IMPACTS OF MODEL STRUCTURES AND SOIL PARAMETERS ON RUNOFF CHARACTERISTICS IN LAND SURFACE MODELS

Abstract

 This research focused on investigation of impacts of model structures and soil parameters of Land Surface Models (LSMs) from the view point of runoff characteristics and simulated river discharge. In this study, MRI-SiB output was used as reference data. While, SiBUC model was utilized to investigate the impacts of changing model structures and soil parameters. The findings of this study indicated that: (1) introducing a structure for direct infiltration into root zone resulted in decreased of surface runoff by 60% and 7% using SiBUC and MRI-SiB soil parameters, respectively, and (2) consideration of gravitational drainage for soil water flux calculation contributed to an increase of surface runoff by 56% and decrease of evapotranspiration by 5%. Impact of changing soil parameters and model structures was further investigated by analyzing the change of soil moisture movement and evapotranspiration components.