The persistent rapid decline of the Arctic sea ice in the last decades is a dramatic indicator of climate change. The Arctic sea ice cover is now thinner, weaker and drifts faster. Extreme air temperatures over land and ocean are more common, contributing to accelerated ice sheet melting and summer sea ice loss in the Kara and Laptev Seas. On land, the permafrost is dramatically thawing, glaciers are disappearing, and forest fires are raging. The ocean is also changing: the volume of freshwater stored in the Arctic has increased as have the inputs of coastal runoff from Siberia and Greenland and the exchanges with the Atlantic and Pacific Oceans. As the global surface temperature rises, the Arctic Ocean is speculated to become seasonally ice-free by the mid 21st century, which prompts us to revisit our perceptions of the Arctic system as a whole. What could the Arctic Ocean look like in the future? How are the present changes in the Arctic going to affect and be affected by the lower latitudes? What aspects of the changing Arctic should observational, remote sensing and modelling programmes address in priority?
In this session, we invite contributions from a variety of studies on the recent past, present and future Arctic. We encourage submissions examining interactions between ocean, atmosphere and sea ice; on emerging mechanisms and feedbacks in the Arctic; and on how the Arctic influences the global ocean. Submissions taking a cross-disciplinary, system approach and focussing on emerging cryospheric, oceanic and biogeochemical processes and their linkages with land are particularly welcome.
We aim to promote discussions on future plans for Arctic Ocean modelling and measurement strategies, including on constraining models with observations, and encourage submissions on CMIP , as well as on recent observational programs, such as the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC), which cosponsors this session.

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 decade, several observational projects have been focused on the Atlantic circulation changes, for instance ACSIS, OSNAP, OVIDE, RACE and RAPID, and new projects have started such as CANARI and EPOC. Most of these programs include also a modelling component. Another important issue is the interaction between the atmosphere, the ocean and the cryosphere, and how this affects the climate.

This year we celebrate the 20th year of the RAPID array and we plan to dedicate part of the session to this anniversary. Abstracts for this part of the session are particularly welcome.

We also welcome contributions from observers and modellers 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

The Indian and tropical Atlantic Oceans exhibit pronounced variability in ocean processes and air-sea interactions on daily to decadal time scales, and are fringed by some of the most densely populated regions in the world. Both basins host, and are in turn influenced by, processes and teleconnections that shape our global climate, for instance: monsoons, the Benguela and Dakar Niños, the Atlantic Meridional Mode, the Indian Ocean Dipole and the Madden-Julian Oscillation. Interactions between these systems and climate modes are complicated and lead to a dynamic environment that can remain challenging to predict.

This session invites contributions based on observations, modelling, theory and palaeo proxy reconstructions that advance our understanding of Indian and tropical Atlantic Ocean variability, and its physical, biogeochemical and ecological influence on the ocean and atmosphere. We welcome studies on high-impact events of societal relevance, such as marine heat waves, tropical cyclones and extreme rainfall, that might affect the human populations of the tropical Indo-Atlantic. Studies relating to the prediction of such events, and on the impacts of systematic model errors in simulating regional climate, are particularly welcome, including those that make use of novel methodologies such as machine learning.

The Southern Ocean is vital to our understanding of the climate system. It is a key region for vertical and lateral exchanges of heat, carbon, oxygen, and nutrients, with significant past and potential future global climate implications, especially around the latitudes of the Antarctic Circumpolar Current. The role of the Southern Ocean as a dominant player in heat and biogeochemical exchanges as well as its response to changing atmospheric forcing and increased Antarctic melting remains uncertain. Indeed, the sparsity of observations of this system and its inherent sensitivity to small-scale physical processes, not fully represented in current Earth System Models, result in large climate projection uncertainties and considerable discrepancies between observations and models. To address these knowledge gaps, the Southern Ocean is currently subject to investigations with increasingly advanced observational platforms as well as theoretical, numerical and machine learning techniques. These efforts are providing deeper insight into the three-dimensional patterns of Southern Ocean changes on sub-annual, multi-decadal and millennial timescales, as well as their potential future modifications under a changing climate. In this session, we welcome contributions concerning the role of the Southern Ocean in past, present, and future climates. These include (but are not limited to) small-scale physics and mixing, water mass transformation, gyre-scale processes, nutrient and carbon cycling, ventilation, ocean productivity, climate-carbon feedbacks, and ocean-ice-atmosphere interactions. We also welcome contributions on how changes in Southern Ocean circulation as well as heat and carbon transport affect lower latitudes and global climate more generally.

The interaction between the ocean and the cryosphere in the Southern Ocean has become a major focus in climate research. Antarctic climate change has captured public attention, which has spawned a number of research questions, such as: Is Antarctic sea ice becoming more vulnerable in a changing climate? Where and when will ocean-driven melting of ice shelves yield a tipping point in the Antarctic climate? What drives the observed reduction in Antarctic Bottom Water production? How does the Antarctic Slope Current interact with the continental shelf? What role do ice-related processes play in nutrient upwelling on the continental shelf and in triggering carbon export to deep waters?

Recent advances in observational technology, data coverage, and modeling provide scientists with a better understanding of the mechanisms involving ice-ocean interactions in the far South. Processes on the Antarctic continental shelf have been identified as missing links between the cryosphere, the global atmosphere and the deep open ocean that need to be captured in large-scale and global model simulations.
This session calls for studies on physical and biogeochemical oceanography linked to ice shelves and sea ice. This includes work on all scales, from local to basin-scale to circumpolar; as well as paleo, present-day and future applications. Studies based on in-situ observations, remote sensing and regional to global models are welcome. We particularly invite cross-disciplinary topics involving glaciology, sea ice physics and biological oceanography.

The ocean surface layer mediates the transfer of matter, energy, momentum and trace gases between the atmosphere, ocean and sea ice, and thus plays a central role in the dynamics of the climate system. This session will focus on the ocean surface layer globally, from the coasts to the pelagic ocean and its interactions with the overlaying low atmosphere. The session covers recent progress in understanding key processes in the ocean surface layer, including wind-driven turbulence, surface-wave effects, convection, surface-layer fronts, surface-layer instabilities, submesoscale dynamics, diurnal warm and rain layers, and surface layer communication with the ocean’s interior. Particular emphasis is placed on the impact of ocean surface-layer processes on air-sea fluxes and feedbacks in field experiments and coupled atmosphere-ocean models. This includes SST coupling with the atmospheric boundary layer, tropical cyclones, extreme events, and parameterizations of air-sea interactions. The interaction of the ocean surface layer with sea ice is also of particular interest. We welcome interdisciplinary studies including atmospheric deposition of nutrients and pollutants to the ocean and impacts on ocean biogeochemistry, ocean-atmosphere fluxes of climate-active species and potential feedbacks to climate. We encourage a diversity of approaches: observational (laboratory, in-situ and remote sensing), theoretical, and numerical modeling studies focusing on the ocean surface layer and its interactions with the atmosphere and sea ice, regardless of the temporal and spatial scales considered. This session also includes a focus on the legacy and activities of the 20-year Surface Ocean - Lower Atmosphere Study (SOLAS) and is jointly sponsored by SOLAS and GESAMP Working Group 38 on ‘The Atmospheric Input of Chemicals to the Ocean’.

Meso- and sub-mesoscale dynamics are vital components of the Earth’s oceanic circulation. They play a critical role in the horizontal and vertical transport of heat, freshwater, phytoplankton and biogeochemical tracers, at regional and local scales, and ultimately mediating local oceanic-atmospheric exchanges. Although more prominent in the upper layers, their impacts can be far-reaching into the ocean interior. Recent scientific and technological advancement have enabled the observations and modelling of the ocean across a wide spectrum of scales, spanning from hundreds of meters to tens of kilometres, and from hours to days. Extensive observational initiatives such as EUREC4A-OA/ATOMIC alongside high-resolution modelling studies are starting to yield new insights into the multidisciplinary impacts of mesoscale and submesoscale processes. Meso- and sub-mesoscale air-sea interaction in regions such as the Tropical Oceans, the Southern Ocean, the western boundary currents and their extensions may have basin and global scale impacts via oceanic and atmospheric teleconnection.

This session welcomes contributions from observational, theoretical and modelling studies focusing on mesoscale and submesoscale dynamics, and their potential impacts on the biogeochemistry, biology and air-sea interactions. Specific topics include:

1. Impacts of meso- and sub-mesoscale processes on the horizontal and vertical transport of physical/biogeochemical/biological tracers in the global ocean
2. Meso- and sub-mesoscale ocean and atmospheric interactions and air-sea fluxes
3. Large scale impacts of the meso- and sub-mesoscale processes

Knowledge of energy, heat, salt, and carbon transports between and within climate components is crucial in order to understand the Earth’s climate system behavior and its variability, predictability, and future changes. In the ocean, the role of the Atlantic Meridional Overturning Circulation and tropical and subtropical gyres is essential for the heat, salt, and carbon budget and the water mass distributions and transformations (in Eulerian, Lagrangian, and tracer coordinates) of individual basins and in both hemispheres. In the atmosphere, the zonal mean Hadley circulation determines meridional energy transport over the tropics, while Rossby and planetary-scale waves modulate the energy exchanges carried by extratropical eddies. Large-scale atmospheric and oceanic circulation, the hydrological cycle, and heat and salt transport are tightly intertwined through physical processes, phase changes, and energy conversions that are sensitive to natural and anthropogenic forcings and feedbacks. From a modelling perspective, understanding of energy transfers from oceanic and atmospheric large-scale circulation to the internal wave field through mesoscale and sub-mesoscale eddies is the basis for the development of new parameterizations for both oceanic and atmospheric small-scale processes.

We invite submissions addressing the interplay between Earth’s energy exchanges and the general circulation, using modeling, theory, and observations across all scales. We encourage contributions regarding the forced response and natural variability of the general circulation, understanding present-day climate, past and future changes, and impacts of global features and changes on global and regional climate, and their importance for climate predictability.

Marine heatwaves (MHWs) are discrete and prolonged warm ocean extremes that can cause substantial ecological and socio-economic impacts. Warming ocean temperatures due to climate change can be expected to exacerbate the severity of MHWs through the 21st century. Understanding of the physical mechanisms that generate MHWs is important to improving our capacity to forecast them. Meanwhile, gaining a better understanding of the impacts of MHWs on ecosystems is significant for promoting sustainable development in the face of climate change. We welcome abstract submissions across all aspects of marine heatwave research and particularly encourage submissions in the following areas:
• Processes and drivers of MHWs at the surface and subsurface: The role of local drivers and remote forcing in MHW generation and evolution.
• Methods for MHW detection and characterization: Discussion of MHW definition and ecologically based indices.
• MHWs in a changing climate: Projections of MHWs in the future under different scenarios.
• Historical analyses of MHWs: Process understanding of past pronounced MHW events and their impacts.
• MHWs and compound events: Interactions between MHWs and other systems (e.g., cyclonic storms, monsoons, and atmospheric heatwaves) or biogeochemical extremes.
• Ecological, socioeconomic, and biological impacts of MHWs.
• MHW predictability and prediction: Insights from advanced statistical methods, climate models, machine learning, etc.

The oceans are changing rapidly in response to the changing climate manifested in record-breaking temperatures in the North Atlantic, altered ocean currents, and changes in the marine carbon system. Further changes are expected in a warmer future climate. Understanding the mechanisms of oceanic climate change are crucial to develop realistic ocean projections. The latest projections, simulated using the recent Climate Model Intercomparison Project (CMIP) phase 6, provide meaningful insights on the ocean circulation responses under various climate change scenarios. These projections are essential to quantify the impacts of oceanic climate change and in developing successful adaptation strategies. This session will bring together people with the common interest of what the future ocean circulation will look like.

We encourage submissions from studies covering global, basin wide, regional, or coastal changes. Topics covering changing ocean circulation and transports, variability and trends, tipping points and extremes, as well as temperature, salinity and biogeochemistry are welcomed. This session is not limited to CMIP analysis but submissions using other modelling datasets and statistical projections are very much encouraged.

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

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.

In recent years, sea ice has displayed behaviour unseen before in the observational record, both in the Arctic and the Antarctic. This fast-changing sea-ice cover calls for adapting and improving our modelling approaches and mathematical techniques to simulate its behaviour and its interaction with the atmosphere and the ocean, both in terms of dynamics and thermodynamics.

Sea ice is governed by a variety of small-scale processes that affect its large-scale evolution. Modelling this nonlinear coupled multidimensional system remains a major challenge, because (1) we still lack the understanding of the physics governing sea-ice dynamics and thermodynamics, (2) observations to conduct model evaluation are scarce and (3) the numerical approximation and the simulation become more difficult and computationally expensive at higher resolution.

Recently, several new modeling approaches have been developed and refined to address these issues. These include but are not limited to new rheologies, discrete element models, advanced subgrid parameterizations, the representation of wave-ice interactions, sophisticated data assimilation schemes, often with the integration of machine learning techniques. Moreover, novel in-situ observations and the growing availability and quality of sea-ice remote-sensing data bring new opportunities for improving sea-ice models.

This session aims to bring together researchers working on the development of sea-ice models, from small to large scales and for a wide range of applications such as idealised experiments, operational predictions, or climate simulations, to discuss current advances and challenges ahead.

While observed volume, concentration and extent of Arctic sea ice have decreased dramatically over the last decades, climate model simulations of the recent past feature a slower sea-ice decline than observed. These same models are then used to project future sea ice changes, raising the question if even the most optimistic future emission scenarios will be enough to preserve the summer sea ice in the future.

Although the sea-ice decrease is the most pronounced in late summer, understanding coupled key processes of ocean/sea-ice/atmosphere-system during the so-called shoulder seasons, the onsets of the melt in spring and freeze up in autumn, is important since the timing of these set the boundaries for the length of the melt season and therefore strongly influence the total melt in any given year.

While the autumn freeze onset has received some attention, substantially less is known about the spring melt onset, partly because of a lack of observations to characterize and understand the processes controlling or leading up to it, on different scales. An improved understanding of this season is important, to inform model development crucial for simulations and assessments of future changes in the Arctic climate system.

This session focuses on the late winter and early spring in the Arctic and especially the onset of the summer sea-ice melt. We invite presentations broadly on ocean, sea-ice and atmospheric processes over a large spectrum of scales governing or being strongly affected by this transition, from long-term observations and reanalysis, process and climate modeling and especially from observations from new field campaigns covering this time period, such as MOSAiC and ARTofMELT.

Feedbacks within the Earth’s system involving the global carbon cycle, ice-sheet dynamics and oceanic circulation played a significant role in shaping the timing and amplitude of Quaternary deglaciations and their preceding glacial periods, as well as abrupt millennial-scale variability within the Last Glacial Cycle. For example, the deep ocean likely played a key role in modulating changes in atmospheric CO2; and ice sheet evolution exerts a strong control on atmosphere and ocean circulation. However, the precise combination of mechanisms and feedbacks responsible for glacial-interglacial and millennial-scale climate transitions remains unresolved. This session invites contributions from studies that provide an improved understanding of the processes and feedbacks occurring during glacial periods and deglaciations during the past 2.6 Ma. This includes new palaeo records, data syntheses and numerical simulations examining climate, the global carbon cycle, continental ice-sheets, ocean circulation, and sea-level.

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

This session covers climate predictions from seasonal to multi-decadal timescales and their applications. Continuing to improve such predictions is of major importance to society. The session embraces advances in our understanding of the origins of seasonal to decadal predictability and of the limitations of such predictions, as well as advances in improving the forecast skill and reliability and making the most of this information by developing and evaluating new applications and climate services. The session welcomes contributions from dynamical as well as statistical predictions (including machine learning methods) and their combination. This includes predictions of climate phenomena, including extremes and natural hazards, from global to regional scales, and from seasonal to multi-decadal timescales ("seamless predictions"). The session also covers physical processes relevant to long-term predictability sources (e.g. ocean, cryosphere, or land) and predictions of large-scale atmospheric circulation anomalies associated to teleconnections as well as observational and emergent constraints on climate variability and predictability. Also relevant is the time-dependence of the predictive skill and windows of opportunity. Analysis of predictions in a multi-model framework and innovative ensemble-forecast initialization and generation strategies are another focus of the session. The session pays particular attention to innovative methods of quality assessment and verification of climate predictions, including extreme-weather frequencies, post-processing of climate hindcasts and forecasts, and quantification and interpretation of model uncertainty. We particularly invite contributions presenting the use of seasonal-to-decadal predictions for assessing risks from natural hazards, adaptation and further applications.

To address societal concerns over rising sea level and extreme events, understanding and quantifying the contributions behind these changes is key to anticipate potential impacts of sea level change on coastal communities and the global economy. In this session, we address these challenges and we welcome contributions from the international sea level community that improve our knowledge of the past, present and future changes in global and regional sea level, extreme events and coastal impacts.
We focus on studies exploring the physical mechanisms for sea level rise and variability and the drivers of these changes, at any time scale (from high-frequency phenomena to paleo sea level). Investigations on linkages between variability in sea level, heat and freshwater content, ocean dynamics, land subsidence and mass exchanges between the land and the ocean associated with ice sheet and glacier mass loss and changes in the terrestrial water storage are welcome. Studies focusing on future sea level changes are also encouraged, as well as those discussing potential short-, medium-, and long-term impacts on coastal environments, as well as the global oceans.

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 global and regional climate-related risks.
The main goals of the session is (i) to identify gaps in current climate prediction methods and (ii) to report and evaluate the latest progress in climate forecasting on subseasonal-to-decadal and longer timescales. This will include presentations and discussions of the developments in predictions for the different time horizons 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, exploration of artificial-intelligence methods, etc.
Following the new WCRP 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 between atmosphere, land, ocean, and sea-ice components, as well as the impacts of coupling and feedbacks in physical, hydrological, chemical, biological, and human dimensions. 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 CMIP6 decadal prediction experiments, and climate-prediction research and application projects.
An increasingly important aspect for climate forecast's applications is the use of most appropriate downscaling methods, based on dynamical, statistical, artificial-intelligence approaches or their combination, that are needed to generate time series and fields with an appropriate spatial or temporal resolution. This is extensively considered in the session, which therefore brings together scientists from all geoscientific disciplines working on the prediction and application problems.

Contributions are invited on recent advances in the understanding of circulation and fluid dynamical processes in coastal and shelf seas. Observational, modelling and theoretical studies are welcome, spanning the wide range of temporal and spatial scales from the shelf break to the shore. In order to capture the dynamic nature of our coastal and shelf seas the session includes processes such as shelf circulation, exchange flows in semi-enclosed seas, eddies, sub-mesoscale processes, river plumes, and estuaries, as well as on flow interactions with bio-geochemistry, sediment dynamics, morphology and nearshore physics. Contributions on impacts of climate change and man-made structures on our shelf seas and estuaries are also welcome.

Coastal oceanographic processes present important differences with deep water oceanography, resulting in higher prediction errors, where topo-bathymetry in shallow areas exerts a strong control on hydrodynamic fields, further modified by stratification, land boundaries and coastal infrastructure. Predictability is limited by strong non-linear interactions (e.g. breaking waves, nearshore circulation and sediment fluxes), choice of numerical strategies (e.g. nested meshes, finite-elements or smooth-particle simulations) or modulations typical of restricted domains (e.g. seiching or vegetation filtering). Coastal observations (in-situ and remote) are therefore necessary to enhance numerical models, where the advent of new satellite capabilities (e.g. Sentinel resolution and sensors) and modelling advances (e.g. coupling or unstructured grids), together with enhanced coastal observatories, are leading to qualitative advances for coastal oceanography applications. Coastal analyses under future scenarios become even more challenging, since transitional areas are more strongly impacted by changing climates (e.g. changing domains due to sea-level rise). For these reasons, it is timely to discuss recent advances in: a) coastal coupled hydro-morpho-ecological modelling at different scales; b) coastal aggregation of in-situ/satellite/numerical data from different sources; c) knowledge-based coastal applications, including the assessment of nature-based interventions; d) use of novel approaches, such as data assimilation or machine learning; and e) uncertainties in coastal decision-making. Building on these challenges, we invite presentations on coastal modelling, data assimilation, boundary effects or operational coastal predictions with/without interactions with Nature-based or traditional interventions. Contributions tackling open questions on non-linear response functions, artificial intelligence or big data for coastal applications are welcome. These coastal topics should conform a fruitful session for discussing coastal oceanography applications, including conventional and nature-based interventions under climate change. We offer the possibility, for interested authors, to submit evolved versions of their presentations to the currently open special issue in Ocean Sciences (see https://www.ocean-science.net/articles_and_preprints/scheduled_sis.html).

The Mediterranean and Black Seas, already referred to as climate 'hotspots', are experiencing rapid and extreme environmental stress that is straining the vulnerability of these semi-enclosed and densely populated basins. The sea surface warming and the increase of the thermal content in the deepest layers, the salinisation of intermediate and deep waters, the sea level rising, and the deoxygenation trend are all tangible elements of the ongoing environmental change in the last decades.

The risks associated with climate variability and, in particular, with extreme environmental events create unprecedented challenges that eventually lead to social and economic stresses. To tackle these challenges a multidisciplinary scientific approach is essential.

The main aim of this session is to bring together oceanographers working on physical and biogeochemical processes at different temporal and spatial scales in the Mediterranean and Black Seas, using new theoretical approaches, in situ observations of the entire water column, including the deep layers, as well as state-of-the-art ocean/climate models.
Studies that embrace these approaches and methodologies are thus invited to contribute in order to provide a comprehensive understanding of the complex interactions and processes occurring in these seas.
Furthermore, this multidisciplinary approach can enhance the predictability of thermohaline dynamics and the related variability of these unique marine environments, helping in the development of further adaptive economic strategies sustainable and resilient to the impacts of climate change.

Storm surges and tides are important drivers of coastal hazards, including flooding, erosion, and other impacts. They interact with each other, as well as with other coastal processes. Energy from the surface tide is also converted to internal tides, driving ocean processes. Both storm surges and tides show large seasonal and decadal variations. They are influenced by sea-level rise and climate change, and local anthropogenic changes such as dredging and alterations to estuaries. Flood defenses need to be designed and operated allowing for increasingly frequent coastal flooding due to sea-level rise, whilst understanding of tide and surge events is also critical for tidal energy generation. Changes in stratification may alter internal tides dynamics in coastal and global regions. This calls for an improved understanding of long-term trends and sea-level interactions. More precision is required of water level forecasts up estuaries and tidal rivers. Both observations (in-situ measurements and remote sensing) and models (numerical and data-driven) are important tools in understanding how storm surges and tide vary across space and time.

The aim of this session to share innovative approaches and recent advancements in understanding these complex processes and their implications for coastal regions globally. We welcome contributions that i) present novel approaches in measurement, numerical and empirical modelling of (surface and internal) tides and storm surges; ii) enhance our understanding of drivers of extreme sea level events and/or their interactions; iii) investigate the influence of past climate variability on storm surges, surface and internal tides, and their long-term variability; or iv) develop future projections of storm surges and tides and the impact of climate change.

With increasing coastal urbanisation and impacts from climate change, there is a pressing need for understanding, monitoring and predicting the environmental conditions and hazards in the global coastal ocean. This challenge requires ocean observing and modelling systems designed to monitor coastal variability at regional to local scales, as well as regional downscaling tailored to include coastal processes absent in the global Earth system models. This session is affiliated with CoastPredict, a UN Ocean Decade endorsed programme dedicated to the design and implementation of an integrated coastal observation and prediction system to support coastal community resilience. With this session we aim to provide a discussion platform around observing, forecasting and projecting coastal processes, from short time scale events to climate projections. We welcome contributions related to:
• Challenges and advances in observing and modelling the global coastal system with high temporal and spatial resolution (e.g. new community science platforms and modelling the coupled coastal system: ocean - atmosphere - hydrology - land – ecosystem - humans system).
• Complementary use of observations and models towards better short-term forecasting and early warnings along the coastal regions; and observing system design experiments focusing on the coastal seas.
• Dynamical and/or statistical downscaling and forecasting methodologies for the coastal ocean including machine learning, bias correction techniques and spectral nudging.
• Uncertainty treatment for short to long-term coastal ocean projections, e.g. ensemble approaches.
• Nature-based solutions for adaptation planning in coastal systems, and coastal carbon dioxide removal for climate mitigation.
• Coastal management, covering the full cycle of transdisciplinary information collection, planning, decision-making, management and monitoring of implementation.

The ocean floor hosts a tremendous variety of forms that reflect the action of a range of tectonic, sedimentary, oceanographic, biological and (bio)geochemical processes at multiple spatio-temporal scales. Many such processes are hazards to coastal populations and offshore installations, and their understanding constitutes a key objective of national and international research programmes and IODP expeditions. High quality bathymetry, especially when combined with sub-seafloor and/or seabed measurements, provides an exciting opportunity to integrate the approaches of geomorphology and geophysics, and to extend quantitative geomorphology offshore. 3D seismic reflection data has also given birth to the discipline of seismic geomorphology, which has provided a 4D perspective to continental margin evolution.
This interdisciplinary session aims to examine the causes and consequences of geomorphic processes shaping underwater landscapes, including submarine erosion and depositional processes, submarine landslides and canyons, sediment transfer and deformation, volcanic activity, fluid migration and escape, faulting and folding, and other drivers of seafloor geomorphic changes. The general goal of the session is to bring together researchers who characterise the shape of past and present seafloor features, seek to understand the sub-surface and surface processes at work and their impacts, or use bathymetry and/or 3D seismic data, combined with borehole petrophysics and geological cores, as a model input. Contributions to this session can include work from any depth or physiographic region, e.g. oceanic plateaus, abyssal hills, mid-ocean ridges, accretionary wedges, and continental margins (from continental shelves to abyss plains). Datasets of any scale, from satellite-predicted depth to ultra-high-resolution swath bathymetry, sub-surface imaging and sampling, are anticipated. We also aim at providing a window into the cross-disciplinary research of seismic geomorphology, exposing participants to differing perspectives, the latest workflows, examples of data integration, and, importantly, the potential pitfalls of equifinality in seismic interpretation and treating geophysical cross-sections as if they are outcrops. Emphasis will be given to contributions illustrating how the reflection seismic data have been investigated and how the results have been applied (e.g. paleogeography/paleoenvironmental reconstruction, seafloor engineering, or carbon/nuclear storage).

Restricted evaporitic basins through geologic time are cradles of biotic and abiotic change. They are controlled by straits linking the open ocean with marginal basins which in turn play an important role in driving global thermohaline circulation through the exchange of heat and salt. When these marine gateways allow only very limited exchange, typically during early stage opening and the final stages of closure, marginal seas can experience extreme fluctuations in salinity, from brackish to hypersaline conditions, with knock-on consequences for the density of the overflow. Restricted gateway exchange in mid-latitude settings can result in the formation of large evaporite deposits or “salt giants”.
In addition to their profound local impact, these salt giants can be sufficiently large to change the chemistry of the ocean, impact the carbon cycle and marine ecosystems, and modify climate on a global scale.
We welcome presentations from researchers investigating the opening or closing of marine gateways, modern or ancient, and their climatic, sedimentological and/or biological consequences. We encourage both modellers and empirical researchers to share their insights into the causes and consequences of marine connectivity change. We seek to draw together scientists focussed on a variety of salt giants including the evaporites that formed as the South Atlantic opened, the Zechstein salt basin, as well as the Mediterranean Messinian Salinity Crisis (MSC). The session will be one of the earliest opportunities to share initial results from IODP Expedition 401 (Dec 2023-Feb 2024), the offshore element of the IMMAGE land-2-sea drilling project which targets the late Miocene records of Mediterranean-Atlantic exchange.

Climate induced alterations to net primary production act alongside changes to biogeochemical cycling of oxygen and nutrients to affect marine ecosystem structure and function, as well as the ocean carbon cycle. Climate change is driving alterations to these key components of ocean health, both via long-term changes and the emergence of extremes. The 6th Climate Model Intercomparison Project provides new opportunities to analyze the long-term changes in biogeochemistry under different emissions scenarios, as well as to explore the emergence and potential impacts of extremes. Additionally, historical variability linked to climate oscillations such as ENSO and the Southern Annular Mode provide an opportunity to bring insights from observed changes and impacts, as well as developing fundamental understanding of the marine ecosystem-biogeochemical system.

This session invites submissions, from both observations and modelling efforts, that address the impact of historical variability and climate change on net primary production, biogeochemical cycling of nutrients and oxygen, and the ocean carbon cycle, including cascading effects for marine ecosystems to modulate biodiversity and ecosystem services.

Understanding the carbon cycle and ocean biogeochemistry, and how they relate to each other, is important for our understanding of the Earth’s environment in the past, present, and future. This session will discuss these interactions through different timescales and processes, from the ‘short-term’ biological pump to the ‘long-term’ burial in marine carbonates.
The ocean biological pump stores enough CO2 in the ocean interior to keep atmospheric pCO2 200ppm lower than it would otherwise be, with the depth at which this storage occurs being a key determinant of the size of this effect. This storage results from the surface production and interior respiration of organic matter, however, the transfer between surface and interior, and hence the depth at which remineralization occurs is driven by a wide array of processes including sinking, active fluxes, packaging of material by grazing, egestion and likely affected by plankton community composition and temperature. Understanding the relative importance of these processes is key to predicting the response of ocean biological C storage to climate change and human exploitation. The current intensification of human exploitation impacts on the ocean coupled with climate change is driving multiple projects (e.g. Ocean ICU, BioCarbon, Apero and Exports) to address these issues with the general objective of better predicting the evolution of future ocean C storage.
Ocean chemistry is linked to both short- and long-term C cycles via alkalinity input, saturation of carbonate minerals, and transfer of organic and inorganic C from the surface to the deep ocean. The sources and sinks of different elements and isotopes dictate their concentrations and isotope ratios in the ocean. Weathering and transport in rivers and reactions at mid-ocean ridges are major sources of elements to the ocean, while reactions with seafloor basalt, precipitation, scavenging, and adsorption onto particles are major sinks. These processes have also an important role in the C cycle. For example, silicate weathering removes CO2 and volcanism provides CO2 to the atmosphere over the long-term, and elements, such as Fe and Cd, are scavenged by the biological pump. Thus, studying oceanic geochemical budgets constrained by multiple isotope systems (e.g., δ11B, δ26Mg, δ30Si, δ88/86Sr) and concentrations (e.g., Fe, Sr, Ba, Li, S), and their variation over time, provides a useful tool in constraining the carbon cycle.

Due to the growing pressures on marine resources and the ecosystem services demand, the interest of the scientific and political world is moving to ensure marine ecosystems conservation and environmental sustainable development providing policies to meet the UN 2030 Agenda Goal 14 to “Conserve and sustainably use the oceans, seas and marine resources for sustainable development”.
To act against the decline of ocean health and to create a framework of stakeholders, the UN proposed the establishment of the “Decade of Ocean Science for Sustainable Development” able to bring regional knowledge and priorities together in an international action plan. Anthropogenic activities could have an impact on the marine environment and affect the ecosystem equilibrium.
The marine environment is a dynamic, sensitive and fragile area in which it is advantageous to apply new methodologies and observing methods to increase the quantity and quality of the data. Since ocean dynamics affect the dispersion of pollutants such as chemicals, plastics, noise and invasive species, the ecosystem status should be analyzed through the study of abiotic variables distribution at a proper spatio-temporal scale. To analyze the ocean environmental quality, a large amount of data obtained by global observation systems (e.g. GOOS, EMODNET) is needed, which requires the development of cost-effective technologies for integrated observing systems and to support the study of, e.g., biological variables.
The session focuses on marine ecosystems, technological developments for the study of abiotic and biotic factors, with a focus on anthropogenic impacts. Multidisciplinary approaches using data coming from multiple sources are encouraged. Integration of mathematical models, and in-situ and remote observations are suggested to develop methods, technologies and best practices to maintain, restore and monitor biodiversity and to guarantee sustainable use of marine resources. The following topics will be discussed: effects of pollution on biota considering their natural and anthropogenic sources; global change effects on marine ecosystem; new technology development; advanced methods for collection, data processing, and information extraction; benthic and pelagic community dynamics; economic evaluation of natural capital, and marine ecosystem restoration initiatives.

There is growing awareness that our ongoing efforts to reduce CO2 emissions will be insufficient to limit global warming to below 2℃ of the pre-industrial global average. In order to reach this goal, Carbon Dioxide Removal (CDR) of 10 – 20 Gt CO2/year will be required before the end of the century. While a majority of current CDR technologies focus on terrestrial approaches, marine CDR (mCDR) includes technologies that have some of the largest removal potentials. However, further research is required before mCDR can be considered for large scale deployments. This session will focus on the various mCDR technologies and their potential for large scale deployment, as well as the required Monitoring, Reporting, and Verification (MRV). We welcome research focusing on laboratory experiments, small- and large-scale field trials, and modelling approaches addressing the potential and application of mCDR.

Pyrite is the most common sulphide in the Earth’s crust and occurs in many different types of rock. Following many decades of research, the morphology, trace element and isotopic composition of pyrite can be used to reconstruct a range of bio- and geological processes across a broad spectrum of scales.
In the oceans, pyrite is the dominant sink for reduced sulphur and is intimately connected to biological pathways of sulphate reduction, meaning the formation and isotopic composition of pyrite can be used to reconstruct the redox architecture of ancient marine environments. As a major gangue mineral phase in hydrothermal ore deposits, the formation and geochemistry of pyrite can be used to investigate and potentially detect ore forming processes. At the other end of the life-cycle, the weathering of pyrite during acid mine drainage and subsurface geological storage is a major environmental concern.
This session will bring together scientists investigating pyrite across a range of physico-chemical conditions in various earth science disciplines e.g. nuclear waste, ore deposits or acid mine drainage. Our aim is to foster intradisciplinary knowledge transfer of experiences between different research areas. We invite contributions presenting geochemical field studies, in-situ and laboratory investigations of rocks and formations as well as numerical simulation studies within the given context.

The stable isotopic composition of seawater and the carbon isotopic composition of dissolved inorganic carbon are essential ocean tracers that have been widely measured since the 1960s. They are in particular used to investigate the hydrological cycle and the exchanges between the ocean, sea ice, ice sheets, the atmosphere and continental runoffs, as well as the bio-geochemical cycles, the anthropogenic carbon penetration, and the associated acidification of the oceans. Moreover, they are used to validate proxy-tracers measured in natural archives for reconstructing past climate evolution. Modeling studies suggest that these isotopes are currently experiencing large changes linked to global warming and the associated changes in the hydrological and biogeochemical cycles. However, using and interpreting current data sets is often hampered by substantial issues in data collection, analysis, and synthesis.
This session welcomes presentations that highlight some of these issues, illustrate current or potential future use, and present newest results of the ocean water and carbon isotope analyses in observation or modeling studies of present, past, and future ocean conditions, as well as derived processes in the hydrological cycle and biogeochemical cycles.

Phosphorus (P) is an essential element for life on Earth and is tightly cycled within the biosphere. Throughout geological history, P availability has regulated biological productivity with impacts on the global carbon cycle. Today, human activities are significantly changing the natural cycling of P. Phosphate mining has depleted geological P reserves, while increased inputs of P to terrestrial ecosystems have enhanced fluxes of P to lakes and the oceans.

Direct anthropogenic perturbations of the P cycle, coupled with other human-induced stresses, have impacted numerous environments. Forest ecosystems may be losing their ability to recycle P efficiently, due to excessive N input, extensive biomass removal, and climatic stress. Soils, which serve as the biogeochemical fulcrum of the terrestrial P cycle, have been greatly altered by fertilizer use in recent decades. Changes in the P cycle on land impact on the magnitude and timing of P fluxes into aquatic ecosystems, influencing their trophic state. Burial in sediments returns P to the geological sink, eventually forming economically viable P deposits. Throughout the P cycle, redox conditions play a key role in transformations and mobility of P.

This interdisciplinary session, now celebrating its 10th anniversary at EGU, invites contributions to the study of P from across the geosciences, and aims to continue fostering links between researchers working on different aspects of the P cycle. We target a balanced session giving equal weight across the continuum of environments in the P cycle, from forests, soils and groundwater, through lakes, rivers and estuaries, to oceans, marine sediments and geological P deposits. We welcome studies of both past and present P cycling, with a focus on novel techniques and approaches.

Coastal and marine sedimentary systems are crucial components of the global carbon cycle and potentially play an important role in global climate regulation over varying timescales. Coastal vegetated habitats (classical Blue Carbon) such as seagrass, saltmarsh and mangroves, alongside marine sedimentary environments are estimated to trap and store globally significant quantities of carbon and potentially provide an important climate regulation service. Though these environments are clearly valuable both for carbon storage and climate change mitigation, these ecosystems are under growing natural and anthropogenic pressure with seagrass and saltmarsh extent decreasing annually and marine sediments being regularly disturbed (e.g., trawling, dredging).

These anthropogenic activities can modify sedimentary alkalinity generation and the burial efficiency of carbon, either through direct disturbance of the seafloor or indirectly by changing carbon supply, physical fields and/or ecosystem functions. These activities, their connection to the global carbon cycle, and implications for marine spatial management strategies are clearly significant. However, the magnitude of C release from such disturbance and what effect this has on the climate remains poorly quantified, hindering the development of policy and management.

To tackle the science questions and fill the policy needs in the field of Blue Carbon, we seek to bring together expertise from across the geosciences (e.g., ecology, biogeochemistry, sedimentology, minerology, spatial modelling). In this multidisciplinary session, we invite presentations from across these disciplines, scales (local, national, and/or global) and across study types (observational, experimental, modelling, and/or theoretical) to discuss recent advances in coastal and marine sedimentary carbon research.

In addition to rapid emission reductions, swift and large-scale carbon dioxide removal (CDR) is needed to reduce the risks of severe climate change. Multiple CDR approaches will be needed to deliver the targeted amounts of 10s of Gt CO2 yr-1. This session solicits multidisciplinary and novel contributions of research on two CDR approaches: enhanced rock weathering (ERW) and river alkalinity enhancement (RAE), including: 1) technical aspects, 2) ecosystem impacts, both negative and positive, 3) best practices, 4) community engagement, 5) techno-economic and life cycle aspects, and 6) monitoring, reporting and verification approaches. Both ERW and RAE aim to drawdown CO2 and convert it to bicarbonate for eventual delivery to oceans via rivers for long-term storage. This session thus aims to inform decision making on how and whether ERW and RAE can be used to help us reach our climate targets.

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

Energy conservation is a fundamental physical principle, yet it is generally not achieved in state-of-the-art models of geophysical flows owing to, for instance, the governing equations and their discretization, the coupling between model components, or the parameterization of unresolved processes. It is thus non-trivial to close the energy budget, which becomes even more challenging due to the multitude of oceanic processes that undergo nonlinear interactions and drive energy transfers across a range of scales: from (sub-)mesoscale eddies to internal waves to small-scale turbulence. This session is devoted to understanding these multi-scale interactions and associated energy transfers, which are ultimately crucial for developing energetically consistent models, confidently predict climatic changes, and quantify associated uncertainties, and thus improve our understanding of the climate system.

We invite contributions on oceanic energy pathways and their consistent representation in numerical models from theoretical, modeling, and observational perspectives. These include, but are not limited to, the processes involving (sub-)mesoscale eddies, internal gravity waves, instabilities, turbulence, small-scale mixing, and ocean-atmosphere coupling. Contributions on energy transfer processes and their quantification from in-situ measurements, (semi-)analytical approaches, and numerical models, as well as their parameterizations and spurious energy transfers associated with numerical discretizations, are also welcome along with interdisciplinary contributions such as novel applications in data science that diagnose, quantify, and minimize energetic inconsistencies and related uncertainties.
We particularly encourage early career researchers to participate in this session.

Despite their socio-economic and environmental impacts, extreme events in the marine environment are generally poorly understood, simulated or predicted. In particular, the dynamics of these events involve multiple temporal and spatial scales and can be driven by different mechanics and complex feedback involving the ocean and its interaction with the other spheres of the climate system.
In response to climate change, frequency and magnitude of these events could dramatically change with significant impacts on human life and properties as well as on marine ecosystems. Hence, advancing our understanding on the dynamics leading to extremes in marine environments is crucial to improving their predictability, which in turn will help to achieve environmental and social sustainability.
Starting with this rationale, the session will focus on marine extremes at multiple time and spatial scales. Studies discussing ocean dynamics and air-sea interactions that can influence the evolution of marine extremes are particularly welcome, as well as ones using techniques ranging from in-situ to remote sensing observations, from numerical models to innovative AI techniques (e.g., machine learning). Coastal extremes are also of specific interest, addressing both physical drivers and impacts on biogeochemistry, marine ecosystems, fishing and coastal communities. This diversity of topics will make for a highly multidisciplinary session, open to multiple applications in the field of marine extremes.
Contributions related to the investigation of marine heatwaves, marine storminess and events driven by air-sea-wave interactions, storm surge and sea level rise, dense water formation and convective dynamics, deep ocean extreme events, waves storms or biogeochemical extremes are examples of potential topics.

Advanced remote sensing capabilities have provided unprecedented opportunities for monitoring and studying the ocean environment as well as improving ocean and climate predictions. Synthesis of remote sensing data with in situ measurements and ocean models have further enhanced the values of oceanic remote sensing measurements. This session provides a forum for interdisciplinary discussions of the latest advances in oceanographic remote sensing (using electromagnetic or acoustic waves) and the related applications and to promote collaborations.

We welcome contributions on all aspects of the oceanic remote sensing and the related applications. Topics for this session include but are not limited to: physical oceanography, marine biology and biogeochemistry, biophysical interaction, marine gravity and space geodesy, linkages of the ocean with the atmosphere, cryosphere, and hydrology, new instruments and techniques in ocean remote sensing, new mission concepts, development and evaluation of remote sensing products of the ocean, and improvements of models and forecasts using remote sensing data. Applications of multi-sensor observations to study ocean and climate processes and applications using international (virtual) constellations of satellites are particularly welcome.

The NASA/CNES international Surface Water and Ocean Topography (SWOT) mission was launched in December 2022 to provide the first global survey of the Earth’s surface waters. SWOT provides collocated surface elevation and SAR imagery over two 50-km wide swaths; the first global mission using Ka-band SAR radar interferometry techniques. SWOT has global coverage up to 78° in latitude, with an orbit specifically chosen to resolve barotropic tides and internal tides. SWOT is designed with very low measurement noise, required to reveal small-scale open-ocean dynamics and their variations, extending into the coastal and regional seas and deltas/estuaries. SWOT’s global ocean/coastal data products have:
- highest height precision at 2 x 2 km, in order to resolve open and coastal ocean dynamics and tides at spatial scales of about 10 km in wavelength.
- enhanced resolution at 250m x 250m, to more accurately monitor nearshore, estuarine, wetland and fluvial areas, and the sea-ice interface.

During the first 6 months of the mission, SWOT was in a 1-day fast-repeat orbit, firstly for engineering checkout and then for scientific validation from April to July 10, 2023. From July 27, 2023, the satellite began sampling with global coverage in its 21-day orbit. Numerous field campaigns were conducted in 2023 to validate SWOT in the open ocean, nearshore and coastal regions sampled by SWOT’s repeat orbits.

SWOT’s unique, high-resolution 2D observations, combined with the field campaign data, other satellite data and models, provide a new view of many dynamical phenomena from ocean and nearshore zones (mesoscale eddies, dynamical fronts, tides and internal tides, effects of air-sea interactions) to coastal and estuarine contexts (tidal deformation, multi-scale water level changes, flooding). Papers are encouraged on these SWOT themes, including the challenges of : (1) Building a full 2D or 3D observation dataset from SWOT products by developing new approaches based on physics-based or statistical algorithms and/or artificial intelligence.
(2) Assessing the calibration and the validation of the SWOT products; and the relevance of SWOT for improving numerical models by assimilating data and reducing uncertainties.

The ocean represents a vast and largely untapped resource, which is being explored as a source of low carbon renewable energy. There is much research within the ocean science community into resource characterization and the interaction of energy conversion technologies with the ocean environment. We seek contributions spanning a broad range of topics relating to ocean renewable energy, including offshore wind, wave, ocean current and tidal resources over timescales ranging from semi-diurnal to decadal, and feedbacks between the available resource and energy extraction at local and regional scales. The session also seeks discussions on the application of ocean energy for ocean instrumentation/observation, powering off-grid buoys, unpiloted surface and underwater vehicles, and desalination. This session will gather and relate research methods and results from investigations into field techniques, and numerical/statistical modelling used to assess interactions of ocean renewable energy with ocean processes. The session will also include studies of physical impacts (e.g. impacts on sedimentary systems), and societal interactions (e.g. marine spatial planning). We also invite innovative research on ocean energy arrays/sites for co-located applications (e.g. offshore wind combined with aquaculture) that would benefit from combined infrastructure and reduced levelized costs.

Oceanographic monitoring and modeling are both widely used to study the pathways and fate of marine pollutants such as anthropogenic hydrocarbons, marine litter and plastic, heavy metals, POPs, HNS, radionuclides, pharmaceutics, etc. This session focuses on monitoring frameworks, computational tools, lab experiments and emerging technologies related to tracing pollutants and their impacts on local, regional, and global scales. Coupling with met-ocean and biogeochemical datasets provided, for example, by the Copernicus Programme will also be discussed. State-of-the-art observational techniques and protocols, ensemble simulations, risk assessment algorithms and decision support systems are solicited topics. Integration of modeling, observations, and experimental data for both data assimilation and model validation are also very welcome.

We welcome studies based on in situ and lab observations, as well as modeling work looking at physical, chemical and biological transformation of pollutants such as fragmentation, degradation, biofouling, ingestion, adsorption/desorption. Discussions about newly discovered phenomena, as, for example, the mucilage outbreaks including harmful algal blooms (HABs), the role of Extracellular Polymeric Substances (EPS), and other ecotoxicological issues are also encouraged.

Studies that link single pollutant effects to broader ecosystem stressors like environmental degradation and climate change are particularly encouraged. Monitoring and modeling the pollutant transport under ice conditions, related to the increase in shipping traffic in the Arctic Ocean as a consequence of Polar ice melting, are also appreciated.

Key questions of the session include: Which factors affect the dispersion of pollutants in the marine environment and how do they influence pollutant fate at the ocean’s surface, in the water column, and sediments, thereby affecting marine habitats and resources?

The impact of other environmental stressors, such as artificial light, noise, and thermal pollution, on marine ecosystems, is a significant topic for discussion.

The Copernicus Marine Service provides regular and systematic reference information on the physical (including sea-ice and wind waves) and biogeochemical states of the global ocean and European regional seas. This capacity encompasses the description of the current ocean state, the prediction of the ocean state a few days ahead, and the provision of consistent retrospective data records for recent decades. In the coming years, Copernicus Marine will prepare the implementation of the next generation of ocean monitoring and forecasting systems and new services for the coastal ocean and for marine biology. Copernicus Marine will also progressively embrace the new capabilities of digital services in synergy with the EU Digital Twin of the Ocean (DTO) developments. The EU DTO will connect and interoperate, on a common digital platform, a large variety of ocean and coastal numerical models, allowing for global, regional-to-coastal model configurations and the co-development of new simulations and what-if-scenarios for enhanced on-demand ocean forecasting and ocean climate prediction.
The session focuses on the main Copernicus Marine Service research and development activities on ocean modelling; data assimilation; processing of observations, impact and design of in-situ and satellite observing systems; verification, validation, and uncertainty estimates; monitoring and long-term assessment of the ocean physical and biogeochemical states. The session also includes research activities that are required to prepare the next generation of ocean monitoring and forecasting systems (improved Arctic monitoring, ensemble forecasting, higher resolution, regional ocean climate projections, use of artificial intelligence techniques) and new services for the coastal ocean and for marine biology. The session will also encompass research activities that are required for the development of the European DTO, including the next generation of ocean models combining artificial intelligence and high-performance computing, dedicated infrastructures, and platforms as well as protocols and software and the definition of what-if-scenarios.
Presentations are not limited to research teams directly involved in the Copernicus Marine Service and the future European DTO. Participation from external teams from relevant Horizon Europe projects, from downstream applications and contributing to reinforcing global capacity in ocean forecasting and digital integration is strongly encouraged.

Machine learning (ML) methods have emerged as powerful tools to tackle various challenges in ocean science, encompassing physical oceanography, biogeochemistry, and sea ice research.
This session aims to explore the application of ML methods in ocean science, with a focus on advancing our understanding and addressing key challenges in the field. Our objective is to foster discussions, share recent advancements, and explore future directions in the field of ML methods for ocean science.
A wide range of machine learning techniques can be considered including supervised learning, unsupervised learning, interpretable techniques, and physics-informed and generative models. The applications to be addressed span both observational and modeling approaches.

Observational approaches include for example:
- Identifying patterns and features in oceanic fields
- Filling observational gaps of in-situ or satellite observations
- Inferring unobserved variables or unobserved scales
- Automating quality control of data

Modeling approaches can address (but are not restricted to):
- Designing new parameterization schemes in ocean models
- Emulating partially or completely ocean models
- Parameter tuning and model uncertainty

The session welcomes also submissions at the interface between modeling and observations, such as data assimilation, data-model fusion, or bias correction.

Cloud computing has emerged as the dominant paradigm, supporting practically all industrial applications and a significant number of academic and research projects. Since its inception and subsequent widespread adoption, migrating to cloud computing has presented a substantial challenge for numerous organisations and enterprises. Leveraging cloud technologies to process big data in proximity to their physical location represents an ideal use case. These cloud resources provide the requisite infrastructure and tools, especially when accompanied by high-performance computing (HPC) capabilities.

Pangeo (pangeo.io) is a global community of researchers and developers that tackle big geoscience data challenges in a collaborative manner using HPC and Cloud infrastructure. This session's aim is threefold:
(1) Focuses on Cloud/Fog/Edge computing use cases and aims to identify the status and the steps towards a wider cloud computing adoption in Earth Observation and Earth System Modelling.
(2) to motivate researchers who are using or developing in the Pangeo ecosystem to share their endeavours with a broader community that can benefit from these new tools.
(3) to contribute to the Pangeo community in terms of potential new applications for the Pangeo ecosystem, containing the following core packages: Xarray, Iris, Dask, Jupyter, Zarr, Kerchunk and Intake.

We warmly welcome contributions that detail various Cloud computing initiatives within the domains of Earth Observation and Earth System Modelling, including but not limited to:
- Cloud federations, scalability and interoperability initiatives across different domains, multi-provenance data, security, privacy and green and sustainable computing.
- Cloud applications, infrastructure and platforms (IaaS, PaaS SaaS and XaaS).
- Cloud-native AI/ML frameworks and tools for processing data.
- Operational systems on the cloud.
- Cloud computing and HPC convergence and workload unification for EO data processing.

Also, presentations using at least one of Pangeo’s core packages in any of the following domains:
- Atmosphere, Ocean and Land Models
- Satellite Observations
- Machine Learning
- And other related applications

We welcome any contributions in the above themes presented as science-based in other EGU sessions, but more focused on research, data management, software and/or infrastructure aspects. For instance, you can showcase your implementation through live executable notebooks.

Humans have been successfully mapping the remotest and most inhospitable places on Earth, and the surfaces and interiors of other planets and their moons at highest resolution. The remaining blank spots are located in areas that are hardly accessible either through field surveys, geophysical methods or remote sensing due to technical and/or financial challenges. Some of these places are key areas that would help to reveal geologic history, or provide access to future exploration endeavours.

Such extreme and remote locations are commonly associated with the ocean floor, or planetary surfaces, but these extreme worlds might also be found in hot deserts, under the ice, in high-mountain ranges, in volcanic edifices, hidden underneath dense canopy cover, or located within the near-surface crust. All such locations are prime targets for remote sensing mapping in a wider sense. The methodological and technical repertoire to investigate extreme and remote locations is thus highly specialized and despite different contexts there are commonalities not only with respect to technical mapping approaches, but also in the way how knowledge is gathered and assessed, interpreted and visualized regarding its scientific but also its economic value.

This session invites contributions to this field of geologic mapping and cartography of extreme (natural) environments with a focus on the scientific synthesis and extraction of information and knowledge.

A candidate contribution might cover, but is not limited to, topics such as:

- ocean mapping using manned and unmanned vehicles and devices,
- offshore exploration using remote sensing techniques,
- crustal investigation through drilling and sampling,
- subsurface investigation using radar techniques,
- planetary geologic and geophysical mapping,
- subglacial geologic mapping
- geologic investigation of desert environments.

The aim of this session is to bring together researchers mapping geologically and geophysically inaccessible environments, thus relying on geophysical and remote sensing techniques as single source for collecting data and information. We would like to keep the focus on geologic and geophysical mapping of spots for which we have no or only very limited knowledge due to the harsh environmental conditions, and we would thus exclude areas that are inaccessible for political reasons.

The process of “fluid venting” is a global phenomenon recognized in different geodynamic contexts, giving rise to diverse surface morphologies (e.g. pockmarks and mud volcanoes) and a range of geological, geochemical and biological phenomena. Venting implies the upward migration of fluids (including gas) due to subsurface overpressures and/or buoyancy, via plumbing systems that remain poorly understood. Sedimentary layers and geological structures (faults, fractures) may act either as pathways for, or barriers to, fluid migration. It is useful to distinguish two main types of fluid vent: (i) “cold seeps” characterized by low temperature fluid emissions, and (ii) hydrothermal vents where fluids emerge at temperatures between 200-400°C. In submarine settings, marine geophysical data of varying frequency may be used to identify fluid-related features at the seafloor, as well as the presence of gas both in the water column, as acoustic flares, and below the seafloor, as acoustic anomalies including focused or diffused acoustic turbidity and blanking, bright spots, high-amplitude reflections, chimney or pipe structures, and bottom simulating reflectors (BSRs) associated with gas hydrate. Sampling and direct observation can also be useful to assess the chemosynthetic ecosystems living in such extreme environmental conditions. This session aims to explore the role of submarine fluid flow and venting: (i) as a geomorphic process that shapes the seafloor; (ii) as a potential marine geohazard, and (ii) as a driver of biological processes. Contributions are invited from any offshore region, from continental shelves to abyssal plains, based on multi-scale datasets including hydro-acoustic imagery, 2D/3D seismic reflection data, samples and ROV observations.

Internal gravity waves (IGWs) still pose major questions in the study of both atmospheric and ocean sciences, and stellar physics. Important issues include IGW radiation from their various relevant sources, IGW reflection at boundaries, their propagation through and interaction with a larger-scale flow, wave-induced mean flow, wave-wave interactions in general, wave breaking and its implications for mixing, and the parameterization of these processes in models not explicitly resolving IGWs. The observational record, both on a global scale and with respect to local small-scale processes, is not yet sufficiently able to yield appropriate constraints. The session is intended to bring together experts from all fields of geophysical and astrophysical fluid dynamics working on related problems. Presentations on theoretical, modelling, experimental, and observational work with regard to all aspects of IGWs are most welcome, including those on major collaborative projects, which seek to accurately parameterize the role of IGWs in numerical models.

This session invites innovative Earth system and climate studies employing geodetic observations and methods. Modern geodetic observing systems have been instrumental in studying a wide range of changes in the Earth’s solid and fluid layers at various spatiotemporal scales. These changes are related to surface processes such as glacial isostatic adjustment, the terrestrial water cycle, ocean dynamics and ice-mass balance, which are primarily due to changes in the climate. To understand the Earth system response to natural climate variability and anthropogenic climate change, different time spans of observations need to be cross-compared and combined with several other datasets and model outputs. Geodetic observables are also often compared with geophysical models, which helps in explaining observations, evaluating simulations, and finally merging measurements and numerical models via data assimilation.

We look forward to contributions that:​

1. Utilize geodetic data from diverse geodetic satellites including altimetry, gravimetry (CHAMP, GRACE, GOCE and GRACE-FO, SWOT), navigation satellite systems (GNSS and DORIS) or remote sensing techniques that are based on both passive (i.e., optical and hyperspectral) and active (i.e., SAR) instruments.​

2. Cover a wide variety of applications of geodetic measurements and their combination to observe and model Earth system signals in hydrological, ocean, atmospheric, climate and cryospheric sciences.​

3. Show a new approach or method for separating and interpreting the variety of geophysical signals in our Earth system and combining various observations to improve spatiotemporal resolution of Earth observation products.​

4. Work on simulations of future satellite mission (such as MAGIC and NGMM) that may advance climate sciences.​

5. Work towards any of the goals of the Inter-Commission Committee on "Geodesy for Climate Research" (ICCC) of the International Association of Geodesy (IAG).​

We are committed to promoting gender balance and ECS in our session. With author consent, highlights from this session will be tweeted with a dedicated hashtag during the conference in order to increase the impact of the session.

The modeling of the Earth Climate System has undergone outstanding advances to the point of resolving atmospheric and oceanic processes on kilometer-scale, thanks to the development of high-performance computing systems. Models resolving km-scale processes (or storm-and-eddy-resolving models) on a global scale are also able to resolve the interaction between the large and small-scale processes, as evidenced by atmosphere- and ocean-only simulations. More importantly, this added value comes at the expense of avoiding the use of parameterizations that interrupts the interaction between scales, i.e., convective parameterization in the atmosphere or mesoscale eddy parameterization in the ocean. These advantages are the bases for the development of global-coupled storm-and-eddy-resolving models, and even at their first steps, such simulations can offer new insights into the importance of capturing the air-sea interface and their associated small-scale processes in the representation of the climate system.
The objective of this session is to have an overview of the added values of global simulations using storm-resolving atmosphere-only configuration, eddy-resolving ocean-only models, and to identify which added values stay after coupling both components, i.e., mechanisms not distorted by the misrepresentation of sub-grid scale processes in the atmosphere and ocean. In addition to highlighting the importance of the already resolved processes in shaping the climate system in global storm-and-eddy-resolving models, this session is also dedicated to presenting the current challenges in global storm-and-eddy-resolving models (identification of biases and possible solutions) by pointing to the role of the sub-grid scale processes in shaping processes on the large scale.
We call for studies contributing to highlighting the advantages and challenges of using global storm-and-eddy-resolving models in ocean-only, atmosphere-only, and coupled configurations, such as the ones proposed by NextGEMS, EERIE, DestinE, and WarmWorld, as well as studies coming from independent institutions around the world.

Disk-integrated solar irradiance is the primary input of energy to the Earth climate system. Precise estimates of the absolute irradiance and how it varies are essential for understanding the dynamics of the Earth’s atmosphere. The Sun’s spectrum changes on all timescales, from seconds for space weather events to climate-relevant periods of centuries or longer.
Moreover, for understanding the state of the Earth's climate, the Earth Energy Imbalance (EEI) is the key parameter. It is the global annual mean difference between the incoming solar and reflected solar and emitted terrestrial radiation. A positive EEI corresponds to the heat continuously accumulated in the Earth's climate system – mainly the oceans, and which will - with a time delay - cause the global warming of the surface and the atmosphere. The exact knowledge of the EEI and its trend is key for a predictive understanding of global warming and assessing the efficiency of global carbon reduction policies. To determine the EEI with higher accuracy and stability, independent measurement approaches are required.
We invite contributions describing recent successes in solar irradiance observations, composite datasets, calibration reanalysis, and modelling the solar atmosphere. Measurement concepts with an emphasis on space observations, but also ground-based and in-situ measurements, as well as modeling efforts that help to better determine the energy storage in the Earth's system and the terrestrial outgoing radiation are also warmly welcome.

Projections of future climate rely on increasingly complex, high-resolution earth system models (ESMs). At the same time, nonlinearities and emergent phenomena in the climate system are often studied by means of simple conceptual models, which offer qualitative process understanding and allow for a broad range of theoretical approaches. Simple climate models are also widely used as physics-based emulators of computationally expensive ESMs, forming the basis of many probabilistic assessments in the IPCC 6th Assessment.

Between these two approaches, a persistent “gap between simulation and understanding” (Held 2005, see also Balaji et al. 2022) challenges our ability to transfer insight from simple models to reality, and distill the physical mechanisms underlying the behavior of state-of-the-art ESMs. This calls for a concerted effort to learn from the entire model hierarchy, striving to understand the differences and similarities across its various levels of complexity for increased confidence in climate prediction.

In this session, we invite contributions from all subfields of climate science that showcase how modeling approaches of different complexity advance our process understanding, and/or highlight inconsistencies in the model hierarchy. We also welcome studies exploring a single modeling approach, as we aim to foster exchange between researchers working on different rungs of the model hierarchy. Contributions may employ dynamical systems models, physics-based low-order models, explainable machine learning, Earth System Models of Intermediate Complexity (EMICs), simplified or idealized setups of ESMs (radiative-convective equilibrium, single-column models, aquaplanets, slab-ocean models, idealized geography, etc.), and full ESMs.

Processes and phenomena of interest include, but are not limited to:
* Earth system response to forcing scenarios (policy-relevant, extreme, counterfactual)
* Tipping points and abrupt transitions (e.g. Dansgaard-Oeschger events)
* Coupled modes of climate variability (e.g. ENSO, AMV, MJO)
* Emergent and transient phenomena (e.g. cloud organization)
* Extreme weather events

The nonlinear nature of fluid flow gives rise to a wealth of interesting and beautiful phenomena. Many of these are of fundamental importance in the understanding of lakes, oceans and the atmosphere because of their role in such things as transport, the energy cascade and, ultimately, in mixing.

This session is intended to bring together researchers interested in the fundamental nature of nonlinear processes. Particular attention will be paid to intrinsically nonlinear flows that are driven by a gravitational forces acting on density variations, e.g. those due to temperature (e.g. katabatic winds) and/or salinity (e.g. density currents) differences, and/or the presence of particles (e.g. snow avalanches, debris-flows turbidites). While occurring in various planetary environments, and involving different fluids and particles, they share numerous features due to the common and similar physical processes that govern their dynamics. Yet, a universal description of their dynamics remains elusive, as specifically the feedback on the flow of various processes is difficult to predict.

We therefore welcome contributions including (but not limited to) diverse occurrences of geophysical gravity currents, nonlinear and solitary waves, wave-mean flow and wave-wave interactions, flow instabilities and their nonlinear evolution, frontogenesis, double diffusion and the nonlinear equation of state, convection, and river plumes.

This session then aims to present complementary physical-based approaches, by gathering researchers from different communities, all focusing on these flows by studying field data, using analogue laboratory experiments or numerical simulations or focusing on analytical modelling. We particularly encourage the participation of early-career researchers and students.

This session will focus on studies in geophysical fluids including atmospheres and oceans (on Earth and elsewhere) that are approached from a Lagrangian perspective, together with topics associated with turbulence.

Lagrangian tools allow to predict the dispersion of pollutants and track their sources, capture unresolved physics, and reveal transport pathways and barriers between flow regimes that have different dynamical fates. As such, Lagrangian methods are used in a vast array of applications from turbulent scales to planetary scales in the atmosphere, oceans, and cryosphere.

Furthermore, turbulence is a major driver of nonlinear behavior and variability in geophysical fluids, influencing both passive and active scalars via changes in the velocity field and fluxes (air-sea exchanges). As such, turbulence is a key forcing in marine ecology: it modulates the contact rate between organisms and nutrients, re-suspension processes, the formation of blooms and thin layers, and even the adaptation of organisms to their environment.

We invite presentations on topics including – but not limited to – the following:
- Large-scale circulation studies (jets, gyres, overturning circulations) using direct Lagrangian modeling and/or age and chemical tracers;
- Exchanges between reservoirs and mixing studies (e.g. transport barriers in the stratosphere and in the ocean, stratosphere-troposphere exchange);
- Tracking long-range anthropogenic and natural influence (e.g. effects of recent volcanic eruptions and wildfire smoke plumes on the composition, chemistry, and dynamics of the atmosphere, transport of pollutants, dusts, aerosols, plastics, and fluid parcels in general, cirrus seeding by aviation, etc);
- Inverse modeling techniques for the assessment and constraint of emission sources;
- Turbulent flows, physical oceanography, biogeochemistry, marine ecology, marine sciences;
- Lagrangian Coherent Structures;
- Model and tool development, numerical and computational advances.

Geoscience knowledge and practices are essential for effectively navigating the complexities of the modern world. They play a critical role in addressing urgent global challenges on a planetary scale (including, climate change and its social, humanitarian, and health impacts), informing decision-making processes and guiding education at all levels. However, the response to these challenges remains largely inadequate across the board.
By equipping both citizens and the wider societal stakeholders with the necessary knowledge background, geosciences empower them to engage in meaningful discussions, shape policies, contribute to reduce inequities and injustice, and implement solutions for local, regional, and global social-environmental problems. Within this broad scope, geoethics strives to establish a shared ethical framework that guides geoscientists’ engagement with sensitive and significant issues concerning the interaction between geoscience and society.
This session will cover a variety of topics, including theoretical and practical aspects of geoethics, ethical issues in professional practice, climate and ocean education, geoscience communication, and strategies for bridging the gap between geosciences and society.
This session is co-sponsored by the International Association for Promoting Geoethics, the Commission on Geoethics of the International Union of Geological Sciences and the Chair on Geoethics of the International Council for Philosophy and Human Sciences (www.geoethics.org).

The visualization and user-friendly exploration of information from scientific data is one of the main tasks of good scientific practice. But steady increases in temporal and spatial resolutions of modeling and remote sensing approaches lead to ever-increasing data complexity and volumes. On the other hand, earth system science data are getting increasingly important as decision support for stakeholders and other end users far beyond the scientific domains.

This poses major challenges for the entire process chain, from data storage to web-based visualization. For example, (1) the data has to be enriched with metadata and made available via appropriate and efficient services; (2) visualization and exploration tools must then access the often decentralized tools via interfaces that are as standardized as possible; (3) the presentation of the essential information must be coordinated in co-design with the potential end users. This challenge is reflected by the active development of tools, interfaces and libraries for modern earth system science data visualization and exploration.

In this session, we hence aim to establish a transdisciplinary community of scientists, software-developers and other experts in the field of data visualization in order to give a state-of-the-art overview of tools, interfaces and best-practices. In particular, we look for contributions in the following fields:

- Developments of open-source visualization and exploration techniques for earth system science data
- Co-designed visualization solutions enabling transdisciplinary research and decision support for non-scientific stakeholders and end-users
- Tools and best-practices for visualizing complex, high-dimensional and high frequency data
- Services and interfaces for the distribution and presentation of metadata enriched earth system science data
- Data visualization and exploration solutions for decentralized research data infrastructures

All contributions should emphasize the usage of community-driven interfaces and open-source solutions and finally contribute to the FAIRification of products from earth system sciences.