The Multi-annual to Decadal Climate Predictability in the North Atlantic-Arctic Sector workshop aims to foster scientific exchanges and collaborations on multi-annual to decadal climate predictability, including research on:

• climate predictability from interannual to multi-decadal timescales and our understanding of the associated physical processes and their representation by models
• improvement of dynamical prediction systems, and
• increasing need for actionable information dependent on skillful climate predictions.

1/ MECHANISMS AND PREDICTABILITY

This session aims to cover a wide range of scientific topics related to climate predictability from interannual to multi-decadal timescales, our understanding of the associated physical processes and their representation by models. Topics of specific interest include: AMOC and Arctic sea ice variability, coupled variability modes, internal versus externally forced variability, the role of the Gulf Stream SST front variability on the atmosphere and related feedbacks, extremes in the decadal timescale, and last but not least the overarching signal-to-noise problem.

Invited speakers:

• Katinka Bellomo, Institute of Atmospheric Sciences and Climate (CNR-ISAC), on “External forcing on Atlantic Multidecadal Variability”
• Elizabeth Maroon, University of Wisconsin (UW-Madison), on “The role of ocean as a source of decadal predictability and the prediction of the cold blob”
• Leon Hermanson, Met Office (UKMO), on “Limits of predictability and the signal-to-noise problem”
• Shoshiro Minobe, Hokkaido University (Hokudai), on “Air-sea interactions” 

2/ ADVANCES IN MODEL & INITIALISATION 

This session aims to cover a wide range of scientific topics related to the improvement of dynamical prediction systems. Topics of specific interest include: 1) use of advance data assimilation such as strongly coupled data assimilation and its combination with artificial intelligence to better handle the multi-scale variability modes and reduce model error, 2) use of improved modelling such as high resolution, improved parameterization, innovative modelling approaches, such as supermodelling and breakthroughs in the use of supercomputing platforms, and 3) use of novel observation networks to better constrain dynamical models.

Invited speakers:

• Terence O’Kane, Commonwealth Scientific and Industrial Research Organisation (CSIRO), on “Strongly coupled data assimilation, and combination of data assimilation and machine learning”
• Helene T. Hewitt, Met Office (UKMO), on “High resolution Earth System Modelling in decadal climate predictions”
• Francine J. Schevenhoven, University of Bergen & Bjerknes Centre for Climate Research (UiB & BCCR), on “Supermodel for correcting model error”
• Shaoqing Zhang, Ocean University of China (OUC), on “Strongly coupled data assimilation and breakthrough in High Performance Computing use for very high resolution”

3/ APPLICATIONS & SERVICES 

This session covers all topics related to the increasing need for actionable information dependent on skilful climate predictions. In particular, a new and important dimension opens ahead ready to benefit from the now-matured decadal predictions. Prototype climate services are being developed, while a universe of applications awaits to be born. A number of initiatives point in this direction, including the WMO Lead Centre for Annual-to-Decadal Climate Prediction and the Copernicus Climate Change Service (C3S). Dealing with the above, this session aims at communicating best practices and protocols and discussing off-line prediction refinements and the needs and standards in the development of climate services and applications.

Invited speakers:

• Chiara Cagnazzo, European Centre for Medium-Range Weather Forecasts (ECMWF), on “Overview of C3S scope, progress and plans” 
• Nick Dunstone, Met Office (UKMO), on “C3S_34c Prototype decadal climate services”
• Isadora Christel Jimenez, Barcelona Supercomputing Center (BSC), on “What happens to the data after they are produced?”
• Mark Payne, Danish Meteorological Institute (DMI), on “Marine climate services”

• Panos Athanasiadis, Foundation Euro-Mediterranean Centre on Climate Change
• Joan Ballester, Barcelona Institute for Global Health
• Francois Counillon, Nansen Environmental and Remote Sensing Center
• Fei Li, University of Bergen
• Gerard McCarthy, ICARUS, Maynooth University
• Juliette Mignot, LOCEAN-IPSL, Institut de recherche pour le développement
• Juan José Sáenz de la Torre, Predictia Intelligent Data Solutions
• Shuting Yang, Danish Meteorological Institute

• Noel Keenlyside, University of Bergen, Coordinator of Bjerknes Climate Prediction Unit
• Steffen Olsen, Danish Meteorological Institute, Coordinator of Blue-Action
• Daniela Matei, Max Planck Institute for Meteorology, Coordinator of ROADMAP
• Laura Jackson, UK Met Office, CLIVAR Atlantic Region Panel representative
• Dorotea Iovino, Foundation Euro-Mediterranean Centre on Climate Change, CLIVAR/CliC Northern Oceans Region Panel representative