What numerical models do we need to build the European Digital Twin of the Ocean?

February 2022 saw the launch of the development of the European Digital Twin of the Ocean (European DTO) under the EU Mission Restore our Oceans and Waters, announced by President von der Leyen at the One Ocean Summit in Brest. The European DTO will be a virtual, dynamic representation of the ocean. Its main goal is to make ocean knowledge readily available to all, so that our society can better understand the complexities of the marine world and make informed decisions to safeguard the ocean and coastal environments. Furthermore, it is being built to provide an innovative set of user-driven, interactive, and decision-making tools. These tools are backed by the latest science and data, and they aim to support a more sustainable blue economy by empowering stakeholders to identify and address environmental challenges and opportunities in the ocean sector.

To develop the operational core of the European DTO, the European Commission has invested about €10 million in two Horizon Europe research and innovation interdependent projects that will build the public infrastructure and digital framework (EDITO-Infra) and core modelling suite (EDITO-Model Lab).

The European DTO will provide consistent, high-resolution, multi-dimensional descriptions of the ocean and coastal waters’ physical, chemical, biological, and socio-economical dimensions, with forecasting periods ranging from days to multi-decades. This tool is therefore very relevant to the European Commission, namely in terms of the implementation and monitoring of its strategies and policies on ocean conservation, sustainability, and climate change.

Fed by continuous real-time and historical observations, including thousands of in-situ sensors across the world’s ocean and numerous satellites in space, the European DTO will allow the integration of alternative data flows with ocean simulations that are performed in operational frameworks (reanalysis and forecast) as well as in research projects (reference simulation, climate change projection, etc.). Hence, the new tool will integrate advanced numerical modelling, powered by Artificial Intelligence and Machine learning, and operate on high-performance computers.

Started in January 2023, the EDITO-Model Lab will demonstrate the feasibility, usefulness, and performance of a DTO. Led by Mercator Ocean International (MOi), the project involves 14 European partners (MOi, IMT, FONDAZIONE CMCC, CNRS, DELTARES, UNIBO, DMI, HEREON, CINECA, BSC CNS, SOCIB, NERSC, +ATLANTIC and NVIDIA). Each partner will bring in its complementary expertise and key skills needed to develop the underlying model suite to be integrated into the European DTO, including:

• Ocean numerical modelling, from global scale to coastal, for ocean physics, biogeochemistry, and marine environments, a large diversity of models will be used in the project and made available in our Virtual Ocean Model Lab. NEMO, which is the model mainly used in the framework of the EU’s Copernicus Marine Service, will be used for global, regional, and downscaling applications, but other physical models will also be used, including specificities such as unstructured grid (SHYFEM) and coastal models (HBM, SCHISM and Delft3D). Wave models (WAM and WW3) and ocean biogeochemistry and marine environments (such as PISCES, ECOSMO, BFM, WAQ, VEG, and XBEACH) will also be used.
• Supercomputing: BSC and CINECA High performance Computing Centre will be used as EUROHPC components, with the possibility of connecting to other computing facilities to optimise the EDITO numerical models and demonstrate interoperability. The cloud computing platform also used in the Copernicus Marine and WEkEO frameworks will be available through EDITO-Infra and used for different applications in the EDITO-Model Lab.
• Artificial Intelligence and Machine Learning applied to ocean applications: Deep Differentiable Emulators will be developed, addressing three main objectives: optimisation of model parameterisation, ocean field reconstruction and forecast, and data assimilation.
• Software development, numerical models, and tool co-development in the framework of a Virtual Ocean Model Lab providing facilities for models and tools co-development and for the usage of the models. Specific tools as validation tools, workflow managers, and a graphic user interface will be made available on the platform and connected with the different models to build the core model suite of EDITO-Model Lab.
• Operational oceanography with strong links with the Copernicus Marine Service, OceanPredic, and the UN OceanPrediction Decade Collaborative Centre
• Developing intermediate to final user applications to demonstrate feasibility and provide concrete examples of Focus Applications addressing Marine Protected Areas for biodiversity, ship routes for zero carbon and pollution sources for zero pollution. What-If Scenarios developed will answer key questions about nature-based solutions for biodiversity and coastal hazards, aquaculture for zero carbon and marine plastic for zero pollution.

The project will serve a large diversity of users including:

• Intermediate users, already partners of the project and connected to international programmes (OceanPredict, UN Decade of Ocean Science for Sustainable Development, DITTO, CoastPredict and ForeSea)
• Other EU projects, such as Mission Ocean Lighthouses and ILIAD project
• Numerical model developers
• Ocean and coastal researchers

Consequently, EDITO-Model Lab will respond to the following intermediate and end-user needs:

• Portability and interoperability of numerical models and simulation techniques
• Optimisation and adaptation to new and future computing platforms
• Coupling, interaction and hybridisation between different numerical models and Machine Learning components to represent ocean physics, biogeochemistry, biology and ecology
• Flexibility in use, configuration design and simulations to suit applications
• Virtual Ocean Model Lab is a co-development platform to connect developers of various models, users willing to produce simulations using AI and ML, and associated infrastructure providing access to different computing (HPC, CLOUD) and data storage and dissemination resources (data lake)
• Usage examples and user support for Focus Applications and What-if Scenarios

The whole EDITO initiative, through EDITO-Infra and EDITO-Model Lab, will make ocean knowledge freely available to researchers, scientific experts, decision-makers, entrepreneurs, policymakers, and citizens alike. It will enable them to become partners in knowledge generation, explore desirable futures, develop ocean management scenarios, and assemble their own digital twins. This way, the initiative will engage a wide global community to help ensure a safe, healthy, and productive ocean.