The UK Hydro-MIP: Evaluating modelled river flows from a diverse set of models over a large sample of British catchments

Model intercomparison projects (MIPs) have many benefits, including improving understanding of model capabilities, furthering advancements in model development, providing a benchmark of model performance, helping to quantify modelling uncertainties and fostering collaboration. Here, we introduce the UK Hydro-MIP, a community-led hydrological and land surface model intercomparison for streamflow simulation across Great Britain. This MIP encouraged members of the community to submit modelled daily river flows, following an agreed model protocol to ensure consistency in driving data and output formats. A diverse range of model types were represented, including land surface models, physically based to conceptual hydrological models, and machine learning models. The resultant large sample dataset, including modelled river flows and evaluation metrics from over 16 models for over 628 catchments, will be released later this year.

Initial analysis of the dataset was carried out during a hackathon event, where all contributors and stakeholders were invited to an in-person meeting to discuss priorities and analyse results together. Here, we present initial results from the UK Hydro-MIP and the hackathon, highlighting the relative strengths of different modelling approaches and common modelling challenges across Great Britain.