Satellite inspired hydrology in an uncertain future: a H SAF and HEPEX workshop

Flow forecasting systems are in operational use widely. They are based today on a modelling chain where the output of numerical weather prediction models forms the input of conceptual distributed or semi-distributed hydrological models. Furthermore, statistical meteorological data pre-processing and hydrological post- processing procedures round up a modelling chain. In some systems hydrodynamic models for flood routing are embedded. With the growing availability of meteorological forecast ensembles the hydrological ensemble technique strengthened. Within these modelling systems the assessment of the initial states of the hydrological system like snow water content, soil moisture, groundwater levels etc. and their surrounding uncertainty is underrepresented. This can be attributed partly to the missing operational availability of data with appropriate temporal and spatial accuracy, and to the complexity of data assimilation techniques. In addition some software issues have to be solved. The data of EUMETSAT H SAF offers among other data provider a wide range of data products which have the potential to bridge this gap. With this initiative it is planned to set up a testbed for a medium range river basin in Germany which should serve for optimizing the use of remote sensing data in combination with appropriate data assimilation techniques.