board NASAs ICESat-2. Further, new orbits with high inclination and long-repeat time are used for CryoSat-2 and ICESat-2.


Fully exploiting this unprecedented availability of observables will enable new applications and results but also require novel and adapted methods of data analysis.
Across the different applications for satellite altimetry, the data analysis and underlying methods are similar and a knowledge exchange between the disciplines has been proofed to be fruitful.
In this multidisciplinary altimetry session, we therefore invite contributions which discuss new methodology and applications for satellite altimetry in the fields of geodesy, hydrology, cryosphere, oceanography, and climatology.
Topics of such studies could for example be (but not limited to); creation of robust and consistent time series across sensors, validation experiments, combination of radar and laser altimetry for e.g. remote sensing of snow, classification of waveforms, application of data in a geodetic orbit, retracking, or combination with other remote sensing data sets.

The half-century since the first deep ice core drilling at Camp Century, Greenland, has seen extensive innovation in methods of ice sample extraction, analysis and interpretation. Ice core sciences include isotopic diffusion analysis, multiple-isotope systematics, trace gases and their isotopic compositions, ice structure and physical properties, high-resolution analysis of major and trace impurities, and studies of DNA in ice, among many others. Several projects (e.g. Beyond EPICA Oldest Ice) are to surface ice as old as 1.5 million years old from very compressed layers at the very bottom of the Antarctic ice sheet in the coming years. Analysis and interpretation of this ice will bring new challenges, including the potential for in situ processes to impact the climatic signals. Furthermore, a variety of ice cores have been drilled recently in the framework of the ICE MEMORY initiative to preserve environmental and climate information from glaciers threatened by climate change.
This session welcomes all contributions reporting the state-of-the-art in ice coring sciences, including drilling and processing, dating, analytical techniques, results and interpretations of ice core records from polar ice sheets and mid- and low-latitude glaciers, remote and autonomous methods of surveying ice stratigraphy, and related modelling research.

Ice sheets play an active role in the climate system by amplifying, pacing, and potentially driving global climate change over a wide range of time scales. The impact of interactions between ice sheets and climate include changes in atmospheric and ocean temperatures and circulation, global biogeochemical cycles, the global hydrological cycle, vegetation, sea level, and land-surface albedo, which in turn cause additional feedbacks in the climate system. This session will present data and modelling results that examine ice sheet interactions with other components of the climate system over several time scales. Among other topics, issues to be addressed in this session include ice sheet-climate interactions from glacial-interglacial to millennial and centennial time scales, the role of ice sheets in Cenozoic global cooling and the mid-Pleistocene transition, reconstructions of past ice sheets and sea level, the current and future evolution of the ice sheets, and the role of ice sheets in abrupt climate change.

This session is intended to attract a broad range of ice-sheet and glacier modelling contributions, welcoming applied and theoretical contributions. Theoretical topics that are encouraged are higher-order mechanical models, data inversion and assimilation, representation of other earth sub-systems in ice-sheet models, and the incorporation of basal processes and novel constitutive relationships in these models.

Applications of newer modelling themes to ice-sheets and glaciers past and present are particularly encouraged, in particular those considering ice streams, rapid change, grounding line motion and ice-sheet model intercomparisons.

Subglacial environments are among the least accessible regions on Earth and represent one of the last physical frontiers of glaciological research, while emerging as a unique ecological habitat. The subglacial environment is a key component in the dynamic behaviour of ice sheets and glaciers, involving complex and precise mass and energy transfers between the ice and its substrate of water, air, bedrock, or sediment, and the oceans at ice sheet boundaries. In particular, determining the distribution and nature of water flows at the ice-mass bed is highlighted as a priority for understanding and predicting ice dynamics. For example, both remote sensing and ground-based observations across Antarctica and Greenland highlight the existence of subglacial water in a variety of forms, ranging from vast subglacial lakes (providing distinctive habitats for potentially unique life forms) to mm-thick water flows at the ice-substrate interface. Feedbacks between increased surface melting, glacier bed conditions and ice flow also affect alpine glaciers, potentially contributing to increased glacial retreat in low and mid-latitude mountain regions.

It is clear that subglacial processes impact ice dynamics, transcending ice-mass scales from valley glaciers to large ice sheets and, through feedback loops, contribute to changes in sea level, ocean circulation, and climate evolution. Quantitative characterisation of the basal environment therefore remains an outstanding glaciological problem, as does scaling of this knowledge for use in modelling ice sheet and glacier behaviour.

We invite scientific contributions that include, but are not limited to, measurements and/or modelling of: (i) flow of subglacial water at the bed and through subglacial sediments; (ii) linkages between subglacial hydrology and ice dynamics; (iii) theoretical-, field-, or laboratory-based parameterisation of subglacial processes in numerical ice-flow models; (v) formation, geometry and potential hydrological linkages between subglacial lakes; (v) subglacial and supraglacial lake drainage and subglacial floods from ice margins; and (vi) geomorphological evidence of subglacial water flows from contemporary ice-sheet margins and across formerly glaciated continental-scale regions.

Ice shelves and tidewater glaciers are sensitive elements of the climate system. Sandwiched between atmosphere and ocean, they are vulnerable to changes in either. The recent disintegration of ice shelves such as Larsen B and Wilkins on the Antarctic Peninsula, current thinning of the ice shelves in the Amundsen Sea sector of West Antarctica, and the recent accelerations of many of Greenland's tidewater glaciers provide evidence of the rapidity with which those systems can respond. Changes in marine-terminating outlets appear to be intimately linked with acceleration and thinning of the ice sheets inland of the grounding line, with immediate consequences for global sea level. Studies of the dynamics and structure of the ice sheets' marine termini and their interactions with atmosphere and ocean are the key to improving our understanding of their response to climate forcing and of their buttressing role for ice streams. The main themes of this session are the dynamics of ice shelves and tidewater glaciers and their interaction with the ocean, atmosphere and the inland ice, including grounding line dynamics. The session includes studies on related processes such as calving, ice fracture, rifting and mass balance, as well as theoretical descriptions of mechanical and thermodynamic processes. We seek contributions both from numerical modelling of ice shelves and tidewater glaciers, including their oceanic and atmospheric environments, and from observational studies of those systems, including glaciological and oceanographic field measurements, as well as remote sensing and laboratory studies.

The increasing availability of remotely sensed observations and computational capacity, drive modelling and observational glacier studies towards increasingly large spatial scales. These large scales are of particular relevance, as they impact policy decisions and public discourse. In the European Alps, for instance, glacier changes are important from a touristic perspective, while in High Mountain Asia, glaciers are a key in the region’s hydrological cycle. At a global scale, glaciers are among the most important contributors to present-day sea level change.

This session focuses on advances in observing and modelling mountain glaciers and ice caps at the regional to global scale. We invite both observation- and modelling-based contributions that lead to a more complete understanding of glacier changes and dynamics at such scales.

Contributions may include, but are not limited to, the following topics:
• Observation and modelling results revealing previously unappreciated regional differences in glacier changes or in their dynamics;
• Large-scale impact studies, including glaciers' contribution to sea level change, or changes in water availability from glacierized regions;
• Advances in regional- to global-scale glacier models, e.g. inclusion of physical processes such as ice dynamics, debris-cover effects, glacier calving, or glacier surging;
• Regional to global scale process-studies, based on remote sensing observations or meta-analyses of ground-based data;
• Innovative combinations of observation and modelling techniques, for example blending different remote sensing products, or integrating machine learning algorithms;
• Inverse modelling of subglacial characteristics or glacier ice thickness at regional scales.

Note that this session is organized as a PICO.

Dynamic subglacial and supraglacial water networks play a key role in the flow and stability of ice sheets. The accumulation of meltwater on the surface of ice shelves has been hypothesized as a potential mechanism controlling ice-shelf stability, with ice-shelf collapse triggering substantial increases in discharge of grounded ice. Observations and modelling also suggest that complex hydrological networks occur at the base of glaciers and these systems play a prominent role in controlling the flow of grounded ice. This session tackles the urgent need to better understand the fundamental processes involved in glacial hydrology that need to be addressed in order to accurately predict future ice-sheet evolution and mass loss, and ultimately the contribution to sea-level rise .

We seek contributions from both the modelling and observational communities relating to any area of ice-sheet hydrology. This includes but is not limited to: surface hydrology, melt lake and river formation; meltwater processes within the ice and firn; basal hydrology; subglacial lakes; impacts of meltwater on ice-sheet stability and flow; incorporation of any of these processes into large-scale climate and ice-sheet models.

The evolution of the large ice sheets and the Earth’s rheology control the process of glacial isostatic adjustment, while bedrock topography and geothermal heat flux have strong feedbacks on ice sheet dynamics. For changing climates, this interplay exerts a fundamental control on the global and regional sea level and, in turn, influences ice sheet stability.

In this session, we focus on feedback mechanisms between climate relevant components, such as ice sheets, ice shelves, solid Earth, oceans and atmosphere (e.g., as in the German Climate modelling initiative PalMod). We invite global, regional and conceptual studies that consider reconstructions of the past and/or estimates of future ice sheet evolution in fields related to the climate system dynamics of glacial processes (the cryosphere, geosphere, oceanography, climatology, geodesy and geomorphology). In particular, we welcome studies of recent and paleo observations (geodetic, geological, geophysical), coupled numerical modelling and strategies, data-constrained model calibration and data assimilation.

Growth and decay of ice sheets and glaciers reshape the solid Earth via isostasy and erosion. In turn, the shape of the bed exerts a fundamental control on ice dynamics as well as the position of the grounding line—the location where ice starts to float. Additionally, this behaviour is affected by large spatial variations in rheological properties of the Earth's subsurface. These properties govern the timescale and strength of feedbacks between ice-sheet change and solid Earth deformation, and hence must be accounted for, e.g., when considering the future evolution of the Polar Ice Sheets. This session invites contributions discussing geodetic, geological and geophysical observations (such as deformation fields and past sea-level indicators), analyses, and modelling of the coupling of the Solid Earth and glacial isostatic adjustment (GIA) and/or addressing the Earth properties from seismological, gravity, magnetic and heat-flow studies. We welcome contributions related to both polar regions and previously glaciated areas. We also welcome contributions highlighting the effect of GIA on tectonical processes and petroleum reservoirs, and the GIA contribution in natural hazard assessments.

Invited Speaker: Harriet Lau, University of California, Berkeley, USA

Sea ice and snow are key elements of the central Arctic system, and are tightly coupled to changes in the atmosphere and ocean. Today’s sea ice is thinner, younger, and drifts faster than the historical multi-year ice pack. However, modern climate models are still limited in their ability to reproduce the rapid changes this system is undergoing. Progress has been limited by observations of the processes governing the annual evolution.

The MOSAiC campaign 2019-2020 targeted improving understanding of this system with a year-long drifting platform across the central Arctic Ocean, as well as intensive remote sensing and modeling studies. This campaign provided the opportunity to monitor changes in various aspects of the ice and snow cover through the entire annual evolution. This session aims to begin synthesizing data from MOSAiC to better understand processes governing the evolution of snow and sea ice in the Arctic Ocean. We welcome studies using observations from the field campaign, remote sensing, and modeling, and especially that examine the interactions of changes in the sea ice and snow system with atmosphere, ocean, ecological and biogeochemical systems.

Recent years have seen significant reductions in Arctic sea ice extent, and a redistribution of sea ice in the Antarctic. Climate projections suggest a reduction of the sea ice cover in both poles, with the Arctic becoming seasonally ice free in the latter half of this century.

The scientific community is investing considerable effort in organising our current knowledge of the physical and biogeochemical properties of sea ice, exploring poorly understood sea ice processes, and forecasting future changes of the sea ice cover.

In this session, we invite contributions regarding all aspects of sea ice science and sea ice-climate interactions, including snow and sea ice thermodynamics and dynamics, sea ice-atmosphere and sea ice-ocean interactions, sea ice biological and chemical processes, and sea ice models. A focus on emerging processes and implications is particularly welcome.

In recent years the interaction between the ocean and the cryosphere in the Southern Ocean has become a major focus in climate research. Antarctic climate change has captured public attention, which has spawned a number of research questions, such as: Is Antarctic sea ice becoming more vulnerable in a changing climate? What controls the inflow of warm water into ice shelf cavities and what is the impact of enhanced meltwater outflow? What role do ice processes play in nutrient upwelling on the shelf? Recent advances in observational technology, data coverage, and modeling provide scientists with a better understanding of the mechanisms involving ice-ocean interactions in the far South. Processes on the Antarctic continental shelf have been identified as missing links between the cryosphere, the global atmosphere and the deep open ocean that need to be captured in large-scale and global model simulations.

This session calls for studies on physical and biogeochemical interactions between ice shelves, sea ice and the ocean. The ice-covered Southern Ocean and its role in the greater Antarctic climate system are of major interest. This includes work on all scales, from local to basin-scale to circumpolar. Studies based on in-situ observations and remote sensing as well as regional to global models are welcome. We particularly invite cross-disciplinary topics involving physical and biological oceanography, glaciology or biogeochemistry.

The rapid decline of the Arctic sea ice in the last decade is a dramatic indicator of climate change. The Arctic sea ice cover is now thinner, weaker and drifts faster. Freak heatwaves are common. On land, the permafrost is dramatically thawing, glaciers are disappearing, and forest fires are raging. The ocean is also changing: the volume of freshwater stored in the Arctic has increased as have the inputs of coastal runoff from Siberia and Greenland and the exchanges with the Atlantic and Pacific Oceans. As the global surface temperature rises, the Arctic Ocean is speculated to become seasonally ice-free by the mid 21st century, which prompts us to revisit our perceptions of the Arctic system as a whole. What could the Arctic Ocean look like in the future? How are the present changes in the Arctic going to affect and be affected by the lower latitudes? What aspects of the changing Arctic should observational, remote sensing and modelling programmes address in priority?
In this session, we invite contributions from a variety of studies on the recent past, present and future Arctic. We encourage submissions examining interactions between the ocean, atmosphere and sea ice, on emerging mechanisms and feedbacks in the Arctic and on how the Arctic influences the global ocean. Submissions with a focus on emerging cryospheric, oceanic and biogeochemical processes and their implications are particularly welcome.
The session promotes results from current Arctic programmes and discussions on future plans for Arctic Ocean modelling and measurement strategies, and encourages submissions on the first results from CMIP6 and the recently completed Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC). This session is cosponsored by the CLIVAR /CliC Northern Ocean Regional Panel (NORP) that aims to facilitate progress and identify scientific opportunities in (sub)Arctic ocean-sea-ice-atmosphere research.

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

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

This session is 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.

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.

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.

Deformation microstructures (e.g. fabrics, textures, grain sizes, shapes, cracks etc) give insight into the conditions and processes of brittle failure and ductile flow of geomaterials. Microstructures and textures are a key tool in unraveling deformation histories and processes, kinematics and conditions in deformed rocks or ice. Processes such as grain-size reduction, phase changes, and development of crystallographic preferred orientations modify the rheological, elastic, and thermal properties of these rocks, providing key information on the evolution and dynamics of the litho- and cryosphere. In this session, we invite contributions based on microstructure and texture analysis from field observations, laboratory experiments, and numerical modelling that aim to constrain deformation mechanisms, physical and mechanical properties of geomaterials using well established or novel techniques.

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.

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 Permafrost Open Session is intended as a forum for current research on permafrost and permafrost-dominated landscapes. It addresses (1) novel observations of permafrost-related phenomena; (2) the impact of permafrost changes on the natural and human environment; (3) advances and new developments in the measurement, modeling, parameterization, and understanding of periglacial processes. It will bring together investigations of high-latitude, mountain, and planetary permafrost.

We seek contributions that reflect diverse scientific fields, approaches, and geographic locations. With its broad focus, this session is designed to complement related but more specialized sessions. We particularly encourage contributions that (a) present novel measurement and monitoring approaches; (b) outline new strategies to improve process understanding; (c) come from or interface with neighboring fields of science or apply innovative technologies and methods; (d) investigate model validation, model uncertainty, and scaling issues; (e) couple models of diverse processes or scales.

The multifaceted influence of rocky debris on glacier systems has been increasingly recognized as having an important influence on long-term glacier and landscape evolution. The focus of this session is to exchange and discuss the latest understanding of the dynamics of debris within glacier systems, and the role of debris-covered glaciers in landscape evolution. We solicit contributions from all career stages pertaining to the debris-covered glacier system and its interaction with the atmosphere and climate, ice melt patterns and runoff, and ice dynamics and landscape evolution. We seek a broad range of topics related to debris supply (e.g. headwall erosion and avalanching), transport (englacial and supraglacial), and export from glaciers within the broader context of the mountain land system. We additionally welcome contributions examining debris cover development, how glacier processes are influenced by debris, and how debris-covered glaciers interact with the wider land system, for example in terms of geohazards, erosion, sediment transport and deposition, debris-covered glacier/rock glacier interactions, water resource management, and paraglacial change within alpine settings.

We would be excited to include the full range of methods, established and novel, used to investigate these systems, including remote sensing, numerical modelling, field observations and more! We also welcome contributions related to the standardisation of methodologies with the aim of coordinating efforts and advancing the current understanding of debris covered glacier land systems. The session is closely aligned with the goals of the International Association of Cryospheric Sciences (IACS) and International Permafrost Association (IPA) working group on Debris Covered Glaciers https://cryosphericsciences.org/activities/wgdebris/, which is open to membership and new contributions to anyone.

Wide-spread permafrost thaw is expected to amplify the release of previously frozen material from terrestrial into aquatic systems: rivers, lakes, groundwater and oceans. Current projections include changes in precipitation patterns, active layer drainage and leaching, increased thermokarst lake formation, as well as increased coastal and river bank erosion that are further enhanced by rising water temperatures, river discharge and wave action. In addition, subsea permafrost that formed under terrestrial conditions but was later inundated might be rapidly thawing on Arctic Ocean shelves. These processes are expected to substantially alter the biogeochemical cycling of carbon but also of other elements in the permafrost area.

This session invites contributions on the mobilization of terrestrial matter to aquatic systems in the permafrost domain, as well as its transport, degradation and potential interaction with autochthonous, aquatic matter. We encourage submissions focusing on organic and inorganic carbon as well as on other elements such as nitrogen, phosphorus, silica, iron, mercury and others, from all parts of the global permafrost area including mountain, inland, coastal and subsea permafrost, on all spatial scales, in the contemporary system but also in the past and future, based on field, laboratory and modelling work.

Throughout Earth’s history, there have been few periods, when the climate was sufficiently cold to sustain large volumes of ice to cover the planet’s surface. Glaciers and ice-sheets in polar and mountain regions repeatedly grew during the Quaternary, advancing far into mid-latitudes and adjacent lowlands, respectively. Traces of this glacial activity can be manifested in characteristic deposits, e.g. vast till-covered and outwash plains, and landforms such as moraines and drumlins. At glacial-interglacial timescales, multiple glacial advances tend to overprint landforms and create fragmented terrestrial sedimentary successions. There are inherent challenges to understand the records, e.g. how glacial activity varies and affects landscapes over multiple glacial-interglacial cycles. How did landscapes evolve under glacial influence? What is the impact of early glaciations? How well were different glaciations chronicled? How did climate patterns and gradients affect glaciation? These questions will be addressed in this session.

The abundance of proxy data on timing, extent, and driving mechanisms of the last glacial cycle has significantly improved the understanding of the last c. 100 ka of landscape evolution. However, landscape evolution and trends in topographic preconditioning remain poorly constrained for previous cycles.
Glacial sedimentary records can be investigated through various methods to overcome some of the limitations imposed by the records’ fragmentation. Firstly, discovering and retrieving persistent glacial deposits, for example contained in subglacially formed basins (overdeepened basins, tunnel valleys), extend the accessible sedimentary record. Secondly, modern and ancient analogues help to understand erosion and deposition mechanisms in a glacial environment. Thirdly, relative and absolute chronostratigraphy allow the development of a temporal framework, and reconstructing landscape and environment evolution.

This session aims to stimulate discussions concerning terrestrial glacial records. Contributions may include investigations based on field observations, scientific drilling, geophysical measurements, and/or modelling of modern, Quaternary, and pre-Quaternary glacial settings. Possible topics cover: (a) glacial and interglacial stratigraphic successions, (b) subglacial erosion and deposition, (c) glaciation chronology, and (d) landscape evolution.

Present-day glacial and periglacial processes in cold regions, i.e. arctic and alpine environments, provide also modern analogues to processes and climatic changes that took place during the Pleistocene, including gradual retreat or collapse of ice sheets and mountain glaciers, and thawing and shrinking of low-land permafrost. Current geomorphological and glaciological changes in mid-latitude mountain ranges could also serve as a proxy for future changes in high-latitude regions within a context of climate change. Examples are speed-up or disintegration of creeping permafrost features or the relictification of rock glaciers.

For our session we invite contributions that either:
1. investigate present-day glacial and/or periglacial landforms, sediments and processes to describe the current state, to reconstruct past environmental conditions and to predict future scenarios in cold regions; or
2. have a Quaternary focus and aim at enhancing our understanding of past glacial, periglacial and paraglacial processes, also through the application of dating techniques.

Case studies that use a multi-disciplinary approach (e.g. field, laboratory and modelling techniques) and/or that highlight the interaction between the glacial, periglacial and paraglacial cryospheric components in cold regions are particularly welcome.

Mountain and ice sheet glaciations provide an invaluable record for past and present climate change. However, varying geomorphological process-systems, specific glaciological conditions and topography can make regional, intra-hemispheric and global correlations challenging. This problem is further enhanced by ongoing specialisation within the scientific community. Despite such challenges glacier and ice sheet reconstructions remains a crucial palaeo-enviormental proxy.

The primary aim of this session is to evaluate the potential of mountain and ice sheets glaciation records and stimulate further research in this important field of research. Contributions on all relevant aspects are welcomed, for example: (a) glacial landforms and reconstruction of past glaciers/ice sheets, (b) dating techniques and geochronology compilations, (c) glacier dynamics and palaeoclimatic interpretations, or (d) impacts of ecosystems and human evolution/society.

We would in particular like to invite contributions highlighting the specific conditions of mountain glaciations/ice sheet or addressing the relationship and connections between different of their aspects. To address the diversity of glaciations, contributions from high-, middle-, and low-latitude mountain ranges as well as from continental to maritime regions are all welcomed. The time scale of the session will range from Early Pleistocene glaciations to the LGM and Holocene/modern glaciers.

This session has steadily become more popular and attracted contributions from a wide range of research topics and study areas, both with a high diversity of methodological approaches. It has become a platform for everyone interested in the emerging collaborative research network “The Legacy of Mountain Glaciations” and given an opportunity to meet and exchange ideas and expertise.

The polar climate system is strongly affected by interactions between the atmosphere and the cryosphere. Processes that exchange heat, moisture and momentum between land ice, sea ice and the atmosphere, such as katabatic winds, blowing snow, ice melt, polynya formation and sea ice transport, play an important role in local-to-global processes. Atmosphere-ice interactions are also triggered by synoptic weather phenomena such as cold air outbreaks, polar lows, atmospheric rivers, Foehn winds and heatwaves. However, our understanding of these processes is still incomplete.

This session aims at showcasing recent research progress and augmenting existing knowledge in polar meteorology and climate and the atmosphere-land ice-sea ice coupling in both the Northern and Southern Hemispheres. It will provide a setting to foster discussion and help identify gaps, tools, and studies that can be designed to address these open questions. It is also the opportunity to convey newly acquired knowledge to the community.
We invite contributions on all observational and numerical modelling aspects of Arctic and Antarctic meteorology and climatology, that address atmospheric interactions with the cryosphere. This may include but is not limited to studies on past, present and future of:
- Atmospheric processes that influence sea-ice (snow on sea ice, sea ice melt, polynya formation and sea ice production and transport) and associated feedbacks,
- The variability of the polar large-scale atmospheric circulation (such as polar jets, the circumpolar trough and storm tracks) and impact on the cryosphere (sea ice and land ice),
- Atmosphere-ice interactions triggered by synoptic and meso-scale weather phenomena such as cold air outbreaks, katabatic winds, extratropical cyclones, polar cyclones, atmospheric rivers, Foehn winds and heatwaves,
- Role of clouds in polar climate and impact on the land ice and sea ice through interactions with radiation,
- Teleconnections and climate indices and their role in land ice/sea ice variability.
Presentations including new observational (ground and satellite-based) and modelling methodologies specific to polar regions are encouraged. Contributions related to results from recent field campaigns in the Arctic and in the Southern Ocean/Antarctica are also welcomed.

THIS SESSION IS A MERGE OF 2 SESSIONS. PLEASE CHECK PUBLIC INFORMATION FOR MORE INFORMATION.
BELOW YOU FIND BOTH SESSION DESCRIPTIONS
Coupled modelling in the polar regions
In recent decades, the climate in the polar regions has undergone dramatic changes. Quantifying the individual contributions of Earth system components (cryosphere, ocean, atmosphere, and land) to the observed changes is challenging due to feedback between the components. Examples include (but are not limited to) ice shelf – ocean interactions (through basal melting and cavity geometry evolution) and elevation feedback (through surface mass balance). Hence, studies based on individual components of the Earth System have limited capacity to represent all relevant processes. This session aims to provide a platform for sharing coupled modelling experiences incorporating the cryosphere in the polar regions.
=====
Facilitating remote sensing applications across the terrestrial Arctic
We solicit both technical and scientific contributions from modelling studies in which feedback and emergent properties between the cryosphere and other Earth System components in polar regions are investigated, better understood, and possibly even quantified. In addition to application of coupled modelling to real world domains, contributions are also invited from idealised studies and intercomparisons, such as the Marine Ice Sheet – Ocean Intercomparison Project (MISOMIP).
Environmental changes in terrestrial ecosystems and coastal areas across the Arctic can only be fully addressed by using remote sensing observations and modelling. However, due to the multiscale complexity of the landscape, to limitations related to illumination and atmospheric conditions, bridging the gap between field and satellite observations remains a major challenge. Contributions may include recent advances in instrumentation and methodology for validation and calibration of remote sensing products, applications of joint use of in situ and satellite records to tackle science questions, demonstrate the utility of UAV for bridging the scale gap, progress for standardization (protocols) or reviewing challenges.
We specifically welcome contributions within the framework of T-MOSAiC aiming to coordinate activities that will both aid and benefit from MOSAiC (especially the modelling components) by extending the work to the lands surrounding the Arctic Ocean and to the northern communities.
=====

By accumulating precipitation at high elevations, snow and ice change the hydrologic response of a watershed. Water stored in the snow pack and in glaciers thus represents an important component of the hydrological budget in many regions of the world and a sustainment to life during dry seasons. Predicted impacts of climate change in headwater catchments (including a shift from snow to rain, earlier snowmelt and a decrease in peak snow accumulation) will affect both water resources distribution and water uses at multiple scales, with potential implications for energy and food production.
Our knowledge about snow/ice accumulation and melt patterns is highly uncertain, because of both limited availability and inherently large spatial variability of hydrological and weather data in remote areas at high elevations. This translates into limited process understanding, especially in a warming climate. The objective of this session is to integrate specialists focusing on snow accumulation and melt within the context of catchment hydrology and snow as a source for glacier ice and melt, hence streamflow. The aim is to integrate and share knowledge and experiences about experimental research, remote sensing and modelling.
Contributions addressing the following topics are welcome:
- experimental research on snowmelt runoff processes and potential implementation in hydrological models;
- development of novel strategies for snowmelt runoff modelling in various (or changing) climatic and land-cover conditions;
- evaluation of remote-sensing (time-lapse imagery, laser scanners, radar, optical photography, thermal and hyperspectral technologies) or in-situ snow products (albedo, snow cover or depth, snow water equivalent) and application for snowmelt runoff calibration, data assimilation, streamflow forecasting or snow and ice physical properties quantification;
- observational and modelling studies that shed new light on hydrological processes in glacier-covered catchments, e.g., impacts of glacier retreat on water resources and water storage dynamic or the application of techniques for tracing water flow paths;
- studies on cryosphere-influenced mountain hydrology, such as landforms at high elevation and their relationship with streamflow, water balance of snow/ice-dominated, mountain regions.

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.

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

To address societal concerns over rising sea level and extreme events, understanding the contributions behind these changes is key to predict potential impacts of sea level change on coastal communities and global economy, and is recognized as one of the Grand Challenges of our time by the World Climate Research Programme (WCRP). To continue this discussion, we welcome contributions from the international sea level community that improve our knowledge of the past and present changes in sea level, extreme events, and flooding, and produce improved predictions of their future changes. We welcome studies on various drivers of sea level change and linkages between variability in sea level, heat and freshwater content, ocean dynamics, land subsidence from natural versus anthropogenic influences, and mass exchange between the land and the ocean associated with ice sheet and glacier mass loss and changes in the terrestrial water storage. Studies focusing on future sea level changes are also encouraged, as well as those discussing potential short-, medium-, and long-term impacts on coastal and deltaic environments, as well as the global oceans.

The Arctic Realm is changing rapidly and the fate of the cryosphere, including Arctic sea ice, glaciers and ice caps, is a source of concern. Whereas sea ice variations impact the radiative energy budget, thus playing a role in Arctic amplification, the Greenland Ice Sheet retreat contributes to global sea level rise. Moreover, through various processes linking the atmosphere, ice and ocean, the change in the Arctic realm may modify the atmospheric and ocean circulation at regional to global scales, the freshwater budget of the ocean and deep-water formation as well as the marine and terrestrial ecosystems, including productivity. The processes and feedbacks involved operate on all time scales and it require a range of types of information to understand the processes, drivers and feedbacks involved in Arctic changes, as well as the land-ocean-cryosphere interaction. In this session, we invite contributions from a range of disciplines and across time scales, including observational (satellite and instrumental) data, historical data, geological archives and proxy data, model simulations and forecasts, for the past, present and future climate. The common denominator of these studies will be their focus on a better understanding of mechanisms and feedbacks on short to long time scales that drive Arctic and subarctic changes and their impact on climate, ocean and environmental conditions, at regional to global scales, including possible links to weather and climate outside the Arctic.

The Arctic sea ice and high latitude atmosphere and oceans have experienced significant changes over the modern observational era. The polar climate is crucial for the Earth’s energy and water budget, and its variability and change have direct socio-economic and ecological impacts. Thus, understanding high-latitude variability and improving predictions of high latitude climate is highly important for society. Long-term variability in ocean and sea ice are the largest sources for predictability in high latitudes. Dynamical model predictions are not yet in the position to provide us with highly accurate predictions of the polar climate. Main reasons for this are the lack of observations in high latitudes, insufficient initialization methods and shortcomings of climate models in representing some of the important climate processes in high latitudes.

This session aims for a better understanding and better representation of the mechanisms that control high latitude variability and predictability of climate in both hemispheres from sub-seasonal to multi-decadal time-scales in past, recent and future climates. Further, the session aims to discuss ongoing efforts to improve climate predictions at high latitudes at various time scales (as e.g. usage of additional observations for initialization, improved initialization methods, impact of higher resolution, improved parameterizations, novel verification approaches) and potential teleconnections of high latitude climate with lower latitude climate. We also aim to link polar climate variability and predictions to potential ecological and socio-economic impacts and encourage submissions on this topic.

The session offers the possibility to present results from ongoing projects and research efforts on the topic of high-latitude climate variability and prediction, including, but not limited to, the WMO Year of Polar Prediction (YOPP), NordForsk-project ARCPATH, MOSAiC, and the H2020-projects APPLICATE, INTAROS, BlueAction, and KEPLER.

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.

In 2015, the UN Sustainable Development Goals and the Paris Agreement on climate recognised the deteriorating resilience of the Earth system, with planetary-scale human impacts constituting a new geological epoch: the Anthropocene. Earth system resilience critically depends on the nonlinear interplay of positive and negative feedbacks of biophysical and increasingly also socio-economic processes. These include dynamics in the carbon cycle, large-scale ecosystems, atmosphere, ocean, and cryosphere that can absorb geophysical shocks (e.g. volcanic eruptions), as well as the dynamics and perturbations associated with human activities.

Maintaining Earth in the Holocene-like interglacial state within which the world’s societies evolved over the past ~10,000 years will require industrialised societies to embark on rapid global-scale socio-economic transformations. In addition to incrementally increasing environmental hazards, there is a risk of crossing tipping points in the Earth system triggering partly irreversible and potentially cascading changes.

In this session we invite contributions on all topics relating to Earth resilience, such as assessing the biophysical and social determinants of the Earth’s long-term stability, negative feedback processes, modelling and data analysis and integration of nonlinearity, tipping points and abrupt shifts in the Earth system, and the potential for rapid social transformations to global sustainability.

This session is intended to provide an interdisciplinary forum to bring together researchers working in the areas of high-latitude meteorology, atmospheric chemistry, stable isotope research, oceanography, and climate. The emphasis is on the role of boundary layer processes that mediate exchange of heat, momentum and mass between the Earth's surface (snow, sea-ice, ocean and land) and the atmosphere as well as the local to large-scale influences on these exchanges. An adequate understanding and quantification of these processes is necessary to improve modeling and prediction of future changes in the polar regions and their teleconnections with mid-latitude weather and climate, including meridional transport of heat, moisture, chemical trace species, aerosols and isotopic tracers (indicating airmass origins and atmospheric processes); and regional emission and vertical mixing of climate active trace gases and aerosol, such as cloud-forming particles (CCN/INP) and their precursors. It is expected that the recent implementation of new measurements such as those from pan-Arctic water vapor isotope networks, observations such as those obtained during the MOSAiC field program, and data from existing networks will help diagnose long-range moisture and aerosol sources and the coupling between local and large-scale dynamics. We encourage submissions such as (but not limited to):
(1) External controls on the boundary layer such as clouds, radiation and long-range transport processes
(2) Results from field programs, such as MOSAiC, and routine observatories, insights from laboratory studies, and advances in modeling and reanalysis,
(3) Use of data from pan-Arctic and Antarctic observing networks,
(4) Surface processes involving snow, sea-ice, ocean, land/atmosphere chemical and isotope exchanges, and natural aerosol sources
(5) The role of boundary layers in polar climate change and implications of climate change for surface exchange processes, especially in the context of reduced sea ice, wetter snowpacks, increased glacial discharge and physical and chemical changes associated with an increasing fraction of first year ice and increasing open water.

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

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

- Drivers of cloud/precipitation microphysics at high latitudes,
- Sources of cloud nuclei both at local and long range,
- Linkages of polar clouds/precipitation to the moisture sources and transport,

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

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

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

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

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


The climate system as a whole can be viewed as a highly complex thermal/heat engine, in which numerous processes continuously interact to transform heat into work and vice-versa. As any physical system, the climate system obeys the basic laws of thermodynamics, and we may therefore expect the tools of non-equilibrium thermodynamics to be particularly useful in describing and synthesising its properties. The main aim of this short course will be twofold. Part 1 will provide an advanced introduction to the fundamentals of equilibrium and non-equilibrium thermodynamics, irreversible processes and energetics of multicomponent stratified fluids. Part 2 will illustrate the usefulness of this viewpoint to summarize the main features of the climate system in terms of thermodynamic cycles, as well as a diagnostic tool to constrain the behavior of climate models. Although the aim is for this to be a self-contained module, some basic knowledge of the subject would be beneficial to the participants. Registration is not needed, but indication of interest would be helpful for planning purposes.

Age models are applied in paleoclimatological, paleogeographic and geomorphologic studies to understand the timing of climatic and environmental change. Multiple independent geochronological dating methods are available to generate robust age models. For example, different kinds of radio isotopic dating, magneto-, bio-, cyclostratigraphy and sedimentological relationships along stratigraphic successions or in different landscape contexts. The integration of these different kinds of geochronological information often poses challenges.
Age-depth or chronological landscape models are the ultimate result of the integration of different geochronological techniques and range from linear interpolation to more complex Bayesian techniques. Invited speakers, Sebastian Breitenbach from CL division and Rachel Smedley from the GM division, will share their experience in several modelling concepts and their application in a range of Quaternary paleoenvironmental and geomorphologic records. The Short Course will provide an overview of age models and the problems one encounters in climate science and geomorphology. Case studies and practical examples are given to present solutions for these challenges. It will prepare the participants from CL, GM and other divisions for independent application of suitable age-depth models to their climate or geomorphologic data. For registration please send a request via this email address (ecs-cl@egu.eu) prior to 15th April.

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)

Remote sensing data from Earth orbiting satellites have become indispensable in modern geo-spatial sciences. The technologies underlying the capture of remote sensing data have evolved over the decades which have resulted in an improvement in the data quality, rate of availability and processing.
The workshop will cover tasks such as generating Land Surface Temperature (LST) product from satellite imagery from scratch, extraction of information from ready-made products and raster algebra. Participants will go through a workflow that will present itself as a solution to a real life problem. The main Python libraries or frameworks to be used are rasterio, earthpy, pandas, matplotlib and geopandas. The data to be used will be Landsat 8 satellite imagery.
The first part of the workflow focuses on the extraction of intermediate products that are useful for the calculation of LST from satellite imagery. These products are Normalized Difference Vegetation Index (NDVI), Land Surface Emissivity (LSE) and Fractional Vegetation Cover (FVC). These products are not only useful for calculation of LST but are applicable in other remote sensing applications such as vegetation health monitoring and land cover classification. This section will also equip participants with raster algebra skills using Python.
The second part will cover the pre-processing activity of correcting Landsat 8 thermal bands for the extraction of LST and ultimately generate the LST. The participants will learn how to perform other mathematical operations on raster data using Python.
Finally, LST values at certain desired locations will be extracted. This will equip participants with skills on how to extract information stored as raster files to point features using geospatial Python libraries. In all sections of the workshop, intermediate results will be visualized within the Jupyter Notebook to give participants a hands-on feel of visualization with Python.
It is expected that at the end of a successful completion of the workshop, participants will be able to generate LST from scratch using Landsat 8 imagery and by extension all Landsat imagery with thermal bands. Also, participants should be able to derive other useful products like NDVI from any remote sensing image using the appropriate data and finally acquire raster processing skills useful in other applications.

Satellite based climate data records play an increasing role in climate monitoring and help to answer climate related questions. Nowadays satellite based climate data records cover a time period of several decades. EUMETSAT and it’s Satellite Application Facilities (SAF) provide a number of high quality climate data records for various geophysical variables, such as solar radiation, land surface temperature, cloud fractional cover, soil moisture, and many more, derived from both, geostationary and polar orbiting satellites.

These climate data records are free and open to everyone. They continue to be reprocessed to account for improvements of the algorithm and to include recent time periods. In addition to the data, free software tools, such as the CM SAF R Toolbox, are developed and provided by the SAF’s for users to work with the data.

This short course is an opportunity to get an overview about the climate data records available from the EUMETSAT Satellite Application Facilities, learn how to access them and gain some first experiences in how to work with the software tools provided.

World-wide an increasing number of research projects focus on the challenges associated with changes in the Arctic regions. Whereas these often have a natural and physical science focus, this session focuses on trans-disciplinary approaches to study the multiple phenomena associated with global warming, especially but not exclusively in Arctic regions. Another focus is to understand better how to tackle these in large, trans-disciplinary research projects, initiatives and programs (e.g. HORIZON2020 Nunataryuk, INTAROS and the T-MOSAIC program of the International Arctic Research Council, NSF Navigating the New Arctic), as well as communicating results effectively to the public in terms of outreach and education. Contributions are invited, but are not limited, to the following themes:
• science communication, education and outreach tools, and co-production of knowledge
• integration of social and natural science approaches
• indigenous and collaborative approaches to adaptation and mitigation, equitable mitigation, and risk perception
• socio-economic modelling in relation to Arctic environmental change,
• examining the impacts of permafrost thaw and other phenomena on health and pollution as well as infrastructure (and consequences of the built environment).

One of the aims of this session is to bring together researchers from both social and natural sciences who are involved or interested in reaching out to stakeholders and the general public, and share successful experiences. Examples from past, ongoing and future initiatives that include traditional indigenous knowledge and scientific tools and techniques are welcome.

We are also excited to let you know that our ERL special issue called 'Focus on Arctic Change: Transdisciplinary Research and Communication’ is now open for submission. See the webpage: https://iopscience.iop.org/journal/1748-9326/page/Focus_on_Arctic_Change_Transdisciplinary_Research_and_Communication Please consider submitting your manuscript until or preferably before the 31st of May 2021.