HS.2 New approaches to hydrological prediction in data sparse regions


Uncertainty assessment of hydrological predictions due to sparse precipitation stations


S. Wagner1), H. Kunstmann1), A. Bárdossy2)


1) Institute for Meteorology and Climate Research (IMK-IFU), Forschungszentrum Karlsruhe, Germany

2) Institute for Hydraulic Engineering, University Stuttgart, Germany



The spatial variability of precipitation is often termed as the major source of uncertainty in investigations of rainfall-runoff processes and water balance estimations. Therefore, two geostatistical approaches are applied for the uncertainty assessment of hydrological predictions due to the network structure and density of precipitation stations. First, different spatial interpolation methods (Thiessen polygon, inverse distance weighting, ordinary, and external drift kriging) for areal precipitation are applied, and their impact on water balance estimates is analysed. Second, geostatistical simulations using the turning band method for areal precipitation are performed in order to investigate the propagation of consequential uncertainties in water balance estimations. These results provide ranges of the temporal and spatial distribution of water balance variables as consequence of uncertainties from the calculation of areal precipitation interpolation and simulation from station data.

This study is performed for the White Volta basin (100,000 km˛), a hydrometeorological data sparse region in the semi-arid environment of West Africa. The water balance and the uncertainty propagation are investigated by a distributed hydrological model in 1km˛ spatial and daily temporal resolution with a focus on the year 2004. The impact of the selected spatial interpolation method for areal precipitation on the temporal and spatial distribution of water balance variables is minor for spatially aggregated variables and the corresponding time series. However, the selected interpolation method affects the spatial distribution of water balance variables. The results of the turning band simulations for precipitation show for example that the range of possible realizations of routed discharge varies considerable for the specific subcatchments.