On the impact of explicitly predicted runoff on the simulated atmospheric response to small-scale land-use changes—an integrated modeling approach

An integrated modeling approach was developed to simulate the water cycle in a closed manner. It consists of (1) procedures for up- and downscaling of the variables and fluxes important for both the hydrological and atmospheric processes, (2) a module to explicitly predict surface and channel runoff, (3) the hydro-thermodynamic soil–vegetation scheme (HTSVS) which was introduced in the (4) nonhydrostatic meso-β/γ-scale meteorological model GESIMA (Geesthacht's simulation model of the atmosphere). Comparison of the results provided by simulations with and without consideration of surface and channel runoff shows a remarkable impact of surface runoff on the water cycle within the domain. The results of simulations, wherein, along the rivers, grassland and agriculturally used land were substituted by deciduous forest demonstrate that the atmospheric response to land-use changes is more distinct when surface runoff is considered explicitly than if not. It can be concluded that an integrated modeling techniques of the water cycle, like presented here, can be an important tool for studies on water availability under altered future conditions.