As climate change continues to impact our planet, a better understanding of the Earth’s water cycle and its related processes becomes increasingly necessary. Global Hydrological Models (GHMs) have emerged as a crucial tool to analyze complex, large-scale hydrological systems and predict the availability, distribution, and movement of water resources across the world. 

GHMs look at hydrology from the perspective of the earth behaving as one interconnected system, rather than as separate catchments. They integrate global data on precipitation, evaporation, infiltration, soil moisture, streamflow, and human water use in a comprehensive simulation. These models are indispensable for numerous applications, from predicting potential flood and drought situations to devising water resource management strategies, and even working towards creating climate-resilient societies. 

The continuous advancements in computation capabilities, satellite-based remote sensing technologies, and data assimilation techniques further enhance the performance and accuracy of GHMs. DHI’s GHM uses a combination of over 1 million catchment runoff models to represent almost the whole world on a 10x10km grid. The models are running operationally and are updated hourly, harvesting global datasets including live Earth Observation data. They also produce medium range forecasts up to 15 days, and seasonal forecasts up to 6 months. The models produce parameters such as runoff, groundwater baseflow, and root zone storage, as well as natural flow river discharges. 

With DHI’s GHM, you can: 

• Access up-to-date hydrological data for operational real-time or forecasts and hindcasts 
• Access data on global water quality and inform decision making for transboundary water management at local, regional and global scales 
• Obtain a starting place for local hydrological models, which can be automatically clipped out of the global one and used to inform boundaries in MIKE HYDRO BASIN or can be updated with local forcing data and calibrated for even better results 
• Downscale to extremely fine resolution where weather products would allow 

UNEP-DHI’s projects that used DHI’s GHM: 

• Rapid Integrated Water Assessment in Ten Arid and Semi-Arid Land (ASAL) Counties, Kenya 
• The GPML Risk & Warning System for Macroplastic Litter 

Learn more about GHMs: 

• Read an interview on how Global Hydrological Models are revolutionizing the measurement and management of water resources. The interview links to a scientific article that was published in the Journal of Hydrology and co-written by experts from DHI. 

• From DHI’s website. 

For more information, contact us.