EGU ESSI–WMO–UNESCO Synergies for Interoperable Hydrological Data

Many promising initiatives are advancing FAIR data in hydrology, yet a substantial semantic and technical interoperability gap remains between water data used in operational services and in research, from in situ observations to model-derived products. At present, national hydrological services and the Earth system science community often develop data structures, vocabularies and workflows in parallel, which hampers seamless reuse of water information across mandates and scales. Addressing this fragmentation requires a collaborative effort to co-design shared semantic and ontological standards that can underpin interoperable data exchange for both operational water management and scientific analysis. This includes the FAIR Water community, including OGC Hydrology Domain Working Group (OGC HydroDWG), WMO, UN bodies (UNEP, UNESCO IGRAC and ICWRGC), DANUBIUS, eLTER RIs, TERENO and the Water4all partnership amongst others.This contribution presents the state-of-the-art in and a conceptual and practical framework for connecting the Earth and Space Science Informatics community with the implementation of an emerging international hydrological data exchange standard that serves both operational hydrology and Earth system science. It aligns the objectives of the WMO Plan of Action for Hydrology – in particular the ambitions “high-quality data supports science” and “science provides a sound basis for operational hydrology” – with the development of WIS2-based hydrological data exchange under the WMO Task Team on WIS2 for Hydrology (TT‑W2FH), which is responsible for defining hydrology-specific topic hierarchies, metadata, KPIs and implementation guidance for the WMO Hydrological Observing System “WHOS” within the WMO Information System “WIS”. The contribution supports also the strategy process of the water program of the UNESCO “IHP‑IX” and deals with output 3.3 on validating open-access data on water quantity, quality and use, with a focus on workflows, quality control, and governance arrangements required to make such data reliably reusable in transboundary and global assessments.The presentation discusses concrete pathways to embed FAIR digital object concepts, interoperable metadata and federated workflows from the ESSI community into the WMO and UNESCO implementation processes, thereby fostering cultural change towards open, standards-based data sharing. The definition of how to reach a high FAIRness level within the water community in the light of the existing international standards and best practices (OGC, W3C, INSPIRE, RDA) with the target to produce FAIR Implementation Profiles (FIP). By explicitly linking EGU ESSI user-centric research data infrastructures developments with WMO and UNESCO programmes, the contribution aims to strengthen international collaboration and to co-develop sustainable, community-driven practices for a hydrological data exchange standard that equally supports real-time operations, long-term water resources assessment and integrated Earth system modelling.