This open session invites contributions in the field of ocean and land
climates, which do not fit into the specialized sessions. It will
welcome presentations of modelling studies as well as
(paleo)-observations. Here, papers will be collected from those
sessions, which attracted a too small amount of contributions and did
not fit into other specialized sessions both on climatology and
paleoclimatology. However this is a session by itself and you must feel
free to submit directly your paper to the Open session. This guarantees
all authors an appropriate representation.
Opportunities of publishing your contribution is proposed in the on-line
and open access EGU journal "Climate of the Past"
www.climate-of-the-past.net

Join us to help put some of the world's most vulnerable places on the map. A mapathon is a mapping marathon, where we get together to contribute to OpenStreetMap - the world's free map.
No experience is necessary - just bring your laptop and we will provide the training. Learn more about crowdsourcing, open data and humanitarian response - we will also provide some tips for how to host a mapathon at your home institution.

Processes responsible for formation and development of the early Earth (> 2500Ma) are not
well understood and strongly debated, reflecting in part the poorly preserved, altered, and
incomplete nature of the geological record from this time.
In this session we encourage the presentation of new approaches and models for the development of Earth's early crust and mantle and their methods of interaction. We encourage contributions from the study of the preserved rock archive as well as geodynamic models of crustal and mantle dynamics so as to better understand the genesis and evolution of continental crust and the stabilization of cratons.
We invite abstracts from a large range of disciplines including geodynamics, geology, geochemistry, and petrology but also studies of early atmosphere, biosphere and early life relevant to this period of Earth history.

This session aims to showcase an interesting diversity of state-of-art advances in all aspects of Cambrian to Cretaceous paleoceanography, paleoclimatology and stratigraphy. Within this broad topic we intend to invite an exciting range of contributions including, but not limited to, organic and inorganic geochemistry, sedimentology, (micro-)paleontology, and modelling. Inter- or multidisciplinary studies are also encouraged. The session will potentially be organized into thematic blocks to allow more in-depth exploration and discussion of topics.

The geological record provides insight into how climate processes may operate and evolve in a high CO2 environment and the nature of the climate system during a turnover from icehouse to greenhouse state — a transition that may potentially occur in the near future. In recent years we have seen major advances in many geochemical techniques and an increase in the complexity of Earth System Models. The aim of this session is to share progress in our understanding of global changes occurring during the pre-Quaternary based on the integration of geochemical/paleobotanical/sedimentological techniques and numerical models. Specifically, we encourage submissions describing research in which both model and data approaches are embedded. We invite abstracts that reconstruct Earth’s climate from the Cambrian to the Pliocene, investigate how the interconnections of the key surface reservoirs (vegetation-ocean-atmosphere-cryosphere-biogeochemistry) impact climate, and identify tipping points and thresholds. Pertinent themes may include greenhouse-icehouse transitions and intervals testifying for extreme changes.

The pacing of the global climate system by orbital variations is clearly demonstrated in the timing of e.g. glacial-interglacial cycles. The mechanisms that translate this forcing into geoarchives and climate changes continue to be debated. We invite submissions that explore the climate system response to orbital forcing, and that test the stability of these relationships under different climate regimes or across evolving climate states (e.g. mid Pleistocene transition, Pliocene-Pleistocene transition, Miocene vs Pliocene, and also older climate transitions). Submissions exploring proxy data and/or modelling work are welcomed, as this session aims to bring together proxy-based, theoretical and/or modelling studies focused on global and regional climate responses to astronomical forcing at different time scales in the Phanerozoic.
Anna-Joy Drury will give an invited presentation about 'Fingerprinting the climate heartbeat of the late Miocene'.

The mid-Pleistocene Transition (MPT) is a crucial changes in climate dynamics, leading us into our current regime of long, asymmetric glacial cycles. However, evidence about the differences in how climate behaved before and after the MPT remains sparse and we also lack evidence to decide between theories that aim to explain the MPT. Here we hope to gather new datasets that compare climate on either side of the MPT or that offer new evidence about glacial cycles before it. Modelling and conceptual work about the causes of the MPT are also wlecome. Finally we would like to hear about work that paves the way for new projects, including plans and methodologies to obtain pre-MPT ice cores such as (but not limited to) the IPICS Oldest Ice challenge, like Beyond EPICA and other endeavours.

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 and radiochemistry in ice, among many others. Many climate and geochemical proxies have been identified from ice cores, with ongoing effort to extend their application and refine their interpretation. Great challenges remain in the field of ice coring sciences, including the identification of suitable sites for recovery of million-year-old ice; spatial integration of climate records (e.g. PAGES groups Antarctica2k and Iso2k); and deeper understanding of glaciological phenomena such as streaming flow, folding of layers and basal ice properties. 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.

Global ocean circulation plays a key role in redistributing heat and in setting the oceanic carbon gradients, and thus modulates global climate on centennial to millennial time scales. With the emergence of new methods, greater spatial and temporal paleo-record coverage, and model simulations with numerous tracers, significant improvement has been made in the understanding of past oceanic changes and their impacts on global climate and the carbon cycle. New proxy approaches and increasing geographical coverage fill important gaps in the reconstruction of different ocean states and decrease uncertainty that arises from interpretations based on individual parameters and sites. Similarly, refined model approaches and increased computing capacity allow for the integration of important small- and intermediate scale processes as well as the direct inclusion of proxies in numerical models.

This session welcomes contributions on the role of the ocean circulation in Pleistocene climate and glacial-interglacial climate transitions. This comprises proxy and model assessments of ocean heat and carbon content, circulation strength and other climatic and biogeochemical parameters, including details on their regional variation, given they are relevant for understanding global processes. Furthermore, we encourage contributions of reconstructions that seem contradictory to the prevailing view insofar as their discussion may hint towards processes or pitfalls that are under appreciated and thus potentially important for future research.

The millennial-scale variability associated with Dansgaard-Oeschger (D-O) cycles during the last glacial is known to have affected the climate system on a global scale. New high-resolution sediment and ice core proxy records document in increasing detail local and global variability of ice sheets, sea ice, as well as oceanic and atmospheric circulation during the D-O cycles. In addition, insights into the dynamics of the coupled ocean-cryosphere-atmosphere system during the millennial-scale climate cycles are emerging from improved model simulations. Documenting the precise timing and sequence of events in proxy records and capturing the processes responsible for the global pattern of rapid climate changes, which stretch from Greenland to Antarctica, remains a major challenge. However, understanding the underlying dynamics will provide fundamental information on the stability of the global climate system. In this interdisciplinary session, we welcome proxy- and model-based research that tests hypotheses on causes and processes behind the D-O events and helps understanding past, present and future changes to the climate system. The session is hosted by the ERC synergy project ice2ice.

Solicited talks include:
Oeschger medal lecture by Edward Brook, Oregon State University
Marlene Klockmann, Helmholtz-Zentrum Geesthacht Centre
Bradley Markle, University of Washington

Documenting the diversity of human responses and adaptations to climate, landscapes, ecosystems, natural disasters and the changing natural resources availability in different regions of our planet, cross-disciplinary studies in Geoarchaeology provide valuable opportunities to learn from the past. Furthermore, human activity became a major player of global climatic and environmental change in the course of the late Quaternary, during the Anthropocene. Consequently, we must better understand the archaeological records and landscapes in context of human culture and the hydroclimate-environment nexus at different spatial and temporal scales. This session seeks related interdisciplinary papers and specific geoarchaeological case-studies that deploy various approaches and tools to address the reconstruction of former human-environmental interactions from the Palaeolithic period through the modern. Topics related to records of the Anthropocene from Earth and archaeological science perspectives are welcome. Furthermore, contributions may include (but are not limited to) insights about how people have coped with environmental disasters or abrupt changes in the past; defining sustainability thresholds for farming or resource exploitation; distinguishing the baseline natural and human contributions to environmental changes. Ultimately, we would like to understand how strategies of human resilience and innovation can inform our modern strategies for addressing the challenges of the emerging Anthropocene, a time frame dominated by human modulation of surface geomorphological processes and hydroclimate.

This session aims to place recently observed climate change in a long-term perspective by highlighting the importance of paleoclimate research spanning the past 2000 years.
We invite presentations that provide insights into past climate variability, over decadal to millennial timescales, from different paleoclimate archives (ice cores, marine sediments, terrestrial records, historical archives and more). In particular, we are focussing on quantitative temperature and hydroclimate reconstructions, and reconstructions of large-scale modes of climate variability from local to global scales.

This session also encourages presentations on the attribution of past climate variability to external drivers or internal climate processes, data syntheses, model-data comparison exercises, proxy system modelling, and novel approaches to producing multi-proxy climate field reconstructions.

The session is co-sponsored by the PAGES 2k project (http://www.pastglobalchanges.org/ini/wg/2k-network/intro).

As the number of palaeoclimate data from glacial, marine, and continental archives is growing continuously, large-scale compilation and cross-comparison of these data is the imperative next phase in paleoclimate research. Large data sets require meticulous database management and new analysis methodologies to unlock their potential for revealing supra-regional and global trends in palaeoclimate conditions. The compilation of large scale datasets from proxy archives faces challenges related to record quality and data stewardship. This requires record screening and formulation of principles for quality check, as well as transparent communication.

This session aims to bring together contributions from paleoclimatic studies benefiting from the existence of such large data sets, e.g., providing a novel perspective on a proxy and the represented climate variables from the local to the global scale. We want to bridge the gap between data generation and modelling studies. In particular, comparing such large proxy-based datasets with climate modelling data is crucial for improving our understanding of palaeoclimate archives (e.g., bias effects and internal processes), to identify signal and noise components and their temporal dynamics, and to gain insight into the quality of model data comparisons.

We encourage submissions on data compilations, cross-comparison and modelling studies utilizing data repositories and databases (e.g., SISAL, PAGES2k, ACER, EPD), including, but not limited to:
-Comparative studies using one or several archives (e.g., including tests of temporal and spatial synchronicity of past regional to global climate changes)
-Proxy system models (and their tuning)
-Model data comparisons (including isotope enabled models or local calibration studies)
-Integrative multi-proxy/multi archive approaches at multiple study sites
-Large scale age model comparisons and record quality assessment studies, including methods aimed at cross validation between different records and variable spatial and temporal scales.

From modest beginnings some 50 years ago, the field of speleothem palaeo-climatology has seen improved analytical capacity produce ever more detailed, well-dated, and highly resolved records of climate proxies such as stable isotope ratios and trace element compositions. The last two decades have seen a great expansion of cave monitoring campaigns designed to improve understanding of the causal links between these proxies and the surface environment. Cave monitoring over a few years provides a wealth of detailed information about the links between local meteorology, soil processes, karst hydrochemistry, ventilation and carbonate precipitation but the crucial challenge lies in using this information to interpret proxy records on much longer timescales, from centennial to glacial-interglacial.

We invite contributions to discuss new developments in measurement and interpretation of speleothem proxies and how proxy-related environmental monitoring can be applied as an interpretive tool in palaeoclimate reconstruction.

Stable and radiogenic isotopic records have been successfully used for
investigating various settings, such as palaeosols, lacustrine, loess, caves, peatlands, bogs, arid, evaporative and marine environments. We are
looking for contributions using isotopes along with mineralogical, sedimentological, biological, paleontological and chemical records in
order to unravel the past and present climate and environmental changes.
The session invites contributions presenting an applied as well as a
theoretical approach. We welcome papers related to both reconstructions
(at various timescales) as well as on fractionation factors, measurement, methods, proxy calibration, and verification.

In recent decades, quantitative methods have become increasingly important in the field of palaeoenvironmental, palaeoclimatic and palaeohydrological reconstruction, due to the need for comparison between different records and to provide boundary conditions for computational modelling. Continental environmental archives (e.g. speleothems, lakes, land snails, rivers, or peatlands) are often highly temporally resolved (subdecadal to seasonal) and may provide more direct information about atmospheric and hydrological processes than marine archives. The wide variety of archive types available on land also allows for intercomparison and ground-truthing of results from different techniques and different proxies, and multi-proxy reconstructions from the same archive can disentangle local and supra-regional environmental conditions. This approach is particularly useful for the reconstruction of hydrological dynamics, which are challenging to reconstruct due to their high spatial variability, signal buffering, nonlinearities and uncertainties in the response of available paleoclimate archives and proxies. For example, climate-independent factors such as land cover change can affect the local to regional water availability recorded in proxies.

This session aims to highlight recent advances in the use of innovative and quantitative proxies to reconstruct past environmental change on land. We present studies of various continental archives, including but not limited to carbonates (caves, paleosols, snails), sediments (lakes, rivers, alluvial fans), and biological proxies (tree rings, fossil assemblages, plant biomarkers). We particularly include studies involving the calibration of physical and chemical proxies that incorporate modern transfer functions, forward modeling and/or geochemical modeling to predict proxy signals, and quantitative estimates of past temperature and palaeohydrological dynamics. We also include reconstructions of temperature and hydrologic variability over large spatial scales and paleoclimate data assimilation. This session will provide a forum for discussing recent innovations and future directions in the development of terrestrial palaeoenvironmental proxies on seasonal to multi-millennial timescales.

This session aims to highlight recent advances in the use of innovative and quantitative proxies to reconstruct past environmental change on land. We welcome studies of any continental archive, including but not limited to carbonates (caves, paleosols, snails), sediments (lakes, rivers, alluvial fans), ice, and biological proxies (tree rings, fossil assemblages, plant biomarkers). We particularly encourage studies involving the calibration of physical and chemical proxies that incorporate modern transfer functions, forward modeling and/or geochemical modeling to predict proxy signals, and quantitative estimates of past temperature and precipitation amounts. We also welcome reconstructions of temperature and hydrologic variability over large spatial scales, including paleoclimate data assimilation studies. This session will provide a forum for discussing recent innovations and future directions in the development of terrestrial palaeoenvironmental proxies on seasonal to multi-millennial timescales.

During the last decade significant advances in our understanding of the development of Cenozoic polar continental margins have been made. These include more detailed reconstructions of the climatic, oceanographic, and tectonic evolution of high northern and southern latitudes over various time scales, as well as reconstructions of past ice-sheet dynamics and studies of marine geohazards. Results have been obtained from conventional and high-resolution 2D and 3D seismic surveying, as well as from short sediment cores and longer drill cores (e.g. IODP, MeBo).
Fjords are regarded as “small oceans” that incise high latitude coastlines and link continental margins with the interiors of landmasses. Fjord settings allow us to study a variety of geological processes similar to those that have occurred on glaciated continental margins, but typically at smaller scales. The contribution of several sediment sources (e.g. glacial, fluvioglacial, fluvial, biological) to fjord basins along with relatively high sedimentation rates also provides the potential for high-resolution palaeoclimatic and palaeooceanographic records on decadal to centennial timescales.
The aim of this multi-disciplinary session is to follow on from the success of previous years by bringing together researchers working on northern and southern high-latitude continental margins and fjords, investigating the dynamics of past ice sheets, climate, tectonics, sedimentary processes, physical oceanography, and palaeo-biology/ecology.

What role did climate dynamics play in human evolution, the dispersal of Homo sapiens within and beyond the African continent, and key cultural innovations? Were dry spells, stable humid conditions, or rapid climate fluctuations the main driver of human evolution and migration? In order to evaluate the impact that different timescales and magnitudes of climatic shifts might have had on the living conditions of prehistoric humans, we need reliable and continuous reconstructions of paleoenvironmental conditions and fluctuations from the vicinity of paleoanthropological and archaeological sites. The search for the environmental context of human evolution and mobility crucially depends on the interpretation of paleoclimate archives from outcrop geology, lacustrine and marine sediments. Linking archeological data to paleoenvironmental reconstructions and models becomes increasingly important.

As a contribution towards a better understanding of these human-climate interactions the conveners encourage submission of abstracts on their project’s research on (geo)archaeology, paleoecology, paleoclimate, stratigraphy, and paleoenvironmental reconstructions. We especially welcome contributions offering new methods for dealing with difficult archive conditions and dating challenges. We hope this session will appeal to a broad audience by highlighting the latest research on paleoenvironmental reconstructions in the vicinity of key sites of human evolution, showcasing a wide variety of analytical methods, and encouraging collaboration between different research groups. Conceptual models, modelling results and model-data comparisons are warmly welcomed, as collaborative and interdisciplinary research.

Prof. Dr. Daniel M. Deocampo (Department of Geosciences, Georgia State University, Atlanta) will talk on 'Silicate diagenesis and environmental change in eastern Africa: Examples from key hominin localities'.

Dr. Alice Leplongeon (Institute of Advanced Studies & Department of Cultural Heritage, University of Bologna) will talk about how technological variability, environmental change, and human dispersals may be linked, particularly in the Late Pleistocene in eastern Africa, north-eastern Africa and the Levant.

In the last 20 years, a major breakthrough in palaeo-environmental research has been the utilisation of 2D and 3D seismic reflection data and its integration with borehole petrophysics and core lithologies: the so-called “geological Hubble”. This step-change in seismic data quality and interpretive techniques has allowed imaging and analysis of the subsurface from the seafloor down to the Moho, and for palaeo-geographies and contemporary processes to be reconstructed across 1D (borehole) to 4D (repeat seismic) scales.

Though many Earth scientists know the basic principles of these subsurface datasets, they are often unaware of the full capability of seismic data paired with borehole data. We hope that this session will provide a window into the exciting and cross-disciplinary research currently being performed using geomorphological approaches, state-of-the-art seismic interpretation, and integrative methodologies.

Submissions are welcome from a range of geological settings, thus, exposing seismic interpreters and non-specialists to differing geological perspectives, the latest seismic workflows, and examples of effective seismic and borehole integration. Examples could include (but are not restricted to), glacigenic tunnel valley complexes, igneous intrusions, submarine landslides, channel and canyon systems, salt tectonics overburden expression, methane hydrates, and subsurface fluid flow, all under the theme of how seismic data are interpreted and how the results are applied (e.g. palaeo-environmental reconstruction, seafloor engineering, or carbon sequestration).

The submissions will highlight the rationale behind the interpretation of seismic geometries and will generate discussions around potential issues of equifinality (i.e. similar seismic geometries arising from different Earth processes). We thus invite submissions that aim to present new insights in seismic geomorphology and particularly welcome studies integrating borehole and geotechnical drilling information with shallow high-resolution seismic data and deeper traditional legacy oil industry data. Such studies are a crucial component in seismic inversion and refining or elucidating the accuracy of palaeo-geographies that are interpreted from just seismic data.

The session will be an excellent opportunity for subsurface geoscientists to showcase and discuss with contemporary geomorphologists and environmental scientists what can be achieved by utilising seismic and borehole data to unravel the Earth’s past.

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, and 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.

Solicited speaker: Christine Y. Chen (MIT, USA): “Establishing robust lake sediment chronologies: Lessons from U/Th dating the deep drill core from Lake Junín, Peru”

Scientific drilling through the International Ocean Discovery Program (IODP) and the International Continental Scientific Drilling Program (ICDP) continues to provide 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 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 invites contributions that present and/or review recent scientific results from deep Earth sampling and monitoring through ocean and continental drilling projects. Furthermore, we encourage contributions that outline perspectives and visions for future drilling projects, in particular projects using a multi-platform approach.

Arid to sub-humid regions contribute ca. 40 % to the global land surface and are home of more than 40 % of the world’s population. During prehistoric times many important cultures had developed in these regions. Due to the high sensitivity of dryland areas even to small-scale environmental changes and anthropogenic activities, ongoing geomorphological processes but also the Late Quaternary palaeoenvironmental evolution as recorded in sediment archives are becoming increasingly relevant for geomorphological, palaeoenvironmental and geoarchaeological research. Dryland research is also boosted by methodological advances, and especially by emerging linkages with other climatic and geomorphic systems that allow using dryland areas as indicator-regions of global environmental change.
This session aims to pool contributions from the broad field of earth sciences that deal with geomorphological processes and different types of sediment archives in dryland areas (dunes, loess, slope deposits, fluvial sediments, alluvial fans, lake and playa sediments, desert pavements, soils, paleosols etc.) at different spatial and temporal scales. Besides case studies from individual regions and archives, methodical and conceptual contributions, e.g. dealing with the special role of eolian, fluvial, gravitational and biological processes in dryland environments, their preservation over time in the sedimentary records, and emerging opportunities and limitations to resolve past and current dynamics, are especially welcome in this session.

Earth history is punctuated by major extinction events, by perturbations of global biogeochemical cycles and by rapid climate shifts. Investigation of these events in Earth history is based on accurate and integrated stratigraphy. This session will bring together specialists in litho-, bio-, chemo-, magneto-, cyclo-, sequence-, and chronostratigraphy with paleontologists, paleoclimatologists and paleoceanographers. An emphasis is placed upon the use of a variety of tools for deciphering sedimentary records and their stratigraphy across intervals of major environmental change. This session is organized by the International Subcommission on Stratigraphic Classification (ISSC) of the International Commission on Stratigraphy (ICS) and it is open to the Earth science community at large.

During the Quaternary Period, the last 2.6 million years of Earth's history, changes in environments and climate shaped human evolution. In particular, large-scale features of atmospheric circulation patterns varied significantly due to the dramatic changes in global boundary conditions which accompanied abrupt changes in climate. Reconstructing these environmental changes relies heavily on precise and accurate chronologies. Radiocarbon dating continues to play a vital role in providing chronological control over the last 50,000 years, but advances in recent years on a range of other geochronological techniques that are applicable to the Quaternary have made available a much wider diversity of methods. In this session, contributions are particularly welcome that aim to (1) reduce, quantify and express dating uncertainties in any dating method, including high-resolution radiocarbon approaches, (2) use established geochronological methods to answer new questions, (3) use new methods to address longstanding issues, or (4) combine different chronometric techniques for improved results, including the analysis of chronological datasets with novel methods, such as Bayesian age-depth modelling. Applications may aim to understand long-term landscape evolution, quantify rates of geomorphological processes, or provide chronologies for records of climate change.

To fully diagnose the mechanisms behind the complex teleconnections of past abrupt climate transitions accurate dating and correlation is imperative. This is one of the main goals of the INTIMATE initiative. Furthermore, we aim towards a global approach to integrating climate data, by considering archives from the tropics to the poles and develop our understanding of proxy-sensitivities to different aspects of climate and environmental change (e.g. temperature, precipitation, nutrient availability, sunlight). Finally, we should test our hypotheses and challenge our ideas using models of atmosphere-ocean-biosphere processes. INTIMATE aims to provide a better understanding of the mechanisms of abrupt climate change, with a particular emphasis on the integration and interpretation of global records of abrupt climate changes during the last glacial to interglacial cycle.

Our invited speaker is Prof. Tim Jull, the Editor of the Radiocarbon Journal who will speak about
"Annual carbon-14 variability in tree-rings: Causes and Implications for the calibration curve."

Tree rings are a key terrestrial archive providing insight into past climate conditions at annual and intra-annual resolution and from local to hemispheric scales. Tree ring proxies are also important indicators of plant physiological responses to changing environments and of long-term ecological processes. In this broad context we welcome contributions using one or more of the following approaches to either study the impact of environmental change on growth and physiology of trees and forest ecosystems or to assess and reconstruct past environmental change: (i) traditional dendrochronological methods including studies based on tree ring width and density, (ii) stable isotopes in tree rings and related plant compounds, (iii) dendrochemistry, (iv) quantitative wood anatomy, (v) sap flow, dendrometer and related monitoring data analyses, and (vi) mechanistic modelling, all at different temporal and spatial scales.

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

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

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

Invited Speakers: Professor Ric Williams, University of Liverpool, UK
Dr. Arnaud Czaja, Imperial College, London, UK

The rapid decline of Arctic sea ice in the last decade is a dramatic indicator of climate change.  The last 12 years have seen lower Arctic summer sea ice extents than in the previous 29 years of satellite records. The Arctic sea ice cover is now thinner, weaker and drifts faster. The ocean is also changing, the volume of freshwater stored in the Arctic and has increased as have the inputs of coastal runoff from Siberia and Greenland. Concurrently inflows from the Atlantic and Pacific Oceans have warmed. As the global surface temperature rises, the Arctic Ocean is speculated to become seasonally ice-free in the 21st century, which prompts us to revisit our perceptions of the Arctic system as a whole. What could the Arctic look like in the future? How are the present changes in the Arctic going to affect the lower latitudes? What aspects of the changing Arctic should future observations and modelling programs address? The scientific community is investing considerable effort in organising our current knowledge of the physical and biogeochemical properties of the Arctic, exploring poorly understood coupled atmosphere-sea-ice-ocean processes to improve prediction of future changes in the Arctic.
 
In this session, we invite contributions on a variety of aspects of past, present and future climates of the Arctic. We encourage submissions addressing interaction between ocean, atmosphere and sea ice and on studies linking changes in the Arctic to the global ocean. Submissions with a focus on emerging cryospheric, oceanic and biogeochemical processes and their implications are particularly welcome. The session promotes results from current Arctic programmes and discussions on future plans for Arctic Ocean modelling and measurement strategies. 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.

The Southern Ocean, which stretches from Antarctic ice-shelf cavities to the northern fringe of the Antarctic Circumpolar Current, is a key region for water mass formation and for the uptake, storage and lateral exchanges of heat, carbon and nutrients. At present, the Southern Ocean acts as a sink of anthropogenic carbon and heat and as a source of natural carbon, but its role in future climate conditions remains uncertain. Processes on the Antarctic continental shelf also need to be better understood in order to assess the ocean’s role in Antarctic ice loss and the resulting meltwater impact on sea level. To reduce these uncertainties, it is critical to investigate the mechanisms underlying Southern Ocean's internal variability and its response to external forcing. Recent advances in observational technology, data coverage, circulation theories, and numerical models are providing a deeper insight into the three-dimensional patterns of Southern Ocean change. This session will discuss the current state of knowledge and novel findings concerning Southern Ocean circulation, water mass formation and pathways, mixing and mesoscale dynamics, ocean-ice-atmosphere interactions, sea ice changes, inflow of warm water to ice shelf cavities, and biological productivity, as well as the heat, nutrient and carbon budgets. This includes work on all spatial scales (from local to basin-scale to circumpolar) and temporal scales (past, present and future). We particularly invite cross-disciplinary topics involving physical and biological oceanography, glaciology, or biogeochemistry.

The climate state of the Atlantic Ocean is known to exert a huge control and hence a decisive role on the surface climate over the neighbouring continents as well as that of the Arctic Ocean. Heat in the South Atlantic converges from both the Pacific and Indian Oceans and is carried northward to higher latitudes along the dynamically-rich oceanic current systems to key deep water formation regions where the atmosphere is in direct contact with the deep ocean. Understanding what drives the variability of the Atlantic Ocean on multiple time scales and long-term trends is thus imperative for more confident predictions of the climate in the future decades.

This session will offer the opportunity to focus on the dynamics, variability and trends along the key climatic current systems from the South Atlantic to the North Atlantic and into Arctic Ocean and how they are influenced by local-, large- or global-scale processes or teleconnections. We aim to bring together researchers using observations, ocean models and state-of-the-art climate models.

We welcome presentations addressing:

- Sources, dynamics, pathways and meridional connectivity of heat and freshwater anomalies from lower to higher latitudes
- Impact of large- and global-scale atmospheric modes on Atlantic Ocean circulation
- Variations and long-term trends in Atlantic overturning circulation and relationship to sea-level and sea-ice change

Invited speaker: Penny Holliday, National Oceanography Centre, UK

The WMO World Weather Research Programme (WWRP)–World Climate Research Programme (WCRP) Sub-seasonal to Seasonal (S2S) Prediction Project has the goal of improving forecast skill of the 2 week to 2 month lead time range and now provides research communities with unprecedented access to a comprehensive database of forecasts and hindcasts from a large number of forecasting centres from across the globe.

This session invites contributions that span all aspects of S2S meteorological, hydrological and oceanographic prediction, including impacts studies that may or may not make use of the S2S databases.

Specifically we welcome contributions that focus on phenomena such as

- The Madden Julian Oscillation (MJO)
- Tropical/extra-Tropical waves
- Stratospheric variability and stratosphere -troposphere coupling
- Predictability and skill of atmospheric or surface variables
- Transition of weather regimes
- Case studies of extreme weather events on the S2S scale

Contributions regarding impacts studies at the S2S time-range are also highly welcome, including the areas of water management (e.g floods, drought), health (vector-borne diseases, heat waves, air quality) and security (fires), agriculture and energy. These can include modelling studies of the impacts through to presentations of how S2S-derived information can be integrated into decision support systems at the local, regional and country level.

*********** UPDATE ********************

Solicited talks:

Dr Andrea Manrique-Suñén from Barcelona Supercomputer Centre (BSC) will talk about the S2S4E project which aims to bring sub-seasonal to seasonal climate predictions to the renewable energy sector. To illustrate the potential benefits of S2S predictions the S2S4E projects have analysed several case studies, i.e. periods pointed out by the energy companies as having an unusual climate behavior that affected the energy market. Two of these case studies show how the climate predictions of each event would have helped stakeholders to take precautionary actions several weeks ahead.

Dr Andrew Robertson from Columbia University will give a review of the status of the S2S project, and show some examples of the sub-seasonal forecast products which have been developed at IRI

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

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

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

· How extremes have varied or are likely to vary under climate change;
· How well climate models capture extreme events;
· Attribution of extreme events;
· Emergent constraints on extremes;
· Linking dynamical systems extremes to geophysical extremes;
· Geophysical flows as a dynamical system: classification of large-scale flows and metastable states;
· Advances in diagnosing local and mean properties of the climate system as a dynamical system (e.g. maximum entropy production principles);
· Extremes in dynamical systems;
· Dynamical systems metrics as indicators of climate change;
· Dynamical downscaling of weather and climate extremes.

Confirmed Invited Speakers are:
-David Barriopedro (Complutense University of Madrid, Spain)
-Pascale Braconnot (IPSL, France)
-Nikki Vercauteren (Freie Universitaet Berlin, Germany)

The occurrence of extremes such as droughts, flash floods, hailstorms, storm surges and tropical storms can have significant and sometimes catastrophic consequences to society. However, not all low probability weather/climate events will lead to “high impacts” on human or natural systems or infrastructure. Rather, the severity of such events depend also intrinsically on the exposure, vulnerability and/or resilience to such hazards of affected systems, including emergency management procedures. Similarly, high impact events may be compounded by the interaction of several, e.g., in their own right less severe hydro-meteorological incidents, sometimes separated in time and space. Or they may similarly result from the joint failures of multiple human or natural systems. Consequently, it is a deep transdisciplinary challenge to learn from past high impact events, understand the mechanisms behind them and ultimately to project how they may potentially change in a future climate.

The ECRA (European Climate Research Alliance) Collaborative Programme on “High Impact Events and Climate Change” aims to promote research on the mechanisms behind high impact events and climate extremes, simulation of high impact events under present and future climatic conditions, and on how relevant information for climate risk analysis, vulnerability and adaptation may be co-created with users, e.g., in terms of tailored climate services. For this aim, this Interdisciplinary and Transdisciplinary Session invites contributions that will serve to (i) better understand the mechanisms behind high impact events from a transdisciplinary and interdisciplinary perspective, e.g. case studies and the assessment of past high impact events, including detection and attribution; (ii) project changes to high impact events through, e.g. high resolution climate and impacts modelling (including economic modelling); (iii) produce climate information at the relevant scales (downscaling); and co-create climate services with users to help deal with the risk and/or impacts of high-impact events, e.g. risk analysis and climate adaptation. Abstracts that highlight recent advances from a transdisciplinary perspective for example through the innovation of climate services will be particularly encouraged. Authors and contributors to this session will be offered to present their work in a Special Issue of the journal “Sustainability”.

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.

ENSO is the dominant source of interannual climate variability in the tropics and across the globe. Understanding ENSO's dynamics, predicting El Niño and La Niña, and anticipating changes in ENSO's characteristics and impacts are thus of vital importance for society. This session invites contributions regarding the dynamics of ENSO, including multi-scale interactions; low frequency, decadal and paleo ENSO variability; ENSO theory; ENSO diversity; ENSO impacts on climate, society and ecosystems; ENSO teleconnections; seasonal forecasting of ENSO; and climate change projections of ENSO. Studies aimed at understanding ENSO in models of a range of complexity are especially welcomed, including analysis of CMIP model intercomparisons.

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 change. Glaciers are monitored on different spatio-temporal scales, from extensive seasonal mass balance studies at selected glaciers to multi-decadal 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. This session invites studies from a variety of disciplines, from tropical to polar glaciers, addressing both in-situ and remotely sensed monitoring of glaciers, as well as uncertainty assessments.
Keynotes:
Laura Thomson & David Burgess (Canada): The role and response of Canada's Arctic glaciers: Lessons learned from >50 years of mass balance observations
Bryn Hubbard (UK): 3D structure of Khumbu Glacier, Nepal, from borehole experiments.

Understanding the impacts of climate change on ice sheets and glaciers requires accurate surface mass balance. The interaction of ice sheets and glaciers with the atmosphere means that coupled atmosphere-ocean modes and large-scale weather patterns, meso-scale circulations over mountains, and local-scale energy and mass exchanges in the near-surface boundary layer can control the surface mass balance. Surface processes including melt-albedo feedbacks and firn densification introduce further complexity in determining surface mass balance. The Ice Sheets Model Intercomparison Project (ISMIP6), part of the Climate Model Intercomparison Project (CMIP6), aims to constrain the total mass balance contribution of ice sheets and glaciers to sea level rise. In this context, accurate estimates of surface mass balance from both models and observations are crucial, and so intercomparisons of models are currently underway.

This session focuses on (i) novel field- and remotely-sensed advances in measuring the surface energy balance and surface mass balance and (ii) process-based modelling that improves our understanding of glacier and ice sheet surface mass balance and atmospheric interaction. We invite contributions from a broad range of theoretical, numerical or observational studies that explore historic, recent and projected changes to glacier and ice sheet surface mass balance and atmospheric interaction. The range of topics includes but is not limited to: surface energy balance; improvements to satellite SMB retrievals; firn densification; future atmospheric circulation impacts; changes in cloudiness; and the impact of impurities upon albedo. We particularly welcome contributions which focus on improvements to process understanding that will lead to better SMB estimates in the future.

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 linked closely to the session HS2.1.2/CR3.11. While the focus of our session is on monitoring and modelling snow processes across scales, session HS2.1.2/CR3.11 addresses monitoring and modelling of snow for hydrologic applications.

Variations in stratospheric aerosol -- arising primarily from sporadic volcanic eruptions -- are an important contributor to climate variability. Major volcanic eruptions have led to pronounced decreases in global surface temperature over seasonal-to-decadal timescales.

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 the radiative forcings of past eruptions and the microphysical, chemical and dynamical processes which affect the evolution of stratospheric aerosol properties. This can only be achieved by combining information from satellite and in-situ observations of recent eruptions, stratospheric aerosol modelling activities, and reconstructions of past volcanic histories from proxies.

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

This year contributions addressing volcanic influences on atmospheric composition, such as changes in stratospheric water vapour, ozone and other trace gases are also particularly encouraged.

The session also aims to highlight research on volcanoes and climate contributing to current international SPARC-SSiRC, CMIP6-VolMIP, CMIP6-PMIP, and PAGES-VICS co-ordinated activities.

Atmosphere and Cryosphere are closely linked and need to be investigated as an interdisciplinary subject. Most of the cryospheric areas have undergone severe changes in last decades while such areas have been more fragile and less adaptable to global climate changes. This AS-CR session invites model- and observational-based investigations on any aspects of linkages between atmospheric processes and snow and ice on local, regional and global scales. Emphasis is given on the Arctic, high latitudes and altitudes, mountains, sea ice, Antarctic regions. In particular, we encourage studies that address aerosols (such as Black Carbon, Organic Carbon, dust, volcanic ash, diatoms, bioaerosols, bacteria, etc.) and changes in the cryosphere, e.g., effects on snow/ice melt and albedo. The session also focus on dust transport, aeolian deposition, and volcanic dust, including health, environmental or climate impacts at high latitudes, high altitudes and cold Polar Regions. We emphasize 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.

The regional climate change assessment reports for the Baltic (BACC I and II) and North Sea regions (NOSCCA) have recently estimated the extent and impact of climate change on the environments of the North and Baltic Sea regions. A major outcome of these reports is the finding that climate change is one of multiple drivers, which have a continuing impact on terrestrial, aquatic and socio-economic (resp. human) environments. These drivers interact with regional climate change in ways, which are not completely understood.
This session invites contributions, which focus on the connections and interrelations between climate change and other drivers of environmental change, be it natural or human-induced, in different regional seas and coastal regions. Observation and modelling studies are welcome, which describe processes and interrelations with climate change in the atmosphere, in marine and freshwater ecosystems and biogeochemistry, coastal and terrestrial ecosystems as well as human systems. In particular, studies on socio-economic factors like aerosols, land cover, fisheries, agriculture and forestry, urban areas, coastal management, offshore energy, air quality and recreation, and their relation to climate change, are welcome.
The aim of this session is to provide an overview over the current state of knowledge of this complicated interplay of different factors, in different coastal regions all over the world.

The energy of a closed system is steady. It is not lost but rather converted into other forms, such as when kinetic energy is transferred into thermal energy. However, this fundamental principle of natural science is often still a problem for climate research. For example, in case of the calculation of ocean currents and circulation, where small-scale vortices as well as diapycnal mixing and the deep convection processes they induce, need to be considered, to compute how heat content is redistributed along the entire water column and how such processes may change in the future. Similarly, in the atmosphere, the conversion of available potential energy into kinetic energy is the key driver of atmospheric dynamics at a variety of scales, from the zonal-mean general circulation to mesoscale convection. Local turbulent processes can drive larger movements and waves on a larger scale can disintegrate into small structures. All these processes are important for the Earth’s climate and determine its evolution in the future.

How exactly the energy transfers between waves, eddies, local turbulence and mixing in the ocean and the atmosphere works, often remains unclear. This session wants to discuss this by inviting contributions from oceanographers, meteorologists, climate modelers, and mathematicians. We are particularly interested in coupled atmosphere-ocean studies, we are also aiming at filling a knowledge gap on deep ocean processes, as well as novel subgrid-scale parameterizations, and studies of the energy budget of the complex Earth system, including the predictability of the global oceanic thermohaline circulation and thus climate variability.

Invited speakers:
Martin Wild, ETH, Zürich, Switzerland
Raffaele Ferrari, MIT, USA
Robert Weller, WHOI and OOI Research Infrastructures, USA

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

We invite studies

* focusing on extensive transient features of the atmospheric water
cycle, such as Atmospheric Rivers, Cold-Air Outbreaks, warm conveyor
belts, tropical moisture exports, precipitation extremes, and the
monsoon systems.

* investigating the large-scale drivers of the water cycle features’
variability and change by looking at observations, reanalyses or
global/regional climate simulations, in order to improve their
predictability

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

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

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

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

Remote sensing techniques and earth system modelling have been widely used in earth science and environmental science. In particular, the world is suffering significant environmental changes such as hydro-climatic extremes, sea level rise, melting glaciers and ice caps and forest fires. The earth observations and earth system models provide valuable insight into climate variability and environmental change. Meanwhile, the question on how to derive and present uncertainties in earth observations and model simulations has gained enormous attention among communities in the earth sciences.

However, quantification of uncertainties in satellite-based data products and model simulations is still a challenging task. Various approaches have been proposed within the community to tackle the validation problem for satellite-based data products and model simulations. These progress include theory advancement, mathematics, methodologies, techniques, communication of uncertainty and traceability.

The aim of this session is to summarize current state-of-the-art in uncertainty quantification and utilization for satellite-based earth observations and earth system models.

Climate changes (CC) are expected affecting weather forcing regulating the triggering and reactivation of slope movements. The influence of CC on landslides can be different, according to the area, the time horizon of interest and the actual trends of socio-economic factors driving greenhouse gases concentration. However, even the simple identification of weather patterns regulating landslide occurrence represents a not trivial issue, also assuming steady conditions, due to crucial role played by geomorphological details.
In last years, such elements partly prevented the investigations aimed to assess how CC influence slope stability at different temporal and spatial scales.
In this regard, the Session has the main aim to gather test cases and investigations carried out in different geographical contexts in evaluation of ongoing and future landslide activity.
Researches may concern: (i) modeling of future slope stability conditions exploiting downscaled climate projections or (ii) analyses of historical records of landslides (using both historical research or paleo-evidences) and climate variables and their combinations.
Analysis at different detail from slope to regional scale to global scale, considering variations in landslide occurrence, frequency, susceptibility, hazard and risk result of interest. Nevertheless, studies considering the coupled effect of environmental (e.g., land use/cover) and climate changes will be taken into account.

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

This session solicits submissions from both the observational and modelling communities examining urban atmospheric dynamics, processes and impacts owing to urban induced climate change, the efficacy of various strategies to reduce such impacts, and techniques highlighting how cities are already using novel science data and products that facilitate urban adaptation to and mitigation of the effects of climate change.

As discussed by EGU2017 DB2 and EGU 2018 TM16, there had been an impressive series of international agreements and development of large networks of cites that call for qualitative improvements of urban systems and their interactions with their environment. The main goal of this ITS is to mobilise geoscientists, highlight their present contributions and encourage holistic approaches beyond the traditional silos of urban meteorology/hydrology/climatology/ecology/resilience, as well as some other terms.

Public information:
See also Town Hall TM 19 "Cities and Interdisciplinary Geosciences"
to be held on Thursday 11 April in room 1.85 from 19:00 to 20:00.
https://meetingorganizer.copernicus.org/EGU2019/session/33913

Cities all over the world are facing rising population densities. This leads to increasing fractions of built-up and sealed areas, consequencing in a more and more altered and partly disrupted water balance - both in terms of water quantities and qualities. On top, climate change is altering precipitation regimes.

This session focuses on according urban ecohydrological problems and approaches to solve them spanning from technical to nature-based solutions in different time and spatial scales from the building to the whole city.

The originality of the session is to emphasize on the central position of human activities in environmental research (both terrestrial and atmospheric), as a driving factor and/or a response, by combining different spatio-temporal scales.
Continental environments (under various climatic conditions) experience profound societal and physical changes, which prompt scientists to investigate the complex interactions between environmental functioning and human activities.
The complexity originates from the multiplicity of factors involved and resulting spatial and temporal variabilities, of their multiple origins in time (historical integration) and/or legacy.
As a consequence, causal links in this societal-environmental relationship are difficult to establish but, it is fundamental to understand these causal links to adapt, conserve, protect, preserve and restore the functioning of the environment as well as human activities. From this point of view, the geographical approach highlights the relationships (or their absence) through the expression of the spatial and temporal trajectories of the processes studied by clarifying the observation of signals.
The ensuing issues on the relevance of indicators used in different supports of nowadays research (imagery, archives, models ...) are raised as a methodological open up.
In this context, oral and poster presentations dealing with any studies related to the following issue(s) are welcome:
- human forcing on the environments and environmental resilience
- response of socio-systems to environmental changes
- scenarios, prospective and retrospective models of the evolution of environments and human activities
- management modes (adaptive management) of anthropised continental environments, reciprocity, mutual benefits (ecosystem services), positive feedback

The session may include the following methodological aspects:
- in situ metrology,
- statistical and numerical modeling,
- spatio-temporal analysis,
- remote Sensing,
- surveys,
- landscape analysis,
- paleoenvironmental approach,
at various scales:
- spatial scales, from the station and site through watershed,
- time scales from the event to the Holocene.

Hydroclimatic variability is an emerging challenge with increasing implications on water resources management, planning, and the mitigation of water-related natural hazards. The above variability, along with the continuous development of water demands, and aging water supply system infrastructure make the sustainability of water use a high priority for modern society. In fact, the Global Risk 2015 Report of the World Economic Forum highlights global water crises as being the biggest threat facing the planet over the next decade.
To mitigate the above concerns we need to shed light on hydroclimatic variability and change. Several questions and mysteries are still unresolved regarding natural fluctuations of climate, anthropogenic climate change and associated variability, and changes in water resources. What is a hydroclimatic trend? What is a (long term) cycle? How can we distinguish between a trend and a cycle? Is such discrimination technically useful? How do human activities affect rainfall, hydrological change and water resources availability? How to set priorities and take action to ensure sustainability in light of variability and change?
The objective of this session is to explore hydrological and climatic temporal variability and their connections and feedbacks. More specifically, the session aims to:
1. investigate the hydrological cycle and climatic variability and change, both at regional and global scales;
2. explore the interplay between change and variability and its effect on sustainability of water uses;
3. advance our understanding of the hydrological cycle, benefiting from hydrological records and innovative techniques; and
4. improve the efficiency, simplicity, and accurate characterization of data-driven modeling techniques to quantify the impacts of past, present and future hydroclimatic change on human societies.
This session is sponsored by the International Association of Hydrological Sciences (IAHS) and the World Meteorological Organization – Commission for Hydrology (WMO CHy) and it is also related to the scientific decade 2013–2022 of IAHS, entitled “Panta Rhei - Everything Flows”.

The Anthropocene is a topic of broad and current interest that is being discussed across various disciplines, within Earth Sciences, but also in the humanities and in the media. Its significance and usefulness as the youngest epoch of the Geological Time Scale is examined by the Working Group of the Anthropocene of the Subcommission on Quaternary Stratigraphy, part of the International Commission on Stratigraphy. A multidisciplinary and transdisciplinary approach for investigating and discussing the Anthropocene is feasible, including not only various Earth Sciences disciplines such as stratigraphy, sedimentology, geochemistry and palaeontology, but also archaeology, geography, geomorphology and various disciplines of the humanities and the arts. This session invites transdisciplinary and interdisciplinary contributions on the significance, usefulness and application of the term, as well as case studies including proposals on possible GSSPs (Global Boundary Stratotype Section and Point) for a definition of the Anthropocene as part of the Geological Time Scale. The session will foster transdisciplinary dialogue and interdisciplinary cooperation and understanding on the scale and reach of anthropogenic changes within the Earth System.

Accurate and precise atmospheric measurements of greenhouse gas (GHG) concentrations reveal the rapid and unceasing rise of global GHG concentrations due to human activity. The resulting increases in global temperatures, sea-level, glacial retreat, and other negative impacts are clear. In response to this evidence, nations, states, and cities, private enterprises and individuals have been accelerating GHG reduction efforts while meeting the needs of global development. The urgency, complexity and economic implications of GHG reductions demand strategic investment in science-based information for planning and tracking emission reduction policies and actions. In response, the World Meteorological Organization (WMO) Global Atmosphere Watch Program (GAW) and its partners have initiated the development of an Integrated Global Greenhouse Gas Information System (IG3IS). IG3IS combines atmospheric GHG concentration measurements and human-activity data in an inverse modeling framework to help decision-makers take better-informed action to reduce emissions of greenhouse gases and pollutants that reduce air quality. This service is based on existing and successful measurement and analysis methods and use-cases for which the scientific and technical skill is proven or emerging.
This session intends to gather presentations from researchers and decision-makers (user-community) on the development, implementation and use of atmospheric measurement-based “top-down” and data-driven “bottom-up” GHG emission inventory estimates, and the combination of both approaches, explicit in space and time, to deliver actionable emissions information at scales where human activity occurs and emission reduction is most effective. This session is part of the EGU General Assembly 2019 30th anniversary celebration of the WMO’s Global Atmosphere Watch Program and its commitment to science-based services.

Carbon budgets are a finite quantity of carbon that can be emitted whilst holding warming below some given temperature level, such as the 1.5 and 2.0ºC temperature limits specified in the Paris Agreement. Carbon budgets emerge from the near-proportional relationship between total anthropogenic emissions of CO2 and change in global mean temperature seen in virtually all Earth System Models. This relationship is known as the Transient Climate Response to Cumulative CO2 Emissions (TCRE). Carbon budgets and the associated cumulative emissions framework have recently been used to: estimate the fraction of known fossil fuel reserves that can be burnt, attribute historical responsibility for climate change, and to scrutinize national emissions commitments towards meeting the Paris Agreement goal.

The session invites contributions examining a wide range of aspects related to carbon budgets and the TCRE framework, including: the governing mechanisms that lead to the emergence of TCRE, how carbon budgets are affected by previously unquantified feedbacks (e.g. permafrost carbon feedback, wetland methane feedback) and non-CO2 forcings (e.g. aerosols, non-CO2 greenhouse gases ext.), quantification of the remaining carbon budget to reach given temperature goals (for example, from the Paris Agreement), uncertainties associated with these budgets, the role of pathway dependence, and the behaviour of TCRE in response to artificial CO2 removal from the atmosphere. Contributions from the fields of climate policy and economics focused on applications of carbon budgets are also encouraged.

Mountain glaciers and ice caps are major contributors to sea-level rise and have large impacts on water balance of local basins. This is a general session on glaciers and ice caps where the relationship to climate forms a particular focus. The IPCC AR5 of Working Group 1 covers Earths Glaciers and Ice Caps outside the ice sheets under the heading of Glaciers and shows that, despite much progress recently provided by the community, we are still left with substantial unknowns. We need to acquire more data, both from new fieldwork and release of unpublished data from prior years on mass changes of glaciers and ice caps from all regions of the world. We need to improve the understanding of the processes behind the changes, and we need to improve the application of models of different complexity. We welcome presentations on all aspects of mass changes; current, past and future changes based on field observations, remote sensing and modeling. Studies of physical processes controlling accumulation and ablation including calving and submarine melting, are especially welcome.

Several large ensemble model simulations, either from Global Climate Models (GCM), Earth System Models (ESM), or Regional Climate Models (RCM), have been generated over the recent years. These ensembles, typically simulating historical climate and making future projections, are powerful because they can be used to accurately estimate forced changes in the climate system and to determine the magnitude and realism of simulated internal climate variability. They can further be applied to investigate how climate change signals may emerge from internal variability over time. Combining large ensemble simulations also provides long time series to investigate the dynamics of hydro-meteorological extremes and to assess compound events (e.g., successive or simultaneous extreme events) under conditions of climate change.

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

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

Estimating the impact of climate change on both the natural and socio-economic environment plays an important role in informing a range of national and international policies, including energy, agriculture and health. Understanding these impacts, and those avoided, has never been more pertinent since the adoption of the 2015 Paris Agreement, which sought to hold “the increase in the global average temperature to well below 2°C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5°C, recognizing that this would significantly reduce the risks and impacts of climate change".

Policies may aim to mitigate (i.e. reduce emissions), counteract (i.e. negative emissions) and/or adapt to anthropogenic climate change and it is equally important to quantify the impact of implementing these options. While rapid, deep mitigation is clearly a pre-requisite to success, delays to such measures imply a greater reliance upon large scale negative emissions technologies. Those based on land are likely to face competing pressure from wide ranging economic activity, and knowledge of these interactions and synergies is limited. Similarly while adaptation options are wide ranging, the uses of nature-based solutions, which often provide mitigation co-benefits and are often highly cost effective, are under-researched and rarely integrated into overall natural hazard or climate change risk management strategies.

Furthermore, the methods used to evaluate impact in the climate context are many and varied, including empirical, econometric and process-based. These methods continue to evolve implying that the assessment of impact may depend upon the analytical approach chosen.

This inter- and transdisciplinary session aims to draw together scientists, developing climate-impact evaluation methods, evaluating the impact (or avoided impact) of anthropogenic climate change upon natural and socio-economic environments, investigating the potential for mitigation and counteraction options to reduce long term risk, and studying the value of multiple adaptation options to stakeholders when planning how to manage vulnerability.

Invited speaker: Sonia Seneviratne

Natural hazards and climate change impacts in coastal areas
Coastal areas are vulnerable to ocean, atmospheric and land-based hazards. This vulnerability is likely to be exacerbated in future with, for example, sea level rise, increasing intensity of tropical cyclones, increased subsidence due to groundwater extraction. Drawing firm conclusions about current and future changes in this environment is challenging because uncertainties are often large. This calls for a better understanding of the underlying physical processes and systems. Furthermore, while global scale climate and detailed hydrodynamic modelling are reaching a mature development stage the robust assessment of impacts at regional and local scales remains in its infancy. Numerical models therefore play a crucial role in characterizing coastal hazards and assigning risks to them.

This session invites submissions focusing on assessments and case studies at global and regional 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.

The Sustainable Development Goals (SDGs) (or Global Goals for Sustainable Development) are a collection of 17 global goals set by the United Nations Development Programme.The formal name for the SDGs is: "Transforming our World: the 2030 Agenda for Sustainable Development." That has been shortened to "2030 Agenda." The goals are broad and interdependent, yet each has a separate list of targets to achieve. Achieving all 169 targets would signal accomplishing all 17 goals. The SDGs cover social and economic development issues including poverty, hunger, health, education, global warming, gender equality, water, sanitation, energy, urbanization, environment and social justice.
For this interdisciplinary session, we invite contributions discussing How Earth, Planetary and Space Scientists can address UN Sustainable Development Goals . We shall discuss the relevance of fields of research disciplines covered by EGU, and how they can inform and support society government bodies, and stakeholders for the SDGs.
The session will include invited and contributed oral papers, as well as interactive posters, and panel discussions.

Many water management sectors are already having to cope with extreme weather events, climate variability and change. For this purpose, climate services provide science-based and user-specific information on possible impacts. Such information can be based on weather forecasts or on climate projections. In this context, predictions on sub-seasonal, seasonal to decadal timescales are an emerging and essential part of hydrological forecasting. With horizons ranging from months to a decade, these probabilistic forecasts are used in industries such as transport, energy, agriculture, forestry, health, insurance, tourism and infrastructure.

This session aims to cover the advances in climate and hydrological forecasting, and their implications on forecasting extreme events and servicing water users. It welcomes, without being restricted to, presentations on:

- Making use of climate data for hydrological modelling (downscaling, bias correction, temporal disaggregation, spatial interpolation and other technical challenges),
- Methods to improve forecasting of hydrological extremes,
- Improved representations of hydrological extremes in a future climate,
- Seamless forecasting, including downscaling and statistical post- and pre-processing,
- Propagation of climate model uncertainty to hydrological models and impact assessment,
- Lessons learnt from forecasting and managing present day extreme conditions,
- Effective methods to link stakeholder interests and scientific expertise,
- Operational climatic forecasting systems.

The session will bring together research scientists and operational managers in the fields of hydrology, meteorology and climate with the aim of sharing experiences and initiating discussions on this emerging topic. We encourage presentations from initiatives such as the H2020 IMPREX, BINGO, S2S4E and CLARA projects, and from WWRP/WCRP S2S projects that utilise the recently established S2S project database, and all hydrological relevant 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 timescales will be discussed and evaluated in this session. 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).

Solicited talk:
Multi-year prediction of ENSO
By Jing-Jia Luo from the Institute for Climate and Application Research (ICAR), Nanjing University of Science Information and Technology, China

The Tibetan Plateau and surrounding mountain regions, known as the Third Pole, cover an area of > 5 million km2 and are considered to be the water tower of Asia. The Pan Third Pole expands on both the north-south and the east-west directions, going across the Tibetan Plateau, Pamir, Hindu Kush, Iran Plateau, Caucasian and Carpathian, and covering an area of about 20 million km2. Like the Arctic and Antarctica, the Pan Third Pole’s environment is extremely sensitive to global climate change. In recent years, scientists from around the globe have increased observational, remote sensing and numerical modeling research related to the Pan Third Pole in an effort to quantify and predict past, current and future scenarios. Co-sponsored by TPE (www.tpe.ac.cn), this session is dedicated to studies of Pan Third Pole atmosphere, cryosphere, hydrosphere, and biosphere and their interactions with global change. Related contributions are welcomed.

Climate education is often underestimated, both in terms of the role it can play in meeting the challenges of climate change, and with regards the difficulty of delivering it effectively. Climate change poses not only interdisciplinary scientific challenges around understanding the problem, but also socio-economic, technological, ethical and political challenges to implement appropriate responses at local to global scales. To rise to these challenges there is a growing need for climate education approaches and resources that adopt integrative learning objectives and pedagogically effective practices. Key objectives of climate education include furthering learners’ content knowledge of climate science and options for action (e.g., climate feedbacks, impacts, adaptation measures, renewable energy), cultivating science and communication skills (e.g., quantitative literacy, critical thinking, writing to inform), and initiating positive attitudes and actions (e.g., empathy and behavioural change).

This session invites contributions on climate education and outreach across all age levels (primary, high school and adult), settings (formal and informal) and approaches (e.g., websites, lab demos, serious games, pedagogic research, course design, citizen science, filmmaking, art). Contributions related to upper primary and middle school levels and those concerning adaptation of technical scientific materials for teaching, are particularly encouraged. The session is an opportunity for educators, resource developers, pedagogical experts and scientists to network and share ideas and research on climate education.

Modelling paleoclimates and the transitions between different climatic states still represents a challenge for models of all complexities. At the same time, the past offers a unique possibility to test models that are used to predict future climate.
We invite papers on paleoclimate model simulations, including time-slices (as in the Paleoclimate Modelling Intercomparison Project) and transient simulations of climate variations on timescales ranging from millennial to glacial cycles and beyond.
Comparison of different models (complex GCMs, EMICs and/or conceptual models), between different periods, between past and future climate states, and between models and data are particularly encouraged.

The hydrological processes (floods and droughts) in the Asian region are largely controlled by the interaction between Indian Summer monsoon, East Asian monsoon, mid-latitude westerlies, along with the high mountain glaciers. Studies based on the natural archives, such as lake and marine sediments, speleothem and tree rings indicate that these components are independent of each other. However, the significant interaction between these components has a direct impact on the billions of people in the Asian continent. The impact of these components points out that the monsoon variability is in a transitional phase and heads towards a significant “tipping point.” Tipping points are critical states at which a small perturbation can alter the system either to its previous state or towards a future state. However, in the climate system, the factors controlling the tipping points are not clearly understood. The natural as well as the anthropogenic factors are the critical tipping elements that could cause the significant irreversible change in the tipping points in the natural climate systems. The paleo-data can be used to validate the climate models for the future climate prediction and delineate the role of anthropogenic versus natural climate variability in the region.
In this session we invite scientists working with palaeoclimate data, instrumental observations and climate modelling, to discuss: (i) the challenges associated with an accurate prediction of climate system on various timescales for identifying the tipping points in the Asian region; (ii) role of different teleconnections (such as El-Niño, land-sea temperature differences and north Atlantic oscillations) controlling the Asian monsoonal systems; and (iii) the anthropogenic influence on shaping the Asian climate.

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

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

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

The seasonal reversal of monsoon winds and concurrent ocean currents, relatively deep thermocline along the equator due to the lack of steady easterlies, low-latitude connection to the neighboring Pacific and a lack of northward heat export due to the position of the Asian continent make the Indian Ocean unique among the other tropical ocean basins. These characteristics shape the Indian Ocean’s very dynamic intraseasonal, seasonal, and interannual variability, as well as its air-sea interactions. They also make the basin and its surrounding regions, which are home to a third of the global population, particularly vulnerable to anthropogenic climate change, and robust warming and trends in heat and freshwater fluxes have been observed in recent decades. Advances have recently been made in our understanding of the Indian Ocean’s circulation, interactions with adjacent ocean basins, and its role in regional and global climate. Nonetheless, significant gaps remain in understanding, observing, modeling, and predicting Indian Ocean variability and change across a range of timescales.

This session invites contributions based on observations, modelling, theory, and palaeo proxy reconstructions in the Indian Ocean that focus on understanding and predicting the links between Indian Ocean variability and monsoon systems on (intra)seasonal to interannual timescales, interactions and exchanges between the Indian Ocean and other ocean basins, decadal variability and its prediction, response to climate change, extreme events, as well as interactions between physical, biogeochemical, and ecological processes. Contributions are also sought that address research on the Indian Ocean grand challenges, as formulated by the Climate and Ocean: Variability, Predictability, and Change (CLIVAR), the Sustained Indian Ocean Biogeochemistry and Ecosystem Research (SIBER), and the International Indian Ocean Expedition 2 (IIOE-2) programs.

Mountain glaciations provide an invaluable record for past and present climate change. They are vital for any palaeoclimatologic interpretation and many related research questions. The utilization of this potential is, however, not trivial because of the wide diversity of formerly and currently glaciated mountain ranges. Apart from their specific complex and interacting geomorphological process-systems different climatic and glaciological conditions cause any subsequent global or intra-hemispheric correlations to become incredible challenging. This problem is further enhanced by ongoing specialisation within the scientific community. Working groups primarily focusing on either individual aspects of related research or selected mountain regions often remain somewhat disconnected. As a consequence of the challenges imposed on mountain glaciations, they occasionally seem to become sidelined in the context of Quaternary environmental reconstructions in comparison with other formerly glaciated regions. This discrepancy constitutes an unfortunate and unsatisfactory consequence that should be conquered.

The primary aim of this session is to evaluate the potential of mountain glaciations records and stimulate further research in this important field of research. Contributions on all relevant aspects of the topic are welcomed, for example: (a) glacial landforms and reconstruction of past glaciers, (b) dating techniques and geochronology compilations, (c) glacier dynamics and palaeoclimatic interpretations, or (d) impacts of ecosystems and human evolution/society. Submissions targeting these connections are specifically encouraged. While we encourage submitting abstracts from all abovementioned topics within the broad field of mountain glaciations, we would like to invite in particular those highlighting the specific conditions of mountain glaciations or addressing the relationship and connections between different of their aspects. To address the diversity of mountain 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 cover the whole time range from Early Pleistocene glaciations to the LGM and Holocene/modern glaciers.

During the past years, precursors of this session have 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. Their common target was to allow a better understanding of how glacial landforms should be interpreted in a (palaeo)climatic and/or chronological context. The session ultimately aims to facilitate a closer connection between different topological, methodological, and regional working groups related to various aspects of mountain glaciations in space and time. It is further designed to give everyone interested in the emerging collaborative research network “The Legacy of Mountain Glaciations” an opportunity to meet and exchange ideas and expertise.

We are pleased that Benjamin Chandler has accepted our invitation and will present a solicited talk about "Mapping the legacy of mountain glaciations".

Please note that the session conveners organized a public splinter meeting on Tuesday (April 9th) between 12.45 and 13.45 in room 0.51 (SMP 6) to meet all colleagues involved with the new application for a COST Action “Legacy of Mountain Glaciations” and those interested in the topic, We will use the opportunity to make this initiative more public and to discuss possible future directions.

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.

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 (GIS) 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. The processes and feedbacks involved operate on all time scales and thus require several types of information: satellite and instrumental data, climate models, and reconstructions based on geological archives. In this session, we invite contributions from a range of disciplines and across time scales, including observational data, historical data, proxy data, model simulations and forecasts, for the past climate and the future. 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 Arctic-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.

South America is home to hundreds of millions of people and harbors a wide range of unique and valuable ecosystems and resources. This makes South America, which extends from the tropics to high southern latitudes, vulnerable to a diverse range of climate change impacts. For example, future climate change scenarios suggest tropical South America is a drought hotspot due to its high sensitivity in responding to warming and drying. Thus, it is of great scientific, societal, environmental, and economic interest to better understand how climate varies and is changing over South America.

This session seeks contributions from a wide range of topics focusing on climate research over South America. Topics include, but are not limited to: climate change, climate variability, and extreme events in the past, present, and future using diagnostic, modeling, and statistical approaches.

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. Predictability studies indicate that decadal to multi-decadal variations in the oceans and sub-seasonal to multi-year sea ice variations are the largest sources of predictability in high latitudes. However, dynamical model predictions are not yet in the position to provide us with 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 climate variability and predictability in both hemispheres at 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) and potential teleconnections of high latitude climate with lower latitude climate. We also aim to link polar climate variability and predictions to potential ecologocal and socio-economic impacts and encourage submissions on this topic.
This session offers the possibility to present results from the ongoing projects and research efforts on the topic of high-latitude climate variability and prediction, including, but not limited to Year of Polar Prediction (YOPP), and the ARCPATH-project (Arctic Climate Predictions - Pathways to Resilient, Sustainable Societies).

Multiple environmental pathways have emerged from the climatic variability and extreme weather events, which have affected the state of well-being of human health. These phenomena have affected the spatiotemporal distribution of diseases such as Zika, Dengue, Cholera, Influenza, and others through the influence of vectors on making the hosts more susceptible to diseases- ultimately leading to conditions of trigger and transmission of infections in the human population. Remote sensing and station based hydroclimatic data can be used as an early indicator to mitigate the adverse impact of these outbreaks on human health.
This session will provide a platform to discuss the impacts of enhanced climatic variability on the spatiotemporal movement of diseases and the development of early warning systems. We encourage abstract submissions on the topics of climate-linked to diseases, disease monitoring and climate-based predictions of diseases.

Recent years have seen a substantial progress in the understanding of the nonlinear and stochastic processes responsible for important dynamical aspects of the complex Earth system. The Earth system is a complex system with a multitude of spatial and temporal scales which interact nonlinearly with each other. For understanding this complex system new methods from dynamical systems, complex systems theory, complex network theory, statistics and climate and Earth sciences are needed.

In this context the session is open to contributions on all aspects of the nonlinear and stochastic dynamics of the Earth system, including the atmosphere, the ocean and the climate system. Communications based on theoretical and modeling studies, as well as on experimental investigations are welcome. Studies that span the range of model hierarchy from idealized models to complex Earth System Models (ESM), data driven models, use observational data and also theoretical studies are particularly encouraged.

Invited speaker: Cecile Penland (NOAA)

The Earth system, consisting many interacting (sub)components, has strong internal variability on many time scales, is subject to a non-stationary forcing and mostly out of equilibrium with the changes in the radiative forcing. Large-scale transitions occur, for example due to the existence of tipping points in components of the climate system, and these in many cases depend on the complex interaction between different sub-systems. Moreover, the role of small-scale processes (in many models represented as noise) to induce these transitions is not well known for many important tipping elements.

In climate science, the concept of equilibrium and transient climate sensitivity is widely used for understanding how the climate changes in response to natural and anthropogenic radiative forcing. Over the last decade considerable progress has been made in understanding and defining climate sensitivity. Nevertheless, the uncertainty in climate sensitivity remains high. Moreover, its scope is quite limited, because it deals only with long term changes of the globally averaged surface temperature and is unable to account for the existence of tipping elements and large scale transitions.

The session aims at addressing the problem of connecting fluctuations and response for the climate system, including issues like climate sensitivity, climate variability, extreme events and tipping points. In particular, general approaches and novel measures to quantify the climate response to non-stationary forcing in the climate system are encouraged.
We also aim at studying the complex interactions between the different components and subcomponents of Earth system in order to understand how these interactions influence on system/subsystems (potentially tipping) behavior. External forcing may also impact the nature of interaction between connected subsystems. The submissions which are focused on the study of reasons and mechanisms of the emergent behavior are especially welcome. Such behavior may be inferred from time-dependent connectivity in data, first principle and data-driven modelling.

We welcome contributions that investigate specific feedbacks and their impact on climate sensitivity in all components of the climate system; processes on intermediate to long time scales that are generally difficult quantify such as ocean heat uptake are particularly encouraged. In addition, we welcome contributions studying the state dependence of climate sensitivity, including those focusing on the potential proximity of tipping points.

This is a merged session of 'Climate Sensitivity, Climate Response, and Tipping Points' and 'Networked connections in geosystems: revealing, studying of mechanisms, evolution in time, influence on emergent behavior'.

Tipping elements in the Earth's climate system are continental-scale subsystems that are characterized by a threshold behavior. It has been suggested that these include biosphere components (e.g. the Amazon rainforest and coral reefs), cryosphere components (e.g. the Greenland and Antarctic ice sheets) and large-scale atmospheric and oceanic circulations (e.g. the thermohaline circulation, ENSO and Indian summer monsoon). Once operating near a threshold or tipping point, these components can transgress into a qualitatively different state by small external perturbations. The large-scale environmental consequences could impact the livelihoods of millions of people.

In this session, we aim to bring together experts presenting and discussing the state-of-the-art research on tipping elements in the Earth's climate system, both in empirical data and numerical modelling of past, present and future climate. Among other topics, issues to be addressed in this session include critical thresholds for specific tipping elements, typical time scales of tipping, interactions and feedbacks between tipping elements, the potential for tipping cascades as well as environmental and socio-economic impacts of tipping.

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

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

Climate change in the Mediterranean region poses critical environmental issues and can affect many sectors of human activities. Contrasting climate trends, levels of exposure and vulnerability are present across this region with associated potential conflicts. Climate research is expected to contribute an increasingly precise information on the future climate and impacts of climate change in this region. A large set of instrumental records and climate proxies allows in many areas of the Mediterranean region to bridge present trends and past climate over a wide range of timescales. This session encourages contributions adopting a multidisciplinary approach and it aims to promote a dialogue between climatologists and researchers interested on the impacts of climate on human and natural systems. It aims at including contributions describing new scientific findings on the climate of the Mediterranean region, its dynamics, variability, change, and studies of climate related impacts on societies and ecosystems. The session considers different time scales (from paleoclimate to future model projections), different components (atmosphere, ocean, land and its hydrology) and factors (chemical, biological, anthropic) as well as highlights of sub-regional hotspots and climate processes.

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

Complementary to this, assessing the extent to which extreme weather events and impacts are attributable to anthropogenic climate change is a rapidly developing science, with emerging schools of thought on the methodology. Once again, the attribution of hydrometeorological events, long-term trends in these events and/or their impacts is less straightforward than temperature-related events.

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

From interannual to multidecadal time scales, there is strong climate variability over both the tropical and extratropical regions of the globe. Several modes of both extratropical atmospheric circulation (NAM/AO, NPO, PNA, NAO, SAM/AAO, etc.) and sea surface temperature (AMO, PDO, North Pacific Gyre Oscillation (NPGO), North Atlantic tripole (NAT), etc.) have been proposed to explain the extratropical climate variability. These modes have profound impacts on the global and regional climates (i.e., temperature, precipitation, frequency of high-impact weather/climate events such as hurricane/typhoon, drought/flood and cold/heat waves, etc.). The associated dynamics and physical processes, such as the ocean-atmosphere interaction, coupled oceanic-atmospheric bridge, atmospheric internal dynamics and oceanic dynamics, are important for understanding the tropical-extratropical climate variability and thus have implications for the interannual to decadal predictability. However, the relevant dynamics and processes are not very well represented in current climate system models. Often this is due to a lack of observations of the processes being modelled. Contributions are welcome from, but not limited to, research on observational, theoretical and modeling studies on the following topics:
1. Physical processes and dynamics in the atmosphere/ocean and atmosphere-ocean coupling associated with the tropical-extratropical climate variability on time scales from years to multi-decades.
2. The impacts and teleconnections of the tropical-extratropical climate variability on a broad range of time scales and underlying physical mechanisms.
3. Comparison of observed and simulated tropical-extratropical climate variability and its climate impacts.
4. Predictability, prediction and projection of tropical-extratropical atmospheric and oceanic variability at various time scales.

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

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

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.

This session is the result of a merger of two sessions:
Session CL4.28/AS3.6/GM10.2/SSP3.25
"Aeolian dust: initiator, player, and recorder of environmental change", and
Session AS3.7
"Atmospheric Desert Dust characterisation through Remote Sensing observations".

Together, these two sessions cover a huge range of scientific disciplines that study mineral-dust generation, transport, and deposition, as well as the many roles that mineral dust plays in environmental change.

The merger has resulted in a very nice set of interesting dusty abstracts covering huge ranges of spatial and temporal scales and with contributions from many scientific disciplines including atmospheric science, remote sensing, (palaeo)climate science, geomorphology and sedimentology but also human health and environmental science. We look forward to an inspiring and challenging PICO session and we invite you to participate!

Public information:
We have three PICO blocks and two invited speakers (in between the 2-minute madness and PICOs):
1) Vassilis Amiridis (10.45 - 11.00) - Dust remote sensing advances in the framework of ACTRIS
2) Carlos Pérez García-Pando (14.00 - 14.15) - FRontiers in dust minerAloGical coMposition and its Effects upoN climaTe (FRAGMENT)

The interaction of processes between the land surface, the planetary boundary layer (PBL), and the free troposphere are crucial for the understanding of weather and climate including extremes such as heavy precipitation and droughts. This requires an advanced understanding and modeling of the exchange of momentum, water, energy, and carbon at interfaces. In this session, we present and discuss current research activities contributing to this understanding, including L-A interaction and feedback to the diurnal cycle of the PBL, clouds, and precipitation as well as surface fluxes such as evapotranspiration and entrainment. We accept observational and modeling approaches to address these challenges. With respect to the observations, emphasis is put on the application of new sensor synergies, e.g., using active remote sensing for studying land surface exchange processes and entrainment at the PBL top, which have been addressed in field campaigns. With respect to theoretical understanding and modeling, we are focusing on new insights by feedback diagrams and grey zone experiments down to the large eddy simulation scale.

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

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

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

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

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

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

A planned outcome of this session is a summary document providing a mountains perspective and input for the IPCC Sixth Assessment Report, more specifically for Working Group I report on the Physical Sciences Basis and the cross-chapter paper on 'Mountains', which is flagged for the Working Group II report. This summary document is organized and supported by the Mountain Research Initiative (MRI).

The Arctic realm hosts vast extended continental shelves bordering old land masses, one of the largest submarine Large Igneous Provinces (LIPs) -the Alpha-Mendeleev Ridge - of Mesozoic age, and the slowest mid-ocean spreading ridge (the Gakkel Ridge) on the globe. Extreme variations in the evolution of landscapes and geology reflect the tug-of-war between the formation of new oceans, like the North Atlantic, and the destruction of older oceans: the South Anyui, Angayucham and North Pacific, which were accompanied by rifting, collision, uplift and subsidence. The causal relationships between the deep-mantle and surface processes in the Circum-Arcic region remain unclear. Geoscientific information on the relationship between the onshore geology and offshore ridges and basins in combination with variations in the mantle is the key for any deeper understanding of the entire Arctic Ocean.
This session provides a forum for discussions of a variety of problems linked to the Circum-Arctic geodynamics and aims to bring together a diversity of sub-disciplines including plate tectonics, mantle tomography, seismology, geodynamic modelling, igneous and structural geology, geophysical imaging, sedimentology, geochemistry. Particularly encouraged are papers that address lithospheric-mantle interactions in the North Atlantic, the Arctic and North Pacific regions, mantle dynamics and vertical and horizontal motion of crustal blocks and consequences for paleogeography. As geologic and tectonic models are inherently tied with changes in the oceanographic and climatic development of the Arctic, we also invite studies that focus on the interplay between these processes and across timescales. Lastly, we would like to invite contributions from studies concerning the implications of how the Arctic’s geography and geology are portrayed by modern data and issues related to jurisdiction and sovereign rights with particular focus on the UN Convention on the Law of the Sea.

Public information:
This session provides a forum for discussions of a variety of problems linked to the Circum-Arctic geodynamics and aims to bring together a diversity of sub-disciplines including plate tectonics, mantle tomography, seismology, geodynamic modelling, igneous and structural geology, geophysical imaging, sedimentology, geochemistry. As geologic and tectonic models are inherently tied with changes in the oceanographic and climatic development of the Arctic, we also show results from studies that focus on the interplay between these processes. The implications of how the Arctic’s geography and geology are portrayed by modern data and issues related to jurisdiction and sovereign rights with particular focus on the UN Convention on the Law of the Sea are also discussed.

Present-day glacial and periglacial processes in cold regions, i.e. arctic and alpine environments, provide 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 melting and shrinking of low-land permafrost. Current changes in mid-latitude mountain ranges could also serve as a proxy for future changes in arctic regions within a context of climate change (e.g. speed-up of creeping permafrost features, relictification of rock glaciers).

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.

Keynote lecture:
Hanne Hvidtfeldt Christiansen (Svalbard): Permafrost thermal dynamics in periglacial landforms in Svalbard during the last decade
Martin Margold (Prague): The retreat chronology of the western Laurentide Ice Sheet

Water and energy are essential to human society, and their supplies are vulnerable to climate change. For example, climate change will have impacts on the quantity and quality water resources, which may affect water availability for cooling at power plants, and on the yield of clean energy such as hydropower, wind power and solar energies. Considering increasing intensity and frequency of climate extremes in a warming world, understanding and quantifying the interdependence and challenges among climate, water and the energy system is critical. Considerable research is being conducted on some aspects of the climate-water-energy nexus, but this nexus is regionally diverse and has many unexplored facets. We aim to bring together researches focusing on the climate-water-energy nexus to both share current research and identify knowledge gaps.
To assess the integrative impacts of climate and climate change on water and energy systems and advance our understanding of the climate-water-energy nexus, we welcome contributions that focus on water and energy issues under a warming climate, including, but not limited to:
• climate modelling and future climate simulation with a focus on water availability
• Regional analyses of precipitation and water availability
• impacts of climate change on water resources
• impacts of climate change on clean energy yield, operation and management
• impacts of climate extremes on traditional energy production and delivery

Water is the defining feature of the habitable Earth; it is essential for all life as we know it. Evolution and maintenance of life in extremely water limited environments, which cover significant portions of the Earth, is not well understood. Akin to life, water-driven processes leave unique marks on the Earth’s surface. Mars is the only other planet currently known to bear the marks of water-driven surface processes, albeit fossil and of great age. The slow biotic and abiotic surface processes that may operate even in the virtual absence of liquid water are still essentially unknown. What is evident is that transient episodes of increased water availability can leave long lasting traces in extremely water limited environments. Intriguingly, those traces of bursts in Earth surface evolution have rarely been related to bursts in biological colonization/evolution, and vice versa, although both relate to the same trigger: water.

The objective of this session is to showcase research on the mutual evolutionary relationships between Earth surface processes and biota in arid to hyper-arid systems, where both biota and Earth surface process are severely and predominantly limited by the availability of water (rather than by extreme temperatures).
Solicited topics include (not exhaustive):
• fingerprints of biological activity at the (water) limit of the habitable Earth
• surface processes operating in the (virtual) absence of liquid water on Earth or extraterrestrial analogues (e.g. Mars)
• thresholds for biological colonization and concurrent fluvial transformation of landscapes
• tipping point(s) of biotically and abiotically controlled Earth surface systems
• chronometric and spatial information on the colonization and radiation of biota
terrestrial climatic records of (hyper-) arid regions on Earth

Marine geological processes cover a range of different disciplinary fields and their understanding usually requires an interdisciplinary approach. The interaction of geological, physical oceanographic, chemical and biological mechanisms in marine geological processes ranging from sediment erosion and deposition, to hydrothermal and fluid flow systems, to early diagenesis and geomicrobiology, is of specific interest. Such processes may take place in shallow or deep, in tropical and glacial environments, and they may be natural or partly human-influenced. Climate-induced perturbations in marine geological processes have occurred in present and past, and potentially will also occur in the future. Several of these processes may also have a profound human impact, such as tsunamis generated by tectonic or mass-slumping events, coastal erosion in response to changed currents or river discharge, and sediment gravity flow in deep waters affecting human infrastructures. /We encourage comprehensive and interdisciplinary abstracts within the broad field of marine geology and with direct relevance to marine processes or deposits concerned with rocks, sediments, and geo-physical and geo-(bio)chemical processes that affect them.

Ongoing climate change and a shorter return period of climate and hydrological extremes has been observed to affect the distribution and vitality of ecosystems. In many regions, available water is a crucial point of survival. Risk can be enhanced by the exposure and/or by the vulnerability of the affected ecosystem.
The session focuses on the complex assessment of all determining factors through a joint utilization of a broad spectrum of databases and methods (e.g. field and laboratory measurements, remote sensing, modelling and monitoring techniques) that can provide a suitable basis for developing long-term strategies for adaptation.
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 ecosystems induced by climate and hydrological extremes;
• correlation between the underlying environmental factors (e.g. climate, water holding capacity, soil characteristics) 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;
• expected tendencies of abiotic risk factors affecting and limiting the survival of the vulnerable species.
Contributions are encouraged from international experiences, ongoing research activities as well as national, regional and local initiatives.

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.

The nature of science has changed: it has become more interconnected, collaborative, multidisciplinary, and data intensive. Accordingly, the main aim of this session is to create a common space for interdisciplinary scientific discussion, where EGU-GA delegates involved in geoscientific networks can share ideas and present the research activities carried out in their networks. The session represents an invaluable opportunity for different networks and their members to identify possible synergies and establish new collaborations, find novel links between disciplines, and design innovative research approaches.

Part of the session will be focused on COST (European Cooperation in Science and Technology) Actions*. The first edition of the session (successfully held in 2018) was actually entirely dedicated to the COST networking programme and hosted scientific contributions stemming from 25 Actions, covering different areas of the geosciences (sky, earth and subsurface monitoring, terrestrial life and ecosystems, earth's changing climate and natural hazards, sustainable management of resources and urban development, environmental contaminants, and big data management). Inspiring and fruitful discussions took place; the session was very well attended. We are looking forward to continuing the dialogue this year and to receiving new contributions from COST Action Members.

Another part of the session will be dedicated to the activities of other national and international scientific networks, associations, as well teams of scientists who are carrying out collaborative research projects.

Finally, the session is of course open to everyone! Accordingly, abstracts authored by scientists not involved in wide scientific networks are most welcome, too! In fact, in 2018 we received a good number of such abstracts, submitted by individual scientists or small research teams who wished to disseminate the results of their studies in front of the multidisciplinary audience that characterizes this session, as an alternative to making a presentation in a thematic session. This may be a productive way to broaden the perspective and find new partners for future interdisciplinary research ventures. We hope to receive this kind of abstracts this year, as well.


-- Notes --

* COST (www.cost.eu) is a EU-funded programme that enables researchers to set up their interdisciplinary research networks (the “Actions”), in Europe and beyond. COST provides funds for organising conferences, workshops, meetings, training schools, short scientific exchanges and other networking activities in a wide range of scientific topics. Academia, industry, public- and private-sector laboratories work together in Actions, sharing knowledge, leveraging diversity, and pulling resources. Every Action has a main objective, defined goals and clear deliverables. This session was started as a follow up initiative of COST Action TU1208 “Civil engineering applications of Ground Penetrating Radar” (2013-2017, www.GPRadar.eu).

Regional climate modeling has tremendously grown in the last decades, encompassing a large and diverse scientific community. Regional climate models (RCMs) are run on a wide range of resolutions, from a few to a few tens of km, and applications, from process studies to past and future climate simulations. In addition, the Coordinated Regional climate Downscaling EXperiment (CORDEX) has been recently implemented to increase international coordination among different research efforts and produce large ensembles of high resolution climate projections over regiona worldwide. Specifically, the Phase II CORDEX framework has been launched, including a CORDEX-CORE initiative aimed at generating a coherent set of projections over all CORDEX domains at increased resolution (12-25 km) and a number of Flagship Pilot Studies (FPSs) addressing specific research challenges, such as convection permitting modeling. These two initiatives are also intended to provide a strong input to the upcoming sixth assessment report of the Intergovernmental panel on Climate Change (IPCC). The session seeks for contributions on:
1) New developments in RCM research
2) Key methodological issues, such as Added Value and metrics for model assessment
3) Application of RCMs for different scientific challenges, e.g. extreme events, the hydrologic cycle, effect of land-use change and aerosols
4) Contributions to the CORDEX CORE and FPS initiatives
5) Use of RCMs to provide multi-model ensemble-based climate information for Vulnerability, Impacts and Adaptation (VIA) studies)

Accurate and homogeneous long-term data records (i.e., data that are forced to look like a common reference) are essential for researching, monitoring, or attenuating changes in climate, for example to describe the state of climate or to detect climate extremes. Likewise, reanalysis needs accurate and homogenized/harmonized data records (i.e., data records in which the unique nature of each sensor is maintained). Temporal changes, such as degradation of instruments, changes of instruments, changes of observation practices, or changes of station location and exposure, cause artificial non-climatic sudden or gradual changes in data records. The magnitude and uncertainty of these changes impact the results of climate trend analyses. Therefore, data intended for applications, such as making a realistic and reliable assessment of historical climate trends and variability, require to be homogenized or harmonized consistently so as to obtain well calibrated data records including measurement uncertainties.

The above described factors influence the quality of different essential climate variables, including atmospheric (e.g., air temperature, precipitation, wind speed), oceanic (e.g., sea surface temperature), and terrestrial (e.g., albedo, snow cover) variables from in-situ observing networks, satellite observing systems, and climate/earth-system model simulations. Our session calls for contributions related to the:

• Calibration, quality control, homogenization/harmonisation and validation of either fundamental or essential climate data records.

• Development of new data records and their analysis (spatial and temporal characteristics, particularly of extremes).

• Examination of observed trends and variability, as well as studies that explore the applicability of techniques/algorithms to data of different temporal resolutions (annual, seasonal, monthly, daily, and sub-daily).

• Rescue and analysis of centennial meteorological observations, with focus on data prior to the 1960s, as a unique source to fill in the gap of knowledge of climate variability over century time-scales. In particular, we encourage wind studies dealing with the observed slowdown (termed “stilling”) of near-surface winds in the last 30-50 years.

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

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

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

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

The session will include a solicited talk from Christoph Schär (ETH Zürich) on prospects and challenges in convection-resolving modelling. The session will be chaired by M Tölle and H Truhetz.

The quality of predictions of weather and climate depends on both resolution and complexity of the models that are used. However, resolution and complexity are limited by the computational performance that is available on today's supercomputers. While weather and climate models run on some of the fastest supercomputers of the world, models typically fail to run close to peak performance such that there is still room for a significant speed-up if efficiency is improved. The increase in parallelisation in high performance computing and the availability of various computing platforms is imposing significant challenges for the community to find the optimal hardware/model configuration and to achieve the best performance. On the other hand, the evaluation of high resolution simulations is often tedious due to large data volumes, limited statistic that is affordable and changed model behaviour that needs to be studied (e.g. if convection or eddies are resolved explicitly or if non-hydrostatic equations need to be used).
These challenges can only be addressed appropriately in a close collaboration between Computing and Earth System Scientists. This session aims to bring together scientists who run and evaluate atmosphere and ocean models with high resolution and complexity as well as scientists who enable these models to run as efficiently as possible on existing and future high performance computing architectures (regarding both model development and model optimisation). The session will also be an opportunity for scientists from the EU projects PRIMAVERA, ESCAPE and ESiWACE as well as HighResMIP from CMIP6 to meet and interact.

V. Balaji from Princeton University will be our keynote speaker invited by the ESiWACE EU Horizon2020 COE (grant number 675191).

Weather and climate models used for weather forecasts, seasonal predictions and climate projections, are essential for decision making on timescales from hours to decades. However, information about future weather and climate relies on complex, though imperfect, numerical models of the Earth-system. Systematic biases and random errors have detrimental effects on predictive skill for dynamically driven fields on weather and seasonal time scales. Biases in climate models also contribute to the high levels of uncertainty in many aspects of climate change as the biases project strongly on future changes. A large source of uncertainty and error in model simulations is unresolved processes, represented through parameterization schemes. However, these errors typically materialize at large spatial scales. Our physical understanding of the mechanical and dynamical drivers of these large-scale biases is incomplete. Incomplete mechanistic understanding hinders marked improvements in models, including identification of the parameterizations most in need of improvement.

Understanding and reducing the errors in weather and climate models due to parameterizations and poorly represented mesoscale to regional scales processes is a necessary step towards improved weather and climate prediction. This session aims to bring together these two perspectives, and unite the weather and climate communities to address this common problem and accelerate progress in this area.

This session seeks submissions that aim to quantify, understand, and reduce sources of error and bias in weather and climate models. Themes covered in this session include:

- Theory and development of parameterization. Impact on errors in mean state, model variability and physical process representation;

- Improved physical understanding of the drivers of large-scale biases including the use of process studies, idealized modeling studies and studies with strong observational components;

- Growth and propagation of error and bias in models; model errors across temporal and spatial scales; dependency of errors on model resolution and the development of scale-aware parameterization schemes;

- Use of “emergent constraints” to relate present day model biases with the climate change signal;

- Understanding and representing random model error.

Invited presentations: Felix Pithan (AWI) and Bob Plant (University of Reading)

Lead Convenors: Hannah Christensen and Stefan Sobolowski
Co-convenors: Craig Bishop, Ariane Frassoni, Daniel Klocke, Erica Madonna, Isla Simpson, Keith Williams, Giuseppe Zappa

From the perspective of Earth System predictions, the use of machine learning, and in particular deep learning, is still in its infancy. There are many possible ways how machine learning could improve model quality, generate significant speed-ups for simulations or help to extract information from numerous Earth System data, in particular satellite observations. However, it has yet to be shown that machine learning can hold what it is promising for the specific needs of the application of Earth System predictions. This session aims to provide an overview how machine learning can/will be used in the future and tries to summarise the state-of-the-art in an area of research that is developing at a breat