Expanding distributed hydrological modelling to the continental scale

Applying a grid-based distributed hydrological model to a continent cannot be achieved simply by increasing the grid size. This is due to the spatial heterogeneity and nonlinear nature of soil-vegetation-atmosphere transfer processes. Sub-grid hydrological parameterization is required to capture the spatial variability in a large grid. The methodology presented in this study expanded a grid-based distributed hydrological model to the continental scale, and addressed both sub-grid hydrological parameterization based geomorphological property and the basin-based flow routing. The spatial information related to topography, land cover, and soil properties was estimated from the available finest resolution data sets. Application to the Asian continent has shown good simulations of river discharge in the main rivers, and the model could represent the general spatial hydrological characteristics. This continental-scale hydrological model can be coupled with GCMs for complete simulation of the continental water-energy cycle.