Side Events
Disciplinary sessions
Inter- and Transdisciplinary Sessions

Session programme


OS – Ocean Sciences

OS1 – Ocean General Circulation and Climate


For the open session, we welcome contributions on all aspects of ocean circulation from observations, models and theory, from regional to global scales, from air-sea exchanges to abyssal mixing. We particularly encourage studies on the interannual to decadal variability and the internal and externally forced physical processes in the ocean. Because accurate estimation of energy and mass fluxes is critical for the closure of the ocean energy budget and the ocean’s impact on the atmosphere, this session also welcomes works dealing with processes at the ocean’s boundaries. This includes studies focusing on the fundamentals of air-sea physics, on the ocean’s interaction with the cryosphere, as well as physical processes occurring at topographic boundaries. As usual the OS1.1 session also welcomes submissions that do not fit to any of the other special sessions; this includes equatorial oceanography and the Pacific Ocean.

Convener: Alejandra Sanchez-FranksECSECS | Co-conveners: Sophie Cravatte, Maria Paz Chidichimo, Clement VicECSECS

Since the Industrial Revolution, the earth’s radiative imbalance has been altered by human activity. Anthropogenic greenhouse gas emissions have led to the accumulation of excess heat causing a global warming trend. More than 90% of the excess heat in the climate system has been stored in the ocean, which mitigates the rate of surface warming. Better understanding of ocean ventilation mechanisms, as well as the uptake, transport, and storage of oceanic heat are therefore essential for reducing the uncertainties on global warming projections. In this session we welcome abstracts presenting results based on observations and/or modelling of the uptake, storage, and redistribution of heat in the ocean.

Convener: Marie-Jose Messias | Co-conveners: Damien DesbruyeresECSECS, D. Gwyn EvansECSECS, Yavor KostovECSECS, Herle Mercier
OS1.4 | PICO

The ocean's role in climate involves a rich tapestry of physical and biogeochemical processes. Water-mass transformation analyses, which exploit fundamental understanding of the ocean’s layering, are a prominent and promising means to disentangle and quantify leading processes. This session is aimed to disseminate and stimulate such analyses across oceanographic disciplines.

Water mass transformation analyses assess the state and evolution of water masses, defined as ocean layers, in combination with the driving forces of ocean circulation. By framing ocean circulation as moving layers the framework complements Eulerian and Lagrangian approaches. It has traditionally been used to analyze the steady-state overturning circulation. However, recent advances have allowed for applications of this framework to understand climate variability and the interplay of the overturning circulation and origin and fate of biogeochemical tracers. As such, the water mass transformation framework weaves together ocean dynamics, thermodynamics, biogeochemical processes, and interactions with the atmosphere, cryosphere and solid Earth.

We welcome studies that utilize water-mass analyses and the water-mass transformation framework to further our understanding of the ocean’s role in the climate system. This includes efforts to better understand processes that contribute to water mass formation, such as (sub)mesoscale air-sea fluxes or interior ocean mixing, and that have a broader perspective on effects on water masses. We especially welcome frontier interdisciplinary applications that analyze climate variability or combine physics with biogeochemistry through water mass analyses.

Co-organized by BG4/CL2
Convener: Ivy FrengerECSECS | Co-conveners: Casimir de LavergneECSECS, D. Gwyn EvansECSECS
OS1.5 | PICO

Theoretical and model studies show that the ocean is a chaotic system interacting with the atmosphere: uncertainties in ocean model initial states may grow and strongly affect the simulated variability up to multidecadal and basin scales, with or without coupling to the atmosphere. In addition, ocean simulations require both the use of subgrid-scale parameterizations that mimick crudely unresolved processes, and the calibration of the parameters associated with these parameterizations, while respecting numerical stability constraints. Oceanographers are increasingly adopting ensemble simulation strategies and probabilistic analysis methods, and developing stochastic parameterizations for modeling and understanding the ocean variability in this context of multiple uncertainties.

Presentations are solicited about the conception and analysis of ocean ensemble simulations, the characterization of ocean model uncertainties, and the development of stochastic parameterizations for ocean models. The session will also cover the dynamics and structure of the ocean chaotic variability, its relationship with the atmospheric variability, and the use of dynamical system or information theories for the investigation of the oceanic variability. We welcome as well studies about the propagation of the ocean chaotic variability towards other components of the climate system, about its consequences regarding ocean predictability, operational forecasts, detection and attribution of climate signals, climate simulations and projections.

Co-organized by NP5
Convener: Thierry Penduff | Co-conveners: William K. Dewar, Guillaume Sérazin, Laure Zanna

Sustained observations at sea are being made within a wide variety of programmes and are leading to significant advances in our ability to understand and model climate. Further efforts to make sustained observations at the sea surface and through the water column are planned under the Global Climate Observing System (GCOS), the Global Ocean Observing System (GOOS), and the UN Decade for Ocean Research for Sustainable Development. This session will explore ongoing and planned sustained ocean observing efforts and illuminate their roles in improving understanding of climate. At the same time it seeks to probe the interfaces between observing, modelling, and the development of products. Various sustained observations are being used to obtain new insights into climate variability and to guide the development of products. For example, air-sea flux moorings are being maintained at select sites to assess models and air-sea flux fields. They also form a valuable tool to calibrate and validate remote sensing of the ocean. Deep temperature and salinity measurements are being made at time series moorings and will be made by deep ARGO floats. Moored arrays have been established to measure meridional transports. Such sustained observations provide the means to investigate model biases and errors and motivate improvements to models. This session seeks to encourage the growth of linkages between sustained ocean observing and climate modeling. In particular, we ask for contributions both on sustained observation-based studies of climate variability and present or future improved collaborations between observing and modelling.

Co-organized by CL2
Convener: Simon Josey | Co-conveners: Rena Czeschel, Maria Valdivieso, Robert Weller

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

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

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

Co-organized by AS1
Convener: Richard Greatbatch | Co-conveners: Monika Rhein, Bablu Sinha

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

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

We welcome presentations focusing on

- Pathways and connectivity of water masses in the Atlantic Ocean and their variability
- Sources of heat and freshwater anomalies and their role for the Atlantic Meridional Overturning Circulation (AMOC)
- Impact of large- and global-scale atmospheric modes on the Atlantic ocean circulation
- Atlantic ocean circulation and influence on on sea-level and sea-ice change

Co-organized by CL2
Convener: Léon ChafikECSECS | Co-conveners: Joakim KjellssonECSECS, Iselin Medhaug, Gilles Reverdin

Observations and simulations of ocean circulation and marine atmosphere processes are rapidly growing for meso to basin scale, on diurnal to interannual scale. This session focuses on tropical and subtropical ocean dynamics as well as local interaction between the ocean and the overlying atmosphere from the equator to mid-latitudes. Relevant processes in the ocean include upper and deep ocean circulation variability, mild SST gradients to sharp fronts, eddies, filaments, tropical instability waves, warm pools, upper ocean various layers, cold tongues and eastern boundary upwelling. Regarding air-sea interactions, we seek studies that analyse the local to regional scales, and those discussing the conditions under which they may lead to a large-scale atmospheric response. Surface wind modulations, Madden-Julian Oscillation, cyclones, and convective systems, as well as scale interactions are welcome. In the extra-tropics, we seek also contributions on the role of extra-tropical fronts in regional and large-scale atmospheric circulation. We welcome contributions on how the air-sea interactions may shape modes of climate variability and determine regional climate sensitivity.

Co-organized by AS2
Convener: Peter Brandt | Co-conveners: Alban Lazar, Marie-Lou BacheleryECSECS, Noel Keenlyside

The Indian Ocean is unique among the other tropical ocean basins due to the seasonal reversal of monsoon winds and concurrent ocean currents, lack of steady easterlies that result in a relatively deep thermocline along the equator, low-latitude connection to the neighboring Pacific and a lack of northward heat export due to the Asian continent. These characteristics shape the Indian Ocean’s air-sea interactions, as well as its variability on (intra)seasonal, interannual, and decadal timescales. They also make the basin and its surrounding regions, which are home to a third of the global population, particularly vulnerable to anthropogenic climate change: robust trends in heat transport and freshwater fluxes have been observed in recent decades in the Indian Ocean and Maritime Continent region. Advances have recently been made in our understanding of the Indian Ocean’s circulation, interactions with adjacent ocean basins, and its role in regional and global climate. Nonetheless, significant gaps remain in understanding, observing, modeling, and predicting Indian Ocean variability and change across a range of timescales.
This session invites contributions based on observations, modelling, theory, and palaeo proxy reconstructions in the Indian Ocean that focus on understanding recent observed and projected changes in Indian Ocean physical and biogeochemical properties and their impacts on ecological processes, links between Indian Ocean variability and monsoon systems on (intra)seasonal to interannual timescales, interactions and exchanges between the Indian Ocean and other ocean basins, natural decadal variability, and extreme events. Contributions are sought in particular that address research on the Indian Ocean grand challenges highlighted in the recent IndOOS Decadal Review, and as formulated by the Climate and Ocean: Variability, Predictability, and Change (CLIVAR), the Sustained Indian Ocean Biogeochemistry and Ecosystem Research (SIBER), and the International Indian Ocean Expedition 2 (IIOE-2) programs.

Co-organized by BG4/CL4
Convener: Caroline Ummenhofer | Co-conveners: Yan Du, Alejandra Sanchez-FranksECSECS, Jérôme Vialard

The rapid decline of Arctic sea ice in the last decade is a dramatic indicator of climate change. The Arctic sea ice cover is now thinner, weaker and drifts faster. The ocean is also changing; the volume of freshwater stored in the Arctic and has increased as have the inputs of coastal runoff from Siberia and Greenland. Concurrently inflows from the Atlantic and Pacific Oceans have warmed. As the global surface temperature rises, the Arctic Ocean is speculated to become seasonally ice-free in the 21st century, which prompts us to revisit our perceptions of the Arctic system as a whole. What could the Arctic look like in the future? How are the present changes in the Arctic going to affect the lower latitudes? What aspects of the changing Arctic should future observations, remote sensing and modelling programmes address? The scientific community is investing considerable effort in making the current knowledge of the physical and biogeochemical properties of the Arctic more systematic, in exploring poorly understood coupled atmosphere-sea-ice-ocean processes to improve prediction of future changes in the Arctic.

In this session, we invite contributions from a variety of studies addressing the recent past, present and future Arctic. We encourage submissions examining interactions between the ocean, atmosphere and sea ice and on studies linking changes in the Arctic to the global ocean. Submissions with a focus on emerging cryospheric, oceanic and biogeochemical processes and their implications are particularly welcome.

The session promotes results from current Arctic programmes and discussions on future plans for Arctic Ocean modelling and measurement strategies, and encourage submissions on the results from the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC).

Co-organized by AS4/BG4/CL2/CR6
Convener: Yevgeny Aksenov | Co-conveners: Paul A. Dodd, Céline Heuzé, Krissy Reeve

The Southern Ocean around the latitudes of the Antarctic Circumpolar Current is a key region for the vertical and lateral exchanges of heat, carbon and nutrients, with significant impacts on the climate system as a whole. The role of the Southern Ocean as a sink of anthropogenic carbon and heat, and as a source of natural carbon in present and future climate conditions remains uncertain. To reduce this uncertainty, understanding the physical and biogeochemical processes underlying the Southern Ocean internal variability and its response to external forcing is critical. Recent advances in observational capabilities, theoretical frameworks, and numerical models (e.g. CMIP6 simulations) are providing a deeper insight into the three-dimensional patterns of Southern Ocean change. This session will discuss the current state of knowledge and novel findings concerning the role of the Southern Ocean in past, present, and future climates. In particular, it will address physical, biological, and biogeochemical processes, including interior ocean mixing and transport pathways, the cycling of carbon and nutrients, as well as ocean-ice-atmosphere interactions, and their wider implications for lower latitudes and the global climate.

Highlight: Solicited speaker Michael Meredith will report on the outcomes of the Polar Regions chapter of the recent "IPCC Special Report on the Ocean and Cryosphere in a Changing Climate" during this session.

Co-organized by BG4/CL4
Convener: Alexander HaumannECSECS | Co-conveners: Ivy FrengerECSECS, Lavinia Patara, Christian Turney

In recent years the interaction between the ocean and the cryosphere in the marginal seas of the Southern Ocean has become a major focus in climate research. Questions such as "Why has Antarctic sea ice only recently begun to decline?", "What controls the inflow of warm water into ice shelf cavities and where does this destabilize the ice?", and “How do ocean and climate respond to enhanced melting of Antarctic ice?” have attracted scientific and public attention. Recent advances in observational technology, data coverage, and modeling provide scientists with a better understanding of the mechanisms involving ice-ocean interactions in the far South. Processes on the Antarctic continental shelf have been identified as missing links between the cryosphere, the global atmosphere and the deep open ocean that need to be captured in large-scale and global model simulations.

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

Co-organized by BG4/CL2/CR6
Convener: Xylar Asay-Davis | Co-conveners: Torge Martin, Nadine SteigerECSECS, Ralph Timmermann

Comprehensive studies to address ocean science issues require synergistic collaboration across the globe between many subdisciplines including science, engineering, environment, society and economics. However, it is a challenge to unify these aspects under a common program or study, and as such has been recognized as a main goal of the United Nations “Decade of Ocean Science for Sustainable Development (2021-2030)”. Consequently, this session will bring together early-career representatives from a wide range of subdisciplines to demonstrate the strength of an interdisciplinary and intercultural approach when addressing global concerns, such as the dynamic impacts of climate change, focusing on the North Atlantic region as an example.

Continuous and comprehensive data is crucial to our understanding of the ocean. Yet, developing the advanced tools and technologies required for long-term ocean monitoring is not merely an engineering problem, as the data produced by these instruments will have future environmental and socio-economic impacts. A comprehensive view of the ocean also requires an understanding of past conditions. Thus, this session will also include contributions from paleo-oceanography to link the past to the future. In this vein, we will discuss our attempts at transdisciplinary and transcultural collaboration and share what we have learned for future approaches.

We invite contributions from a wide range of enthusiasts, including those in the natural sciences (e.g. biology, physics), applied sciences (e.g. engineering and technology, business), humanities (e.g. law), and social sciences (e.g. economics, political science). We also invite contributions from educators and administrators who are interested in experimenting with novel methods of building and encouraging research within interdisciplinary and multicultural graduate school programs.

Co-organized by EOS4/CL4
Convener: Allison ChuaECSECS | Co-conveners: Jacqueline BertlichECSECS, Kriste MakareviciuteECSECS, Subhadeep RakshitECSECS

Interdisciplinary study of the Northeast Atlantic region offers an extraordinary opportunity to advance understanding of interactions and co-dependencies between the solid Earth, ocean, atmosphere, cryosphere and climate. Understanding these issues are of critical importance to Europe and Scandinavia, and they are of global relevance. The unprecedented surge in exploration of the Northeast Atlantic Realm that has unfolded in recent years has delivered major leaps forward in understanding its geological structure, dynamics and development, economic resources and volcanism. Examples include the complexity of the conjugate volcanic rifted margins, contact metamorphism of carbon-rich shales by sill intrusions, producing thermogenic methane, the discovery of widespread continental crust in the ocean, the critical role of the Greenland-Iceland-Faroe bathymetric ridge in influencing ocean circulation between the Arctic and the Atlantic south of Iceland, mapping of gas hydrates and the study of crustal structure beneath the Greenland icecap. Throughout the Cenozoic these factors have influenced ocean and atmosphere composition and circulation, climate change, and the growth, wastage and transport of ice. Detailed understanding of the interdependencies of these phenomena in the past and through time is arguably of critical importance to understanding the current, rapid changes in the natural environment. The goal of this special session is to bring together diverse contributions drawing on all the above disciplines in order to identify potentially fertile areas for broad, cross-disciplinary study of the Northeast Atlantic Realm moving forward.

Co-organized by CL1/OS1/TS6
Convener: Laurent Geoffroy | Co-conveners: G.R. Foulger, Dieter Franke, Catherine Kissel

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

Co-organized by CL4/G3/OS1
Convener: Steven Phipps | Co-conveners: Florence Colleoni, Chris Fogwill, Taryn Noble

This session explores improvements in our understanding and quantification of past, present and future ice sheet and sea-level changes. We invite contributions about the following topics:

How to improve the reliability of the projections using observations (paleo and present), models and model intercomparison exercises (ISMIP6, and others); assessment of uncertainties and probability distributions of the ice sheets' contribution to sea level change; emerging processes; feedbacks coming from interactions between components (ice sheets, ocean, atmosphere, solid earth). We focus on the present and future (multi-centennial) Greenland and Antarctic ice sheets, but paleo-studies are encouraged if they shed a light on the mentioned topics.

This session is related to both ISMASS (http://www.climate-cryosphere.org/activities/groups/ismass) and ISMIP6 (http://www.climate-cryosphere.org/activities/targeted/ismip6).

Co-organized by CL4/OS1, co-sponsored by CliC
Convener: Frank Pattyn | Co-conveners: Guðfinna Aðalgeirsdóttir, Helene Seroussi, Donald SlaterECSECS

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

Co-organized by OS1
Convener: Adrian Jenkins | Co-conveners: Rachel CarrECSECS, Angelika Humbert, Nicolas Jourdain, Inga Monika Koszalka

Recent observations and modelling of this critical region suggest an ongoing interaction between climate change, ocean circulation, and basal melting that leads to rapid ice loss. Processes that connect these components are key to understanding the future of the region and the likelihood of rapid, and potentially irreversible, ice sheet change in West Antarctica.

Co-organized by CL4/OS1
Convener: Ted Scambos | Co-conveners: Karen J. Heywood, Kiya RivermanECSECS, David Vaughan

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

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

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

Co-organized by OS1
Convener: Daniel Feltham | Co-conveners: Daniela Flocco, Andrew Wells

Ice-ocean-atmosphere interactions in the Weddell Sea play an important role in the formation of dense water masses and in modulating the rate of ice discharge from Antarctica. Recent ocean- and atmosphere-induced changes to the ice shelves that fringe the margins of the Weddell Sea, including the disintegration of Larsen A and B, have been linked to the acceleration, retreat and thinning of the glaciers that once drained into and sustained the ice shelves. Together with the calving of iceberg A-68 from Larsen C Ice Shelf, these phenomena have raised questions about the past and future stability of this sector, and have motivated much scientific research focused on elucidating the role of ice, ocean and atmosphere interactions in controlling rates of glaciological and oceanographic change over palaeo- to contemporary timescales. In addition, this research plays a key role in informing on-going international discussions regarding the inclusion of the Weddell Sea Sector as a marine protected area (MPA).

In light of on-going research within these themes, we welcome contributions examining the range of controls driving cryospheric, oceanic and atmospheric change in the Weddell Sea, across a range of timescales. Remotely sensed observations, model results, and fieldwork-based studies are particularly encouraged.

Co-organized by CL2/OS1
Convener: Christine BatchelorECSECS | Co-conveners: Frazer ChristieECSECS, Katherine HutchinsonECSECS
CR5.3 | PICO

In recent decades, the climate in the polar regions has undergone dramatic changes. Quantifying the individual contributions of atmosphere, ice and ocean to the observed changes is challenging, since not all processes in each component are fully understood or not yet captured by models. In addition, there are strong feedback mechanism between ice, ocean and atmosphere which limits any attempt to understand the system by studying individual components separately. This session focuses on coupled models to better understand the key processes that control the ice-ocean-atmosphere system and thereby improve future projections of climate change.

The main objective of this session is to address the challenges to include the land ice dynamics in the Earth System Models. The submitted abstracts should work on coupled models of at least two of the following: atmosphere, land ice, ocean. Studies can also deal with inclusion of additional components to the coupling scheme, like sub-glacial hydrology, biochemistry, firn, calving and ice bergs. We encourage studies addressing any aspect – no matter physical or technical - of coupling. Among others, topics of submitted abstracts could be interface development and maintenance, coupling workflows, aspects of variable exchange (like mass and energy conservation, interpolation), coupled simulation results in the Arctic or Antarctic and comparisons of online- and offline-coupled models.

This session is submitted as a PICO session giving each scientist the opportunity to verbally present their main results briefly followed by more detailed explanations and discussions using interactive screens.

Co-organized by AS4/OS1
Convener: Konstanze HaubnerECSECS | Co-conveners: Rupert Gladstone, Stefanie MackECSECS, Shuting Yang, Yoshihiro Nakayama

Several subsystems of the Earth system have been suggested to react abruptly at critical levels of anthropogenic forcing. Well-known examples of such Tipping Elements include the Atlantic Meridional Overturning Circulation, the polar ice sheets and sea ice, tropical and boreal forests, as well as the Asian monsoon systems. Interactions between the different Tipping Elements may either have stabilizing or destabilizing effects on the other subsystems, potentially leading to cascades of abrupt transitions. The critical forcing levels at which abrupt transitions occur have recently been associated with Tipping Points.

It is paramount to determine the critical forcing levels (and the associated uncertainties) beyond which the systems in question will abruptly change their state, with potentially devastating climatic, ecological, and societal impacts. For this purpose, we need to substantially enhance our understanding of the dynamics of the Tipping Elements and their interactions, on the basis of paleoclimatic evidence, present-day observations, and models spanning the entire hierarchy of complexity. Moreover, to be able to mitigate - or prepare for - potential future transitions, early warning signals have to be identified and monitored in both observations and models.

This interdisciplinary session invites contributions that address Tipping Points in the Earth system from the different perspectives of all relevant disciplines, including

- the mathematical theory of abrupt transitions in (random) dynamical systems,
- paleoclimatic studies of past abrupt transitions,
- data-driven and process-based modelling of past and future transitions,
- early-warning signals
- the implications of abrupt transitions for Climate sensitivity and response,
- ecological and societal impacts, as well as
- decision theory in the presence of uncertain Tipping Point estimates

Co-organized by CL4/CR7/OS1
Convener: Niklas BoersECSECS | Co-conveners: Peter Ditlevsen, Timothy Lenton , Anna von der Heydt, Ricarda Winkelmann

Earth system resilience critically depends on the nonlinear interplay of positive and negative feedbacks of biophysical processes. Earth system science has established a robust understanding of dynamics in the carbon cycle, large-scale ecosystems, atmosphere, ocean, and cryosphere. Recent developments in policy, including the UN Sustainable Development Goals and the Paris Agreement on climate, and also in cross-discipline scientific debate about entering the Anthropocene have recognised the need for better understanding and characterization of the resilience of the Earth system to planetary-scale human impacts.

Maintaining Earth in the Holocene-like conditions that have enabled the development of the world’s societies will require better understanding of tipping dynamics in both the human world and the biophysical Earth. Societies will need to embark on rapid global-scale socio-economic transformations, to reduce the risk of crossing tipping points in the Earth system, potentially triggering cascading changes at multiple temporal and spatial scales.

Earth resilience brings the complex dynamics and perturbations associated with human activities into Earth system analysis, and increasingly captures socio-economic as well as biophysical dynamics. In this session we invite contributions on all topics relating to Earth resilience, such as assessing the biophysical and social determinants of the Earth’s long-term stability, modelling and analysis of nonlinearity, feedback processes, tipping points and abrupt shifts in the Earth system, and the potential for rapid social transformations to global sustainability.

Co-organized by BG1/CR7/NP8/OS1
Convener: David Armstrong McKayECSECS | Co-conveners: Sarah Cornell, Jonathan Donges, James Dyke, Ricarda Winkelmann

Significant advances in our understanding of the development of Cenozoic polar continental margins have been made over the last two decades by studying continental shelf and slope sediment sequences. These include more detailed reconstructions of the climatic, oceanographic, and tectonic evolution of high northern and southern latitudes over various time scales, as well as reconstructions of past ice-sheet dynamics and studies of marine geohazards. Data have been obtained from conventional and high-resolution 2D and 3D seismic surveying, as well as from a growing number of short sediment cores and targeted high-latitude deep drilling expeditions (e.g. IODP, MeBO). The same techniques have also been applied in fjords, which link the continental margins with the interiors of landmasses and act as “miniature ocean basins”. Fjord settings allow us to study similar geological processes to those that acted on glaciated continental margins but at smaller scales. The variety of sediment inputs (e.g. glacial, fluvioglacial, fluvial, biological) to fjord basins along with relatively high sedimentation rates provides the potential for high-resolution palaeoclimatic and palaeooceanographic records on decadal to centennial timescales.

The aim of this session is to bring together researchers working on both northern and southern high latitudes processes spanning various spatio-temporal scales from continental margins to fjords, to provide a multi-disciplinary picture of polar areas. We welcome submissions focussing on (but not limited to) records of past climatic change, tectonics, oceanography and ecosystems, and the associated links with ice sheets and glacier behaviour, ice-ocean interactions and glacial-marine sedimentary processes. Studies that integrate different datasets, data types, or that marry observations with numerical modelling are also encouraged.

Co-organized by OS1/SSP3
Convener: Johann Philipp KlagesECSECS | Co-conveners: Florence Colleoni, H. Christian Hass, Kelly Hogan, Michele Rebesco

Climate variations in the tropical Atlantic Ocean are of high importance at both regional and global scales. Regionally, tropical Atlantic variability (TAV) strongly affects precipitation over Africa and South America and also modulates the Angola-Benguela and Mauritania-Senegal upwelling systems. At the global scale, TAV is able to impact the adjacent tropical oceans (e.g. increasing ENSO predictability or modulating the Indian monsoon) and remote areas, such as the Euro-Mediterranean and East-Asian sectors. However, coupled models still fail to reproduce the tropical Atlantic seasonal cycle, variability and teleconnections. Understanding the mechanisms underlying TAV as well as finding the root causes for its poor representation in global climate models is therefore an area of active research.

This session is devoted to the understanding of tropical Atlantic climate variability from interannual to multi-decadal time scales, with a special focus on its regional impacts and teleconnections to other basins. We therefore invite contributions that examine TAV with respect to its drivers, modulation on multi-decadal time scales, impacts on rainfall over the adjacent continents and coastal upwelling systems (including extremes), interactions with other ocean basins, and applications for climate services. Furthermore, we seek contributions examining the causes and impacts of systematic model errors in the region. Studies based on model simulations as well as direct observations, reanalysis or reconstructions are welcome

Co-organized by AS1/OS1
Convener: Marta Martín-ReyECSECS | Co-conveners: Teresa Losada, Ingo Richter

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

Co-organized by AS1/NP2/OS1
Convener: Dietmar Dommenget | Co-conveners: Daniela Domeisen, Eric Guilyardi

This session investigates mid-latitude cyclones and storms on both hemispheres. We invite studies considering cyclones in different stages of their life cycles from the initial development, to large- and synoptic-scale conditions influencing their growth to a severe storm, up to their dissipation and related socioeconomic impacts.
Papers are welcome, which focus also on the diagnostic of observed past and recent trends, as well as on future storm development under changed climate conditions. This will include storm predictability studies on different scales. Finally, the session will also invite studies investigating impacts related to storms: Papers are welcome dealing with vulnerability, diagnostics of sensitive social and infrastructural categories and affected areas of risk for property damages. Which risk transfer mechanisms are currently used, depending on insured and economic losses? Which mechanisms (e.g. new reinsurance products) are already implemented or will be developed in order to adapt to future loss expectations?

Co-organized by CL4/NH1/OS1
Convener: Gregor C. Leckebusch | Co-conveners: Joaquim G. Pinto, Uwe Ulbrich

Changes in the Arctic and Antarctic climate systems are strongly related to processes in the boundary layer and their feedbacks with the free troposphere, ocean and ice. An adequate understanding and quantification of these processes is necessary to improve predictions of future changes in the polar regions and their teleconnection with mid-latitude weather and climate, including meridional transport of heat, moisture and chemical constituents. Processes include atmosphere-ocean-ice (AOI) interactions, physical and chemical snow processes (e.g. snow photochemistry), exchange of chemical constituents including biogeochemical impacts , sources of aerosol, polynya formation processes, sea ice production and loss, and cloud formation, which represent key processes for the atmosphere, ocean and the cryosphere. AOI interactions are also triggered by and have feedbacks with synoptic systems and mesoscale weather phenomena such as cold air outbreaks, katabatic winds and polar lows. Associated processes also include the effect of extreme events such as warm air advection and clouds on the surface energy budget and related boundary layer exchanges. In addition, understanding natural processes including AOI interactions is essential to understand of the background atmosphere to quantify the anthropogenic impacts. Shallow inversions, mostly during winter-time, lead to high air pollutant concentrations. Even though severe air pollution episodes are frequently observed in the Arctic, knowledge on urban emission sources, transport and atmospheric chemical processing of pollution, especially under cold and dark conditions, are poorly understood. Similarly, the polar boundary layer can involve complicated radiative processes such as shallow stable layers with fog present. In addition, polar boundary layers can mediate chemical, aerosol, and isotope exchanges between the atmosphere and the firn important to the interpretation of ice core records.
This session is intended to provide an interdisciplinary forum to bring together researchers working in the area of boundary layer processes and high-latitude weather and climate (including snow physics, air/snow chemistry, and oceanography). Cryosphere and atmospheric chemistry processes (the focus of the IGAC/SOLAS activity “CATCH” and the IGAC/IASC activity “PACES”) are highly relevant to this session. We also encourage preliminary results from field programs such as MOSAiC and other high-latitude research efforts.

Co-organized by CL2/CR7/OS1
Convener: William Neff | Co-conveners: Jo Browse, Julia Schmale, Michael Tjernström, Gillian Young

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

Co-organized by CR7/OS1
Convener: Marit-Solveig Seidenkrantz | Co-conveners: Anne de Vernal, Michal Kucera, Mimmi OksmanECSECS

The Arctic sea ice and high latitude atmosphere and oceans have experienced significant changes over the modern observational era. The polar climate is crucial for the Earth’s energy and water budget, and its variability and change have direct socio-economic and ecological impacts. Thus, understanding high-latitude variability and improving predictions of high latitude climate is highly important for society. Predictability studies indicate that decadal to multi-decadal variations in the oceans and sub-seasonal to multi-year sea ice variations are the largest sources of predictability in high latitudes. However, dynamical model predictions are not yet in the position to provide us with accurate predictions of the polar climate. Main reasons for this are the lack of observations in high latitudes, insufficient initialization methods and shortcomings of climate models in representing some of the important climate processes in high latitudes.
This session aims for a better understanding and better representation of the mechanisms that control high latitude climate variability and predictability in both hemispheres at sub-seasonal to multi-decadal time-scales in past, recent and future climates. Further, the session aims to discuss ongoing efforts to improve climate predictions at high latitudes at various time scales (as e.g. usage of additional observations for initialization, improved initialization methods, impact of higher resolution, improved parameterizations) and potential teleconnections of high latitude climate with lower latitude climate. We also aim to link polar climate variability and predictions to potential ecological and socio-economic impacts and encourage submissions on this topic.
This session offers the possibility to present results from the ongoing projects and research efforts on the topic of high-latitude climate variability and prediction, including, but not limited to WWRP Year of Polar Prediction (YOPP), NordForsk-project ARCPATH, and the H2020-projects APPLICATE, INTAROS, BlueAction, PRIMAVERA.

Co-organized by AS4/OS1
Convener: Torben Koenigk | Co-conveners: Neven-Stjepan Fuckar, Yongqi Gao, Helge Goessling

The North Pacific’s sensitivity to forcing and feedbacks to background climate are an important, but largely open question in assessments of global climate, both in the modern and geological past. Enhanced knowledge of processes of past climate change is crucial to separate between natural and anthropogenic forcing, and to enhance the reliability of future climate projections. On a spatial scale, this region also comprises major oceanographic patterns including Boundary Current systems e.g., Kuroshio/Oyashio, or the Alaskan Stream and several frontal regions. In addition, complex exchange processes and interactions between the open North Pacific and its marginal seas from low to high latitudes create a spatially heterogenous region, with small-scale mixing and both temporal and spatial variations in the system at atmospheric, and oceanic surface, subsurface and deep levels.
We aim to provide a comprehensive collection of original contributions and syntheses that foster the dynamic and four-dimensional understanding of the evolution of climate and oceanic modes in the North Pacific, including links and teleconnections to low latitudes (e.g. West Pacific Warm Pool) and polar regions, as well as to global ocean circulation and climate patterns.
We welcome contributions across all time scales, from the geological past to present. Results may be based on instrumental or proxy data, as well as climate modelling. The session should advance our process-oriented understanding of the complex role of the North Pacific and its marginals seas in regulating biogeochemical cycles, ocean overturning circulation, and ocean-atmosphere carbon budgets. These past climate scenarios can be used to create a framework for the identification of potential thresholds in the current, warming Earth system.

Co-organized by OS1
Convener: Xun GongECSECS | Co-conveners: Lester Lembke-JeneECSECS, Gerrit Lohmann, Xuefa Shi

State of the art climate models are now run for past, present and future climates. This has opened up the opportunity for paleoclimate modelling and data together to inform on future climate changes. The Earth's climate is highly variable on all spatial and temporal scales. These changes in variability (spatial or temporal) can impact the recurrence frequency of extreme events which can have catastrophic effects on society. Yet, it is unclear if a warmer future is one with more or less climate variability, and at which scales. A multitude of feedbacks are involved.

We welcome contributions that improve quantification, understanding and prediction of past, present and future climate and its variability. The session is multidisciplinary and brings together studies related to atmospheric science, oceanography, glaciology and paleoclimatology to examine the complementarity of ideas and approaches. We particularly encourage submissions that combine models run for the past, present and future with data syntheses to constrain the spread of future predictions, submissions which combine models and data in the past to make strong conclusions or testable hypotheses about the future, as well as work highlighting future experiments and data required to strengthen the link to the future.

Co-organized by AS4/CR7/OS1
Convener: Julia Hargreaves | Co-conveners: Chris Brierley, Kira Rehfeld

Today the Indo-Pacific Warm Pool (IPWP) represents a crucial part of the global thermohaline circulation by acting as a low latitude heat source for the polar regions. The IPWP’s importance in deciphering past and future coupled ocean-atmosphere dynamics is highlighted by the complex interactions between this region and globally significant climatic systems like the Australasian Monsoon, Intertropical Convergence Zone (ITCZ), El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD).

This session will explore the IPWP’s role in global climate change and its emergence as a biogeographic diversity hot spot from the geological past to the present. We invite submissions on a broad range of topics in sedimentology, palaeontology, paleoclimatology/-oceanography, and data-model comparisons to assemble a comprehensive view of the Cenozoic evolution of the entire Indo-Pacific Region. We encourage submissions stratigraphically synthesising marine-terrestrial multi-proxy archives, and those investigating teleconnections between the IPWP, zonal (ENSO/IOD), and high latitude processes. Finally, this session will examine how the long-term evolution of the global monsoons and the ITCZ affected feedbacks between IPWP, Australasian hydroclimate and tectonic/weathering processes.

Co-organized by CL1/OS1
Convener: Gerald AuerECSECS | Co-conveners: Anna Joy DruryECSECS, Or BialikECSECS, Kate Littler, Mathias Harzhauser

OS2 – Coastal Oceans, Semi-enclosed and Marginal Seas


Contributions are invited on innovative observational, theoretical and modelling studies concerning physical processes in coastal and shelf seas. Processes can include hydrodynamics (e.g., waves, tides, currents and Stokes drift, upwelling, eddies, density structures), transport of material (e.g., sediments, contaminants, litter, nutrients), and morphodynamics and sea-bed structure (e.g., evolution of bed forms, banks, Holocene-Antropogene strata or basin shape). Study areas are envisaged between the base of the shelf break and the seaward limit of the surf zone, including tidal basins. However, contributions on processes outside these geographical limits will be considered where they significantly influence processes within these limits. Equally, contributions on climate dynamics, biogeochemistry, and man-made structures will be considered where they significantly influence, or are significantly influenced by, the processes aimed at in this session. In addition to the above, this session welcomes coastal and shelf seas related abstracts that do not fit into the more specialist sessions. Special attention will be given to interactions between physics and biology/biogeochemistry and to global to local scaling of processes, their relative importance, and the representation of these transitions in models. A subsession is envisaged on the Baltic Sea, with emphasis on the Baltic Earth programme, focusing on sea-level variability, salinity dynamics and water budget, biogeochemical feedbacks, extreme events and anthropogenically induced changes.

Convener: Johan van der Molen | Co-conveners: Huib E. de Swart, Andreas Lehmann

Oceanographic processes at coastal scales present a number of differences with respect to deep water oceanography, which result in higher prediction errors. In shallow water coastal domains the bottom topography exerts a strong control on the resulting wave/current fields and other factors need to be accounted for (stratification and mixing effects, land boundary condition). Moreover, the coupling between wind, waves, currents and sediments at limited scales, or even the choice of numerical strategy (nested meshes, finite-elements, etc.) may also play a critical role in the quality of the predictions. Coastal observations are therefore necessary to drive numerical models, combining in-situ data and satellite images. The advent of new satellite capabilities (resolution and sensors like for instance those of the Sentinel constellation) and new modelling advances (coupling and boundary conditions) with coastal observatories should allow starting a quantum leap in coastal oceanography.

These issues are even more relevant in a framework of changing climate, since coastal and transitional areas are strongly impacted by climate. Because of these reasons, it is timely to discuss recent advances in fields such as: integrated ocean-atmosphere-sediment modelling approaches and the physics of their coupling mechanisms; the hydrological, biogeochemical, geomorphological variability of coastal regions; the availability and use of coastal in-situ observations; and standards, procedures and data formats to make data ready for use in an integrated coastal ocean monitoring system. Following this, some of the themes we invite for this session are satellite/in-situ measurements, coastal assimilation, atmosphere-ocean-sediment model coupling and error/prediction limits as well as the contribution of coastal ocean science to operational oceanography. Finally, how these main processes control coastal variability (hydrodynamics, morphodynamics and bio-geochemical processes) and applications to improve our knowledge on how these processes interact with coastal infrastructure or activities.

Convener: Agustín Sánchez-Arcilla | Co-conveners: Davide Bonaldo, Sandro Carniel, Manuel Espino Infantes, Emil Stanev

This session focuses on interaction between freshwater continental discharge and coastal sea from their initial mixing and transformation in river estuaries to formation of buoyant river plumes and their spreading in coastal and shelf areas. We will discuss dynamics of the related transport and mixing of freshwater discharge, as well as its influence on physical, biological, and geochemical processes at the continental shelf.
River plumes play an important role in land-ocean interactions. Despite their relatively small surface area and volume as compared to adjacent coastal sea, they significantly influence global fluxes of buoyancy, heat, terrigenous sediments, nutrients, and anthropogenic pollutants, which are discharged to the coastal ocean with continental runoff. River plumes are characterized by strong spatial inhomogeneity and high temporal variability caused by external forcing and mixing processes. Regional features (delta/estuary, enclosed bay/open sea, shoreline, bathymetry, etc.) also significantly influence morphology and behavior of river plumes. As a result, dynamics and variability of river plumes are key factors for understanding mechanisms of spreading, transformation, and redistribution of continental discharge and river-borne constituents in coastal sea and their influence on adjacent continental shelf.
The session will discuss recent advances in understanding mechanisms which govern dynamics and variability of river plumes and estuarine processes based on in situ measurements, satellite observations, and numerical modelling. The session will focus on influence of freshwater discharge and river plumes on stratification and circulation in esuaries and coastal areas, transport and fate of river-borne suspended and dissolved constituents (nutrients, terrigenous sediments, anthropogenic pollutants, litter), impact on coastal nutrient cycle and food webs, sediment deposition and seabed morphology.

Convener: Alexander Osadchiev | Co-convener: Julie D. Pietrzak

Operational oceanography in the Mediterranean Sea is available nowadays to thousands of users through services dealing with societal challenges. Oceanographic products from Copernicus Marine Service and downscaled sub-regional, national coastal products and observing systems (in the framework by Mediterranean Sea Oceanography Network for GOOS) are transformed and upgraded and provided to users, private companies, and stakeholders through adding-value chains.
This session will show how operational oceanography (e.g. fusion of observations and modeling products, downstream products development) is engaged in activities related to the production and use of services for continuously advance in the scientific understanding and technological development and supporting sustainable Blue Growth and SDGs implementation. Additionally, examples of best practices for promoting visibility and recognition of the services, enhancing the usability and for supporting the planning and implementation of international initiatives involving operational oceanography will be welcome.

Convener: Vanessa Cardin | Co-conveners: Giovanni Coppini, Laurent Coppola, ALEJANDRO ORFILA, Sarantis Sofianos

The session would like to overview recent developments and understanding, by observations and modelling, of the Southern European Seas (SES) general circulation, physical processes, biogeochemical interactions and their ecosystems. Themes of particular interest are: - Interaction of scales and processes in the SES: hydrodynamic and ecosystem interactions at multiple temporal and spatial scales (down to submesoscale), coastal processes and shelf-to-open sea interactions, straits dynamics, ocean response to atmospheric forcing, impact of environmental conditions on ecosystem functions from local to regional scales; - Assessing, understanding and predicting the potential impact of climate change in the SES: long term trends, occurrence of extreme events, development of downscaled models at basin and regional scales, novel approaches to model marine ecosystems, ecosystem functions and biodiversity; - Integrated Observing System in the SES: development of new sensors, scale of interests, development of advanced methodologies for upscaling local information, new satellite products, processes that need to be monitored, identification of data gaps (eg. observing system experiments); - Science-based Integrated management of the SES: support to Marine Spatial Planning and deployment of Marine Protected Areas , scenario studies, mapping of anthropogenic pressures, habitat and ecosystem services, potential support for nature-based solutions and/or sustainable exploitation of marine resource.

Convener: Gianmaria Sannino | Co-conveners: Arthur CapetECSECS, Katrin Schroeder
OS2.6 | PICO

The nearshore zone is one of the most dynamic places on earth. Here, the perpetual interaction between waves, tides, wind and the seabed drive the fluid motions that initiate sediment transport and, ultimately, shape the world’s coastal areas. The magnitudes and spatiotemporal scales at which these processes act vary tremendously, and understanding the small-scale processes that underlie large-scale coastal dynamics remains a challenge.
This session welcomes contributions that focus on small scale (from turbulence to mean flow, sand grains to ripples) physical processes in the nearshore zone of wave-dominated coasts. Ranging from approximately 10 m water depth up to the shoreline, this region comprises the shoaling, surf and swash zones. Topics include cross-shore and alongshore wave field evolution, wave-breaking and turbulence, swash-zone processes, cross-shore and alongshore current structures, extreme events, sediment mobilisation and transport, and biophysical interactions. This session will include abstracts describing field measurements, numerical and laboratory modelling, theoretical analysis, and model-data assimilation. We particularly welcome studies including innovative data collection approaches, or with a focus on uncertainties in measurements and predictions.

Convener: Angels Fernandez-Mora | Co-conveners: Matthieu De Schipper, Timothy Price, Nadia SENECHAL

This session provides a platform for cross-disciplinary science that addresses the continuum of the river and its catchment to the coastal sea. We invite studies across geographical borders; from the source to the sea including groundwater, and across the freshwater-marine water transition. The session welcomes studies that link environmental and social science, address the impacts of climate change and extreme events, and of human activities on water and sediment quality and quantity, hydromorphology, biodiversity, ecosystem functioning and ecosystem services of River-Sea systems, and that provide solutions for sustainable management of the River-Sea social-ecological system.
We need to fully understand how River-Sea-Systems function. How are River-Sea-Systems changing due to human pressures? What is the impact of processes in the catchment on marine systems function, and vice versa? How can we discern between human-induced changes or those driven by natural processes from climate-induced variability? What will the tipping points of socio-ecologic system states be and what will they look like? How can we better characterise river-sea systems from the latest generation Earth observation to citizen science based observatories. How can we predict short and long term changes in River-Sea-Systems to manage them sustainably? What is the limit to which it is possible to predict the natural and human-influenced evolution of River-Sea-Systems? The increasing demand to jointly enable intensive human use and environmental protection in river-sea systems requires holistic and integrative research approaches with the ultimate goal of enhanced system understanding.

Co-organized by BG4/GM6/NH5/OS2/SSP3, co-sponsored by IAS
Convener: Jana Friedrich | Co-conveners: Debora Bellafiore, Andrea D'Alpaos, Panagiotis Michalopoulos, David Todd

There is a global need for low carbon energy, and marine renewable energy could make a significant contribution to reducing greenhouse gas emissions and mitigation of climate change, as well as providing a high-technology industry. Marine renewable energy includes offshore wind, wave, tidal range (lagoons and barrages), and tidal-stream energy, as well as technologies such as ocean thermal energy conversion, salinity gradients and desalination. Understanding the environment these marine renewable energy devices are likely to operate in is essential when designing efficient and resilient devices. Accurate characterisation of the resource is of clear importance, whilst interactions with the environment, and between other “blue economy” developments, is essential for the development of the industry and marine spatial plans. Indeed, synergies exist when considering the sustainable use of the ocean’s energy, such as multi-purpose platforms integrating marine renewable energy devices and aquaculture.
This session is designed to share information on new research techniques and methods to better understand the resource and the environment, including mapping tools, numerical modelling approaches, and observations. We welcome contributions that will further the development of the blue economy: for example, resource characterization, design considerations (e.g. extreme and fatigue loadings), and environmental impacts. The session will also include studies of impacts, from physical and biological, to societal interactions (e.g. effects to tourism). Research areas are envisaged to include but not restricted to: modelling and quantification of the interaction of the device to the marine environment (e.g. changes in hydrodynamics) as well as on the biology directly; cumulative impacts of large and multiple developments (potentially of differing technologies or marine stressors); new technologies for quantification; management of space; collision; noise.

Co-organized by OS2
Convener: Rory O'Hara Murray | Co-conveners: Michela De Dominicis, Matt Lewis

It has been shown that regional climate change interacts with many other man-made perturbations in both natural and anthropogenic coastal environments. Regional climate change is one of multiple drivers, which have a continuing impact on terrestrial, aquatic and socio-economic (resp. human) environments. These drivers interact with regional climate change in ways, which are not completely understood. Recent assessments all over the world have partly addressed this issue (e.g. Assessment of Climate Change for the Baltic Sea region, BACC (2008, 2015); North Sea Climate Change Assessment, NOSCCA (2011); Canada’s Changing Climate Report, CCCR (2019)).
This session invites contributions, which focus on the connections and interrelations between climate change and other drivers of environmental change, be it natural or human-induced, in different regional seas and coastal regions. Observation and modelling studies are welcome, which describe processes and interrelations with climate change in the atmosphere, in marine and freshwater ecosystems and biogeochemistry, coastal and terrestrial ecosystems as well as human systems. In particular, studies on socio-economic factors like aerosols, land cover, fisheries, agriculture and forestry, urban areas, coastal management, offshore energy, air quality and recreation, and their relation to climate change, are welcome.
The aim of this session is to provide an overview over the current state of knowledge of this complicated interplay of different factors, in different regional seas and coastal regions all over the world.

Co-organized by BG4/HS12/NH10/OS2
Convener: Marcus Reckermann | Co-conveners: Ute Daewel, Helena Filipsson, Markus Meier, Markus Quante

It is well known that climate change affects the Earth and environment at many different time scales and compartments, but currently, only very limited knowledge is available on the importance of distinct stochastic events for long-term trends. Hydrological extreme events, such as floods or low water levels, are highly relevant to climate und environmental change and their socio-economic impacts. New observation concepts are crucially needed following an “event chain” approach. That means the comprehensive observation and modelling of the extent and intensity of the short-term events capturing the processes along and across the surrounding earth compartments (e.g. storm related atmospheric processes followed by terrestrial floods, significant matter fluxes into freshwater and coastal systems and associated habitat degradation). Furthermore, newly developed integrated observation and modelling strategies are required allowing integrated operation in the atmosphere, on land surface and in the coastal regions combining sensors across disciplines and compartments. This approach includes the identification / classification of the events to be considered, the related processes along the event chains and their interlinkages, the spatial and temporal scales of the considered processes, the definition of the essential variables to be monitored and modelled and the recommended strategies for a comprehensive and elaborated observation. Contributions are welcome which analyse the effect of hydrological events in terms of impact chains from land to surface waters and coastal zones including processes covering water quality in general, nutrients, sediments, contaminants and their impact on aquatic ecosystems.

Co-organized by BG4/OS2
Convener: Michael Rode | Co-conveners: George Arhonditsis, Dietrich Borchardt, Claudia Schütze

Low-lying coastal areas can be an early casualty to accelerating rates of sea-level rise, especially if land subsidence enhances such rates. More and more studies indicate that land subsidence due to natural and anthropogenic causes, including excessive groundwater extraction from coastal aquifers, peat oxidation due to surface water drainage through land reclamation, urbanization and agricultural use, as well as sediment starvation due to construction of dams and artificial levees, have caused damages to wetland ecosystems and increased flooding risk. While sea-level rise is a global issue and requires a global collaborative response, natural and anthropogenic coastal subsidence develops mainly at the local to regional scale, and its causes and severity vary substantially from place to place. Therefore, specific communities living on coastal areas can try to offset or reduced land subsidence.

The combination of geological and historical measurements and data from ongoing monitoring techniques is required to understand all drivers of coastal land motion and their contributions to past, present, and future subsidence. Research on coastal subsidence encompasses multidisciplinary expertise, requiring measuring and modeling techniques from geology, geodesy, natural hazards, oceanography, hydrogeology, and geomechanics. In this session, we want to bring together the expertise of all the involved disciplines. We invite contributions on all aspects of coastal subsidence research including recent advances on i) measurement through ground-based and remote sensing techniques, ii) numerical models, iii) their applicability to distinguish between the different drivers contributing to land subsidence, and iv) quantification of coastal hazards associated to relative sea-level rise. In particular, efforts towards characterizing human intervention on coastal land motion are welcome.

Co-organized by HS13/NH8/OS2
Convener: Makan A. KaregarECSECS | Co-conveners: Niamh CahillECSECS, Simon Engelhart, Thomas FrederikseECSECS, Pietro Teatini

The human imprint on the marine realm has rapidly increased during the last century, leaving no area unaffected by human activities. Bottom trawl fishing intensity has boomed since the 1950s, while at the same time dredging activities in coastal zones have intensified to maintain navigable waterways, reclaim land, construct wind farms or counteract coastal erosion. Off-shore drilling platforms have been constructed around the world, and more recently, deep-sea mining has become an attractive avenue for mineral extraction. All of these economic activities physically perturb the seabed, and are expected to have a strong effect on the natural biological, geochemical and physical dynamics of the ocean. However, very little is understood about the short-term and long-term impact of these anthropogenic physical disturbances.
This session aims to create a multidisciplinary discussion on the impact and potential remediation of diverse anthropogenic alterations on the seafloor, and invites contributions ranging from marine ecology over physical oceanography and biogeochemistry, be it observational, theoretical or experimental.

Co-organized by OS2
Convener: Sebastiaan van de VeldeECSECS | Co-conveners: Pere Masqué, Sarah ParadisECSECS

The coastal ocean has been increasingly recognized as a dynamic component of the global carbon budget. This session aims at fostering our understanding of the roles of coastal environments and of exchange processes, both natural or perturbed, along the terrestrial / coastal sea / open ocean continuum in global biogeochemical cycles. During the session recent advancements in the field of coastal and shelf biogeochemistry will be discussed. Contributions focusing on carbon and nutrient and all other element's cycles in coastal, shelf and shelf break environments, both pelagic and sedimentary, are invited.

This session is multidisciplinary and is open to observational, modelling and theoretical studies in order to promote the dialogue. The session will comprise subsections on coastal carbon storage, and on benthic biogeochemical processes.

Co-organized by OS2
Convener: Helmuth Thomas | Co-conveners: William Austin, Alberto V. Borges, Arthur CapetECSECS, Craig SmeatonECSECS

Modelling the interaction of water waves with varying current is an important issue, especially in nearshore and coastal areas and for a variety of engineering applications.
These applications include wave structure interactions, with the problematics related to oil and naval industries, but also renewable energies.
The problematic is also important when considering coastal management, and harbour maintenance and exploitation.
Also, this interaction often leads to the formation of extreme wave events with detrimental effects.
Significant scientific effort was undertaken during the last fifty years to model linear, weakly or strongly nonlinear water waves with constant, or slowly varying currents.
When variations are stronger, the difficulty remains important.
In this session, contributions are invited relating experimental, numerical and theoretical works designed to improve the understanding of water waves and current interactions, including wave and current stability, wave dynamics, and energy propagation.
Contributions describing the specific problematics, from the point of the applications, are also deeply welcome.

Co-organized by NH5/OS2
Convener: Julien Touboul | Co-conveners: Konstandinos Belibassakis, Anne-Claire Bennis, Efim Pelinovsky

Sedimentary landforms play a critical role in defining the lives of human populations as they affect the flow of water and sediment across the landscape and the coast. They thus protect people and assets from flooding and erosion and are increasingly considered as part of ‘nature-based’ or ‘soft engineered’ flood and erosion protection approaches. Understanding how coastal sedimentary landforms evolve over different time-scales has preoccupied geomorphologists for many decades, but altered future environmental forcing requires knowledge of the stability of landforms in the face of a suite of climatic, biological, and chemical drivers in combinations or at magnitudes not yet encountered. Predicting how coastal landforms respond to combinations of such drivers (e.g. the changed frequency/magnitude of storm events) requires greater knowledge of their resistive properties at a range of scales, from landform response to extreme events and/or steadily shifting baselines (e.g. sea level rise) to the response of individual sediment grains embedded within the landform (e.g. to high-magnitude physical forcing by wind or water). Emerging technologies, such as space- and airborne remote sensing, digital imaging, data-logging and transmission of physical, biological, and chemical processes, are allowing new and unique perspectives on landform stability, but bring with them their own specific analytical and interpretative challenges.
This session adds a unique multi-disciplinary perspective to the challenge of understanding coastal landform stability by bringing together contributions from ecological, biogeochemical, geomorphological and sedimentological perspectives. We are committed to supporting early career researchers and this session should be of interest to practitioners working in the field of flood and erosion protection, particularly in the river and coastal context.

Co-organized by OS2/SSP3
Convener: Iris Moeller | Co-conveners: Ben EvansECSECS, Simon J. Carr, Katherine Royse, Kate Spencer

Examining coastal morphodynamics from the nearshore through to inland dune systems is fundamental in understanding their short- to long-term behaviour. Coastal processes operate across large spatial and temporal scales and therefore comprehending their resulting landforms is complex.

At the coast, dunes provide the physical barrier to flooding during high energy storms, while beaches and nearshore areas help dissipate storm impact through a series of dynamic interactions involving sediment transfers and at times rapid morphological changes. Investigation of complex interactions between these three interconnected systems has become essential for understanding coastal behaviour.

This session, sponsored by the IGU-UGI Commission on Coastal Systems, welcomes contributions from coastal scientists interested in the measurement and modelling of the nearshore 25-0 m zone (waves, currents and sediment transport) and terrestrial coastal processes (on beaches and dunes) and responses within the three sub-units at various scales. The session will highlight the latest research developments in this part of the planet's geomorphic system and facilitate knowledge exchange between the submerged and sub-aerial coastal zones.

Co-organized by OS2/SSP3
Convener: Derek Jackson | Co-conveners: Irene Delgado-Fernandez, Emilia Guisado-Pintado

Detailed maps of the seabed, including substrate classification maps and comprehensive habitat maps, are used for a wide range of environmental, scientific and economic maritime applications. They provide a basic concept for ocean and coastal management, and serve as a cornerstone of national and international nature-conservation policy. Fundamental to seabed mapping are acoustic remote-sensing technologies which include singlebeam, multibeam and sidescan sonars along with interferometric and synthetic-aperture sonars. These are deployed on various platforms including manned/unmanned surface and underwater vessels. In relatively shallow and transparent waters optical methods such as aircraft and satellite-based remote sensing and lidar are employed with increasing success. Innovative processing and classification software, image analysis, machine and deep-learning applications are advancing developments in seabed-recognition techniques. The application of which increases the resolution and confidence in the resulting environmental maps produced. This session will provide insights into new developments, methods, and results in the field of seabed mapping and classification; showcasing a range of applications for these decisive datasets.

Co-organized by OS2
Convener: H. Christian Hass | Co-conveners: Markus Diesing, Maria Judge, Kim Picard, Anne-Cathrin WölflECSECS

Coasts worldwide face a great variety of environmental impacts as well as increased anthropogenic pressures of coastal zone urbanization and rapid population growth. Over the last decade coastal erosion has emerged as a widespread problem that causes shoreline retreat and irreversible land losses. The attempts of managers and other stakeholders to cope with erosion using different types of hard engineering methods may often aggravate this problem, damaging natural landscape and coastal ecosystems in unexpected and unpredicted ways. Other negative impacts of human activities on littoral environments are chronic and punctual pollution of beach and coastal sediments with associated health risks for human beings. Chronic pollution is often observed in coastal areas close to factories, industries and human settlements - because of waste water discharges, punctual contamination is often linked to beach oiling.
The session gives priority to the subjects of coastal geomorphology: evolution of coastal landforms, coastal morphodynamics, coastline alterations and various associated processes in the coastal zone, e.g. waves and sediment drift, which shape coastal features and cause morphological changes. Contributions to this session will focus on the mechanisms responsible for coastal erosion and shoreline behaviour (advance or retreat) and will address the many natural and human factors involved. The topics may include work on predictions of shoreline change and discussions on the effects of human activities and their continuing contribution to coastal changes. The session will also cover submissions on coastal vulnerability to the combined effects of natural and human-related hazards, any type of coastal and environmental sensitivity classifications, and risk assessments. Globally, coastal dunes are seriously threatened as people tend to modify landforms and habitats through their actions and regulations, and the session invites also studies on natural and human-induced geomorphological changes of sand dunes, and recent projects and examples of dune eco-restoration and re-building.
Last, but not the least, studies related to Marine Spatial Planning (MSP), including Integrated Coastal Management (ICM), are also welcome. For any MSP and ICM, it is essential to consider the dynamics across the land-sea interface, i.e. the Land-Sea Interactions (LSI) that involve both natural processes and the impact of human activities.

Co-organized by OS2, co-sponsored by CCS - IGU
Convener: Hannes Tõnisson | Co-conveners: Margarita Stancheva, Andreas Baas, Giorgio Anfuso, Guillaume Brunier

The world’s deltas support over 35 million people, yet account for only 0.5% of the Earth’s surface. They are highly productive regions supporting intensive agriculture, an extensive range of ecosystem services and high levels of biodiversity. Yet deltas and their inhabitants are facing myriad threats due to biodiversity loss, habitat degradation, sea-level rise, subsidence, sediment extraction and compaction, groundwater extraction and modifications of their upstream catchments. As such, deltas are sinking relative to sea level and with them the livelihoods and resources they currently support. Recent advances in satellite derived datasets, ground-based high-resolution monitoring, numerical modelling and socio-ecological systems understanding have enabled new insights to be gained as to how deltas and those ecosystems they support are responding to these threats. This session aims to bring together the state-of-the-science knowledge from a range of disciplines (geomorphology, hydrology, ecology, social sciences) to provide a holistic view of the response of deltas to climate change. We encourage submissions from all subject areas focussed on the world’s deltas to provide a broad session. We particularly encourage submissions from early career researchers.

Co-organized by OS2
Convener: Christopher HackneyECSECS | Co-conveners: Rachael CarrieECSECS, Frances DunnECSECS, Grigorios VasilopoulosECSECS

Coastal wetland ecosystems, such as salt marshes, mangroves, seagrass beds and tidal flats, are under increasing pressure from natural and anthropogenic processes shifting climatic conditions, and are declining in area and habitat quality globally. These environments provide numerous ecosystem services, including flood risk mediation, biodiversity provision and climate change mitigation through carbon storage. Hence, the need to get a deeper understanding of processes and interactions in these environments, and how these may be altered by climate change has never been greater. This is the case for ‘managed’, restored wetlands and natural systems alike.
This session will bring together studies of coastal wetland ecosystems across climates and geomorphic settings, to enhance the understanding of ecosystem service provisioning, interactions between hydrodynamics, sediment and ecology, and identify best future management practices. Studies of all processes occurring within coastal wetlands are invited. This includes, but is not exclusive to, sediment dynamics, hydrology, hydrodynamics, biogeochemistry, morphological characterisation, geotechnical analysis, bio-morphodynamics, ecological change and evolution, impact of climate change, sea level rise, anthropogenic and management implications. Multidisciplinary approaches across spatial and temporal scales are encouraged, especially in relation to global climate change. This session aims to enhance our understanding of basic processes governing coastal wetland dynamics and to propose sustainable management solutions for contemporary environmental pressures.

Co-organized by BG4/HS13/OS2
Convener: Mark Schuerch | Co-conveners: Thorsten BalkeECSECS, Helen BrooksECSECS, Ruth Reef, Christian SchwarzECSECS

Tsunamis can produce catastrophic damage on vulnerable coastlines, essentially following major earthquakes, landslides or atmospheric disturbances. After the disastrous tsunamis in 2004 and 2011, tsunami science has grown significantly, opening new fields of research for various domains, and also in regions where the tsunami hazard was previously underestimated.
Numerical modeling, complemented with laboratory experiments, are essential to quantify the tsunami hazard. To this end, it is essential to rely on complete databases of past tsunami observations, including both historical events and results of paleotsunami investigations. Furthermore, a robust hazard analysis has to take into account uncertainties and probabilities with the more advanced approaches such as PTHA.
Because the vulnerability of populations, of infrastructures and of the built environment in coastal zones increases, integrated plans for tsunami risk prevention and mitigation should be encouraged in any exposed coastline, consistent with the procedures now in place in a growing number of Tsunami Warning System.

The tsunami session welcomes multidisciplinary contributions covering any of the aspects mentioned here, encompassing field data, regional hazard studies, observation databases, numerical modeling, risk studies, real time networks, operational tools and procedures towards a most efficient warning.

A focus on recent tsunami events all over the globe is encouraged, as well as on the achievements of recent research and operational projects.

Co-organized by OS2/SM2
Convener: Helene Hebert | Co-conveners: Alberto Armigliato, Miquel Canals, Ira Didenkulova

The scope of this session includes different aspects of large-amplitude wave phenomena in the ocean such as freak or rogue waves, surface and internal waves, as well as waves trapped by currents and bathymetry. The session is focused on the understanding of the physical mechanisms which cause extreme events, and the derivation of appropriate mathematical models for their description and advanced methods for their analysis. An essential part of such studies is the validation of new models and techniques versus laboratory and in-situ data. Special attention is paid to the description of wave breaking processes, and the interaction of large-amplitude waves with coastal structures.

Co-organized by NP7/OS2
Convener: Alexey Slunyaev | Co-conveners: Amin Chabchoub, Henrik Kalisch, Efim Pelinovsky

Coastal areas are vulnerable to ocean, atmospheric and land-based hazards. This vulnerability is likely to be exacerbated in future with, for example, sea level rise, changing intensity of tropical cyclones, increased subsidence (e.g. from groundwater extraction, tectonics), and increasing socio-economic development coupled to coastal squeeze in, particularly, the urbanised low elevation coastal zone. This calls for a better understanding of the underlying physical processes and their interaction with the coast. Numerical models therefore play a crucial role in characterizing coastal hazards and assigning risks to them. Drawing firm conclusions about current and future changes in this environment is challenging because uncertainties are often large, such as coastal impacts of likely and unlikely (also called high-end) sea level changes for the 21st century. Furthermore, studies addressing coastal impacts beyond this century pose new questions regarding the timescale of impacts and adaptation activity.

This session invites submissions focusing on assessments and case studies at global and regional scales of potential physical impacts of tsunamis, storm surge, sea level rise, waves, and currents on coasts. We also welcome submissions on near-shore ocean dynamics and also on the socio-economic impact of these hazards along the coast.

Co-organized by GM6/OS2
Convener: Luke JacksonECSECS | Co-conveners: Joern Behrens, Renske de WinterECSECS, Goneri Le Cozannet, Nicoletta LeonardiECSECS

OS3 – Ocean Biogeochemistry and Biology

OS3.1 | PICO

Ocean oxygen loss is one of the key consequences of climate change and has the potential to critically impact marine biogeochemical cycles and ecology. Current time series projections and climate models identify an unusually rapid decline in oxygen concentrations, particularly in tropical regions. However, our understanding of how stable this trend is over longer time scales, how adaptable ecosystems are, and if negative or positive feedback mechanisms exist is insufficient.

We seek to identify major gaps in knowledge helping to quantify the rate of ocean deoxygenation and its impact on both biogeochemistry and marine life. To do so, this session aims to bring together scientists from across disciplines including physical oceanography, climate modeling, biogeochemistry, and deep time experts. Our aim is not only to bring our results together but to conclude on what changes in ocean oxygen content can be identified across different ocean areas and different geological timescales.

We invite contributions that investigate ocean deoxygenation in the past, present and future ocean, and its physical, chemical and/or biological drivers, using observational or model-based approaches at regional or global scales.

Co-organized by BG4
Convener: Bastien QuesteECSECS | Co-convener: Carolin LöscherECSECS

The production of CaCO3 shell material by marine calcifying planktonic organisms produces a surface-to-depth alkalinity gradient, causing CO2 to be released back to the atmosphere. This mechanism is known as the Calcium Carbonate (CaCO3) Counter Pump because, in terms of air-sea CO2 exchange, it is opposite to the process driving the Biological Carbon Pump.
On the other side, calcifying plankton, through removing calcium carbonate ions from the ocean surface, can influence the export of Particulate Inorganic Carbon (PIC). Calcifying zooplankton for instance, such as pteropods, ostracods and foraminifera, promote PIC sequestration to the deep ocean because the relatively large mass of their shell makes them sink rapidly. By comparison, calcifying phytoplankton such as the unicellular coccolithophores and their calcite platelets hardly sink individually and have a large range in sinking rates depending on the assimilation into larger biological aggregates. The burial of CaCO3 in marine sediments (due to the sinking of post-mortem calcifying organisms) is one of the main mechanisms to reduce atmospheric CO2 on geological timescales related to silicate weathering processes.
The Carbonate Counter Pump can, therefore, have very different effects on ocean carbon, alkalinity, and atmospheric CO2 on different spatial and temporal scales. Further, the level of carbonate precipitation, as well as the ability to act as ballast, depends on the composition of calcifying species within the plankton community and the relative balance between PIC: POC export (rain ratio).
The scientific concern about the impact of Ocean Acidification on the calcifying community structure has recently highlighted the importance of understanding the main process regulating the carbonate production.
The objective of this session is to bring together contributions investigating the biogenic carbonate production, export and fait within the ocean carbon cycle. This session aims also to better characterize the role of calcifying planktic organisms in driving the stretch of the Carbonate Counter Pump.
We welcome a broad range of contributions (original research, methods descriptions, perspectives, opinions, and reviews), from individual-based process studies, to local and global field observations, and modelling approaches. (Note a related thematic topic at https://www.frontiersin.org/research-topics/11274/main-drivers-regulating-the-ocean-carbonate-pelagic-production-and-export)

Co-organized by BG4
Convener: Clara Manno | Co-conveners: Patrizia Ziveri, Adam Subhas, Wolfgang Koeve

Mercury and persistent organic pollutants (POPs) represent major threats to human health and ecosystem functioning.
Mercury and POPs accumulate in the marine environment, bioconcentrate into phytoplankton and Biomagnify along the trophic chain. In parallel to anthropogenic Hg and POP emissions ongoing climate change possible exacerbate possible impacts on ecosystems.
To understand, quantify and assess processes driving their biogeochemical cycling through earth system components therefore remain a major challenge to be taken by scientific community, also in order to foster the development and application of predictive models for the identification of mitigation and adaptation policies.
The session welcomes contributions focusing on every aspects (experiments, observation, modelling) of the Hg and POP cycles in the estuarine, coastal and ocean environment, as well as through other components of the earth system, and related impacts on society and human health.

Co-organized by BG4
Convener: Donata Melaku Canu | Co-conveners: Javier Castro Jiménez, Mario Sprovieri, Lars-Eric Heimbürger-Boavida

The bulk of mesopelagic (200-1,000 m) biomass is comprised mainly of fish, squid, jellyfish and zooplankton, and a large proportion of this biomass vertically migrates daily to the surface to feed during the night to reduce the risk of visual predation. During migration events, vast quantities of carbon and nutrients are transported between the surface and the deep ocean, contributing towards the biological carbon pump and playing a critical role in global biogeochemical cycling. Despite their status as a key component of pelagic food-webs, the mesopelagic community remains poorly sampled and poorly understood. This knowledge gap is a consequence of the technical challenges encountered when observing/sampling communities at great depth that are hypersensitive to changes in their environment. Presently, there is large uncertainty in estimates of mesopelagic biomass and some studies suggest that historical estimates of global mesopelagic fish biomass may have been greatly underestimated, which has triggered interest from commercial fisheries. In response to this, a number of large international projects have been funded to tackle these issues and provide critical insight to guide future fisheries and conservation management, before any substantial exploitation of mesopelagic resources is carried out.

This multidisciplinary session aims to discuss the current state of knowledge of mesopelagic ecosystems and its potential as a sustainable food source for human consumption and aquaculture/agriculture. We invite works addressing the contribution of mesopelagic ecosystems to the biological carbon pump, its role in trophic food-webs, its link with the physical and biogeochemical environment; as well as studies addressing biodiversity, spatio-temporal variability, and commercial interest of the species inhabiting the mesopelagic realm. We also particularly encourage studies where two or more techniques (e.g. acoustic surveys, trawls, eDNA, gut content analysis, modelling etc.) are being simultaneously implemented and combined or contrasted, and studies highlighting new technologies to observe the mesopelagic realm.

Co-organized by BG4
Convener: Joan LlortECSECS | Co-conveners: Alice Della PennaECSECS, Xabier Irigoien, Roland Proud

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

Co-organized by BG4
Convener: Marco Marcelli | Co-conveners: Paola Del Negro, Roberta FerrettiECSECS, XIAOXIA SUN, Markus Weinbauer

Marine anthropogenic pollution is increasingly recognized as a serious issue of global concern with substantial risks for marine ecosystems, fisheries, and food supply to people. Plastic and chemical contaminants are spread on a planetary scale, and may have devastating impacts on marine ecosystems. Yet, they remain poorly studied and much is yet to learn about how plastic and chemical contamination impacts marine nutrient cycles and the lower food chain.

In this session, we invite contributions from experimentalists and modellers trying to understand the impacts of plastics as well as chemical contaminants on the biogeochemistry of the oceans. The objective of this session is to share the current research on how the multiple sources of anthropogenic pollution impact marine biogeochemical cycles, such as pollutant leaching from plastics, plastic ingestion by marine animals, and direct contamination of the water by contaminated rivers, aerosols, or submarine groundwater. The session would welcome all techniques, including direct measurements of contaminant fluxes, isotopic or other approaches to tracing contamination, modelling, experimental incubations with contaminants, mesocosm studies and toxicity assessments. We particularly encourage contributions regarding the quantification of sources and fluxes of contaminants to the marine environment, and the effects of this contamination (toxicity from chemical contaminants such as heavy metals or PCBs, effects of plastic ingestion on zooplankton…).

Convener: Camille RichonECSECS | Co-conveners: Lars-Eric Heimburger, Charlotte Laufkötter, Susan Little

One of the overriding goals of the GEOTRACES mission is “to understand the processes involved in oceanic trace-element [and isotopic] cycles sufficiently well that the response of these cycles to global change can be predicted, and their impact on the carbon cycle and climate understood.” Our understanding of the ocean’s role in the climate system is inherently dependent on the data generated or inspired by the GEOTRACES programme. The accumulation of data and knowledge now provides an opportunity to utilise trace-elements and isotopes to detect and attribute ongoing climate-driven changes. Trace-elements and isotopes are highly sensitive to slight shifts in ecosystem functioning, biogeochemical cycles and ocean circulation, and may therefore act as key detectors of change (i.e. “canaries in the coal mine”) as climate change progresses.

In this session, we welcome contributions that utilise trace-element and/or isotopic measurements to further our understanding of marine ecosystems and biogeochemical cycles. We are open to field, laboratory, data synthesis and modelling studies. Particularly encouraged are abstracts that detect and attribute changes in the modern ocean using trace-elements and/or isotopes. An overriding goal for this session will be to bring the community together to discuss how trace-elements and isotopes may be used as key detectors of change within observational programs in the coming decades.

Convener: Pearse BuchananECSECS | Co-conveners: Rob Middag, Shaun RigbyECSECS, Robyn TuerenaECSECS

Marine dissolved organic matter (DOM) is one of the largest reservoir of carbon on the planet and represents the main source of energy for heterotrophic prokaryotes. Containing as much carbon as the atmosphere and having a great ecological significance, it plays a key role in regulating the air-sea CO2 exchanges and oceanic carbon sequestration that, ultimately, controls the Earth’s climate. Due to its complexity and low concentrations, the comprehension of its dynamics is one of the most pressing issue in marine science. The mechanisms of DOM production, removal and accumulation are far to be unravelled. Limited knowledge exists on the impact of phytoplankton metabolism and environmental conditions on DOM production as well as on the processes (mechanisms) determining its biological lability. In biogeochemical modelling studies, DOM is still over-simplistically parameterized, and CDOM component is seldom included. There is the need to improve our observational and predicting capabilities, combining field studies, modelling and laboratory experiments. The study of DOM concentration needs laboratory analysis, however optical properties (i.e., light absorption and fluorescence) of its chromophoric fraction are a crucial tool to gain information on DOM in short time and with low costs. The use of platforms (e.g., from cruise sampling, to Argo floats and remote sensing) has the great potential to give information on CDOM distribution on the large spatial scale with high temporal resolution, that cannot be achieved with laboratory analyses. Yet, there is the need to investigate the relationships between DOM concentration/composition and optical properties. This session therefore opens to in-field, laboratory and biogeochemical modelling studies that can help to understand where we are and how we can boost our knowledge on marine DOM in next decades. We encourage submissions dealing with in-situ and space-based observational studies, at the global as well as at the regional scale. Technical studies focusing on algorithm development and data quality assessment are also welcome. Inter-disciplinary studies are strongly encouraged. Thanks to this session we aim to gather together experts in physical, biogeochemical, optical and satellite oceanography.

Convener: Emanuele Organelli | Co-conveners: Paolo Lazzari, Chiara Santinelli

Decreasing sea-ice coverage, increasing permafrost-derived inputs and increasing glacier discharge will continue to affect the Arctic Ocean region in coming decades under all future climate scenarios. Such changes at the interface between the ocean and the cryosphere across the Arctic basin raise questions about the downstream effects in marine ecosystems, particularly with respect to ecosystem services such as fisheries and carbon sequestration. In order to understand the effect of changing cryosphere-derived inputs on the Arctic marine environment, knowledge concerning the physical and biochemical perturbations occurring in the sea ice and water column and the structure, function and resilience of affected ecosystems must be integrated.
In this session we explicitly welcome cross-disciplinary attempts to understand how far reaching the effects of sea-ice, permafrost derived material and glacial changes are on marine biogeochemistry, productivity, biodiversity, and ecosystem services. Topics may include, yet are not limited to, the effect of sea-ice, permafrost, and glacier discharge on sea-ice and water column structure, primary and secondary production, community structure, macronutrient and micronutrient availability, microbial processes, the carbonate system, and the biological carbon pump. Modelling experiments, and studies based on long-term observational records including sediment traps and proxy reconstructions from marine sediment cores are also welcome.

Co-organized by BG4/CL4/OS3
Convener: Sofia Ribeiro | Co-conveners: Mark HopwoodECSECS, Anna Pienkowski, Letizia Tedesco

Since its first definition by Vernadsky in 1929, the term Biogeosciences has embraced new concepts that result from emerging interdisciplinary views of established interactions. As a consequence, it is now widely accepted that biology has to be integrated into scientific studies of the Earth and other planets, and that biogeoscientists cut across the boundaries between biology, chemistry, physics, geology and other disciplines. This session welcomes showcase the dramatic evolution of biogeosciences over the past century, including the field’s main achievements and their wider effects on science and society. Future challenges in the field will also be highlighted: How and when did life begin? What were the drivers of biological innovation? How will organisms and ecosystems adapt to environmental and climate changes? How will humans affect global change? Is there life beyond Earth? We would like to bring together world-leading scientists from different disciplines to discuss these directions and how they build on the tremendous legacy of the past. This session is co-organized by EGU, AGU and JpGU.

Co-organized by CL4/OS3/PS3/SSP4, co-sponsored by AGU and JpGU
Convener: Giuliana Panieri | Co-conveners: Ariel D. Anbar, Hiroshi Kitazato, Kurt Konhauser

A remote sensing signal acquired by a sensor system results from electromagnetic radiation (EM) interactions from incoming or emitted EM with atmospheric constituents, vegetation structures and pigments, soil surfaces or water bodies. Vegetation, soil and water bodies are functional interfaces between terrestrial ecosystems and the atmosphere. The physical types of EM used in RS has increased during the years of remote sensing development. Originally, the main focus was on optical remote sensing. Now, thermal, microwave, polarimetric, angular and quite recently also fluorescence have been added to the EM regions under study.
This has led to the definition of an increasing number of bio-geophysical variables in RS. Products include canopy structural variables (e.g. biomass, leaf area index, fAPAR, leaf area density) as well as ecosystem mass flux exchanges dominated by carbon and water exchange. Many other variables are considered as well, like chlorophyll fluorescence, soil moisture content and evapotranspiration. New modelling approaches including models with fully coupled atmosphere, vegetation and soil matrices led to improved interpretations of the spectral and spatio-temporal variability of RS signals including those of atmospheric aerosols and water vapour.
This session solicits for papers presenting methodologies and results leading to the assimilation in biogeoscience and atmospheric models of cited RS variables as well as data measured in situ for RS validation purposes. Contributions should preferably focus on topics related to climate change, food production (and hence food security), nature preservation and hence biodiversity, epidemiology, and atmospheric chemistry and pollution (stratospheric and tropospheric ozone, nitrogen oxides, VOC’s, etc). It goes without saying that we also welcome papers focusing on the assimilation of remote sensing and in-situ measurements in bio-geophysical and atmospheric models, as well as the RS extraction techniques themselves.
This session aims to bring together scientists developing remote sensing techniques, products and models leading to strategies with a higher (bio-geophysical) impact on the stability and sustainability of the Earth’s ecosystems.

Co-organized by AS5/ESSI1/HS6/NH6/OS3
Convener: Frank Veroustraete | Co-convener: Willem Verstraeten

Air-sea fluxes of biogeochemically active constituents have significant impacts on global biogeochemistry and climate. Increasing atmospheric deposition of anthropogenically-derived nutrients (e.g., nitrogen, phosphorus, iron) to the ocean influences marine productivity and has associated impacts on oceanic CO2 uptake, and emissions to the atmosphere of climate active species (e.g., nitrous-oxide (N2O), dimethyl-sulfide (DMS), marine organic compounds and halogenated species). These oceanic emissions of reactive species and greenhouse gases influence atmospheric chemistry and global climate, and induce potentially important chemistry-climate feedbacks. While advances have been made by laboratory, field, and modelling studies over the past decade, we still lack understanding of many of the physical and biogeochemical processes linking atmospheric deposition, nutrient availability, marine biological productivity, and the biogeochemical cycles governing air-sea fluxes of these climate active species. Atmospheric inputs of other toxic substances, e.g., lead, cadmium, copper, and persistent organic pollutants, into the ocean are also of concern.
This session will address the atmospheric deposition of nutrients and toxic substances to the ocean, their impacts on ocean biogeochemistry, the air-sea fluxes of climate active species and potential feedbacks to climate. We welcome new findings from measurement programmes (in-situ and remote sensing) and atmospheric and oceanic numerical models.
This session is jointly sponsored by GESAMP Working Group 38 on ‘The Atmospheric Input of Chemicals to the Ocean’, the Surface Ocean-Lower Atmosphere Study (SOLAS), and the International Commission on Atmospheric Chemistry and Global Pollution (iCACGP).

Co-organized by BG4/OS3, co-sponsored by GESAMP WG38 and SOLAS
Convener: Parvadha Suntharalingam | Co-conveners: Katye AltieriECSECS, Robert Duce, Maria Kanakidou, Arvind SinghECSECS

This symposium seeks to bring together environmental and atmospheric photochemists to help bridge the topics of aquatic photochemistry and aerosol photochemistry. The field of aquatic photochemistry seeks to understand the photochemical properties of dissolved organic matter which lead to the degradation of pollutants, particularly in the context of water treatment. On the other hand, the field of aerosol photochemistry seeks to understand the properties of the organic fraction in atmospheric aerosol capable of impacting climate through aerosol-radiation and aerosol-cloud interactions. Both fields have similar goals of characterizing the response of organic matter whether it be in lakes, rivers and oceans or in the atmosphere to sunlight exposure. This symposium will facilitate these two fields coming together to share techniques, sampling protocols and chemical insights. The symposium will gather field and laboratory researchers, environmental engineers, aerosol scientists, and atmospheric chemistry modelers with the goal of discussing emerging research in photochemistry of organic matter both in the aquatic and aerosol phases.

Co-organized by OS3
Convener: Nadine Borduas-DedekindECSECS | Co-conveners: Nir BluvshteinECSECS, Ulrich Krieger

OS4 – Global ocean processes and oceanographic techniques

OS4.1 | PICO

This open session welcomes presentations in all aspects of ocean processes and oceanographic techniques that are not covered in specialised sessions, as well as advances due to new instruments and techniques such as gliders and AUVs. This includes all marine disciplines as well as interaction with the atmosphere and the cryosphere. Global studies and topics that have global relevance are welcome (i.e. both open ocean and shelf seas). Studies focusing on ocean processes might include turbulent mixing, phytoplankton bloom initiation, or air-sea interactions, for example. Studies about the development of new oceanographic techniques might include robotics, design of numerical models or parameterisations, applications of novel instrumentation, or novel applications of traditional technology.

Convener: Callum RolloECSECS | Co-conveners: Isabelle GiddyECSECS, Matjaz Licer, Charles Troupin

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 AS2
Convener: Alexander Babanin | Co-conveners: Francisco J. Ocampo-Torres, Miguel Onorato, Fangli Qiao

In many respects internal gravity waves (IGWs) still pose major questions both to the atmospheric and ocean sciences, and to stellar physics. Important issues are 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. Also 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.

Co-organized by AS1/NP7
Convener: Alvaro de la CamaraECSECS | Co-conveners: Ulrich Achatz, Riwal Plougonven, Chantal Staquet, Claudia StephanECSECS

This session is open to science on the tides of the ocean, atmosphere and solid earth; on spatial scales from global to coastal, estuarine and river; and on all timescales. Tides can cause flooding, particularly in combination with storm surge, and tidal currents and water levels can be both a help and a hindrance to shipping and energy generation. There is a critical role for tides in ocean mixing and the cryosphere, and accurate tide models are required for the processing of remote sensing and satellite geodesy data.
We welcome presentations on progress in modelling of past, present, and future tides, assessment of the accuracy of tide models, novel methods for tide predictions, advances in instrumentation and data processing, new findings from the analysis of historical tide gauge data, and understanding of secular changes in tides due to sea-level change and other environmental forcing factors. We also invite submissions on tides of lakes and of other planets.

Co-organized by G3/NH5
Convener: Joanne Williams | Co-conveners: Mattias Green, Michael Schindelegger, Sophie-Berenice WilmesECSECS

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 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: Aida Alvera-Azcárate | Co-conveners: Craig Donlon, Christine Gommenginger, Guoqi Han, Tong Lee

Time-series sensor data or repeated observation and sampling of Essential Ocean Variables, acquired at fixed-point observatories or using mobile platforms and research vessels, are essential to understand oceanic processes from the surface to the oceanic sub-bottom. In this session, we welcome presentations that demonstrate the use of such monitoring results to address physical, chemical, biological and geological processes in the water column and at the seafloor. Multidisciplinarity, the use of several sets of complementary data, and an emphasis on the interactions between the hydrosphere, biosphere and geosphere are particularly welcome. We also welcome presentations on new ocean monitoring experiments, and on innovative technologies for marine observatories. This session is sponsored by the European Multidisciplinary Seafloor and water column Observatory - European Research Infrastructure Consortium (EMSO-ERIC). 

Co-sponsored by EMSO ERIC
Convener: Eric Delory | Co-conveners: Mathilde Cannat, Andrew Gates, Katsiaryna Pabortsava

The Copernicus Marine Environment Monitoring Service (CMEMS) provides regular and systematic reference information on the physical and biogeochemical states (including sea-ice and sea state) of the global ocean and the European regional seas. This capacity encompasses the description of the current situation (analysis and near-real time observations), the prediction of the situation a few days ahead (forecast), and the provision of consistent retrospective data records for recent decades (re-analysis and reprocessed datasets). CMEMS provides a sustainable response to private and public user needs, for academic, operational, policy and blue growth activities related to all sectors of the blue economy: polar environment monitoring, marine conservation & policies, science & climate, natural resources & energy, water quality, coastal monitoring, society & education, marine food, marine navigation and safety & disaster.

The session will cover research activities that are required to maintain CMEMS systems at the state of the art and prepare their long-term evolution (e.g. physical and biogeochemical modeling; coupling with coastal systems and hydrology; coupling with sea-ice, atmosphere & waves; data assimilation both for physics and biogeochemistry, probabilistic forecasting; big data, cloud computing and processing, artificial intelligence etc.). Presentations on the use, impact and design of in-situ and satellite (e.g. Sentinel missions) observing systems relevant to CMEMS are also much welcome.

Presentations are not limited to research teams directly involved in CMEMS and participation from external teams is strongly encouraged (e.g. from H2020 projects relevant to CMEMS and downstream applications, from projects on seasonal to multidecadal regional projections for the coastal ocean and marine ecosystems, from projects dealing with the monitoring and forecasting of river discharge of freshwater and nutrients).

We also welcome scientific presentations (i) on the verification, validation and uncertainty estimates of CMEMS products, (ii) on the use of CMEMS products for downstream applications (including support to maritime regulations and directives) and (iii) on the monitoring and long-term assessment of the ocean physical and biogeochemical states.

Convener: Angelique Melet | Co-conveners: Stefano Ciavatta, Emanuela Clementi, Pierre De Mey

NEMO (Nucleus for European Modelling of the Ocean) is a state-of-the-art modelling framework of the ocean that includes components for the ocean dynamics, the sea-ice and the biogeochemistry, so as a nesting package allowing to set up zooms and a versatile data assimilation interface (see https://www.nemo-ocean.eu/).
NEMO is used by a large community in Europe and world-wide (~200 projects, ~100 publications each year) covering a wide range of applications : oceanographic research, operational oceanography, seasonal forecast and climate projections.
NEMO is in particular used in 6 Earth System Models within CMIP6 and in Copernicus Marine Services (CMEMS) model-based products.

This session will provide a forum to properly address the new scientific advances in numerical modelling of the ocean and their implication for NEMO developments associated with:
• Ocean dynamics at large to coastal scales, up to 1km resolution ;
• Ocean biogeochemistry
• Sea-ice
• New numerical schemes associated to energy conservation constraints
• High performance computing challenges and techniques

The session will cover both research and operationnal activities contributing to new analysis, ideas and developments of ocean numerical models.
Presentations of results based on new NEMO functionalities and new NEMO model configurations are welcome.

Co-organized by CL5/ESSI1, co-sponsored by IMMERSE and NEMO
Convener: Claire Levy | Co-conveners: Mike Bell, Jerome Chanut, Dorotea IovinoECSECS, Julien Le Sommer

Oceanographic monitoring and modeling are both widely used to study the pathways and fate of marine pollutants such as hydrocarbons, marine litter, POPs, HNS, radionuclides, etc. In this session, advanced sampling methods, models, operational applications and techniques related to tracing pollutants on local, regional and global scales, as well as the coupling with met-oceanographic transport fields from operational oceanography products such as Copernicus Marine Monitoring Environment Service will be discussed. State-of-the-art observational techniques and protocols, ensemble and multi-model methods, risk assessment algorithms and decision support systems are solicited topics. Integration of modelling and observing systems for both data assimilation and model validation are also very welcome.
Key questions of the session are identified as follows: Which factors affect the dispersion of the pollutants in the marine environment? What happens to the contaminants on the ocean’s surface, in the water column and sediments? How do marine pollutants interact with marine habitats? How do they influence marine and maritime resources? How should Integrated Coastal Zone Management (ICZM) protocols be optimized to minimize negative impact on the coastal zone?
Impacts of pollutants, including light and noise pollution, on the marine ecosystems and resilience to pollution events are also important subjects for discussion: What is the behavior of oil, marine litter, heavy metals, and other pollutants in the water column, on various beach sediments, rocks and seabed? e.g., what is the biodegradation rate of oil droplets in the water column and what are the controlling factors? What is the rate of fragmentation, biofouling, and sedimentation of plastics? What are the mechanisms of beaching, seabed deposition, and resuspension of marine pollutants and what are the ways of entering the marine food chains (including human consumption)? What is the impact of light and noise pollution on the marine environment and habitats?

Co-organized by NH5
Convener: Giovanni Coppini | Co-conveners: Sebastien Legrand, Oleg Makarynskyy, Katerina Spanoudaki, George Zodiatis

Plastic contamination has been reported in all realms of the environment from the tropics to the polar oceans. Our poor knowledge of plastics sources, pathways and hot spots of accumulation prevents an assessment of risks to ecosystems and human health and the development of appropriate mitigation strategies. In order to understand current distributions of plastics and the way they evolve in space and time, much better observations and common consistent measuring methods are required but simultaneously, observations must be systematically combined with computational models
The session aims to set up a forum for multi-disciplinary discussions to create a global picture of plastic contamination in the environment and to suggest approaches for future research, monitoring and mitigation of plastic pollutions impacts. The session will provide a platform for discussions to advise policy and industry on the best ways to assess potential harm to the environment and human health from this contaminant.
This session will draw together research on plastic contamination across all sizes of plastics from shelf seas to the deep ocean including ice covered seas. The forum will facilitate combining observations with state-of-the-art computational modelling to promote the fast advance of research and improve our understanding of how plastic pollution affects environments worldwide. We invite contributions on field and remote observations, laboratory experiments, novel modelling approaches, related scientific initiatives and projects. New ideas for citizen-science involvement and for mitigation strategies to reduce plastic contamination of the environment are especially welcome.

Co-organized by BG4
Convener: Stefanie RyndersECSECS | Co-conveners: Yevgeny Aksenov, H.G. Orr, Ilka Peeken, Anna Rubio

Microplastics are recognised to be one of the most prolific and widespread environmental contaminants today, found worldwide across all environmental compartments. Despite growing research in this field, we still have insufficient understanding of the factors influencing the distribution of microplastics in the environment. It is known that the shape, size and polymer type will significantly influence particle behaviour within water. However, importantly, there are many processes that will further influence the degradation and transformation of microplastics throughout aquatic systems. Physical processes will facilitate the horizontal and vertical transport of microplastics within the water, for example flooding, tides, currents, upwelling and downwelling. Additionally, ecological interactions can significantly influence the behaviour and fate of microplastics, for example by changing their density and physical characteristics as a result of incorporation into faecal pellets, organic aggregate formation and biofilm development.
This session specifically aims to investigate the processes that influence the behaviour, fate and flux of microplastics in freshwater and marine systems. Presentations will cover, for example, biofilms, organic or inorganic aggregate formation, ingestion and egestion of microplastics by aquatic organisms, biodegradable plastics, physical transport processes and process-based models.

Co-organized by OS4
Convener: Alice HortonECSECS | Co-conveners: Simon Dixon, Imogen Napper, Manousos Valyrakis, Jörg-Olaf Wolff

Natural Surroundings are full of plastics. Their particles are detected on macro and micro scales in forests, oceans, glaciers and in organic matters around the globe. Even the most remote polar, permafrost and high mountain areas strive from artificial pollutants and plastic particles are one of the reasons why. Early-career and experienced scientists are kindly invited to discuss approaches for the registration and elimination of plastic pollution in permafrost, remote and polar regions. During this session participants are expected to show details about technological aspects of plastic identification, calculation of its amount and extraction. Feel free to show simple and extraordinary scientific information about instrumentation, laboratories and facilities. Specific details about the management and analysis of data are also welcome.

Co-organized by AS5/OS4
Convener: Anatolii ChernovECSECS | Co-conveners: Denys Pishniak, Birgit Sattler
ITS1.7/SM3.5 | PICO

The International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) senses the solid Earth, the oceans and the atmosphere with a global network of seismic, infrasound, and hydroacoustic sensors as well as detectors for atmospheric radioactivity. The primary purpose of the IMS data is for nuclear explosion monitoring regarding all aspects of detecting, locating and characterizing nuclear explosions and their radioactivity releases. On-site verification technologies apply similar methods on smaller scales as well as geophysical methods such as ground penetrating radar and geomagnetic surveying with the goal of identifying evidence for a nuclear explosion close to ground zero. Papers in this session address advances in the sensor technologies, new and historic data, data collection, data processing and analysis methods and algorithms, uncertainty analysis, machine learning and data mining, experiments and simulations including atmospheric transport modelling. This session also welcomes papers on applications of the IMS and OSI instrumentation data. This covers the use of IMS data for disaster risk reduction such as tsunami early warning, earthquake hazard assessment, volcano ash plume warning, radiological emergencies and climate change related monitoring. The scientific applications of IMS data establish another large range of topics, including acoustic wave propagation in the Earth crust, stratospheric wind fields and gravity waves, global atmospheric circulation patterns, deep ocean temperature profiles and whale migration. The use of IMS data for such purposes returns a benefit with regard to calibration, data analysis methods and performance of the primary mission of monitoring for nuclear explosions.

Co-organized by AS4/NH10/OS4
Convener: Martin Kalinowski | Co-conveners: Lars Ceranna, Yan Jia, Peter Nielsen, Ole Ross

This session aims to attract a wide range of process studies of the ice-ocean boundary layer. While the ultimate goal is to obtain physically based parameterizations for the melt/freeze dynamics in coarse models where the cryosphere interacts with the oceans, we invite studies at any stage of exploration of the ice-water or ice-ocean physics. Contributions from theoretical, modelling, observational and experimental studies are encouraged.

We are particularly interested in studies motivated by the physical interaction of oceans with ice shelves, icebergs, glaciers, and sea ice, but contributions from any ice-water system, such as ice-covered fresh-water lakes and supra-glacial rivers, are welcome. Examples include, but are certainly not limited to: direct numerical and large-eddy simulations of the ice-ocean boundary exploring different ocean regimes, evolution of the ice-ocean interface and pattern formation, frazil ice dynamics, marine and platelet ice formation, turbulence measurements near the ice-ocean boundary interface.

Co-organized by OS4
Convener: Irena VankovaECSECS | Co-conveners: Claudia Cenedese, Louis-Alexandre CoustonECSECS, Peter DavisECSECS, Leo MiddletonECSECS

The Earth and its climate form a complex system. In the last few years, research in machine learning has created new techniques for the analysis of high-dimensional non-linear systems. Many of these new techniques could improve our ability to understand and predict the Earth.

In this session, we aim to connect researchers from machine learning (ML) and computational geoscience to identify opportunities that advance the state-of-the-art in Earth and climate modeling. We invite participants to discuss (1) cutting-edge machine learning advances that are relevant to Earth and climate science problems, such as advances in the modeling and simulation of non-linear systems with generative adversarial networks; new tools for interpretable ML; or methods for placing physical constraints on ML models; (2) creative new applications of reinforcement learning techniques to Earth and climate science problems; and (3) geoscience problems that reveal needs for new research in machine learning, e.g. extreme event problems involving skewed or poorly-labeled datasets.

Co-organized by CR2/ESSI2/HS12/NP4/OS4
Convener: Kelly KochanskiECSECS | Co-convener: Karthik MukkavilliECSECS

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

In recent years, new satellite altimetry missions have been launched carrying new instruments and operating in new orbits; the CryoSat-2/Sentinel-3 missions equipped with a Delay/Doppler altimeter, the Saral AltiKa mission carrying the first Ka band altimeter, and the recently launched photon counting laser altimeter on-board NASAs ICESat-2.

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

Co-organized by CR2/HS6/OS4
Convener: Eva BoergensECSECS | Co-conveners: Stefan Hendricks, Karina Nielsen, Louise Sandberg Sørensen, Bernd UebbingECSECS

The session presents the state of art information systems in oceanography (metadata, vocabularies, ISO and OGC applications, data models), interoperability (Virtual Research Infrastructures, Interoperability forms, Web services, Quality of Services, Open standards), data circulation and services (quality assurance / quality control, preservation, network services) and Education in ocean science (Education and Research, Internet tools for education).
The 2020 session should provide new ideas on the interoperability issues deriving from different sources of data.
ISO standards introduce the necessary elements in the abstract process aiming to assess ‘how’ and ‘how much’ data meets applicable regulatory requirements and aims to enhance user needs. Data management infrastructures should include an evaluation of data by assuring relevance, reliability and fitness-for-purposes / fitness-for-use, adequacy, comparability and compatibility. Presenters are strongly encouraged to demonstrate how their efforts will benefit their user communities, facilitate collaborative knowledge building, decision making and knowledge management in general, intended as a range of strategies and practices to identify, create, represent and distribute data, products and information.

Co-organized by OS4
Convener: Antonio Novellino | Co-conveners: Luca BonofiglioECSECS, Cristian MunozECSECS, Simona Simoncelli

Environmental systems often span spatial and temporal scales covering different orders of magnitude. The session is oriented in collecting studies relevant to understand multiscale aspects of these systems and in proposing adequate multi-platform and inter-disciplinary surveillance networks monitoring tools systems. It is especially aimed to emphasize the interaction between environmental processes occurring at different scales. In particular, a special attention is devoted to the studies focused on the development of new techniques and integrated instrumentation for multiscale monitoring high natural risk areas, such as: volcanic, seismic, energy exploitation, slope instability, floods, coastal instability, climate changes and other environmental context.
We expect contributions derived from several disciplines, such as applied geophysics, geology, seismology, geodesy, geochemistry, remote and proximal sensing, volcanology, geotechnical, soil science, marine geology, oceanography, climatology and meteorology. In this context, the contributions in analytical and numerical modeling of geological and environmental processes are also expected.
Finally, we stress that the inter-disciplinary studies that highlight the multiscale properties of natural processes analyzed and monitored by using several methodologies are welcome.

Co-organized by AS4/CL2/GM2/GMPV9/NH8/NP3/OS4/SM5/SSS10
Convener: Pietro Tizzani | Co-conveners: Francesca Bianco, Antonello Bonfante, Raffaele Castaldo, Nemesio M. Pérez

Data assimilation provides a method to optimally merge observations with Earth system models to make better predictions with these models. Increasingly, coupled models for different compartments of the Earth system are used. This allows to assimilate different observation types for different compartments of the Earth system. This session focuses on weakly and strongly coupled data assimilation across compartments of the Earth system that are used to predict states and fluxes of water and energy. Examples are data assimilation for the atmosphere-ocean system, data assimilation for the atmosphere-land system and data assimilation for the land surface-subsurface system. Optimally exploiting observations in a compartment of the terrestrial system to update also states in other compartments of the terrestrial system still has strong methodological challenges, for example related to the fact that weak correlations between states of different compartments need to be exploited and only a small ensemble of coupled model simulations can be made. Another challenge is the very different time scales at which compartments of the Earth system act. Coupled data assimilation allows to determine the value of different measurement types for the predictions of states and fluxes, and the additional value of measurements to update states across compartments. Another aspect of scientific interest for weakly or fully coupled data assimilation is the software engineering related to coupling a data assimilation framework to a physical model, in order to build a computationally efficient and flexible framework.

Co-organized by AS5/BG2/NP5/OS4
Convener: Harrie-Jan Hendricks Franssen | Co-conveners: Gabriëlle De Lannoy, Lars Nerger, Insa Neuweiler, Clemens Simmer

This session invites innovative Earth system and climate studies based on geodetic measuring techniques. Modern geodetic observing systems document a wide range of changes in the Earth’s solid and fluid layers at very diverging spatial and temporal scales related to processes as, e.g., glacial isostatic adjustment, the terrestrial water cycle, ocean dynamics and ice-mass balance. Different time spans of observations need to be cross-compared and combined to resolve a wide spectrum of climate-related signals. Geodetic observables are also often compared with geophysical models, which helps to explain observations, evaluate simulations, and finally merge measurements and numerical models via data assimilation.
We appreciate contributions utilizing geodetic data from diverse geodetic satellites including altimetry, gravimetry (CHAMP, GRACE, GOCE and GRACE-FO), navigation satellite systems (GNSS and DORIS) or remote sensing techniques that are based on both passive (i.e., optical and hyperspectral) and active (i.e., SAR) instruments. We welcome studies that cover a wide variety of applications of geodetic measurements and their combination to observe and model Earth system signals in hydrological, ocean, atmospheric, climate and cryospheric sciences. Any new approaches helping to separate and interpret the variety of geophysical signals are equally appreciated. Contributions working towards the newly established Inter-Commission Committee on "Geodesy for Climate Research" (ICCC) of the International Association of Geodesy (IAG) would be particularly interesting for this session.
With author consent, highlights from this session will be tweeted with a dedicated hashtag during the conference in order to increase the impact of the session.

Co-organized by AS5/CL2/ESSI1/OS4
Convener: Anna KlosECSECS | Co-conveners: Carmen Boening, Henryk Dobslaw, Roelof RietbroekECSECS, Bert Wouters

In weather prediction and climate modelling, numerical models of the Earth System are used extensively. For both the atmosphere and ocean components such models consist of a fluid dynamics solver (dynamical core) coupled to physical parameterizations to represent processes that occur below the grid scale (physics). Over time these models have become capable of sophisticated simulations. Research and development is constantly being undertaken to improve the accuracy and efficiency of the dynamical core, the physics, and their coupling.

This session encompasses the development, testing and application of novel numerical techniques for Earth system models, including governing equations, horizontal and vertical discretizations, time stepping schemes, advection schemes, adaptive multi-scale models, physics-dynamics coupling, regional and global models, classical and stochastic physical parameterizations (that are not covered in other sessions).

Co-organized by CL5/NP1/OS4
Convener: Werner Bauer | Co-conveners: Christian Kühnlein, Jemma Shipton, Hiroe Yamazaki

This session aims at fostering discussions on the physical processes at work at the air-sea interface, including their observation and their representation in coupled numerical models. Examples of such processes are solar radiation-induced diurnal warming and rain-induced cool and fresh lenses, as well as gustiness associated with atmospheric boundary layer thermals or moist convection and cold pools induced by rain evaporation. Air-sea interaction related to surface temperature and salinity fronts, as well as oceanic meso- and sub-mesoscale dynamics, are also of great interest.

This session is thus intended for (i) contributions presenting observational or theoretical aspects of the processes described above and their impact on energy, water, momentum, gas and aerosols exchanges at the interface; and (ii) contributions focusing on the mathematical and algorithmic methods used to represent these processes in coupled ocean-atmosphere models.

This session seeks observational studies based on recent field campaigns or satellite remote sensing. This session also aims to gather studies using numerical models of any level of complexity (from highly idealized to realistic) and any resolution from Large Eddy Simulation (LES) to global circulation models. Studies describing the impact of the air-sea interaction physical processes on the mean global or regional climates and variability representation are also welcome.

Co-organized by OS4
Convener: Hugo Bellenger | Co-conveners: Kyla Drushka, Audrey Hasson, Brian Ward

This session invites contribution for presentations of high resolution weather and climate model simulations. This includes the latest state-of-the-art storm-resolving simulations (e.g. from the DYAMAND project), high-resolution climate models (e.g. from the PRIMAVERA project) but also large-eddy simulations and high-resolution ocean modelling. Presentations cover developments to improve model fidelity (e.g. via improved parametrisations), detailed studies of modeled phenomena (e.g. tropical cyclones) but also computational and model development challenges (e.g. the use of GPUs or the development of new dynamical cores).

Co-organized by CL2/OS4
Convener: Peter Düben | Co-convener: Daniel Klocke

One of the big challenges in Earth system science consists in providing reliable climate predictions on sub-seasonal, seasonal, decadal and longer timescales. The resulting data have the potential to be translated into climate information leading to a better assessment of multi-scale global and regional climate-related risks.
The latest developments and progress in climate forecasting on subseasonal-to-decadal timescales will be discussed and evaluated in this session. This will include presentations and discussions of predictions for a time horizon of up to ten years from dynamical ensemble and statistical/empirical forecast systems, as well as the aspects required for their application: forecast quality assessment, multi-model combination, bias adjustment, downscaling, etc.
Following the new WCPR strategic plan for 2019-2029, prediction enhancements are solicited from contributions embracing climate forecasting from an Earth system science perspective. This includes the study of coupled processes, impacts of coupling and feedbacks, and analysis/verification of the coupled atmosphere-ocean, atmosphere-land, atmosphere-hydrology, atmosphere-chemistry & aerosols, atmosphere-ice, ocean-hydrology, ocean-ice, ocean-chemistry and climate-biosphere (including human component). Contributions are also sought on initialization methods that optimally use observations from different Earth system components, on assessing and mitigating the impacts of model errors on skill, and on ensemble methods.
We also encourage contributions on the use of climate predictions for climate impact assessment, demonstrations of end-user value for climate risk applications and climate-change adaptation and the development of early warning systems.

A special focus will be put on the use of operational climate predictions (C3S, NMME, S2S), results from the CMIP5-CMIP6 decadal prediction experiments, and climate-prediction research and application projects (e.g. EUCP, APPLICATE, PREFACE, MIKLIP, MEDSCOPE, SECLI-FIRM, S2S4E).

Co-organized by NP5/OS4
Convener: Andrea Alessandri | Co-conveners: Louis-Philippe Caron, Yoshimitsu Chikamoto, June-Yi Lee, Xiaosong Yang

Geophysical Fluid Dynamics (GFD) deals with various aspects of the mathematical descriptions of rotating stratified fluids starting from the physical laws of hydro-thermo-dynamics. Physicists and Mathematicians originating from various disciplines developed physical and numerical models with increasing complexity, adding to our fundamental understanding of such flows and thereby unifying these fields. Today GFD is a truly interdisciplinary field of its own, which encompasses multiscale flows of planetary atmospheres and oceans, their weather and climate, and the motions of 'the solid Earth'.

In this session we invite contributions expanding our understanding of the complex behavior of geophysical flows and Turbulence, presenting novel techniques that either facilitate a deeper understanding or improve the efficiency of numerical procedures involved, and/or reviewing major advances in a particular aspect of geophysical fluid dynamics. In these contexts, the role of waves (non-linear, inertial, internal, vorticity or helicity waves), turbulence and transport are an important factor in the understanding of GFD flows.

The interdisciplinary character of dynamical and computational aspects of this session encourages an exchange of ideas and contributions across various fields, such as meteorology, oceanography, astrophysics, geological fluid dynamics, applied mathematics, and computational fluid dynamics with applications to ocean and atmosphere and their Biological influences.

Co-organized by AS1/OS4
Convener: Uwe Harlander | Co-conveners: Claudia Cherubini, Michael Kurgansky, Andreas Will

Lagrangian trajectories are currently used for vast range of purposes in ocean and atmosphere science. Examples include studying the connectivity of ocean basins, forecasting the spreading of ash clouds, mapping global ocean diffusivities, observing the deep ocean, or tracing plastics and other forms of pollutants in the ocean, etc. There is thus a need for numerical models capable of simulating Lagrangian particles in the ocean and atmosphere as well as accurate methods for analysing the data from surface drifters, floats, and simulated particles.

This session aims at bringing together scientists working on all sorts of Lagrangian methods, e.g. observed or simulated particles in the atmosphere and ocean, and a variety of use cases e.g. studying oceanic mixing/diffusivity, tracing pollution in the atmosphere or ocean, iceberg tracking etc. We welcome presentations on e.g.:

- Connectivity and pathways of air- or water-masses in the atmosphere and ocean
- Development of Lagrangian particle-tracking algorithms and algorithms to model particles with active behaviours, e.g. icebergs, fish, ash clouds, plastics etc.
- Methods and new tools to analyse observed or simulated Lagrangian particles, e.g. diffusivity, spreading rates, etc.
- New instrumentations and developments of balloons, surface drifters and floats.

Co-organized by AS5/OS4
Convener: Joakim KjellssonECSECS | Co-conveners: Kristofer Döös, Bror Jonsson

The multitude of processes of various scales occurring simultaneously under strong winds in the air and sea boundary layers presents a true challenge for nonlinear science. We want to understand the physics of these processes, their specific role, their interactions and how they can be probed remotely, how these processes differ from their counterparts under moderate/weak winds. We welcome theoretical, experimental and numerical works on all aspects of processes in turbulent boundary layers above and below the ocean surface. Although we are particularly interested in the processes and phenomena occurring under strong wind conditions, the works concerned with similar processes under weaker winds which might provide an insight for rough seas are also welcomed. We are also very interested in works on remote sensing of these processes.
The areas of interest include the processes at and in the vicinity of the interface (nonlinear dynamics of surface water, wave-turbulence interactions, wave breaking, generation and dynamics of spray and air bubbles, thermodynamics of the processes in the boundary layers, heat and gas exchange), all the processes above and below the aIr/water interface, as long as they are relevant for strong wind conditions (such as, e.g. inertial waves generated by changing winds). Relevant nonlinear biological phenomena are also welcomed.
The main aims of the session is to initiate discussion of the multitude of processes active under strong winds across the narrow specializations as a step towards creating an integrated picture. Theoretical, numerical, experimental and observational works are welcomed.

Co-organized by AS2/NH1/OS4
Convener: Yuliya Troitskaya | Co-conveners: Guillemette Caulliez, Vladimir Kudryavtsev, Victor Shrira, Wu-ting Tsai

In this session, ocean dynamics for scales from small to submesoscales (i.e. few km) are considered. At these scales, influenced by turbulence and other forcing, ocean dynamics is highly variable in both time and space. The session is devoted to multi-scale methods addressing this nonlinear variability, for velocity, passive scalars as well as other biogeochemical components. Such studies can be done by considering ocean remote sensing observations at different spacial resolutions, and numerical modeling using high resolution models.

We welcome contributions addressing the multi-scale variability of oceanic fields using satellite images, outputs of numerical models, and in situ observations, and we especially welcome studies comparing those different products.

Co-organized by OS4
Convener: Francois Schmitt | Co-conveners: Guillaume Charria, Véronique Garçon, Joël Sudre, Hussein Yahia

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

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

Invited Speaker: Anna van der Heydt (Utrecht University)

Co-organized by AS4/CL4/NH1/OS4
Convener: Christian Franzke | Co-conveners: Hannah Christensen, Balasubramanya Nadiga, Paul Williams, Naiming Yuan

This session welcomes contributions on predicting climate variability on different time-scales (seasonal to decadal and beyond) using realistically initialized climate model ensemble simulations. Particularly, we invite studies assessing different aspects of climate predictability, including extremes, and pinning down the respective sources of predictability. According to the calendar season, the geographical domain and the time-scale of the forecast, different climate realms (e.g. ocean, cryosphere, or land) may be key for predictability. There is a certain focus also on predicting large-scale atmospheric circulation anomalies associated to teleconnections, in the tropics but also in the mid-latitudes, which allow, or in the future may allow, climate-related applications to be run operationally in a wide range of disciplines. This session aims to embrace advances in our understanding of the origins of seasonal to decadal predictability, as well as in improving the respective forecast skill and making the most of this information by building and testing new applications and climate services. Last but not least, we welcome studies on state-of-the-art techniques assisting ensemble prediction, such as subsampling and forecast evaluation conditioned on the initial climate state.

Co-organized by CL2/OS4
Convener: Panos Athanasiadis | Co-convener: Leon Hermanson

The ocean floor hosts a tremendous variety of forms that reflect the action of a range of tectonic, sedimentary, oceanographic and biological processes at multiple spatio-temporal scales. Many such processes are hazards to coastal populations and offshore installations, and their understanding constitutes a key objective of national and international research programmes and IODP expeditions. High quality bathymetry, especially when combined with sub-seafloor and/or seabed measurements, provides an exciting opportunity to integrate the approaches of geomorphology and geophysics, and to extend quantitative geomorphology offshore. 3D seismic reflection data has also given birth to the discipline of seismic geomorphology, which has provided a 4D perspective to continental margin evolution.

This interdisciplinary session aims to examine the causes and consequences of geomorphic processes shaping underwater landscapes, including submarine erosion and depositional processes, submarine landslides, sediment transfer and deformation, volcanic activity, fluid migration and escape, faulting and folding, and other processes acting at the seafloor. The general goal of the session is to bring together researchers who characterise the shape of past and present seafloor features, seek to understand the sub-surface and surface processes at work and their impacts, or use bathymetry and/or 3D seismic data as a model input. Contributions to this session can include work from any depth or physiographic region, e.g. oceanic plateaus, abyssal hills, mid-ocean ridges, accretionary wedges, and continental margins (from continental shelves to abyss plains). Datasets of any scale, from satellite-predicted depth to ultra high-resolution swath bathymetry, sub-surface imaging and sampling, are anticipated.

This session is organised by the IAG Submarine Geomorphology Working Group.

Co-organized by OS4/SSP3
Convener: Aaron Micallef | Co-conveners: Sebastian Krastel, Alessandra Savini

This session welcomes contributions presenting advances in, and approaches to, studying, modelling, monitoring, and forecasting of internal waves in stratified estuaries, lakes and the coastal oсean.

Internal solitary waves (ISWs) and large-amplitude internal soliton packets are a commonly observed event in oceans and lakes. In the oceans ISWs are mainly generated by the interaction of the barotropic tides with the bottom topography. Large amplitude solitary waves are energetic events that generate strong currents. They can also trap fluid with larvae and sediments in the cores of waves and transport it a considerable distance. ISWs can cause hazards to marine engineering and submarine navigation, and significantly impact on marine ecosystems and particle transport in the bottom layer of the ocean and stratified lakes. Contributions studying flows due to internal waves, their origin, propagation and influence on the surrounding environment are of great importance.
The scope of the session involves all aspects of ISWs generation, propagation, transformation and the interaction of internal waves with bottom topography and shelf zones, as well as an evaluation of the role of internal waves in sediment resuspension and transport. Breaking of internal-waves also drives turbulent mixing in the ocean interior that is important for climate ocean models. Discussion of parameterizations for internal-wave driven turbulent mixing in global ocean models is also invited.

Co-organized by NP7/OS4
Convener: Kateryna Terletska | Co-conveners: Marek Stastna, Tatiana Talipova, Zhenhua Xu

OS5 – Short courses associated with Ocean Sciences


Satellite data provides information on the marine environment that can be used for many applications – from water quality and early warning systems, to climate change studies and marine spatial planning. The most modern generation of satellites offer improvements in spatial and temporal resolution as well as a constantly evolving suite of products.

Data from the European Union Copernicus programme is open and free for everyone to use however they wish - whether from academic, governance, or commercial backgrounds. The programme has an operational focus, with satellite constellations offering continuity of service for the foreseeable future. There is also a growing availability of open source tools that can be used to work with this data.

This short course is an opportunity to learn about the data available from the Copernicus Sentinel-3 satellite and downstream services, and then, with support from marine Earth Observation experts, to develop your own workflows. The sessions will be interactive, using the WeKEO DIAS hosted processing, Sentinel Applications Platform (SNAP) software, and Python programming. No experience is necessary as various exercises will be provided for a wide range of skill levels and applications, however participants should bring their own laptops and be prepared to install open source software in advance.

Co-organized by ESSI1/OS5
Convener: Hayley Evers-King | Co-conveners: Lauren Biermann, Oliver Clements, Christine Traeger-Chatterjee

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

Part 1 (1 hour) will have the following learning objectives:
• Equilibrium thermodynamics, master thermodynamic potentials, partial thermodynamic properties
• Interdependence of energy conservation and irreversible entropy production
• Mutually consistent definitions of heat and work in the atmosphere and oceans
• Local versus global theories of Available Potential Energy.
• Standard and non-standard theories of irreversible processes.
• Non-equilibrium theory of sensible and latent heat fluxes at the air-sea interface, reversible and irreversible phase changes.
• Theories for the thermodynamic efficiency of the atmospheric and oceanic heat engines: APE versus entropy-based Carnot approaches.
• Exact partitions of potential energy into sign-definite components. Applications to exact mean/eddy partitions. Concepts of local baroclinic life cycle.

Part 2 (45 mn) will illustrate practical applications rooted in recent research and will cover topics such as:
• Means of energy exchange throughout the atmosphere and in the oceans
• Link to observations, consistency of current climate models with theory. Using theory to improve climate models in the future.
• Importance of extratropical eddies in shaping the meridional energy transport, and how this links to the general circulation of the atmosphere

Co-organized by AS6/CL6/NP9/OS5
Convener: Valerio LemboECSECS | Co-conveners: Valerio Lucarini, Gabriele MessoriECSECS, Remi Tailleux

This short course is designed to give a concrete introduction to multifractal methodologies and tools as applied to a wide variety of nonlinear, geophysical systems, including their interactions with urban systems. These applications range from urban geosciences (e.g. land use patterns, water management and ecosystems) to atmospheric and oceanic turbulence (e.g. wind energy, meso-scale scaling anisotropy) and climate (e.g. across scale evolution of the extremes). Data will include in-situ and remotely sensed data, as well as outputs from physically-based modelling.
The training will be performed with the help of an open access python library.

Co-organized by AS6/NH11/NP9/OS5, co-sponsored by AGU
Convener: Ioulia Tchiguirinskaia | Co-conveners: Auguste Gires, Igor PazECSECS, Yangzi QiuECSECS, Arun RamanathanECSECS