Implementing Standards Suite for Ocean Digital Twins in Iliad

Data discovery, processing and access APIs play an important role in the integration and harmonization of Digital Twins' implementations. Within the Iliad project's System of Systems (SoS) federated approach to the distributed platform architecture for digital twins operating oceanographic data, APIs have been applied. By enabling interoperability between diverse sources—legacy sensors, citizen science projects, third-party data hubs, and models—these APIs ensure standardized access to distributed datasets without requiring a centralized repository. A key focus of this paper is the implementation of flexible, open API architectures that align metadata, standardize access protocols, and facilitate data discovery across the system of systems (SoS). The adoption of cloud-native formats, rich web services, and streaming mechanisms enhances accessibility while supporting both existing and emerging technologies. The paper explores efforts around standards development organizations to refine API frameworks into knowledge services, ensuring they remain adaptable to evolving requirements. These advancements are instrumental in enabling high-resolution modeling, large-scale simulations, and leveraging potential of the AI applications within the environmental Digital Twins ecosystem.