Modelling the water balance in small catchments: Development of a global application for a local scale

The dissertation presents the Global BROOK90 framework, which has been developed at the Chair of Meteorology, TU Dresden by the candidate and co-authors. Global BROOK90 allows modelling the water balance components globally for the local scale of ‘hydrological response units’ in a fully automatic mode. It combines recent advances in global datasets with a physically based model. The framework possesses a vast application range with a special focus on the non-expert users and data scarce regions. To prove the applicability of the framework for different climates, landscapes, soil types and orography, an extensive validation was necessary. Two important components of the water balance – runoff and evaporation– were compared with measured data from all over the globe. Results indicated that considering its build-up and scope, Global BROOK90 performs well on the desired local scale. Certainly, the described approach has substantial shortcomings, thus simulation results must always be treated through the prism of the uncertainties. These limitations result not only from model limitations itself, but also from the input datasets, which were used for parameterization and forcing. Therefore, in this study main uncertainties are addressed allowing the end-user an outlook on their potential impact on the modelling results