System Response Parameter Calibration Method and its Application on Hydrological Model

The existing parameter calibration methods are based on the objective function surface to find the optimal value. This kind of method has the problems such as unstable result, poor convergence performance, low efficiency and failure to find the global optimal value. Based on the analysis of the objective function structure and the information that it provides for the parameter calibration, the essential problems existing in the present method was found in this paper. And the paper also found that the information provided by the parameter function surface is more direct and effective than by the objective function surface. Furthermore, the nonlinear model function can be linearized by the system response relationship between the increment of the dependent variables and the increment of parameters. Based on these researches, this paper proposed the system response parameter calibration method based on the parametric function surface. Firstly, the method is verified by an ideal model. The results showed that all the sensitive parameters could reach the real values not influenced by the different initial parameter values with higher convergence speed and accuracy, which verified that the method is feasible. Lastly, the XAJ Model parameters based on Shaowu basin measured data were also calibrated by the method. The results showed that the stable optimal parameter values could also be quickly got. So the system response parameter calibration method is an effective parameters optimization method.