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OS – Ocean Sciences

Programme Group Chair: Joanna Staneva

MAL45-OS
OS Division Outstanding ECS Award Lecture by Tillys Petit
Convener: Joanna Staneva

OS1 – Ocean Circulation and Climate

Sub-Programme Group Scientific Officer: Joke Lübbecke

OS1.1 EDI

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.

Solicited authors:
Stefan Rahmstorf
Convener: René van WestenECSECS | Co-conveners: Yiwen LiECSECS, Gaurav MadanECSECS, Jennifer Mecking
OS1.2

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

Co-organized by NP7
Convener: Alexander Babanin | Co-conveners: Fangli Qiao, Francisco J. Ocampo-Torres, Miguel Onorato
OS1.3

The understanding of critical small-scale processes in the Arctic Ocean – particularly energetic (sub) mesoscale eddies – remains fundamentally limited, hindered by sparse observations and the inherently small spatial scales. Yet, emerging evidence reveals these processes are important for climate change: driving upward heat flux, modulating atmosphere-ice-ocean exchanges, redistributing biogeochemical constituents, and directly impacting sea ice dynamics, stratification, and circulation. As the Arctic transforms under warming climate – marked by decreasing ice cover, altered seasonality, and intensified air-sea coupling – the prevalence and influence of these fine-scale dynamics will evolve, potentially altering climate feedbacks in the Arctic. This session seeks contributions leveraging theory, modeling, and observations to illuminate the generation, interactions, and impacts of (sub)mesoscale and smaller scale processes. This includes understanding their role in transports (heat, nutrients, freshwater, energy), their representation in ocean models, their effects on basin-scale circulation, and their evolution in a changing Arctic. Interdisciplinary studies about the coupled ice-ocean-atmosphere system, biogeochemical responses, and ecosystem consequences are strongly encouraged.

Convener: Ruijian GouECSECS | Co-conveners: Yingjie Liu, Paul G. Myers
OS1.4

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

Convener: Bablu Sinha | Co-conveners: Caroline Katsman, Damien Desbruyeres, Elodie Duyck, Léon Chafik
OS1.5

Modelling the ocean in the Earth system has undergone significant improvements over the years. Nevertheless, many challenges remain, ranging from uncertainties in carbon and heat transport to accurate simulations of large-scale ocean circulation. Addressing these issues is essential for reliable long-term climate projections and for improving models used for early warning systems. Machine learning offers new opportunities by complementing traditional physical-based approaches, enhancing predictive skill, and accelerating simulations. Further opportunities lie in developing physical predictions of the ocean system based entirely on AI/ML methods.

The merging of these two fields brings with it new challenges. Some of these range from: developing and choosing an appropriate set of training data; agreement on the benchmarking process; ensuring numerical stability and physical consistency in new parameterisations.

Our objective in this session is to bring together researchers across machine learning and ocean model development to synthesise the community's progress and foster new ideas.

This session invites contributions from any of the below points (examples are included but are not limited to):

- Physics emulation: development of ocean parameterisations including their methods and architectures, offline and online performance in idealised and realistic (global or coupled) simulations, AI/ML only models, ocean forecasting.

- Training data: development and availability of new fit-for-purpose datasets, preprocessing techniques, accounting for out of distribution events such as marine heatwaves or system collapse.

- Benchmarking: defining a framework, establishing evaluation datasets and metrics, new tools.

- Calibration and optimisation: use of ML techniques to improve model fidelity, for example through optimisation of parameters and inputs or through online bias reduction.

Convener: Thomas WilderECSECS | Co-conveners: Anna Sommer, Said OualaECSECS, Adam Blaker
OS1.6

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.

Co-organized by CR3
Convener: Sophie GanglECSECS | Co-convener: Marcus Gutjahr
OS1.7 EDI

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.

Convener: Marta Martín-Rey | Co-conveners: Joke Lübbecke, Marie Lou Bachélery, Arthur PrigentECSECS, Jorge López-Parages
OS1.8 EDI

In this session, we focus on the South Atlantic Ocean, which plays a key role in regional to global climate variability but has received considerably less scientific attention than its Northern Hemisphere counterpart.

The South Atlantic connects the North Atlantic, Indian, Pacific and Southern Ocean circulations by channeling the upper and lower limb of the thermohaline circulation and being part of the wind-driven Southern Hemisphere supergyre. Local air-sea fluxes, interior mixing, and inter-basin exchange processes such as Agulhas leakage influence its northward heat and salt transport, with potential implications for the strength and stability of the Atlantic Meridional Overturning Circulation. Moreover, the South Atlantic features intricate regional ocean circulation patterns, such as the Benguela Upwelling System and the Brazil-Malvinas confluence zone. These regions host highly productive ecosystems which sustain diverse marine life and are of fundamental importance for regional fisheries. It is crucial to understand how natural variability and climate change alter South Atlantic dynamics and ecosystems. However, in situ observations are often too sparse in time to robustly infer long-term changes, and model simulations are still showing contrasting trends.

We invite contributions that advance our understanding of the physical and biogeochemical processes governing South Atlantic regional dynamics, inter-basin exchanges, extremes and global impacts. These may cover short (e.g., seasonal) to very large (e.g., millennial) timescales and originate from observational, modelling, and paleo proxy work as well as from interdisciplinary approaches. We aim to promote discussions on future inclusive South Atlantic observing and modelling strategies and to identify gaps and future research priorities, and particularly encourage contributions from the scientific community in countries bordering the South Atlantic.

Solicited authors:
Renellys C. Perez
Convener: Rebecca Hummels | Co-conveners: Siren Rühs, Franz Philip TuchenECSECS, Marius N. Müller, María Paz Chidichimo
OS1.9

The Arctic region has undergone drastic changes over the last decades, with sea ice decline being the most obvious and prominent example. 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; 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.

Co-organized by CR3
Convener: Stefanie RyndersECSECS | Co-conveners: Vasco Müller, Yevgeny Aksenov
OS1.10 EDI

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.

Co-organized by BG4
Convener: Caroline Ummenhofer | Co-conveners: Yan Du, Saurabh RathoreECSECS, Benjamin H. TigerECSECS, Emma Worthington
OS1.11

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.

Solicited authors:
Audrey Delpech
Convener: Knut Klingbeil | Co-conveners: Friederike Pollmann, Stephan Juricke, Manita ChoukseyECSECS, Nils Brüggemann
OS1.12 EDI

Freshwater content in the Arctic Ocean is changing due to sea and land ice loss, shifts in river discharge, and changes in snow and precipitation–evaporation patterns. These changes affect ocean circulation, sea ice, and ecosystems in the Arctic. They also have major implications for the Northern Hemisphere climate, making Arctic freshwater a critical factor in projecting future climate.
In this session, we invite studies that investigate sources of freshwater change and their impacts on both the Arctic and the wider world. We welcome research based on observations, reanalysis, and modeling, including work on ice melt, river discharge, snow and SWE, sea ice, precipitation–evaporation, and ocean transport. Contributions using new data products from in-situ or satellite/remote-sensing observations, or digital twins that enhance our understanding of Arctic freshwater change, are especially encouraged.
We are also interested in work that links freshwater change to ocean dynamics and climate feedbacks, including case studies from the Southern Hemisphere.

Co-organized by CR3
Convener: Carsten Bjerre LudwigsenECSECS | Co-conveners: Roshin Pappukutty Raj, Andreas Dobler, Stephen Howell, Gabriele Dr. Schwaizer
OS1.13 EDI

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.

Convener: Yann Planton | Co-conveners: Nicola Maher, Anna-Lena DeppenmeierECSECS, Fred Kucharski, Carlos ConejeroECSECS
OS1.14

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.

Convener: Ronan McAdamECSECS | Co-conveners: Fabíola Silva, Saurabh RathoreECSECS, Babita JangirECSECS
NP1.2

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—ranging from reduced-complexity climate models to machine learning-based 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—, 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 different modeling approaches advance our understanding of the Earth system and its components, and/or highlight inconsistencies in the model spectrum. We also welcome studies exploring a single modeling approach, as we aim to foster exchange between researchers working on different rungs of the model complexity ladder. 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 (radiative-convective equilibrium, single-column models, aquaplanets, slab-ocean models, idealized geography, etc.) full ESMs, and km-scale models.

Processes and phenomena of interest include, but are not limited to:
* Earth system response to climate forcing
* Tipping behavior and critical transitions (e.g. Dansgaard-Oeschger events)
* Coupled modes of climate variability (e.g. ENSO, AMV, MJO)
* Emergent and transient phenomena (e.g. cloud organization)
* Extremes and predictability

Solicited authors:
Tiffany Shaw
Co-organized by AS5/CL5/CR7/OS1
Convener: Reyk BörnerECSECS | Co-conveners: Oliver MehlingECSECS, Bahar Emirzade, Ann Kristin KloseECSECS
NP1.1 EDI

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.

Solicited authors:
Anna von der Heydt, Meriem Krouma
Co-organized by CL5/OS1
Convener: Vera Melinda GalfiECSECS | Co-conveners: Manita ChoukseyECSECS, Francisco de Melo ViríssimoECSECS, Valerio Lucarini, Valerio Lembo
NP6.2 EDI

Gravity flows are driven by gravity because of a density different from that of the surrounding environment, often 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). This can be observed either as a current along a slope or as an intrusion in the bulk of a stratified environment. 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, such as entrainment, fluid-particle interactions, viscoplastic and elastoplastic rheologies, internal waves, is difficult to predict.

This session then aims to present complementary physical-based approaches, by gathering researchers from different communities, all focusing on these flows by either studying field data, improving risk assessment techniques, using analogue laboratory experiments or numerical simulations (potentially supported by IA approaches) or focusing on analytical modelling. We therefore welcome contributions including, but not limited to:
- 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 the participation of early-career researchers and students.

Co-organized by OS1
Convener: Yvan Dossmann | Co-conveners: Gauthier RousseauECSECS, Claudia Adduce
CL3.2.3 EDI

The Atlantic Meridional Overturning Circulation (AMOC) is a key component of the Earth system, responsible for large-scale oceanic heat and salt redistribution. As a potential tipping element, it plays a vital role in regulating climate variability and abrupt transitions. Multiple lines of evidence from observations, reconstructions, and CMIP5/6 ensemble simulations point to a long-term weakening consistent with anthropogenic warming, and several studies indicate that the risk of a substantial slowdown or even collapse within this century may be underestimated.
While debates continue over the extent to which the observed weakening reflects internal variability, the risks associated with a substantially weakened or collapsed AMOC are profound—particularly for regional climate systems and socio-economic consequences. Despite its potential to trigger widespread disruptions, the AMOC’s vulnerability remains underappreciated and underprepared for by most policy frameworks.
This session welcomes contributions from observational and modeling perspectives and encourages interdisciplinary studies that link ocean dynamics to atmospheric processes, climate extremes, and societal impacts. In particular, we welcome contributions that:
• diagnose AMOC variability, trends, and mechanisms across timescales;
• link ocean dynamics to atmospheric circulation, extreme events, and compound risks;
• reveal impacts on ecosystems and biogeochemical cycles;
• develop decision-relevant tools and policy guidance—such as, prediction and early-warning indicators and adaptation/risk-management strategies.
Interdisciplinary, cross-scale studies—from process-level understanding and theory to high-resolution modeling and data-driven approaches—are also warm welcome. Our overarching aim is to advance robust science while informing preparedness for a potentially weaker AMOC.

Co-organized by OS1
Convener: Qiyun MaECSECS | Co-conveners: Katinka Bellomo, Wei Liu, Monica Ionita-Scholz
CL1.2.9

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.

Co-organized by BG5/OS1
Convener: Aline Govin | Co-conveners: Cristiano M. Chiessi, Natalia Vazquez Riveiros, P.E. Oliveira, Jelena MaksicECSECS
CR2.2 EDI

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.

Co-organized by CL4/OS1
Convener: Heiko Goelzer | Co-conveners: Ronja ReeseECSECS, Jonas Van BreedamECSECS, Ricarda Winkelmann, Alexander Robinson
CR2.6 EDI | PICO

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.

Co-organized by OS1
Convener: Ronja ReeseECSECS | Co-conveners: Irena Vankova, Peter WashamECSECS, Johanna BeckmannECSECS
CL4.10 EDI

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.

Co-organized by NP5/OS1
Convener: Bianca MezzinaECSECS | Co-conveners: André Düsterhus, Leon Hermanson, Leonard BorchertECSECS, Panos J. Athanasiadis
CR7.3 EDI

Atmosphere-ice interactions are triggered by synoptic weather phenomena such as cold air outbreaks, polar lows, atmospheric rivers, Foehn winds and heatwaves. However, our understanding of these processes is still incomplete. 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 and impact on the land ice and sea ice through interactions with radiation,

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

Presentations 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.

Co-organized by AS1/OS1
Convener: Diana Francis | Co-conveners: Michelle MaclennanECSECS, Michiel van den Broeke
AS4.12 EDI

The maritime sector faces the dual challenge of digitalization and decarbonization. The International Maritime Organization (IMO) and the European Union have already adopted measures to increase the technical and operational efficiency of ships, as well as new regulations to improve air quality. Furthermore, greenhouse gas emissions could be curbed in the mid-term if the IMO's net-zero framework is adopted. This regulatory background has profound impacts on both technology and the environment, which this session will explore.
We invite contributions on the use of advanced meteo-oceanographic forecasts, ship weather routing, and machine learning methods for optimizing speed or routes. We also welcome papers on vessel performance evaluations and the modeling of wind-assisted propulsion. This includes inter-comparing models, benchmarking practices, and evaluating the robustness of routing methods under uncertain conditions. Papers that demonstrate the use of advanced technologies such as digital twins, containerization, dockerization, and parallelization are also accepted.
Additionally, we welcome abstracts that address the climate and air quality impacts of both currently implemented and upcoming emission regulations in the shipping sector, as well as the introduction of alternative marine fuels. Topics may include air pollution mitigation, aerosol cloud interactions, ship tracks, radiative forcing, temperature response, unintended impacts of measures for mitigation of air pollution, and broader Earth system effects. We aim to bridge communities that work on measurements, emission inventories and scenarios, and modeling—from climate emulators to Earth system models.

Co-organized by OS1
Convener: Gianandrea Mannarini | Co-conveners: David Gomez Ullate Oteiza, Ragnhild Bieltvedt Skeie, Joanna Szłapczyńska, Antonios ParasyrisECSECS
AS1.22 EDI

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.

Co-organized by NP7/OS1
Convener: Claudia Stephan | Co-conveners: Chantal Staquet, Katherine GraysonECSECS, Ulrich Achatz, C. Eden
EOS1.4

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.

Co-organized by CR8/GM3/GMPV11/HS13/OS1/PS/SSS1
Convener: Solmaz MohadjerECSECS | Co-conveners: Peter Dietrich, Eleni Kritidou, Khizer Zakir, Iris Schneider-PérezECSECS
EOS2.6 EDI

Noam Chomsky has said that humanity is approaching its most dangerous period. Earth and its main irresponsible invasive species have reached a state of unprecedented emergency.

This session aims to address the vital space between science and societal change—a space defined by the intertwined challenges of how we educate and communicate:
o about the increasingly dangerous human and planetary predicament that we face (individually and as a species),
o about devastating global heating (climate change) and ocean degradation, and
o about the accelerating destructive impact of humanity on the very resources that it needs to survive.

We believe that climate, ocean and geoethics literacy must become the focus of all education and training, in all subjects, at all levels, accompanied by vital skills, such as long-term critical thinking, science mindset and resisting denial. Also, strategic communication must mobilize public awareness, shape discourse around specific issues like sea-level rise and marine biodiversity, and create the conditions for clear policy formation and immediate political will. All good communication educates, and all good education involves clear communication.

We invite abstracts on a broad range of topics that bridge any of the above issues and that show promise in progressing positively towards viable, realistic, geoethical and science-based solutions. This includes:
• Novel and traditional pedagogical approaches for educating about climate change, ocean degradation, ecocide, policy, war and other topics.
• The integration of geoethics into climate and ocean curricula.
• Strategies for fostering dialogue, developing intercultural understanding and promoting peace.
• Geoscience pedagogical and curricular innovations and traditional methods.
• Geo-communication and public engagement, such as visualising ocean data, telling compelling stories about climate impacts and using digital outreach.
• Education, communication and strategies for: policy and stakeholder-governance dialogue, the lay public, policymakers, coastal communities and industry leaders.

This session invites you to share your research, practice, experience, action and vision for how our local and global communities can build a more conscious and engaged society ready to safeguard our planet's vital resources upon which humanity depends for survival.

Co-organized by CL3.2/NH14/OS1, co-sponsored by IAPG
Convener: David Crookall | Co-conveners: Giuseppe Di Capua, Svitlana Krakovska, Pimnutcha PromduangsriECSECS, Mario Luiz MascagniECSECS
ESSI4.6 EDI

Good scientific practice includes the visualisation and user-friendly exploration of scientific data. However, increasing data complexity and volumes are a result of higher temporal and spatial resolutions of modelling and remote sensing approaches. Earth system science data is becoming increasingly important for decision support for stakeholders and other users. This poses major challenges for the entire process chain, from data storage to web-based visualisation. For example: (1) data must be enriched with metadata and made available via appropriate and efficient services; (2) visualisation and exploration tools must access decentralised tools via interfaces that are as standardised as possible; (3) the presentation of essential information must be coordinated with potential end users. This challenge is reflected by the development of tools, interfaces and libraries for modern earth system science data visualisation and exploration.
In this session, we 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.

Co-organized by OS1
Convener: Tobias Kerzenmacher | Co-conveners: Christof Lorenz, Berit Arheimer, Lucile Gaultier, Philipp S. SommerECSECS

OS2 – Coastal Oceans, Semi-enclosed and Marginal Seas

Sub-Programme Group Scientific Officer: Sandro Carniel

OS2.1 EDI

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.

Convener: Julie D. Pietrzak | Co-conveners: Evridiki ChrysagiECSECS, Peter Holtermann, Knut Klingbeil, Giorgia Verri
OS2.2 EDI

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.

Convener: Manel Grifoll | Co-conveners: Sandro Carniel, Luciana Villa CastrillonECSECS, Davide Bonaldo, Agustín Sánchez-Arcilla
OS2.3

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.

Co-organized by BG4/GM8
Convener: Laurent Amoudry | Co-conveners: Melanie Biausque, Joonas Virtasalo
OS2.4 EDI

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.

Convener: Giovanni Coppini | Co-conveners: Joanna Staneva, Agustín Sánchez-Arcilla, Vijaya SunandaECSECS, Ghada El Serafy
OS2.5

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.

Convener: Nadia Pinardi | Co-conveners: Murat Gunduz, Adil Sözer, Vanessa Cardin, Marilaure Grégoire
OS2.6

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.

Convener: Aridane González González | Co-conveners: David González-Santana, Melchor Gonzalez-Davila, J. Magdalena Santana-Casiano
CL4.13 EDI

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.

Solicited authors:
Lennart Ramme
Co-organized by CR7/OS2
Convener: Alexander Nauels | Co-conveners: Aimée Slangen, Jennifer WeeksECSECS, Svetlana Jevrejeva, Erwan OulhenECSECS
EOS4.5 EDI

The science policy interface is key to addressing current and future water resilience through translating scientific output into actionable evidence for decision making and policies. Interactions with policy makers are key to formulating academic research towards water resilience and addressing social challenges to support realistic and feasible local adaptation strategies. With the ever-increasing pressures on water availability (both in quantity and quality) and the profound social, economic, ecological, and political impacts, a deeper understanding is needed of the science-policy context of water security and resilience to hydrologic extremes. This can identify hydrological research priorities and improve knowledge transfer and translation to support adaptive local, national, and global policies that focus on water resilience in the face of climate extremes. The recently published European Water Resilience Strategy is a good example of one such initiative.

This session provides the opportunity to show how water research across the entire hydrologic cycle can inform dialogues for science-informed policies on the regional, national, and international level, with a particular focus on shared waters. Our session promotes dialogues focused on understanding the complex interplay between academic water research and policies through stakeholder dialogues and policy labs to promote sustainability. Additionally, we want to address the impact of adaptive policies and directives on promoting water resilience across all stores (i.e. oceans, lakes, rivers and groundwater), as well as across interdisciplinary avenues such as societal or economic uses both locally or globally. We also want to highlight the role of science in providing scientific evidence-based guidelines for fostering blue diplomacy in transboundary river basin cooperation initiatives, ocean governance, water use tradeoffs, and the need for interdisciplinary approaches to addressing water resilience in a changing and extreme climate.

Therefore, we welcome abstracts that contribute to interdisciplinary science-policy research on building water resilience, transboundary water issues, stakeholder dialogues, results from living labs, water diplomacy initiatives, and related topics.

Co-organized by HS13/NH14/OS2
Convener: Jennie C. SteyaertECSECS | Co-conveners: Elena Toth, Micha Werner, Wouter Buytaert, Niko Wanders
BG4.5 EDI

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.

Solicited authors:
Fernanda Adame
Co-organized by OS2/SSS8
Convener: Marie ArnaudECSECS | Co-conveners: William Austin, Gloria ReithmaierECSECS, Carmen B. de los Santos, Pere Masqué
G2.6

GNSS Interferometric Reflectometry (GNSS-IR) is an emerging ground-based remote sensing technique that uses the interference between direct and coherently reflected GNSS signals. This technique has been applied to measure a variety of variables including water level, significant wave height, snow accumulation, ice freeboard, permafrost melt, soil moisture, vegetation water content and coastal subsidence. As the community of GNSS-IR developers and users continues to grow, this session seeks to highlight advances in the (near real-time) acquisition, processing, analysis and application of GNSS-IR in environmental sensing. The session welcomes contributions on algorithmic and technical improvement of GNSS-IR models, as well as the development of open-source hardware and software. We also invite presentations on GNSS-IR data products and their validation, the optimal exploitation of geodetic and affordable GNSS sensors for GNSS-IR applications and initiatives for (near) real-time monitoring of environmental variables.

Co-organized by CR6/GI4/OS2
Convener: Makan KaregarECSECS | Co-conveners: Lin Liu, Angel Martin-Furones, Alvaro Santamaría-Gómez, Surui XieECSECS
ESSI4.7 EDI

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.

Solicited authors:
Urszula Stępień
Co-organized by OS2/PS7
Convener: Kristine Asch | Co-conveners: Philippe Calcagno, Anu KaskelaECSECS, Irene Zananiri

OS3 – Ocean Biogeochemistry and Biology

Sub-Programme Group Scientific Officer: Peter Landschützer

OS3.1 EDI

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.

Convener: Marco Marcelli | Co-conveners: Viviana Piermattei, Raquel Peñas-TorramilansECSECS, Shujin Guo, Daniele Piazzolla
OS3.2

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.

Convener: Gérald GREGORI | Co-conveners: Wuchang Zhang, Jingyuan LI, Raffaella Casotti, Fang Zhang
OS3.3 EDI

The sea surface microlayer (SML; <1 mm)) and near-surface layers (NSL; < 1.2 meters) play a critical role in physical, chemical, and biological processes that regulate air–sea exchange. These layers respond rapidly to fluctuations in meteorological forcing. Episodic events, such as rain, storms, slicks, and fronts, rapidly disrupt the SML and NSL, creating sharp changes in structure and function that fuel short-term variability. In contrast, persistent anomalies, including seasonal stratification, shape more stable biogeochemical patterns in air–sea exchange over extended timescales. This session invites contributions on recent advances in understanding the physicochemical and biological characteristics of the SML and NSL. By integrating perspectives on gradients, episodic forcing, and biogeochemical reactivity, we aim to highlight how physical, chemical, and biological processes are tightly interconnected, and how the functioning of the SML is regulated by its dynamic coupling with the underlying water (ULW) column across different spatial and temporal scales.
We particularly welcome studies that address the SML’s role in modulating exchanges of heat, momentum, freshwater, gases, particles, and biota, as well as its coupling and decoupling with the ULW. Topics of interest include variability in temperature, salinity, organic and inorganic matter, surfactants, nutrients, microbial communities, and gas fluxes, as well as how these multiple interacting drivers influence solubility and turbulence, and affect air–sea CO₂ fluxes. We strongly encourage contributions from diverse approaches, including field observations, laboratory experiments, autonomous platforms, and modeling, to advance a mechanistic understanding of the SML and NSL as dynamic interfaces shaping air–sea exchange.

Convener: Riaz BibiECSECS | Co-conveners: Janina RahlffECSECS, Naama Lang-Yona, Lasse Z. JensenECSECS
OS3.4 EDI

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.

Convener: Svitlana Liubartseva | Co-conveners: George Zodiatis, Sebastien Legrand, Luisa Galgani, Panagiota KerameaECSECS
AS2.3 EDI

Ocean-atmosphere chemical flux exchanges have significant impacts on global biogeochemistry and climate. This session focuses on new research in the following areas: air-sea fluxes of climate-relevant trace gases such as CO2, CH4, N2O and CO; atmospheric deposition of nutrients (e.g., nitrogen, phosphorus, iron) and its impact on ocean biological systems; the influence of ocean emissions of reactive gases and aerosols (including dimethyl sulfide (DMS), marine organic compounds and halogenated species) on atmospheric chemistry and climate; and biogeochemistry-climate feedback loops in the ocean-atmosphere system. We also welcome studies on how these fluxes may change in response to anthropogenic and climate stressors. The session has long-standing 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.

Co-organized by BG1/OS3, co-sponsored by SOLAS and GESAMP WG38
Convener: Damian Leonardo Arévalo-Martínez | Co-conveners: Parvadha Suntharalingam, Maria Kanakidou, Manuela van Pinxteren, Julika ZinkeECSECS
BG1.11 EDI

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.

Solicited authors:
Boris Sauterey, Jaideep Joshi
Co-organized by OS3/SSS5
Convener: Elsa AbsECSECS | Co-conveners: Elisa BruniECSECS, Stefano Manzoni, Iain Colin Prentice, Laurent Bopp
BG1.9

The climate at the Earth’s surface is affected by natural and anthropogenic changes in cloud properties, aerosol emissions, as well as the proposed intervention of Solar Radiation Modification (SRM), which aims to cool the planet by altering the radiation budget. These changes and perturbations alter the energy balance, hydrological cycle, and biogeochemical processes of terrestrial and marine ecosystems through temperature, precipitation, quantity and quality of solar radiation, and nutrient deposition. Ecosystems, in turn, feedback to climate via biogeochemical and biogeophysical processes.

However, major uncertainties remain in understanding how ecosystems respond to changes in clouds, aerosols, and solar radiation, and the resulting climate feedbacks, limiting our ability to project future climate and ecosystems and to inform effective climate policies. SRM, in particular, carries significant risks due to these uncertainties and large knowledge gaps regarding its impacts on biodiversity, agriculture, and ecosystem services.

This session aims to bring together researchers studying the interactions between ecosystems, clouds, aerosols, and solar radiation, using observational, experimental, and modeling approaches. We welcome contributions from studies on terrestrial and marine ecosystems at all scales, including both mechanism investigation and impact assessments. Studies focusing on the potential effects of SRM are especially encouraged.

Co-organized by AS3/OS3
Convener: Yuan ZhangECSECS | Co-conveners: Lili XiaECSECS, Roland Séférian, Long Cao
BG8.6

Since 196 Parties to the Paris Agreement committed to limiting global warming to well below 2°C, ideally 1.5°C, above pre-industrial levels, achieving these goals requires dramatically accelerated action. The latest UNEP Emissions Gap Report 2024 shows that nations must cut greenhouse gas emissions by 42% by 2030 and 57% by 2035. At regional scales, coastal areas face dual challenges of contributing to climate mitigation while adapting to climate impacts including sea-level rise, extreme weather events, and changing precipitation patterns.
Coastal forests, including mangroves, coastal shrublands, and terrestrial forest systems, represent critical nature-based solutions that simultaneously address climate adaptation and mitigation at regional scales. These ecosystems provide essential adaptation services through coastal protection from storm surges, erosion control, flood mitigation, and habitat connectivity for climate-resilient biodiversity corridors. Simultaneously, they deliver significant mitigation benefits through carbon sequestration in vegetation and soils, with mangroves storing up to 1,000 tC ha-1.
Regional variations in climate vulnerability, ecosystem composition, and management capacity create unique opportunities for implementing coastal forest-based climate solutions. Mangrove forests at the land-sea interface provide storm protection and exceptional carbon storage through complex soil-vegetation-water interactions driven by tidal processes, salinity gradients, and sediment dynamics. Coastal shrublands and terrestrial forests contribute through slope stabilization, watershed protection, and terrestrial carbon sequestration while supporting climate adaptation through micro-climate regulation.
Understanding regional-specific approaches to coastal forest management is essential for optimizing both adaptation and mitigation outcomes. This session welcomes interdisciplinary studies on: (1) regional climate adaptation through coastal forests; (2) carbon sequestration and mitigation potential; (3) regional management and governance strategies; and (4) integrated monitoring and co-benefits assessment.

Co-organized by OS3/SSS8
Convener: Bora LeeECSECS | Co-convener: Pin Kar Yong
BG8.2

Warming-induced greenhouse gas emissions (WIE) are a blind spot in climate science and climate policy and affect estimates of the remaining carbon budget inferred by the Transient Climate Response to Cumulative Emissions (TCRE), assumptions related to Earth system stability and the Zero-Emissions Commitment (ZEC), and will also require additional mitigation efforts to maintain a safe climate. This session invites scientists using experimental, observational, and modeling techniques to understand greenhouse-gas climate feedbacks from permafrost, wetlands, wildfires, vegetation and soils, and coastal and marine ecosystems to reduce uncertainties and better inform climate policy and mitigation. The session aims to explore linkages between warming-induced emissions and policy and mitigation activities related to maintaining climate stability and recovery.

Co-organized by CL5/OS3
Convener: Ben Poulter | Co-conveners: Luana Basso, Danie Potocek, Chris Jones, Daniel Hooke
CL3.1.7 EDI

In addition to strong emission reductions, Carbon Dioxide Removal (CDR) strategies are critical to avoid exceeding the temperature limits of the Paris Agreement. At the same time, large-scale CDR deployment might be in conflict with reaching the Sustainable Development Goals (SDG), e.g. massive expansion of bioenergy production conflicts with SDG 2 “zero hunger”, and sustainability considerations are increasingly seen as vital for the success of CDR strategies. CDR approaches, including afforestation and reforestation, bioenergy with carbon capture and storage (BECCS), ocean alkalinity enhancement (OAE), and direct air capture with CCS (DACCS), must scale to remove up to several hundreds of Gt of CO2 in order to reach net-zero as fast as possible. Robust and optimised monitoring, reporting, and verification (MRV) systems are essential in order to enable reliable carbon accounting and guarantee the capacity to continuously and consistently detect the early emergence of CDR-related signals and potential side-effects.

In this session, we invite modelling or observation based contributions on the detection of climatic and biogeochemical signals and their attribution to CDR deployment at different timescales. For example, changes in features of variability, such as, long-term trends, seasonal or diurnal cycles of carbon cycle components but also of variables that could reveal CDR-related side effects (e.g. ocean oxygen, nutrient availability, soil moisture, land-surface properties, etc.).

We welcome studies employing marine mesocosm CDR experiments, pilot CDR field sites, or modelling of novel CDR scenarios and CDR practices. We also welcome studies that use observational networks - including innovative use of existing monitoring networks, such as Argo floats, established land and ocean time series or ICOS data, that can provide insights into CDR potential and impacts. Implementation of machine learning algorithms, optimal fingerprinting or innovative time-of-emergence analysis for MRV are particularly encouraged.

The objective of this session is to gather an understanding of emerging monitoring practices with potential to advance the scientific foundations for robust MRV, and to explore opportunities and challenges for responsible, large-scale implementation of CDR.

Co-organized by BG1/OS3
Convener: Ana C. FrancoECSECS | Co-conveners: Shraddha GuptaECSECS, Sandy AvrutinECSECS, Jörg Schwinger
HS10.14 EDI

This session is dedicated to exploring environmental DNA (eDNA) as a tracer of transport processes, whether hydrological, geophysical, or ecological across multiple spatial and temporal scales. Our primary focus is on genetic signals in freshwater — particularly riverine—but we also welcome contributions that link present-day eDNA patterns to longer-term records preserved in sediments. Beyond rivers, we are interested in studies from wetlands, groundwater, as well as, lakes, coastal waters, and oceans.
Presentations in this session will address the methodologies, applications, and implications of eDNA for understanding the movement, persistence, and transformation of biological material within hydrological and geophysical systems. We encourage contributions that investigate how eDNA distribution is shaped by transport mechanisms, degradation, and environmental drivers such as flow, sediment dynamics, and biogeochemical conditions and what that knowledge can reveal about the physical processes. Studies that integrate laboratory analyses, modeling, or sediment archives to connect scales and processes are particularly welcome.
We also seek contributions that push the boundaries of how eDNA is collected and mobilized. This includes innovative sampling strategies such as custom-built sensors and samplers, automated or distributed collection networks, and citizen science approaches that expand spatial and temporal coverage through crowd sampling.
By bringing together researchers working on diverse systems and approaches, this session aims to advance our understanding of eDNA as both a biological tracer and ecological record, fostering new interdisciplinary collaborations between physical and biological earth sciences.

Solicited authors:
Mikayla A. Borton
Co-organized by BG2/CR7/GM2/OS3
Convener: Yvonne SchadewellECSECS | Co-conveners: Natalie Ceperley, Maria Magdalena WarterECSECS, Olivier Evrard, Peter Chifflard
NP6.4

Geophysical and astrophysical flows in stratified media exhibit stratified turbulence that gives 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. This session aims at bringing together the recent advancements in the field of fluid dynamics, with a focus on geophysical and astrophysical flows, as well as magneto-hydro dynamics.

Our session invites fundamental and applied contributions on stratified turbulence in fluids from theoretical, numerical, and experimental observational perspectives. The topics include, but are not limited to: two dimensional, three dimensional, isotropic, and anisotropic turbulence; regime transitions and energy cascades in turbulent flows; turbulent fluxes and transports; turbulent decay, mixing, and dissipation; stable atmospheric boundary layer flows and intermittent turbulence; wave-vortex dynamics in various turbulent regimes; wave turbulence; clear air turbulence; turbulence in weakly and strongly stratified flows and stratified shear flows.

We particularly encourage participation from early career researchers.

Co-organized by OS3/PS4
Convener: Manita ChoukseyECSECS | Co-conveners: Georg Sebastian Voelker, Mark Schlutow
SSP1.10

Environmental changes and the geodynamic evolution of continents have facilitated both the emergence of life on Earth and the diversification of mineral species from the early Archean until today. However, the physico-chemical conditions of ancient environments remain poorly understood, particularly regarding the processes and consequences of major oxygenation events (e.g., the Great Oxidation Event, Neoproterozoic Oxygenation Event, and Phanerozoic Oceanic Anoxic Events) and associated mass extinctions, as well as the influence of continents and mantle processes in modulating ocean chemistry at different times in Earth’s history.
Understanding key processes shaping modern and ancient environments; such as weathering, hydrothermal alteration of the oceanic crust, bacterial activity, sedimentation, and diagenesis; is crucial for reconstructing paleo-environments. Redox processes and Earth’s oxygenation during critical transitions and biotic crises are central to unraveling the links between environmental change and biological evolution.
With this session, we encourage contributions from the interdisciplinary fields of geochemistry, oceanography, sedimentology, mineralogy, and geo(micro)biology with a particular emphasis on geochemical and isotope-based approaches to redox reconstructions, element cycling, and paleoenvironmental modeling. We welcome studies addressing the evolution of early life habitats, biomineralization, and paleobiological responses during intervals of profound environmental and climatic change, highlighting the links between Earth's chemical evolution and life.

Solicited authors:
Eva Stüeken
Co-organized by BG5/GMPV9/OS3
Convener: Sebastian Viehmann | Co-conveners: Francois-Nicolas Krencker, Johanna KrayerECSECS

OS4 – Global ocean processes and oceanographic techniques

Sub-Programme Group Scientific Officer: Aida Alvera-Azcárate

ITS1.9/OS4.1 EDI

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.

AGU
Convener: Julien Brajard | Co-conveners: Aida Alvera-Azcárate, Rachel FurnerECSECS, Redouane Lguensat, Jan Saynisch-Wagner
OS4.2

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.

Convener: Cristina González-Haro | Co-conveners: Aida Alvera-Azcárate, Adrien Martin, Craig Donlon
OS4.3 EDI

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.

Co-organized by BG4
Convener: Kelli JohnsonECSECS | Co-conveners: Emma Reyes Reyes, Quentin Jamet, Pavel Terskii, Lotta BeyaardECSECS
OS4.4 EDI

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.

Convener: Daniel González-Fernández | Co-conveners: Miguel Jorge Sánchez-Guerrero HernándezECSECS, Lisa WeissECSECS, Bruna de Ramos, Giuseppe SuariaECSECS
OS4.5

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.

Convener: Matjaz Licer | Co-conveners: Antonio RicchiECSECS, Giovanni Liguori, Colinne Poppeschi, Baptiste Mourre
OS4.6 EDI

This session 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.

Co-organized by BG4/CR3/NP4
Convener: Yumeng ChenECSECS | Co-conveners: Lars Nerger, Tsuyoshi Wakamatsu, Anna Teruzzi, Ali Aydoğdu
OS4.7

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.

Convener: Aida Alvera-Azcárate | Co-convener: Chunxue Yang
OS4.8

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.

Convener: Stephanie Guinehut | Co-conveners: Anna Teruzzi, Julien Brajard, Benjamin Jacob, Andrea Storto
CL4.14 EDI

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.

Co-organized by AS5/OS4
Convener: Audrey DelpechECSECS | Co-conveners: Thomas Rackow, Hans SeguraECSECS, Fraser GoldsworthECSECS, Daisuke TakasukaECSECS
NP2.1 EDI | PICO

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.

Co-organized by AS4/OS4
Convener: Christian Franzke | Co-conveners: Naiming Yuan, Paul Williams, Da NianECSECS, Ana M. Mancho
NP3.3

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.

Co-organized by BG1/GD10/HS13/OS4, co-sponsored by AGU and AOGS
Convener: Daniel Schertzer | Co-conveners: Shaun Lovejoy, Yohei Sawada, Klaus Fraedrich, Rui A. P. Perdigão
NP6.6 EDI

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)

Solicited authors:
Erik van Sebille
Co-organized by AS1/OS4
Convener: Louis RivoireECSECS | Co-conveners: Jezabel Curbelo, Silvia Bucci, Ignacio Pisso
SM3.4 EDI

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.

Solicited authors:
Andreas Fichtner, Max Tamussino
Co-organized by CR6/ESSI4/G7/GI4/GMPV12/HS13/OS4/TS10
Convener: Philippe Jousset | Co-conveners: Martina AllegraECSECS, Shane Murphy, Nicolas Luca CelliECSECS, Yara RossiECSECS
GD9.4 EDI

The Atlantic Ocean is one of Earth’s best natural laboratories and has been extensively explored by scientific ocean drilling. Studying the Atlantic archives has led to a wealth of knowledge, including the refinement of the theory of plate tectonics through an understanding of the opening of the mid-ocean ridge, the study of Oceanic Core Complex formation at slow-spreading ridges and the influence that the Mid-Atlantic Ridge has on the Iceland mantle plume. The Atlantic sedimentary record contains key information on the evolution of Atlantic meridional overturning circulation (AMOC) and Northern and Southern Hemisphere glacial initiation and dynamics.

Combined recovery of magmatic and sedimentary sequences enables the study of the interaction of mantle dynamics and crustal accretion, hydrothermal exchanges between the cooling ocean crust and overlying water masses, ocean circulation patterns influenced by gateway changes connected to the Pacific, Southern, and Arctic Oceans and the Mediterranean Sea. Recent drilling efforts have also aimed to shed light on deep-biosphere ecosystems and their interaction with sedimentary and magmatic processes.

This session aims to bring together interdisciplinary studies and to foster discussions on recent advances from scientific ocean drilling expeditions throughout the Atlantic Ocean. We welcome experimental, theoretical, modelling, and observational studies using data (e.g., geophysical, geochemical, sedimentological, and paleontological) from recent and past International Ocean Discovery Program (IODP) expeditions and their predecessors.

Co-organized by OS4
Convener: Chiara AmadoriECSECS | Co-conveners: Michelle Harris, Claudio Robustelli TestECSECS, Matthias SinnesaelECSECS, Emma HansonECSECS
GI2.5 EDI

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).

Co-organized by AS3/OS4
Convener: Daisuke Tsumune | Co-conveners: Roman Bezhenar, Tomoko Ohta, Yu ChiangECSECS, Masatoshi Yamauchi
ESSI3.2

Making data Findable, Accessible, Interoperable and Reusable (FAIR) is now widely recognised as essential to advance open and reproducible research. However, it is very difficult to translate these principles into practical data management guidelines across disciplines. The goal of the session is to explore how best data management practices are developed, implemented, and adopted across disciplines. 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.
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.
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.

Solicited authors:
Martina Stockhause
Co-organized by HS13/OS4/SM9, co-sponsored by AGU
Convener: Alice Fremand | Co-conveners: Shelley Stall, Lesley Wyborn, Natalie Raia
EOS1.1 EDI

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.

Co-organized by CR8/GM4/OS4/PS/SSS1
Convener: Roberta Bellini | Co-conveners: Philip Heron, Nuno Pimentel, Thomas HarveyECSECS, Ashley AkingbadeECSECS
SC2.26 EDI

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

Co-organized by ESSI6/OS4
Convener: Julien Brajard | Co-conveners: Aida Alvera-Azcárate, Alexander Barth, Rachel FurnerECSECS, Matjaz Licer
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