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. 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.

Public information:
This session is the continuation of session OS1.7
(https://meetingorganizer.copernicus.org/EGU2020/session/38390) which will start at 08:30

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.

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.

Public information:
OS1.5 : CHAOTIC VARIABILITY AND MODELLING UNCERTAINTIES IN THE OCEAN: TOWARDS PROBABILISTIC OCEANOGRAPHY
WEDNESDAY : 16:15 - 18:00 : TENTATIVE SCHEDULE FOR THE CHAT (Public on EGU website)
12 minutes for hightlighted talk (Sinha et al)
7 minutes for all other talks

==========================================================================
16:15 - 16:18 SESSION INTRODUCTION
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16:20 - 17:00 FORCED AND CHAOTIC OCEAN VARIABILITY
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01. D2581 | EGU2020-7226 | HIGHLIGHT —> 12 min
Quantifying uncertainty in decadal ocean heat uptake due to intrinsic ocean variability.
Bablu Sinha, Alex Megann, Thierry Penduff, Jean-Marc Molines, and Sybren Drijfhout

02. D2582 | EGU2020-5689 —> 7 min
Forced and chaotic variability of interannual variability of regional sea level and its causes scale over 1993-2015.
Alice Carret, William Llovel, Thierry Penduff, Jean-Marc Molines, and Benoît Meyssignac

03. D2592 | EGU2020-2737 —> 7 min
Forced and chaotic variability of basin-scale heat budgets in the global ocean: focus on the South Atlantic crossroads.
Thierry Penduff, Fei-Er Yan, Imane Benabicha, Jean-Marc Molines, and Bernard Barnier

04. D2583 | EGU2020-19875 —> 7 min
Year-to-year meridional shifts of the Great Whirl driven by oceanic internal instabilities
Kwatra Sadhvi, Iyyappan Suresh, Izumo Takeshi, Jerome Vialard, Matthieu Lengaigne, Thierry Penduff, and Jean Marc Molines.

05. D2584 | EGU2020-20309 —> 7 min
Deconstructing the subtropical AMOC variability.
Quentin Jamet, William Dewar, Nicolas Wienders, Bruno Deremble, Sally Close, and Thierry Penduff

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17:00 - 17:25 OCEAN PROCESSES AND PARAMETERIZATIONS
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06. D2586 | EGU2020-21330 —> 7 min
Eddy-Mean flow oscillations in the Southern Ocean.
Sebastiano Roncoroni and David Ferreira

07. D2585 | EGU2020-22418 —> 7 min
On wind-driven energetics of subtropical gyres.
William K. Dewar, Quentin Jamet, Bruno Deremble, and Nicolas Wienders

08. D2587 | EGU2020-11312 —> 7 min
Stochastic Advection for eddy parameterisation in Primitive Equation Models.
Stuart Patching

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17:25 - 17:50 OCEAN MODELLING UNCERTAINTIES
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09. D2589 | EGU2020-11127 —> 7 min
Ensemble quantification of short-term predictability of the ocean fine-scale dynamics: a western mediterranean test case at kilometric-scale resolution.
Stéphanie Leroux, Jean-Michel Brankart, Aurélie Albert, Pierre Brasseur, Laurent Brodeau, Julien Le Sommer, Jean-Marc Molines, and Thierry Penduff

10. D2590 | EGU2020-6489 —> 7 min
Predictability of estuarine model using Information Theory: ROMS Ocean State Ocean Model
Aakash Sane, Baylor Fox-Kemper, David Ullman, Christopher Kincaid, and Lewis Rothstein

11. D2591 | EGU2020-6000 —> 7 min
Impact of Atmospheric and Model Physics Perturbations On a High-Resolution Ensemble Data Assimilation System of the Red Sea
Siva Reddy Sanikommu, Habib Toye, Peng Zhan, Sabique Langodan, George Krokos, Omar Knio, and Ibrahim Hoteit

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17:50 - 18:00 OPEN DISCUSSION - CLOSING THE SESSION
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This session will focus on variability in the ocean and its role in the wider climate system using both observations and models. Areas to be considered will include both ocean heat uptake and circulation variability as well as exploring the use of sustained ocean observing efforts and models to make progress in understanding the ocean’s role in the climate system. 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. Circulation variability and connectivity, particularly from the South Atlantic to the North Atlantic and Arctic Ocean, are also of interest as well as how they are driven by local-, large- or global-scale processes or teleconnections. 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. Thus, this session will also explore ongoing and planned sustained ocean observing efforts and illuminate their roles in improving understanding of the ocean’s role in the climate system. For example, air-sea flux moorings are being maintained at select sites to assess models and air-sea flux fields. Deep temperature and salinity measurements are being made at time series moorings and will be made by deep Argo floats. Significant advances are also being made using Argo floats for biogeochemistry and carbon measurements. Such observations provide the means to develop linkages between sustained ocean observing and climate modelling. In conclusion, the session will consider key aspects of ocean variability and its climate relevance, as well as encouraging the use of observations and models to enhance understanding of these areas.

Public information:
Announcement: We'll host a webinar with speakers from our session next week. May 13., 15:00-18:30 CEST

Agenda for the webinar: http://iacweb.ethz.ch/staff/medhaugi/files/UnofficialEGUOS1p6ZoomMeetingProgramme.pdf.

The webinar will be open to everyone, but please sign up to receive login details: https://forms.gle/6qwNVrBq7aYc7pn78

Please note that this session will be linked to a special session for the presentation of the Fridtjof Nansen Medal. We also have Daniela Domeisen and Caroline Katsman as invited speakers.

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
-- 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
-- response of the atmosphere to changes in the North Atlantic
-- 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

Public information:
This session will continue at 12:45 with OS1.0 (https://meetingorganizer.copernicus.org/EGU2020/session/38390)

Observations and model simulation illustrate significant ocean variability and associated air-sea interactions from regional to global scale and on diurnal to inter-annual time scales. This session is devoted to the understanding of the tropical and subtropical ocean dynamics, its interaction with the overlying atmosphere from the equator to mid-latitudes and its climate impacts on adjacent to remote areas.
Relevant processes in the ocean include upper and deep ocean circulation, mild SST gradients to sharp fronts, eddies, filaments, tropical instability waves, warm pools, cold tongues and eastern boundary upwellings. Furthermore, we are interested in air-sea interactions related to both the seasonal cycle and the development of modes of variability from local to basin scale. Wind variations related to Madden-Julian Oscillation, cyclones, and convective systems, as well as those leading the air-sea coupled modes (e.g., the Meridional Mode and Atlantic Niño) are welcome. Finally, we also seek contributions examining the causes and impacts of systematic model errors in simulating the local to regional climate.
Studies based on direct observations, reanalysis, reconstructions as well as model simulations are welcome.

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.

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).

Public information:
Session structure file is back.

Yevegny

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.

Public information:
Please join our live text chat on the display items. The displays will be discussed in the order outlined in our program: https://tinyurl.com/y88p7g5o

There will be a joined virtual (video) coffee break (15:45-16:15 CEST) between sessions OS1.12 and OS1.13 as well as a follow-up online open bar (18:00- CEST). Please join us. You can find a registration link in the session program.

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 how does it interact with the ice?", and “What are the dominant processes in ice-ocean boundary layers?” 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 of various types 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. Similarly, our limited knowledge of processes in ice-ocean boundary layers, such as heat and salt fluxes that control the melt rate, has been identified as a limitation on our ability to fully understand, let alone parameterize melting and freezing at interfaces between the ocean and ice shelves, icebergs, glaciers, and sea ice.

This session includes studies of the Southern Ocean's marginal seas including the Antarctic continental shelf and ice shelf cavities, as well as process studies with a particular focus on ice-ocean boundary layers and on all scales, from the ice-ocean interface to local to basin-scale to circumpolar. Physical and biogeochemical interactions between ice shelves, sea ice and the open ocean will be presented, along with their impacts on the greater Antarctic climate system. Presentations include theoretical studies as well as those based on in-situ observations, remote sensing, and process-scale, regional and global models. While the primary focus of the session is on ice-ocean interactions, we also includes contributions on ice-covered freshwater lakes.

Public information:
16:15-16:50 Characteristics of Polar Seas and connection with ice shelves and the open ocean
Chairs: Leo, Louis

16:15-16:20 Raquel Flynn (D2761 | EGU2020-21107)
16:20-16:25 Katherine Hutchinson (D2768 | EGU2020-112)
16:25-16:30 Roberto Grilli (D2772 | EGU2020-2984)
16:30-16:35 Chengyan Liu (D2770 | EGU2020-2319)
16:35-16:40 Ria Oelerich (D2763 | EGU2020-463)
16:40-16:45 Ute Hausmann (D2767 | EGU2020-22464)
16:45-16:50 General Discussion

16:50-17:20 Sea ice and its interaction with ice shelves and the Southern Ocean
Chairs: Nadine, Xylar

16:50-16:55 Lucile Ricard (D2765 | EGU2020-17820)
16:55-17:00 Pierre-Vincent Huot (D2780 | EGU2020-19677)
17:00-17:05 Isabelle Giddy (D2777 | EGU2020-9934)
17:05-17:10 F. Alexander Haumann (D2782 | EGU2020-22008)
17:10-17:15 Sönke Maus (D2762 | EGU2020-6039)
17:15-17:20 General Discussion

17:20-18:00 Turbulent Ice Shelf-Ocean Boundary Layers
Chairs: Irena, Xylar

17:20-17:25 Ryan Patmore (D2769 | EGU2020-10388)
17:25-17:30 Leo Middleton (D2781 | EGU2020-9112)
17:30-17:35 Louis-Alexandre Couston (D2776 | EGU2020-19054)
17:35-17:40 Carolyn Branecky Begeman (D2774 | EGU2020-10848)
17:40-17:45 Peter Davis (D2771 | EGU2020-50)
17:45-18:00 General Discussion

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.

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.

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.

Public information:
We will allocate five minutes of text-based discussion time to each abstract, as follows:

10:45-10:50 Introduction
10:50-10:55 Eelco Rohling
10:55-11:00 Jim Jordan
11:00-11:05 Javier Blasco
11:05-11:10 Emily Hill
11:10-11:15 Felicity McCormack
11:15-11:20 Gordon Bromley
11:20-11:25 Christian Turney
11:25-11:30 Tyler Pelle
11:30-11:35 Liyun Dai
11:35-11:40 Jun-Young Park
11:40-11:45 Christian Ohneiser
11:45-11:50 Catherine Beltran
11:50-11:55 Johannes Sutter
11:55-12:00 Nicolas Ghilain
12:00-12:05 Torsten Albrecht
12:05-12:10 Nicolas Jourdain
12:10-12:15 Christoph Kittel
12:15-12:20 Caroline van Calcar
12:20-12:25 James O'Neill
12:25-12:30 Thore Kausch

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).

Public information:
There will be a chat during our session giving each presenter about 5 min. to answer questions.
The schedule is divided into more ISMASS and ISMIP6 related topics and will follow the following time line (which is fluently adapted if presenters are not present):
14:00 - 14:05 Introduction to the chat
14:05 - 14:10 D2555 Ben Galton-Fenzi - Progress towards coupling ice sheet and ocean models
14:10 - 14:15 D2566 Petra Langebroek - Tipping Points in Antarctic Climate Components (TiPACCs)
14:15 - 14:20 D2572 Nadine Wieters - Modular AWI-CM: An Earth System Model (ESM) prototype using the esm-interface library for a modular ESM coupling approach
14:20 - 14:25 D2558 Jon Bamber - Interpretation and Analysis of Projected Ice Sheet Contributions from a Structured Expert Judgement
14:25 - 14:30 D2557 Andrew Shepherd - Trends and projections in ice sheet mass balance
14:30 - 14:35 D2562 Yijing Lin - Antarctic Ice Sheet mass balance over the past decade from 2005 to 2016
14:35 - 14:40 D2569 Johanna Beckmann - How will the Greenland Ice Sheet develop under Extreme Melt Events?
14:40 - 14:45 D2565 Leo van Kampenhout - A regional atmospheric warming threshold for irreversible Greenland ice sheet mass loss
14:45 - 14:50 D2561 Christiaan van Dalum - Evaluation of a new snow albedo scheme in RACMO2 for the Greenland ice sheet
14:50 - 14:55 D2553 Charlotte Lang - Comparison of the surface mass and energy balance of CESM and MAR forced by CESM over Greenland: present and future
14:55 - 15:00 D2554 Nanna Bjørnholt Karlsson - Basal Melt of the Greenland Ice Sheet: The Invisible Mass Budget Term
15:00 - 15:05 D2551 Heiko Goelzer - The future sea-level contribution of the Greenland ice sheet: a multi-model ensemble study of ISMIP6
15:05 - 15:10 D2560 Tony Payne - Contrasting contributions to future sea level under CMIP5 and CMIP6 scenarios from the Greenland and Antarctic ice sheets
15:10 - 15:15 D2552 Tamsin Edwards - Quantifying uncertainties in the land ice contribution to sea level from ISMIP6 and GlacierMIP
15:15 - 15:20 D2568 Helene Seroussi - ISMIP6 Antarctica: a multi-model ensemble of the Antarctic ice sheet evolution over the 21st century
15:20 - 15:25 D2571 Martin Rückamp - Sensitivity of Greenland ice sheet projections to spatial resolution in higher-order simulations: the AWI contribution to ISMIP6-Greenland using ISSM
15:25 - 15:30 D2573 Thomas Kleiner - ISMIP6 Future Projections for Antarctica performed using the AWI PISM ice sheet model
15:30 - 15:35 D2570 Konstanze Haubner - Changes on Totten glacier dependent on oceanic forcing based on ISMIP6
15:35 - 15:40 D2556 Ronja Reese - The role of history and strength of the oceanic forcing in sea-level projections from Antarctica with the Parallel Ice Sheet Model


note: ISMASS and ISMIP6 homepages have been moved and are now available here:
http://www.climate-cryosphere.org/activities/ismass
http://www.climate-cryosphere.org/mips/ismip6

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.

Fifty years of routine in-situ and satellite observations have revealed the progressive deterioration of Antarctica’s most vulnerable regions to climate change: the Antarctic Peninsula and West Antarctic ice sheets. The rapid destabilisation of Larsen A and B ice shelves in the Antarctic Peninsula and the ongoing, potentially irreversible ice losses at Pine Island and Thwaites glaciers, West Antarctica, have been linked to a complex marriage of ocean and atmosphere forcing mechanisms impinging on the continent from the Weddell, Bellingshausen and Amundsen Seas. These phenomena have raised questions about the past and future stability of the ice sheets and water mass properties, and have motivated research focused on elucidating the precise ice-ocean-atmosphere interactions controlling oceanographic and cryospheric change over palaeo- to contemporary timescales. Offshore, similar questions have arisen regarding the role of seabed topography and changing sea ice and oceanographic conditions, and how such phenomena may ultimately impact ice sheet mass-losses.

This session welcomes contributions examining the range of controls driving cryospheric and oceanic change across the Antarctic Peninsula and West Antarctic Ice Sheet regions, as well as those in the wider Weddell Sea sector. Together with model and remotely sensed studies, this session will showcase early results from the International Thwaites Glacier Collaboration and several recent research campaigns conducted in the Weddell Sea.

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.

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

Confirmed invited speaker: Michael Ghil

Significant advances in our understanding of the Meso- and Cenozoic development of polar regions have been made over the last two decades by studying continental shelf, slope, or deep sea 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, to provide a multi-disciplinary picture of polar regions. 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.

Public information:
Session schedule:

14.00-14.02 Welcome and introduction

14.02-14.10 D3130 | EGU2020-7493 David Hutchinson et al., Arctic closure as a trigger for Atlantic overturning at the Eocene-Oligocene Transition

14.10-14.18 D3131 | EGU2020-7943 Katrien Van Landeghem et al., Relating changes in seabed properties and retreating glacier fronts in West-Antarctic fjords

14.18-14.26 D3135 | EGU2020-12484 Joe Stoner et al., Deriving paleo-perspectives on polar systems: Continued results from the 2012 Sawtooth Lake (Ellesmere Island) and 2015 Petermann (North Greenland) Expeditions

14.26-14.34 D3136 | EGU2020-768 Julia Rieke Hagemann et al., Southern Chilean continent-ocean interaction over the last glacial cycle

14.34-14.42 D3140 | EGU2020-10921 Tom Arne Rydningen et al., New results on the dynamics of the NW part of the Svalbard Ice Sheet during the deglaciation of the Woodfjorden Trough

14.42-14.50 D3142 | EGU2020-12940 Michele Rebesco et al., Multi-proxy analysis of Late Quaternary ODYSSEA Contourite Depositional System (Ross Sea, Antarctica) and the depositional record of contour current and cold, dense waters

14.50-14.58 D3143 | EGU2020-13950 Juliane Müller et al., Deglacial sea ice variability at the continental margin off western Dronning Maud Land

14.58-15.06 D3144 | EGU2020-17953 Jostein Bakke et al., Late glacial and Holocene glacier fluctuations at the Sub-Antarctic Island Kerguelen in the Southern Indian Ocean

15.06-15.14 D3145 | EGU2020-18143 Marie Protin et al., Geological, geochemical and cosmogenic nuclides constraints from the NEEM core basal sediments, Greenland

15.14-15.22 D3147 | EGU2020-19076 Kseniya Mikhailova et al., Glendonites from Mesozoic succession of eastern Barents sea: distribution, genesis and paleoclimatic implications

15.22-15.30 D3148 | EGU2020-19216 Eivind W. N. Støren et al., Reconstruction of Holocene glacier fluctuations at Kongsbreen based on sediments deposited in lake Sarsvatnet, Ossian Sarsfjellet, Svalbard

15.30-15.45 General discussion and outstanding questions

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.

Public information:
Dear all,
welcome to the virtual EGU 2020. This is just a reminder that we will have the "ENSO and Tropical Basins Interactions: Dynamics, Predictability and Modelling" (CL4.20/AS1.12/NP2.6/OS1.27) session Thu, 07 May, 14:00–15:45 (Vienna time zone). It will be an online chat only session.

In addition to the EGU chat session on Thursday we plan to do a video meeting for the "ENSO and Tropical Basins Interactions: Dynamics, Predictability and Modelling" session with presentations from the authors (you) some time later this year (e.g. June/July). More on this we will discuss on Thursday in the EGU chat of this session.

Best regards and hope to chat with you on Thursday!
Dietmar Dommenget, Antonietta Capotondi, Daniela Domeisen and 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?

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.

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.

Public information:
Dear participants in EGU 2020 session CL4.14,

Thanks you all for your various contributions to this session and for participating in the live chat. As this is a new form, we probably all wonder how well it will work, but we are also excited about trying out this new way of discussing our science!
None of the co-conveners have any experience in chats – and not the least managing them, so please accept our apologies if not everything will go as smoothly as we will like.

Process for the chat session:
Hopefully, you have all succeeded in uploading any display that you wish. However, also those who have chosen not to add any further material will still have the option to discuss your research based on your abstracts and any addition information that you can tell us.
Note: This chat is not recorded or stored. Only abstracts and further displays will be available after this session. This provides more freedom to discuss.
Also: All discussion will be in writing via the chat.
To best organize the chat session, we will carry out the chat for one presentation (display) at the time.
We (the conveners) will start up by writing the number of the display in the chat and invite the presenter to give a short introduction. Presenter: It would be advisable if you have a short text ready that you can upload in the chat box. Do not expect to give a full presentation, just give a SHORT introduction and highlight the main points. So, make it short, as we have many displays and people need time to read the chat messages. Do not just copy the entire abstract, as all session participants have had the possibility to read these prior to the chat session

After this short introduction to the presentation, the floor is now open for comments.
If no comments arrive within 30 seconds to 1 minute, we will move to the next display. Also, if no presenter is present for a display, we will also move on to the next display. One minute is a short time to write a detailed question, so it could be a good idea to prepare some comments beforehand.

Timing: We have up to 1h45min available for the session. With 27 presentations, this gives 3-4 minutes for each presentation. We did not succeed in getting a full overview of, who among the presenters, would like to discuss their result. Thus, currently we do not know how many presenters will be present or how much discussion each presentation will cause. Therefore, we need to keep a tight schedule but we will still try to be flexible, if there is a lively discussion. As there are some among the conveners who have indicated that they will likely not join the session, there should be some additional time, which at the first instance will be allocated to those, who have uploaded material in addition to abstracts – you will get 5 min for the discussion. Should there be time in the end after the full round of presentations/discussions, we can always return to discuss.

The chat session ends either when our time runs out or if the discussion ends.

All the best and keep safe,
Marit-Solveig Seidenkrantz, Anne de Vernal, Michal Kucera, Mimmi Oksman & Henrieka Detlef

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 variability and predictability of climate in both hemispheres from 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.
The 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 the WWRP Year of Polar Prediction (YOPP), NordForsk-project ARCPATH, and the H2020-projects APPLICATE, INTAROS, BlueAction, and PRIMAVERA.

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.

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. To date, most research in this area has been on constraining basic metrics such a climate sensitivity. In addition, and just as importantly for mankind, the Earth's climate is highly variable on all spatial and temporal scales with implications for understanding both the industrial epoch
and future climate projections. 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 in the Earth System across space and time scales. This includes contributions looking at "steady state" climate features such as climate sensitivity as well as those investigating changes in climate variability and scaling properties. The session is multidisciplinary and brings together studies related to atmospheric science, oceanography, glaciology, paleoclimatology and nonlinear geoscience, 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. We welcome contributions using case studies, idealised or realistic modelling, synthesis, and model-data comparison studies that provide insights into past, present and future climate variability on local to global, and synoptic to orbital timescales. Members of the PAGES working group on Climate Variability Across Scales (CVAS) are welcome.

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.

Climate change is projected to result in an increase in extreme and compound weather events, which pose a growing threat to human well-being and the achievement of the UN Sustainable Development Goals (SDGs). Further warming is also projected to reduce the efficacy of carbon sinks acting as negative feedbacks on warming and increase the risk of crossing tipping points and triggering cascading changes in the climate and ecosystems. These processes may reduce the Earth system’s resilience, which has the potential to further amplify climate change and extremes and worsen societal impacts.

Maintaining Earth in the Holocene-like conditions that have enabled the development of the world’s societies will require better understanding of feedbacks and tipping dynamics in both the human world and the biophysical Earth. Societies will need to embark on rapid socio-economic and governance transformations in order to both reduce the risk of triggering tipping points and to improve societal resilience to increasingly likely extreme events. 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 welcome transdisciplinary and cross-scale contributions relating to climate extremes, tipping dynamics, and Earth resilience, covering topics ranging from the cascading impacts of extreme and compound events, key feedbacks and tipping points in both biophysical and human systems, enhancing societal resilience to extreme events, and the potential for rapid social transformations to global sustainability.

Public information:
EGU 2020 Session TS3.2/NH10.7
Climate Extremes, Tipping Dynamics, and Earth Resilience in the Anthropocene
6 May, 14:00-18:00

This session will run as an EGU website hosted text-based chat accessible here, as well as through a simultaneous Zoom video room (link to be provided during the livechat).

Both the EGU chatroom and the Zoom video room will be moderated.
Comments on the presentations can be made at the EGU website at any time, for asynchronous responses.
Comments and questions asked in the EGU chatroom will be forwarded to the Zoom presenters. This means all questions will get responses, but this may not happen within the timeslot of the presentation.
To facilitate real-time dialogue with the presenters, please go to the Zoom session.

When joining the Zoom session remember to mute yourself, and to ask questions please raise your hand (available from the 'participants' button) and unmute when the chair calls on you. If you are a presenter, unmute when called on and share your screen if you have a few slides to show. Each presenter gets 10 minutes max including Q&A, so we suggest presenting some summary slides for a few minutes and then taking questions for the rest.