The scope of this session addresses recent developments in the coupling between meteorological and hydrological models. As computational power increases, models become more detailed and ensemble systems emerge. This creates new challenges: forecasting systems get more complex, the data flow between meteorological and hydrological models intensifies, and the interpretation of more complex models and ensemble systems is involved. The coupling of weather forecasting and climate models with hydrological models is similar, but in climate application additional bias correction methods and temporal and spatial disaggregation techniques are applied.

At the same time, expectations from decision makers and the general public are increasing, raising demands for accurate and well-presented forecasts.

This session welcomes contributions from modellers with experience in operational short-term real-time, as well as long-term seasonal forecasting, or climate and climate change projections.

This session also aims to address contributors of large research initiatives such as HEPEX (Hydrological Ensemble Prediction Experiment) and HyMeX (Hydrological cycle in the Mediterranean Experiment) and provide them a platform for disseminating their findings concerning the main research questions of this session.

Major questions to be addressed include:

(i) What is the optimal coupling strategy of meteorological forecasting or climate models and hydrological models/ensembles?

(ii) How can additional information (e.g., remotely sensed data) be used in coupled systems?

(iii) How can these systems be evaluated and the output post-processed?

(iv) How should the forecasts be presented and what type of risk analysis can be used in supporting decision makers?

(v) Can hydrological extreme events be forecasted satisfactorily by coupled systems today?

(vi) How does the scale affect the coupling strategy and the skill of the coupled systems?