Predictions in Ungauged Basins: Promise and Progress (Proceedings of symposium S7 held during the Seventh IAHS Scientific Assembly at Foz do Iguaçu, Brazil, April 2005). IAHS Publ. 303, 2006, 195-203.

 

Influence of spatial variability of precipitation in a distributed rainfall–runoff model

 

TAPASH DAS1, ANDRÁS BÁRDOSSY1 & ERWIN ZEHE2

1       Institute of Hydraulic Engineering, University of Stuttgart, Pfaffenwaldring 61, D-70569 Stuttgart, Germany

tapash@iws.uni-stuttgart.de

2       Institute for Geoecology, University of Potsdam, Germany

 

Abstract The objective of this research was to examine the influence of the spatial variability of precipitation data from different sources on the accuracy of runoff simulation. In this study, interpolated precipitation by external drift kriging and conditional simulated precipitation based on turning band simula­tion are used to represent the spatial variability of precipitation. Also, the precipitation is averaged over different spatial scales ranging from 4 km2 to 614 km2. The original and averaged precipitation is used as a main forcing input in a conceptual distributed rainfall–runoff model. An automatic calibra­tion method based on the combinatorial optimization algorithm simulated annealing is applied. Also, the aggregated Nash-Sutcliffe coefficients at different time scales are used as objective function in the study. The simulated hydrographs obtained using original and averaged precipitation are analysed through comparisons of the Nash-Sutcliffe coefficient and other goodness-of-fit indexes. By means of them, the influence of spatial variability of precipitation data on the accuracy of simulated runoff is assessed.

 

Key words conditional simulation; distributed modelling; simulated annealing; spatial variability