WHOS technologies: Connecting the dots for Advancing Global Hydrological Data Exchange and Harmonization

The rise in climate and weather-related risks such as floods, droughts and landslides affect millions of people and their properties. Early Warning Systems (EWS) coupled with anticipatory actions, are instrumental in tackling these threats. Water, a central focus of Sustainable Development Goal (SDG) 6, is integral to climate action and influences many other SDGs, emphasizing the need for accurate water-related data. The United Nations launched the Early Warnings for All (EW4All) initiative in November 2022 to ensure global EWS coverage. The quantity and quality hydrological data is critical for effective EWS and climate resilience. Moreover, the existence of different hydrological data from different sources, especially from non-traditional sources like machine learning (ML) and artificial intelligence (AI), remain underutilized by National Hydrological Services (NHS) and other users.

Accessing and processing hydrological data is often challenging due to its heterogeneity, necessitating significant effort to harmonize and integrate disparate sources. These barriers hinder effective water management and issuing early warnings in time. The WMO State of Global Water Resources report 2023¹ highlights the urgency of addressing data access and availability issues. Easy access to relevant data relies on machine-to-machine communication, which remains challenging for many agencies.

To address this, the WMO Hydrological Observing System (WHOS) provides an interoperable framework for data sharing, access and visibility using relevant technologies. It provides functionalities such as data publishing, standardization, visualization and linking global data centres and research communities. By integrating data from diverse sources, including ML/AI, global datasets, satellite observations, and individual researchers, WHOS enhances data visibility, fosters co-operation, and demonstrates the value of hydrological data collection. WHOS interfaces the big data and non-traditional data sources with NHS data systems using standardization and brokering approaches and open-source tools.

WHOS employs tools and standards like OSCAR, WHOS DAB, WIS2Box, Hydroserver2.0, HydroShare, WDE, WMDS, WCMP2.0, OGC WaterML2.0, etc. OSCAR serves as WMO’s official metadata repository, enabling users to query and view observing stations. The Discovery and Access Broker (DAB) standardizes and harmonizes data, while WIS2Box simplifies data publication and download. HydroServer2.0 is an open-source data management tool accessible to all users including LDCs and SIDS. Standards such as WCMP2.0 and OGC WaterML2.0 support unified data discovery and access. Additionally, Topic Hierarchy for hydrology enables users to receive real-time data notifications by subscribing to a Message Queuing Protocol broker.

The WHOS portal serves as a one stop data portal connecting hydrological data from countries, regional and basin organizations, research communities and global centres (IGRAC, GRDC, etc). Advances in AI, ML, satellite technology, and citizen science are resulting in vast amounts of data and WHOS integrates these data to support researchers, modelers and practitioners in water resource management.

WHOS provides interoperable data to EW4All, Water Resources Management and HydroSOS systems by bridging gaps between research and operational applications. It supports transboundary cooperation, joint data monitoring and sharing, while demonstrating the return on investment in hydrological data collection. By harmonizing and sharing hydrological data, WHOS is instrumental in mitigating hydrological hazards and fostering global collaboration. 

¹ https://library.wmo.int/records/item/69033-state-of-global-water-resources-report-2023