Progress and perspectives in hydrological modelling and forecasting across scales

The last decades have seen unprecedented progress in ensemble hydro-meteorological modelling and forecasting on a range of temporal and spatial scales. Such progress also raises new challenges, especially with regards to connecting hydrology from global to local scales, as well as hydrological sciences research to operations. To discuss these challenges, the Joint Virtual Workshop "Connecting global to local hydrological modelling and forecasting: challenges and scientific advances” (29 June - 1 July 2021) was recently organized [*]. It brought together over one thousand people from around the world, including scientists, disaster managers and stakeholders operating at the local, national, continental and global scales. In this study, we summarise the state-of-the-art presented and discussed at the workshop. In particular, we provide an early career perspective on the insights and experiences shared during the workshop, highlighting recent advances and ongoing challenges in hydrological modelling and forecasting, as well as on the use of forecasts for decision-making from global to local scales. From the many topics covered during the workshop, which included hydrological model development (including Earth System modelling, machine learning applications and hybrid dynamic-statistical forecasting), skill assessment, uncertainty communication, forecasts for early action, co-production of services and incorporation of local knowledge, Earth Observations, and data assimilation, we focus on the contributions to science and operations from the hydrological forecasting community. Our analysis highlights the critical need to better connect hydrological services and impact models to societal needs and local decision-making through effective communication, capacity building and co-production. The core work of creating new methods and products and the move towards Earth System modelling need to be balanced by multidisciplinary collaborations that effectively bring tools to practice. We expect that research tackling these challenges will increase further in the next decade.

[*] Workshop organizers: European Centre for Medium-Range Weather Forecasts (ECMWF), the Copernicus Emergency Management (CEMS) and Climate Change (C3S) Services, the Hydrological Ensemble Prediction EXperiment (HEPEX), and the Global Flood Partnership (GFP)