Estimation of FAO PenmanMonteith model in the middle reaches of Heihe River based on System Dynamics

The system dynamics software STELLA was used to built a FAO PenmanMonteith model and the system dynamics modeling and the ecological models was firstly combined in this study. This study showed that the simulation value of the actual solar radiation (Rs) was accord with the spatial interpolation by ArcGIS. The estimated value of potential evapotranspiration(ET0) was consistent with the simulated value of SEBS model, indicating that the evapotranspiration changes of time series reflected the heterogeneity of every day evapotranspiration. The sensitivity analysis of STELLA showed that ET0 was insensitive to alpha, As, Bs and area latitude (range from 37-39). This study suggested that the system dynamics change showed the great advantages in the analysis of complex systems dynamics and simulation interaction between the system factors and the response process under different conditions, that STELLAs powerful features and good graphical interface could be applied in the ecology modeling and related research, and that the multidisciplinary approach, more temporal and spatial scale and multiphase coupling of physical processes would be the focus in this field and an important trend in the future.