Development of a Large-Scale Routing Model with Scale Independent by Considering the Damping Effect of Sub-Basins

Damping effect of the overland of a sub-basin has significant impact on the simulation accuracy of large-scale routing models; however, traditional large-scale routing models have often ignored this impact. To address this problem, we propose a sub-basin response function by combining unit hydrograph theory and sub-basin kinematic wave routing. Specifically, supposing that 10 mm net rainfall input in the sub-basin, the kinematic wave is used to route the net rainfall to the outlet pixels based on high resolution routing network, and the outlet discharge are normalized as sub-basin response function. Meanwhile, the geomorphic function was established to determine the river routing parameters based on observed data. The results of model application demonstrate that the model has satisfactory simulation accuracy both in outlet discharges and in spatial distribution. And simulation with different grid scales brings similar results, illustrating that the model is scale independent. Particularly, the outlet simulation accuracy of the routing model involving sub-basin response function is higher than before.