Application of Atmosphere-Land Surface Interaction System (ALSIS) scheme in simulating the streamflow with emphasis on the spatial heterogeneity of land surface in sub-grid scale (Case study: Karkheh river basin)

This study evaluates the application of Atmosphere-Land Surface Interaction System (ALSIS) scheme in simulating the streamflow in Karkheh river basin. The Climate Forecast System Reanalysis (CFSR) data for the period 1982-2011 are used as atmospheric forcing data and sub-grid scale heterogeneity of the land-surface is represented by soil-vegetation mosaics. The cascade of linear reservoirs model is used for modelling the base flow and a routing model, linked to the land surface scheme, is used for modelling river discharge. The comparison of simulated and observed streamflow in six hydrometric stations over Karkheh basin reveals the model ability in simulating the monthly streamflow. Moreover, the model has a good ability in simulating the monthly regime of water balance components, spatial distribution of long-term average of components and their relationships.