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.

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

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 both observational and modelling components. Another important issue is the interaction between the atmosphere, the ocean and the cryosphere, and how this affects the climate.

We welcome contributions from observers and modellers on the following topics:

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

The polar oceans play a crucial role in regulating Earth’s climate by storing vast amounts of carbon, driving global ocean circulation and influencing heat exchange with the atmosphere. Arctic and Antarctic oceans are particularly prone to environmental alterations due to polar amplification of changes in climate and other anthropogenic stressors. Such alterations include marine or continental ice retreat, changes in ocean salinity, circulation patterns, (bio)geochemical cycling, primary productivity and input of environmental toxins. Understanding these processes is vital for predicting their respective future impacts on regional or global climate. Particularly, the study of various elemental and/or isotope systems can advance our ability to track multiple processes, such as continental runoff, water mass sourcing and primary productivity in modern waters as well as during palaeo-oceanographic evolution. The implementation of chemical oceanographic data into Earth System Models further helps to identify key variables in polar environments.
This session focuses on physical, microbiological and chemical oceanographic trends in polar regions in response to past and present climatic changes and other anthropogenic impacts. We particularly encourage submissions focusing on elemental isotope budgets but also welcome contributions that explore elemental concentrations, (bio)geochemical models, plankton assemblages and physical oceanography including, but not limited to, water mass movements and meltwater input, advancing predictions of polar ocean development.

The tropical Atlantic exhibits significant ocean variability from daily to decadal time scales, driven by complex ocean dynamics and air-sea interactions. This session is devoted to advancing the understanding of these dynamics and their climatic impacts on both adjacent and remote regions, including their interactions with other tropical basins. In addition, we are interested in the effects of climate change and variability modes on the tropical Atlantic, with a particular focus on impacts on marine ecosystems.

Relevant ocean processes include upper and deep ocean circulation, eddies, tropical instability waves, mixing, and upwellings. For air-sea interactions, we welcome studies analyzing the seasonal cycle, marine heat waves, the development of variability modes on local to basin scale (e.g., Atlantic, Dakar and Benguela Niños, Atlantic Meridional Mode and South Atlantic Ocean Dipole) and interbasin teleconnections. Wind variations related to high-frequency events, cyclones, convective systems and those shaping air-sea coupled modes are encouraged.

Finally, we seek for studies that explore the causes and impacts of systematic model errors in simulating the local to regional Atlantic climate variability. Submissions based on direct observations, reanalysis, model simulations and machine learning techniques are welcome.

The Arctic region has undergone drastic changes over the last decades, with sea ice decline and changes in freshwater content being the most prominent examples. The ice cover has become thinner and more fragile, drifting faster and more freely. Extreme temperatures are now more common, with 2023 recording the warmest summer temperatures ever. The Arctic has warmed nearly four times faster than the rest of the world, accelerating ice sheet melting, sea ice loss in the Kara and Laptev Seas, permafrost thawing, glacier retreat, and forest fires. The resulting changes in the Arctic Ocean include an increased freshwater volume, heightened coastal runoff from Siberia and Greenland, and greater exchanges with the Atlantic and Pacific Oceans, all of which have significant consequences for the fragile Arctic ecosystems.

As global temperatures continue to rise, model projections suggest that the Arctic Ocean could become seasonally ice-free by mid-century, raising critical questions for the Arctic research community: What could the Arctic Ocean look like in the future? How will the present changes in the Arctic affect and be affected by the lower latitudes? Which oceanic processes drive this sea-ice loss and how will they change in a sea ice-free Arctic? What aspects of the changing Arctic should observational, remote sensing and modeling programs prioritize?

In this session, we invite contributions from a variety of studies on the recent past, present and future Arctic. We welcome submissions that explore interactions between the ocean, atmosphere, and sea ice; Arctic processes and feedbacks; small-scale processes, internal waves, and mixing; sources of freshwater change and their impacts; and the interactions between the Arctic and global oceans. We especially welcome submissions that take a cross-disciplinary approach, focusing on new oceanic, cryospheric, and biogeochemical processes as well as their connections to land.

We want to spark discussions on future plans for Arctic Ocean measurement, remote sensing, and modeling strategies, including the upcoming CMIP7 cycle and ways to validate and improve models using observations. We encourage submissions on CMIP modeling approaches and recent observational programs like MOSAiC, the Nansen Legacy Project and the Synoptic Arctic Survey. We also welcome anyone involved in planning the upcoming International Polar Year 2032-33 to participate in our session and contribute to the discussions.

Despite advances in our understanding of the Indian Ocean’s physical, biogeochemical, and ecological characteristics and their variability across a range of spatiotemporal scales, significant gaps in our knowledge remain in observing, modeling, and predicting the Indian Ocean’s changing environmental conditions and its role in regional and global climate.
This session invites Indian Ocean contributions based on observations, modelling, theory, and palaeo proxy evidence across a range of timescales from synoptic, interannual, decadal to centennial and beyond. Topics of interest include past, current, and projected changes in Indian Ocean physical and biogeochemical properties and their impacts on ecological processes, diversity in Indian Ocean modes of variability, extent of the Indo-Pacific Warm Pool, interactions and exchanges between the Indian Ocean and other ocean basins via both oceanic and atmospheric pathways, as well as impacts on regional hydroclimate and adjacent monsoon systems.
Submissions are sought on assessing and predicting weather and climate extremes of societal relevance in the Indian Ocean and surrounding regions. We especially welcome submissions addressing compound extreme events that span across the ocean, atmosphere, and/or biogeochemical and ecological realms. Furthermore, studies evaluating climate risks, vulnerability, resilience, adaptation and mitigation strategies in coastal regions affected, for example, by tropical cyclones and extremes in sea level are encouraged.
We also welcome contributions that address research on the Indian Ocean, using advanced techniques such as artificial intelligence/machine learning, and new technological advances in observing systems, such as deep and biogeochemical Argo.

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 eddies to internal waves to small-scale turbulence. This session is devoted to understanding these multi-scale interactions and associated energy transfers in the ocean, 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 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.

ENSO and the Tropical Pacific as well as their interactions with other tropical basins are the dominant source of interannual climate variability in the tropics and across the globe. Correctly modelling and understanding the dynamics, predictability, and impacts of ENSO, as well as anticipating their future changes, are thus of vital importance for society. This session invites contributions regarding all aspects of ENSO, Tropical Pacific, and Indo-Pacific interactions, including: dynamics; multi-scale interactions; decadal and paleo variability; theoretical approaches; ENSO diversity; global teleconnections; impacts on climate, society and ecosystems; seasonal forecasting; climate change over the last few decades, including Indo-Pacific mean state changes; climate change projections; ENSO and its Indo-Pacific interactions. Studies aimed at evaluating and improving model simulations of ENSO, the Indo-Pacific mean state as well as Indo-Pacific interactions, with particular attention to the role of mesoscale variability and ocean-atmosphere coupling, are especially welcomed.

Marine heatwaves (MHWs) are prolonged and extreme warm ocean conditions that cause substantial ecological and socio-economic damage. 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, and their interactions with other parts of the climate system, 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 studies of the following themes.

Definition and Methods: novel physics and impact-based definitions which challenge the now-traditional statistical framework; observational and modelling requirements for reliable monitoring; AI/ML-based detection and prediction for surface and subsurface MHWs.
Impacts: Socio-economic damage to marine activities and industries including but not limited to tourism, fisheries, aquaculture; discussions with stakeholders.
Mitigation/Adaptation: forecasting efforts on short-term to decadal timescales; projections of future changes; studies of precursors and predictability.
Interactions: compound and concurrent events, ecosystem and biogeochemical implications (e.g. on nutrient/oxygen availability/harmful algal blooms/ocean acidification and trophic web), impacts on atmospheric circulation/extreme weather events (e.g. Tropical Cyclones/Monsoon Circulation).

This session welcomes studies across all spatial scales; studies on coastal scales and processes are particularly welcome.

Climate modeling is pushing the frontier towards 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 conceptual models, which offer qualitative understanding and permit theoretical approaches. Recent advancements in statistical and physical emulators, from reduced-complexity models to machine learning techniques, are enabling rapid and computationally efficient assessments of climate trajectories, impacts and risks.

Between these approaches, a persistent “gap between simulation and understanding” (Held 2005, see also Balaji et al. 2022) challenges our ability to transfer insight from conceptual 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 — or rather, model spectrum — to understand the differences and similarities across its various levels of complexity for increased confidence in climate predictions.

A diverse and well-integrated model ecosystem is also an indispensable prerequisite for the timely assessment of climate risks and effective decision-making. This places renewed emphasis on the concept of fit-for-purpose modeling, which is intrinsically linked to the climate model spectrum through the need to understand what levels of complexity are required and sufficient for a given scientific question or application. The climate community is increasingly interested in making models useful also beyond the academic domain (Mansfield et al., 2023).

In this session, we bring together contributions from all subfields of climate science that showcase how different modeling approaches advance our understanding of the Earth system, highlight inconsistencies in the model spectrum, and/or enable applications in climate impact projections. The key goal is to foster exchange between researchers working on different rungs of the model complexity ladder, focusing on process understanding. Contributions may employ dynamical systems models, physics-based low-order models, explainable machine learning, fast climate models and Earth System Models of Intermediate Complexity (EMICs), simplified or idealized setups of ESMs, CMIP models, and km-scale models. Processes and phenomena of interest include the Earth system response to transient forcing, tipping behavior, climate variability and extremes, and predictability.

Understanding and predicting the climate system, especially high-impact events such as extremes and tipping points, is an urgent task due to the ongoing climate crisis. This session highlights contributions at the interface of Earth sciences, mathematics, and physics that bring new perspectives and methods to environmental and geoscientific challenges. We are particularly interested in advances that improve the theoretical understanding of complex climate dynamics, enhance numerical modelling with both theory-informed and data-driven approaches, develop innovative data analysis techniques, and quantify the impacts and uncertainties associated with global warming.
Specific topics include: extreme events, tipping points, dynamical systems , statistical mechanics, model reduction techniques, model uncertainty and ensemble design, PDEs, stochastic processes, numerical methods, parametrisations, data assimilation, and machine learning. We invite contributions both related to specific applications as well as more speculative and theoretical investigations. We particularly encourage early career researchers to present their interdisciplinary work in this session.

Tropical and subtropical South America hosts the richest terrestrial biodiversity on Earth, and plays a pivotal role in global hydrological and carbon cycles. However, these exceptional environments face mounting threats. As an example, the Amazon rainforest, identified as a core tipping element of the climate system, may be pushed towards irreversible degradation by anthropogenic climate change and land-use pressures, further exacerbating the regional precipitation decline. Forestalling and preparing for such future changes require a comprehensive understanding of the past natural climate and vegetation dynamics in (sub)tropical South America, and of their controlling oceanic and atmospheric drivers.
This session explores the latest research results aimed at understanding the variability of tropical and subtropical South American climate and vegetation across Quaternary timescales (from glacial-interglacial, orbital, to millennial and multidecadal timescales), and the land-atmosphere-ocean interactions that control these changes. We welcome works exploring these interactions from high-resolution paleoclimatic and paleoceanographic reconstructions in (sub)tropical South American terrestrial archives (e.g. sediments, speleothems), and marine archives (e.g. sediments, corals) from the adjacent Atlantic and Pacific margins. We also invite contributions investigating Quaternary (sub)tropical South American climate and related land-ocean-atmosphere interactions based on paleoclimate modelling efforts and/or model-data comparisons.

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 from climate proxies and direct measurements and modelling results that examine ice sheet interactions with other components of the climate system over several time scales, ranging from millennial to centennial and even decadal timescales to investigate climate variability. Among other topics, issues to be addressed in this session include ice sheet-climate interactions from glacial-interglacial cycles, the role of ice sheets in Cenozoic global cooling and the mid-Pleistocene transition, reconstructions of past ice sheets and sea level during warmer and colder periods than pre-industrial times, the current and future evolution of the ice sheets, and the role of ice sheets in abrupt climate change.

Ice sheets and the surrounding polar oceans and atmosphere form a tightly coupled system whose evolution is central to global sea level, ocean circulation, and the overall climate. This session focuses on the interactions of ice shelves and tidewater glaciers with the ocean, atmosphere, and sea ice on the continental shelves around Greenland, Antarctica, and the Arctic. We welcome contributions addressing any scale and aspect of this physical system or of any of its approximations, simplifications, or analogs. This session aims to bridge observational, laboratory, theoretical, modeling, and data-science perspectives to improve understanding of ice-ocean-atmosphere interactions and their relevance in the climate system. We welcome work from both polar regions or any other planets and across disciplines, including fluid and solid mechanics, glaciology, oceanography, or atmospheric and climate sciences.

We propose an interactive PICO session format to encourage in-person dialog and random human interactions with the hope of fostering in-depth discussions and future scientific collaborations.

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. This includes advances in improving 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 models, machine-learning or other statistical methods and hybrid approaches. It will investigate predictions of various climate phenomena, including extremes, from global to regional scales, and from seasonal to multi-decadal timescales (including seamless predictions). Physical processes and sources relevant to long-term predictability (e.g. ocean, cryosphere, or land) as well as predicting large-scale atmospheric circulation anomalies associated with teleconnections will be discussed. Analysis of predictions in a multi-model framework, and ensemble forecast initialization and generation will be another focus of the session. We are also interested in approaches addressing initialization shocks and drifts. The session welcomes work on innovative methods of quality assessment and verification of climate predictions. We also invite contributions on the use of seasonal-to-decadal predictions for risk assessment, adaptation and further applications.

Atmosphere-ice interactions are triggered by synoptic weather phenomena such as cold air outbreaks, polar lows, atmospheric rivers, Foehn winds, and heatwaves, and they impact snow, ice, and permafrost.

However, our understanding of these processes is still incomplete. Despite being a crucial milestone for reaching accurate projections of future climate change in Polar Regions, deciphering the interplay between the atmosphere, land ice and sea ice on different spatial and temporal scales, remains a major challenge.

This session aims at showcasing recent research progress and augmenting existing knowledge in polar meteorology and climate and the atmosphere-land ice-sea ice coupling in both the Northern and Southern Hemispheres. It will provide a setting to foster discussion and help identify gaps, tools, and studies that can be designed to address these open questions. It is also the opportunity to convey newly acquired knowledge to the community.

We invite contributions on all observational and numerical modelling aspects of Arctic and Antarctic meteorology and climatology, that address atmospheric interactions with the cryosphere. This may include but is not limited to studies on past, present and future of:

- Atmospheric processes that influence sea-ice (snow on sea ice, sea ice melt, polynya formation and sea ice production and transport) and associated feedbacks,

- The variability of the polar large-scale atmospheric circulation (such as polar jets, the circumpolar trough and storm tracks) and impact on the cryosphere (sea ice and land ice),

- Atmosphere-ice interactions triggered by synoptic and meso-scale weather phenomena such as cold air outbreaks, katabatic winds, extratropical cyclones, polar cyclones, atmospheric rivers, Foehn winds, and heatwaves,

- Role of clouds in polar climate.

- Role of aerosols, such as black carbon, organic carbon, dust, volcanic ash, microplastics, pollen, sea salt, diatoms, bioaerosols, bacteria, in snow/ice melt and albedo changes.

- Teleconnections and climate indices and their role in land ice/sea ice variability.

Presentations that include new observational (ground and satellite-based) and modeling methodologies specific to polar regions are encouraged. Contributions related to results from recent field campaigns in the Arctic and in the Southern Ocean/Antarctica are also welcome.

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.

All science has uncertainty. Global challenges such as disaster risk, environmental degradation, and climate change illustrate that an effective dialogue between science and society requires clear communication of uncertainty. Responsible science communication conveys the challenges of managing uncertainty that is inherent in data, models and predictions, facilitating the society to understand the contexts where uncertainty emerges and enabling active participation in discussions. Uncertainty communication can play a major role across the risk management cycle, especially during decision-making, and should be tailored to the audience and the timing of delivery. Therefore, research on quantification and communication of uncertainties deepens our understanding of how to make scientific evidence more actionable in critical moments.

This session invites presentations by individuals and teams on communicating scientific uncertainty to non-expert audiences, addressing topics such as:

(1) Innovative and practical tools (e.g. from social or statistical research) for communicating uncertainty
(2) Pitfalls, challenges and solutions to communicating uncertainty with non-experts
(3) Communicating uncertainty in risk and crisis situations (e.g., natural hazards, climate change, public health crises)

Examples of research fitting into the categories above include a) new, creative ways to visualize different aspects of uncertainty, b) new frameworks to communicate the level of confidence associated with research, c) testing the effectiveness of existing tools and frameworks, such as the categories of “confidence” used in expert reports (e.g., IPCC), or d) research addressing the challenges of communicating high-uncertainty high-impact events.

This session encourages you to share your work and join a community of practice to inform and advance the effective communication of uncertainty in earth and space science.

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, canyon flows, exchange flows in semi-enclosed seas, eddies, submesoscale dynamics, river plumes and estuaries, as well as on flow interactions with bio-geochemistry, sediment dynamics and nearshore physics. Contributions on the impacts of climate change and man-made structures on our coastal seas and estuaries are also welcome. Contributions from early career scientists are particularly encouraged.

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.

Global coastal zones are of high ecological and societal values. As the dynamic interface between land, sea, and air, they are heavily impacted by a combination of climate-driven environmental change and human interventions. Approaches to sustainably manage the coastal zone increasingly seek to provide co-benefits of risk mitigation, climate regulation, preserving biodiversity, and supporting coastal community resilience. These require scientific evidence and discourse that integrate across disciplines.

This session invites multi- and inter-disciplinary contributions focusing on coastal processes, their dynamic interactions, and their role in exchanges across coastal interfaces (e.g. land-sea, air-sea, river-sea, …) under a changing climate and changing human activities. We welcome observational, modelling and theoretical studies reporting on processes linked to coastal hydrodynamics, coastal biogeochemistry, coastal ecology, or coastal sediment dynamics and geomorphology. Studies may span the wide range of spatial and temporal scales characteristic of existing and projected change in coastal seascapes and landscapes from the inner shelf shoreward to beaches and dunes, estuaries, intertidal flats, saltmarshes and coastal wetlands. We encourage the submission of holistic Earth system studies that explore the role of the coastal zone for coastal seas’ dynamics including exchanges across coastal under the impact of climate change and human activities. We also encourage studies that focus on impacts of coastal management or coastal adaptation approaches on coastal processes and dynamics, spanning engineered, hybrid, and nature-based options related to changing activities such as coastal protection, tourism, shipping, fisheries and aquaculture, and the expansion of renewable energies and other coastal infrastructure.

This session, organized by the UN Decade Program CoastPredict, aims to directly contribute to the UN Decade Challenge 6: Enhancing community resilience to ocean hazards. The focus is on addressing critical gaps in scientific knowledge, particularly in key areas such as coastal risk assessment, warning and mitigation strategies. Key topics include: (i) the collection and generation of observational and modeling datasets essential for risk assessment, including downscaled climate projections for coastal regions, all within a robust data-sharing frameworks; (ii) the promotion of interdisciplinary and international research and innovation to comprehensively address these challenges, with a particular emphasis on approaches like Digital Twin technology; (iii) the enhanced People Centred Early Warning Systems for Ocean-related Hazards through Machine learning and Predictive Modelling, and (iv)the development of standards for risk communication at both national and international levels. The session will also explore multi-hazard early warning systems for events such as tsunamis, storm surges, marine heatwaves, and coastal biogeochemical hazards, including pollution and other extreme coastal events such as erratic extratropical cyclones. Contributions on machine learning applications, compound event analysis, and disaster risk reduction strategies are strongly encouraged, as are science-based management practices for enhancing coastal resilience. By leveraging innovative tools like digital twins, this session highlights how predictive modeling can significantly improve risk assessment and response strategies. Its relevance extends to policymakers, scientists, and coastal communities, fostering collaboration to strengthen coastal resilience.

This session is dedicated to showcasing multidisciplinary scientific advancements in the Mediterranean and Black Seas, with a particular emphasis on the pioneering contributions of Prof. Dr. Emin Özsoy of Middle East Technical University, Ankara (Turkey). Prof. Özsoy has played a seminal role in advancing the internationalization of observational and modeling frameworks for the Mediterranean, Marmara, and Black Seas, fundamentally reshaping our understanding of large-scale ocean circulation and strait dynamics.
The concept of the "Southern European Seas"—a term originally introduced by Prof. Özsoy—has since evolved into a focal region for integrated, interdisciplinary research spanning a broad spectrum of spatial and temporal scales. Investigations now range from high-frequency extreme meteo-oceanographic events to long-term climate projections, encompassing the continuum from open ocean to land-coast-river interfaces. Central to these efforts is the development and sustained operation of basin-scale observing systems, the incorporation of citizen science initiatives, state-of-the-art analysis and reanalysis systems, and the application of advanced data-driven and AI-based models for phenomena such as wave dynamics and sea-level variability.
We invite contributions that address these innovative research directions within the Mediterranean, Marmara, and Black Seas. Submissions may include novel methodologies in physical and biogeochemical monitoring, advancements in ocean interdisciplinary modeling, understanding of the short and long-term variability and processes occurring in the Seas, developments in operational oceanography, and the creation of downstream applications and products.

Coastal oceans are dynamic interfaces between land and sea, playing a critical role in global biogeochemical cycles with a high impact on socio-economic activities and social developments. The dynamic and physical processes as well as the human activities that take place in coastal areas make them natural laboratories to improve our knowledge about several biogeochemical interactions. In addition, these regions are affected by both natural and anthropogenic factors such as coastal acidification, organic matter, nutrients, and pollution, among others. All these factors have impacts on the natural cycles and the magnitude of these impacts should be studied and understood in order to propose solutions to the decision makers that could help to know, understand, take decisions, and protect or regulate the coastal environments.
This session aims to bring together researchers from diverse fields to discuss the latest findings on the biogeochemical processes occurring in coastal oceans, improve our knowledge, identify impacts, and propose solutions in terms of coastal management and blue economy. We welcome research studies that focus on both natural and anthropogenic processes that are affecting the biogeochemical cycles in coastal waters, trace metal chemistry, CO2 system, ocean acidification, ocean alkalinization, nutrient cycle, organic matter, CO2 sequestration, blue carbon, etc.

To address societal concerns over rising sea levels, associated extreme events, and their impacts on coastal communities, ecosystems, and the global economy, it is essential to understand the drivers and contributions to these changes. This session responds to this need by inviting research from the international sea level community that advances knowledge of past, present, and future changes in global and regional sea levels, extreme events, and coastal impacts.
The session focuses on studies that explore the physical mechanisms of sea level rise and variability, as well as the underlying drivers, across timescales ranging from paleo records to high-frequency phenomena to long-term projections, using observations and/or model simulations. Research on linkages between sea level variability, heat and freshwater content, ocean dynamics, land subsidence, ice-sheet and glacier mass loss, and terrestrial water storage is welcome. We encourage studies addressing future sea level changes, including high-end projections from rapid ice-sheet mass loss, and those assessing short-, medium-, and long-term coastal impacts and their broader implications.

Blue carbon ecosystems, including mostly salt marshes, mangroves, seagrasses, tidal forests and mudflats, rank among the most carbon-dense ecosystems on Earth. They provide nature-based solutions essential to mitigate residual anthropogenic carbon emissions, while also delivering co-benefits such as biodiversity support or coastal protection. However, their resilience and capacity to sustain these functions are increasingly threatened by climate change and human pressures. To safeguard their role, it is essential to better understand their carbon cycle—particularly the feedback loops between soil and plants, the exchanges of carbon among the atmosphere, soil, and water, but also how human activities, vegetation, and carbon processes interact.
This session seeks to bring together scientists from multiple disciplines, including biogeochemists, ecologists, geographers, geologists, social scientists, biologists, alongside environmental managers.
By bridging perspectives across the natural and social sciences, the session aims to showcase pioneering research that i) advances understanding processes related to biomass and carbon in blue carbon ecosystems under current and future environmental conditions; and ii) spotlights effective management, conservation, and restoration practices to sustain or enhance carbon sequestration and broader ecosystem services, coupling the ecological functioning with social needs. Through this integration, the session will contribute to the goals of the United Nations Decade for Ocean Sciences, with co-convenorship from the Decade Programme for Blue Carbon in the Global Ocean.

Geological mapping and modelling are fundamental pillars of the geosciences, providing the basis for understanding Earth and planetary systems. This session brings together contributions that span the full spectrum of geological mapping and modelling, from traditional field-based methods to cutting-edge approaches, including AI, applied in the most extreme and inaccessible environments on Earth and beyond.
We invite scientists working on:
• Geological field mapping and cross-boundary harmonization
• Mapping of extreme environments such as marine areas, polar regions, deserts, volcanic terrains, high-mountain ranges, and planetary surfaces
• 3D geological modelling in any geological context
• Development of geomodelling methodologies and tools
• Application of AI methods to geological mapping and modelling
• Development of geological information systems
• Remote sensing, geophysical techniques, drilling, sampling, and specialized tools for inaccessible terrains for geological mapping and modelling
The session aims to be highly transdisciplinary, bridging geology, geophysics, geochemistry, mineralogy, hydrogeology, engineering geology, and planetary sciences. By integrating approaches across diverse contexts, from accessible outcrops to remote and hostile terrains, participants will explore common challenges in data acquisition, interpretation, 3D modelling, visualization, and knowledge synthesis.
Outcomes are expected to benefit a wide range of applications and research, including geothermal energy exploration, offshore wind energy, geological risk assessment, groundwater protection, coastal protection, habitat mapping, environmental impact assessment, marine protected area development, mineral and resource exploration, and planetary missions. Ultimately, this session seeks to foster dialogue between communities tackling mapping and modelling challenges in both familiar and extreme environments, to advance scientific understanding and practical applications across the geosciences.

Growing pressures from human activities (e.g., pollution, habitat alteration, and climate change) threaten marine ecosystems, highlighting the need for conservation and sustainable use in line with UN 2030 Agenda Goal 14. In response, the UN launched the “Decade of Ocean Science for Sustainable Development” to promote regional priorities within a global framework. Given the ocean’s dynamic, sensitive, and fragile nature, innovative observing and monitoring methods are essential to enhance spatio-temporal data coverage and quality, enabling integrated analysis of abiotic and biotic factors and the study of marine processes to better manage the effects of anthropogenic pressures.
To assess ocean environmental quality, large datasets from global observing systems and networks (e.g., GOOS, EMODnet) are needed. These need to be complemented by the development of cost-effective technologies and integrated monitoring systems, which can enhance long-term data collection, expand geographical coverage, support the study of physical and biological marine processes, and enable continuous ecosystem monitoring. In this context, Citizen Science initiatives also represent an effective means to broaden observations, raise awareness, and connect society with marine research.
This session focuses on marine ecosystems and processes, observational and monitoring technologies, and the assessment of anthropogenic impacts. Special attention will be given to the design and application of innovative, cost-effective, low-cost and do-it-yourself technologies as well as integrated monitoring approaches. Multidisciplinary contributions are encouraged, combining models, in-situ and remote monitoring, and citizen science to develop methods, technologies, and best practices for biodiversity monitoring, ecosystem restoration, and the sustainable use of marine resources. Topics include the effects of natural and anthropogenic pollution on biota; impacts of global change on marine ecosystems; new approaches for marine environmental monitoring, marine resources and process studies; cost-effective technologies development; marine citizen science applications; advanced methods for data collection and processing; benthic and pelagic community dynamics; and the economic evaluation of natural capital.

Our current understanding of marine ecosystems has largely been shaped by observations at broad spatial and temporal scales. Cruise surveys typically provide only scattered transects, while fixed stations capture variability at a single location. Although these approaches have delivered valuable information on seasonal and interannual patterns, they are constrained by low spatial resolution and limited temporal coverage. As a result, the fine-scale dynamics of plankton and their interactions with environmental gradients have remained largely unresolved, leaving an incomplete picture of ecosystem functioning.

Over the past decade, rapid advances in ocean observing technologies have opened new opportunities to resolve fine-scale plankton dynamics. High-resolution satellites (e.g. SWOT), autonomous buoy networks equipped with sensors for temperature, salinity and fluorescence, and in situ plankton imaging systems (e.g. Imaging FlowCytobot, CytoSense/CytoSub, Imaging Plankton Probe, Video Plankton Recorder) now provide continuous, high-frequency records across multiple platforms. These innovations make it possible to observe plankton processes at unprecedented temporal and spatial resolutions, capturing short-lived events and small-scale environmental gradients that were previously undetectable. Together, these advances are reshaping our understanding of plankton variability and their ecological roles in marine ecosystems.

This session invites contributions on meso- to fine-scale plankton variability and its links to environmental gradients. We particularly welcome studies using in situ and high-resolution observing systems, as well as new developments in intensive monitoring technologies. The goal is to advance understanding of how fine-scale plankton–environment interactions shape ecosystem structure and function, and how they connect to larger-scale ocean and climate processes. A special issue in the Journal of Plankton Research will accompany this session.

To study the pathways and fate of marine contaminants, such as anthropogenic hydrocarbons, marine litter (including plastics), heavy metals, HNSs, POPs, radionuclides, PFAS, pharmaceuticals, and other pollutants, researchers widely use oceanographic monitoring, modeling, and lab experiments. This session explores in situ and remote monitoring approaches, including satellite observations, air and sea drones, laboratory studies, computational tools, and digital (web- and mobile-based) applications to understand the distribution and impact of marine pollutants at various scales. It also welcomes emerging citizen science initiatives that contribute to tracking pollution sources and validating remote observations. Solicited topics include new and varied monitoring protocols, toxicity testing, ensemble and multi-model simulations, machine learning, and AI-based approaches.

Marine pollution and its effects on ecosystems continue to pose serious challenges for the sustainable management of coastal and open-ocean areas. Thus, studies that connect marine pollution to larger ecosystem stressors, such as climate change and environmental degradation, are especially appreciated. The growing human impact on the Arctic Ocean, resulting from the melting of polar ice, underscores the importance of understanding the fate of marine pollutants under ice conditions.

The key questions this session aims to answer are: What do we know about the sources of marine pollution? Which factors influence the dispersion of pollutants in the aquatic environment? What happens to the contaminants in the water column, sediments, and on the sea surface? How do marine pollutants interact with biota?

The impact of other environmental stressors, such as artificial light, noise, and thermal pollution, on marine ecosystem resilience is also an important topic for discussion.

Surface exchange fluxes of heat, momentum and mass above the global oceans and at the poles (snowpack, sea-ice, ocean and land) have significant impacts on atmospheric composition, biogeochemistry and climate at regional to global scales. Atmospheric boundary layer processes mediate these chemical and physical fluxes. This session is intended to provide an interdisciplinary forum to bring together researchers working in the areas of meteorology, atmospheric chemistry, air quality, biogeochemistry, stable isotope research, oceanography, and climate above the global oceans and in the polar regions.

The session focuses on new research in several areas which include: air-sea fluxes of climate-active trace gases (CO2, CH4, N2O) mediated by the atmospheric boundary layer above the oceans and in polar regions; regional emission and vertical mixing of aerosol, such as cloud-forming particles (CCN/INP) and their precursors (including dimethyl sulfide (DMS), marine organic compounds and halogenated species) and their impacts on atmospheric composition and climate; atmospheric deposition of nutrients (e.g., nitrogen, phosphorus, iron) and its impact on ocean biological systems; and biogeochemistry-climate feedback loops in the ocean-atmosphere system. We also welcome studies on how these surface fluxes may change in response to climate warming, as well as the local to large-scale influences on these exchanges. An adequate understanding and quantification of these processes is necessary to improve modeling and prediction of future changes above the oceans and in the polar regions, their teleconnections with mid-latitude weather and climate (including meridional transport of heat, moisture, chemical trace species, aerosols and isotopic tracers), and the coupling between local and large-scale dynamics.

The session has strong links to the Surface Ocean ̶ Lower Atmosphere Study (SOLAS) and the GESAMP Working Group 38 on atmospheric input of chemicals to the ocean. Submissions are encouraged from all areas covered by these programs, using a range of analysis approaches including field measurements, remote sensing, laboratory studies, and atmospheric and oceanic numerical models.

This year we particularly welcome studies on the impact of extreme events on air-sea gas exchange of climate-relevant compounds in marine systems. Here we invite contributions addressing physical drivers such as marine heatwaves, storms and tropical cyclones, circulation anomalies or sea ice changes; biogeochemical drivers such as hypoxic or anoxic conditions and acidification pulses; biological drivers such as harmful algal blooms; or compound events. Relevant studies may address impacts in all oceanic domains; e.g., open ocean, shelf waters and shallow (< 20 m depth) coastal ecosystems. The reporting on progress as well as critical knowledge gaps in polar regions will help define upcoming research programmes as part of Antarctica InSync and the International Polar Year 2032-33.

Functional diversity—the range and distribution of traits within biological communities—shapes how ecosystems respond to environmental change and regulate carbon, nutrient, and energy flows. This session explores the ecological and evolutionary processes that drive changes in functional diversity, and how these changes in turn affect biogeochemical dynamics across terrestrial and aquatic systems.

We invite contributions that examine functional diversity in motion: from shifts in community composition and trait distributions to adaptation via evolutionary change. We particularly welcome studies that link trait dynamics to biogeochemical consequences, whether through experiments, observational time series, comparative biogeography, or trait-based and eco-evolutionary models. Contributions may address open questions such as: How do ecological and evolutionary processes interact to drive functional change? Can trait distributions predict ecosystem responses to perturbations? How transferable are eco-evolutionary insights across biomes and scales?

By bringing together work across soils, vegetation, freshwater, and marine systems, this session aims to foster a cross-system perspective on the dynamic links between diversity, adaptation, and biogeochemical function.

Geophysical and planetary flows in stratified media exhibit stratified turbulence that give rise to a variety of flow phenomena spanning a range of spatial scales from the Kolmogorov to planetary scales. Stratified turbulence significantly influences the flow dynamics on various temporal scales via complex nonlinear interactions, which continue to be challenging to understand, diagnose, and quantify from both theory and numerics. This understanding is fundamental to advance our knowledge of turbulent flow dynamics, and a prerequisite for improved turbulent closures and parameterizations for robust predictions of weather and climate.

Gravity-driven flows, driven by density differences, 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, pyroclastic flows) are an ubiquitous geophysical phenomenon involving stratified turbulent effects. These effects are coupled with entrainment, particle–fluid interactions, non-Newtonian rheologies, and interactions with ambient stratified environments. Although occurring in various planetary environments and similar physical processes governing their dynamics, a universal description of gravity-driven flows remains elusive, as the feedback on the aforementioned flow processes is particularly difficult to predict.

This session aims to bring together the recent advancements in stratified turbulence and gravity-driven flows in geophysical, planetary, and astrophysical flows. We welcome fundamental and applied contributions from theoretical, numerical, and modelling perspectives, as well as complementary approaches based on field observations, laboratory and analogue experiments, and numerical simulations (including data-driven and IA-based methods). Topics include, but are not limited to:
— turbulent fluxes and transports; turbulent decay, mixing, and dissipation
— stable atmospheric boundary layer flows and intermittent turbulence
— wave turbulence and wave-vortex dynamics in various turbulent regimes
— turbulence in weakly and strongly stratified flows and stratified shear flows
— snow avalanches, dust storms, landslides, turbidity currents
— river, volcanic and oceanic plumes, mud, debris and pyroclastic flows
— katabatic winds, oceanic density currents

We particularly encourage participation from early career researchers.

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

Researchers and practitioners working in the domain of ocean science, as well as those interested in the application of ML methods, are encouraged to attend and participate in this session.

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.

Building and improving existing coastal monitoring capabilities and developing innovative coastal products is vital to coastal protection in the face of climate change. Through new coastal observations (satellite and land-based remote sensing data in addition to in situ observational data), advanced hydrology models, coastal models, and unified coastal management systems, coastal protection and forecasting are improved. With the advances in technological progress, it is possible to also implement new approaches with numerical models and Artificial Intelligence (AI) methods, enabling pan-European scale methods. This session focuses on advanced, seamless ocean monitoring and forecasting, from global/regional systems to coastal systems, through demonstrations of new products and improved co-produced services. These services aim to provide the marine knowledge needed for coastal applications addressing environmental and social challenges and those enhanced by climate change, such as: pollution hazard/risk mapping, coastal erosion, resource management, harmful algal blooms, and combating ecosystem degradation, supporting Marine Protected Areas, and addressing natural hazards and extreme events.

Plastic pollution is a widely recognized global problem with significant environmental and ecological risks, which have been a long-standing focus of research, particularly in marine and estuarine environments. Despite extensive studies in recent years, gaps in consistent data and holistic knowledge persist. These gaps are particularly apparent regarding sources contributions, quantities, transformation and transport processes, and the intricate distribution and accumulation hotspots of plastic and litter across environmental matrices and ecosystem compartments at a global scale. Addressing these knowledge gaps is critical to accurately assess potential risks, inform policy, and develop effective mitigation strategies.
In this session, we will explore the current state of knowledge and ongoing research on litter and macro-, micro-, and nanoplastics in estuarine and marine systems. The session will cover a wide range of topics, including:
• Recent findings on plastic distribution and accumulation in estuaries, shorelines, nearshore and open waters, nearshore and deep seafloor environments.
• Source-to-sink investigations, considering quantities and distribution across estuarine and marine environmental matrices (water, sediment and biota) and compartments (coastline, surface water, water column and seabed),
• Transport and accumulation/dispersal processes influenced by ocean currents, tides, waves and gyres.
• The role of extreme weather events, such as storms and floods, in redistributing plastic debris in estuarine and marine environments
• Impacts on biota, their structure and on different habitats from estuary and coastline to open waters, including seabed.
• Modelling approaches for local, regional, and global estimations of marine plastic accumulation and/or release to ocean basins, their impacts, and assessing the effectiveness of prevention and mitigation measures.
• Legislative and regulatory efforts, including international monitoring programs and measures aimed at reducing marine plastic pollution.

Marine extreme events, including phenomena such as storm surges, marine heatwaves, harmful algal blooms, jellyfish blooms, acidification, severe storms and temporally or spatially compounding events are becoming increasingly frequent under climate change. These events have significant impacts on marine ecosystems, coastal communities and global economies. Despite their profound socio-economic and environmental impact, extreme events in the marine environment remain largely understudied, poorly understood and difficult to simulate, making them difficult to predict. The dynamics of these events span a broad range of spatial and temporal scales and are often influenced by complex feedback mechanisms between the ocean and other components of the climate system. Fundamental research remains crucial in enhancing our understanding of these phenomena and in predicting their occurrence and related risks.

This session encourages contributions addressing dynamic mechanisms across an entire spectrum of atmospheric and ocean extremes, event attribution studies and projections under future climate. Relevant submissions also encompass new observation techniques, new modeling and machine learning methods to marine extremes forecasting, novel detection strategies and, finally, ecosystem or socio-economic impact assessments, relevant for prevention, mitigation and adaptation policies.

This session merges the "Applications of ocean reanalyses and reconstructions" session and "'Data assimilation in the ocean and coupled components":

Ocean reanalyses are reconstructions of the recent state of the ocean, using all available observational datasets together with models. They are necessary tools for understanding ocean and climate dynamics and studying the evolution of recent ocean and climate change. They are also used to derive climatologies and anomalies for applied studies, initialisation of forecasts, and training for deep learning applications.

This session aims at deepening our understanding of the way reanalyses are used by the scientific community, by providing a forum for ocean reanalysis producers and users. The session will focus, among others, on the following applications:

- Reanalyses intercomparison studies to understand the strengths and limitations of these data
- Impact of long-term observations on reanalyses quality as well as potential uncertainties stemming from the lack of such observations.
- Representation, analysis and dynamical interpretation of specific events such as extremes.
- Synergies with deep learning applications for ocean reanalyses

The outcome of the session will provide useful insights to ocean reanalysis producers for further developments to meet the community’s needs for their applications.

Data Assimilation:
This session also focuses on recent developments and research on ocean data assimilation. Data assimilation is essential for ocean forecasting, reanalysis, and climate studies. By optimally combining numerical simulations with various observations, data assimilation provides a dynamically consistent and comprehensive estimate of the present and past ocean state. This session invites abstract submissions on developments of data assimilation for the physical ocean together with coupled components such as sea ice, marine ecosystems, land-sea interface and atmosphere for ensuring consistency with other parts of the Earth system. The session also focuses on impact of the assimilation and deployment of novel space-borne and in-situ observations such as autonomous platforms, wide-swath satellite tracks, and deep in-situ observations and biogeochemistry profilers.

Beyond state estimation, this session also welcomes contributions in parameter estimation, uncertainty quantification, and hybrid machine learning and data assimilation methods focused on the ocean.

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 data records for recent decades. In the coming years, Copernicus Marine will implement next-generation ocean monitoring and forecasting systems and prepare new services for the coastal ocean and marine biology. Copernicus Marine will also progressively embrace the new capabilities of digital services in synergy with the European Digital Twin of the Ocean (DTO) developments. The European DTO will connect and interoperate, on a common digital platform, a large variety of ocean and coastal numerical tools, 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 dedicated to the next generation of ocean monitoring and forecasting systems (improved Arctic monitoring, ensemble forecasting, regional ocean climate projections, use of artificial intelligence) and new services for the coastal ocean and for marine biology. The session will also encompass research activities on 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 expected from research teams involved in the Copernicus Marine Service, in the European DTO, in the development of in situ and satellite observing systems and of downstream applications and in relevant Horizon Europe projects. Contributions from the international OceanPredict community and from the relevant UN Decade programmes and projects are strongly encouraged.

Recent advances in high-performance computing have enabled climate models to resolve processes at smaller scales, leading to a new generation of simulations that can explicitly capture km-scale atmospheric and oceanic dynamics like storms and eddies. Traditional low-resolution climate models rely on the use of eddy parameterizations in the ocean, and convective parameterizations in the atmosphere that can partially interrupt the coupling between small and large scale dynamics. Global storm- and eddy- resolving models, by largely removing the need for such parameterizations, allow us to probe the rectified effect of small-scale processes on the large-scale climate system. This new modeling frontier offers unprecedented opportunities to uncover the importance of small-scale processes in the ocean, atmosphere, and at the air-sea interface in Earth’s climate.

In this session, we welcome submissions on the added value of high-resolution ocean, atmosphere, or coupled modeling, and the importance of small-scale processes in shaping the Earth’s climate. This includes studies at global to regional scales and over all timescales, from multidecadal variability to extreme events. We also welcome contributions addressing current limitations and challenges in km-scale modeling, such as persistent model biases, computational costs, and the complexities of initializing and validating models. Studies using models from coordinated projects such as NextGEMS, EERIE, DestinE and WarmWorld, and other similar efforts are encouraged.

The Earth system is a complex, multiphysics system with nonlinear interactions on multiple spatial and temporal scales. Understanding constituent processes (linear, nonlinear, stochastic, etc.) on the one hand, and the complexity of individual subsystems or the full integrated system on the other, is key to being able to better model the Earth System in a predictive fashion. The renaissance of machine and deep-learning in the past decade has led to rapid progress in the development of advanced approaches in, e.g., nonlinear time series analysis, dynamical and stochastic systems theory, critical slowing down theory, complex systems theory, and these approaches, in turn show promise in facilitating further advances in modeling the Earth system.



In this context, this session seeks contributions on all aspects of complexity, nonlinearity, tipping points and stochastic dynamics of the Earth system, including the atmosphere, the hydrosphere, the cryosphere, the solid earth, etc. Communications on theoretical, experimental and modeling studies are all welcome, where the latter modeling studies can span the range of model hierarchy from idealized models to complex Earth System Models (ESM). Studies based on emerging approaches such as data driven models, Artificial Intelligence approaches, complex network methods, critical slowing down analysis, dynamical and stochastic systems theory, etc., are particularly encouraged.

This session addresses the interdisciplinary and challenging issue of extreme variability across scales, from theory to applications. Because this variability is ubiquitous this session focuses on edge-cutting research in various geophysical domains.

Connect with colleagues across disciplines at the 4th Lagrangian session!

This session provides an open venue for scientists to share the latest advances in Lagrangian techniques, explore diverse applications, and build new connections.

We invite presentations on topics including, but not limited to:
- Planetary circulations and variability (fundamental processes shaping jets, gyres, waveguides, overturning circulations, transport barriers across atmosphere and ocean)
- Mesoscale eddies and coherent structures (eddy transport, wave-mean flow interactions, blocking)
- Turbulence and mixing (turbulent and convective entrainment, breaking internal waves, boundary layers)
- Numerical and computational advances (incl. data-driven techniques, GPU acceleration, graph-theoretical formulations, adaptive methods, data assimilation)
- Inverse modeling techniques (long-range transport of volcanic plumes, wildfire smoke, hazardous material, aerosols, plastics, micro-organisms, and their impacts on global composition, health, and climate)
- Field campaigns (drifters, floats, superpressure balloons, etc)

Fibre optic based techniques allow probing highly precise point and distributed sensing of the full ground motion wave-field including translation, rotation and strain, as well as environmental parameters such as temperature at a scale and to an extent previously unattainable with conventional geophysical sensors. Considerable improvements in optical and atom interferometry enable new concepts for inertial rotation, translational displacement and acceleration sensing. Laser reflectometry on commercial fibre optic cables allows for the first time spatially dense and temporally continuous sensing of the ocean’s floor, successfully detecting a variety of signals including microseism, local and teleseismic earthquakes, volcanic events, ocean dynamics, etc. Significant breakthrough in the use of fibre optic sensing techniques came from the new ability to interrogate telecommunication cables to high temporal and spatial precision across a wide range of environments. Applications based on this new type of data are numerous, including: seismic source and wave-field characterisation with single point observations in harsh environments such as active volcanoes and the seafloor, seismic ambient noise interferometry, earthquake and tsunami early warning, and infrastructure stability monitoring.

We welcome contributions on developments in instrumental and theoretical advances, applications and processing with fibre optic point and/or distributed multi-sensing techniques, light polarization and transmission analyses, using standard telecommunication and/or engineered fibre cables. We seek studies on theoretical, instrumental, observation and advanced processing across all solid earth fields, including seismology, volcanology, glaciology, geodesy, geophysics, natural hazards, oceanography, urban environment, geothermal applications, laboratory studies, large-scale field tests, planetary exploration, gravitational wave detection, fundamental physics. We encourage contributions on data analysis techniques, novel applications, machine learning, data management, instrumental performance and comparison as well as new experimental, field, laboratory, modelling studies in fibre optic sensing studies.

The radioactive materials are known as polluting materials that are hazardous for human society, but are also ideal markers in understanding dynamics and physical/chemical/biological reactions chains in the environment. Therefore, man-made radioactive contamination involves regional and global transport and local reactions of radioactive materials through atmosphere, soil and water system, ocean, and organic and ecosystem, and its relations with human and non-human biota. The topic also involves hazard prediction, risk assessment, nowcast, and countermeasures, , which is now urgent important for the nuclear power plants in Ukraine.

By combining long monitoring data (> halftime of Cesium 137 after the Chernobyl Accident in 1986, 15 years after the Fukushima Accident in 2011, and other events), we can improve our knowledgebase on the environmental behavior of radioactive materials and its environmental/biological impact. This should lead to improved monitoring systems in the future including emergency response systems, acute sampling/measurement methodology, and remediation schemes for any future nuclear accidents. Furthermore, as part of the decommissioning of the Fukushima Daiichi Nuclear Power Station, the discharge of ALPS-treated water is being carried out, which has attracted international attention. The discharge rate is published in real time and monitoring is being conducted, providing a valuable opportunity for analyzing the behavior of radionuclides in the ocean. In addition, past nuclear contamination events and other data sets also welcome.

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

Making data Findable, Accessible, Interoperable and Reusable (FAIR) is now widely recognised as essential to advance open and reproducible research. Increasingly, this requires not only shared principles but also concrete digital implementations that enable interoperability across systems, disciplines, and infrastructures. However, it is very difficult to translate these principles into practical data management guidelines or operational digital solutions across disciplines. The goal of the session is to explore how best data management practices are developed, implemented, and adopted across disciplines, including through interoperable digital objects, persistent identifiers, and emerging data space concepts.

As part of this session, we invite submissions that:
1) Share good or bad experiences developing, implementing, and adopting data practices that align with both FAIR principles and the evolving needs of specific research communities.
2) Propose strategies for engaging researchers in adopting and refining best practices, with a focus on community-driven approaches to technical standards and infrastructures.
3) Explore the role of cultural change in enabling adoption of sustainable data practices.
4) Highlight efforts that harmonise data formats and workflows across disciplines while respecting domain-specific requirements, for example through interoperable data architectures or research data spaces.
5) Present technical or conceptual approaches that support the transition from data silos to interoperable, FAIR-aligned data ecosystems.

This session is aligned with the objectives of the Research Data Alliance (RDA) Earth, Space, and Environmental Sciences (ESES) Data Community of Practice and aims to foster cross-disciplinary dialogue, particularly among researchers in hydrology, seismology, and ocean sciences. However, we welcome contributions from all disciplines, especially where they provide insights or novel approaches to community engagement.
By learning from diverse experiences, this session seeks to advance collective understanding of how to build and sustain data practices that are both FAIR and fit for purpose, from community processes to concrete, interoperable digital implementations.

Science communication includes the efforts of natural, physical and social scientists, communications professionals, and teams that communicate the process and values of science and scientific findings to non-specialist audiences outside of formal educational settings. The goals of science communication can include enhanced dialogue, understanding, awareness, enthusiasm, influencing sustainable behaviour change, improving decision making, and/or community building. Channels to facilitate science communication can include in-person interaction through teaching and outreach programs, and online through social media, mass media, podcasts, video, or other methods. This session invites presentations by individuals and teams on science communication practice, research, and reflection, addressing questions like:

What kind of communication efforts are you engaging in and how are you doing it?
What are the biggest challenges or successes you’ve had in engaging the public with your work?
How are other disciplines (such as social sciences) informing understanding of audiences, strategies, or effects?
How do you spark joy and foster emotional connection through activities?
How do you allow for co-creation of ideas within a community?
How are you assessing and measuring the positive impacts on society of your endeavours?
What are lessons learned from long-term communication efforts?

This session invites you to share your work and join a community of practice to inform and advance the effective communication of earth and space science.

Deep learning algorithms have seen rapid and widespread adoption in ocean science. For many tasks, such as classification and error correction, they now represent the state of the art. However, applying deep learning in the field of oceanography also presents unique challenges, including the various temporal scales of oceanic processes, heterogeneously distributed and noisy observational data, and unresolved processes in numerical models.

In this short course, we aim to present a set of best practices for applying and assessing deep learning methods in oceanographic research. We will also highlight common pitfalls and how to avoid them.

The course will be structured around a series of short presentations and practical examples covering key topics, including:

- Types of oceanographic problems suited for deep learning: reconstruction, prediction, …
- Building datasets appropriate for deep learning applications: constitution of - training/validation/test datasets, effect of non-stationnarity, type/quality/number of data, …
- Training strategies and model selection: normalization, supervised training, generative models, …
- Validation and evaluation of ocean products derived from deep learning: accuracy, realism, …
- Ethical considerations: reproducibility, open science, and the environmental impact of deep learning